refactor: comprehensive code quality improvements

- Add logger to all exporters for consistent error handling
- Add Course.Validate() method with ValidationError type
- Create shared test fixtures in internal/testdata
- Refactor config passing: NewArticulateParser now takes *config.Config
- Add NewLoggerFromConfig() factory for logger creation
- Add context cancellation with signal handling (SIGINT/SIGTERM)
- Add godoc examples for loggers and exporters
- Add HTML exporter error path tests
- Add fuzz tests for parser and HTMLCleaner
- Fix markdown output: trim whitespace, collapse blank lines
- Remove test output files from repo

.dprint.jsonc

@@ -1,30 +1,31 @@
 {
-  "typescript": {
+	"$schema": "https://dprint.dev/schemas/v0.json",
+
+	"useTabs": true,
+
+	"typescript": {},
+	"json": {},
+	"markdown": {},
+	"toml": {},
+	"dockerfile": {},
+	"oxc": {},
+	"ruff": {},
+	"jupyter": {},
+	"malva": {},
+	"markup": {},
+	"yaml": {},
+	"exec": {
+		"cwd": "${configDir}",
+		"commands": [
+			{
+				"command": "golangci-lint fmt --config .golangci.yml --color never --stdin {{file_path}}",
+				"exts": ["go"],
+				"cacheKeyFiles": [".golangci.yml"],
+				"stdin": true,
 			},
-  "json": {
-  },
-  "markdown": {
-  },
-  "toml": {
-  },
-  "dockerfile": {
-  },
-  "oxc": {
-  },
-  "ruff": {
-  },
-  "jupyter": {
-  },
-  "malva": {
-  },
-  "markup": {
-  },
-  "yaml": {
-  },
-  "excludes": [
-    "**/node_modules",
-    "**/*-lock.json",
 		],
+	},
+	"excludes": ["**/node_modules", "**/*-lock.json"],
 	"plugins": [
 		"https://plugins.dprint.dev/typescript-0.95.13.wasm",
 		"https://plugins.dprint.dev/json-0.21.1.wasm",

.golangci.yml

@@ -1,6 +1,7 @@
+# yaml-language-server: $schema=https://golangci-lint.run/jsonschema/golangci.jsonschema.json
 # golangci-lint configuration for articulate-parser
 # https://golangci-lint.run/usage/configuration/
-
+---
 version: "2"
 
 # Options for analysis running
@@ -51,6 +52,7 @@ formatters:
     - gofmt
     - goimports
     - gofumpt
+  exclusions: { paths: [".zed"] }
   settings:
     # gofmt settings
     gofmt:

.opencode/opencode.jsonc

@@ -0,0 +1,25 @@
+{
+	"$schema": "https://opencode.ai/config.json",
+	"lsp": {
+		"golangci-lint": {
+			"command": ["golangci-lint-langserver"],
+			"extensions": [".go"],
+			"initialization": {
+				"command": [
+					"golangci-lint",
+					"run",
+					"--output.json.path",
+					"stdout",
+					"--show-stats=false",
+					"--issues-exit-code=1",
+				],
+			},
+		},
+	},
+	"formatter": {
+		"dprint": {
+			"command": ["dprint", "fmt", "$FILE"],
+			"extensions": [".go", ".md", ".Dockerfile", ".Dockerfile.dev", ".md"],
+		},
+	},
+}

.zed/settings.json

@@ -0,0 +1,40 @@
+{
+	"tab_size": 2,
+	"hard_tabs": true,
+	"prettier": { "allowed": false },
+	"formatter": [
+		{ "language_server": { "name": "dprint" } }
+	],
+	"languages": {
+		"Go": {
+			"language_servers": ["gopls", "golangci-lint-langserver", "..."]
+		}
+	},
+	"lsp": {
+		"gopls": {
+			"enable_lsp_tasks": true,
+			"initialization_options": {
+				"workspaceFiles": ["go.mod", "go.work", "*.go"]
+			}
+		},
+		"golangci-lint": {
+			"enable_lsp_tasks": false
+		},
+		"golangci-lint-langserver": {
+			"binary": {
+				"path": "golangci-lint-langserver",
+				"arguments": ["-debug"]
+			},
+			"initialization_options": {
+				"command": [
+					"golangci-lint",
+					"run",
+					"--output.json.path",
+					"stdout",
+					"--show-stats=false",
+					"--issues-exit-code=1"
+				]
+			}
+		}
+	}
+}

internal/exporters/bench_test.go

@@ -6,12 +6,13 @@ import (
 
 	"github.com/kjanat/articulate-parser/internal/models"
 	"github.com/kjanat/articulate-parser/internal/services"
+	"github.com/kjanat/articulate-parser/internal/testdata"
 )
 
 // BenchmarkFactory_CreateExporter_Markdown benchmarks markdown exporter creation.
 func BenchmarkFactory_CreateExporter_Markdown(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	b.ResetTimer()
 	for b.Loop() {
@@ -22,7 +23,7 @@ func BenchmarkFactory_CreateExporter_Markdown(b *testing.B) {
 // BenchmarkFactory_CreateExporter_All benchmarks creating all exporter types.
 func BenchmarkFactory_CreateExporter_All(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 	formats := []string{"markdown", "docx", "html"}
 
 	b.ResetTimer()
@@ -36,15 +37,15 @@ func BenchmarkFactory_CreateExporter_All(b *testing.B) {
 // BenchmarkAllExporters_Export benchmarks all exporters with the same course.
 func BenchmarkAllExporters_Export(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	course := createBenchmarkCourse()
+	course := testdata.BasicCourse()
 
 	exporters := map[string]struct {
 		exporter any
 		ext      string
 	}{
-		"Markdown": {NewMarkdownExporter(htmlCleaner), ".md"},
+		"Markdown": {NewMarkdownExporter(htmlCleaner, nil), ".md"},
-		"Docx":     {NewDocxExporter(htmlCleaner), ".docx"},
+		"Docx":     {NewDocxExporter(htmlCleaner, nil), ".docx"},
-		"HTML":     {NewHTMLExporter(htmlCleaner), ".html"},
+		"HTML":     {NewHTMLExporter(htmlCleaner, nil), ".html"},
 	}
 
 	for name, exp := range exporters {
@@ -66,10 +67,10 @@ func BenchmarkAllExporters_Export(b *testing.B) {
 // BenchmarkExporters_LargeCourse benchmarks exporters with large course data.
 func BenchmarkExporters_LargeCourse(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	course := createLargeBenchmarkCourse()
+	course := testdata.LargeCourse(50)
 
 	b.Run("Markdown_Large", func(b *testing.B) {
-		exporter := NewMarkdownExporter(htmlCleaner)
+		exporter := NewMarkdownExporter(htmlCleaner, nil)
 		tempDir := b.TempDir()
 
 		b.ResetTimer()
@@ -80,7 +81,7 @@ func BenchmarkExporters_LargeCourse(b *testing.B) {
 	})
 
 	b.Run("Docx_Large", func(b *testing.B) {
-		exporter := NewDocxExporter(htmlCleaner)
+		exporter := NewDocxExporter(htmlCleaner, nil)
 		tempDir := b.TempDir()
 
 		b.ResetTimer()
@@ -91,7 +92,7 @@ func BenchmarkExporters_LargeCourse(b *testing.B) {
 	})
 
 	b.Run("HTML_Large", func(b *testing.B) {
-		exporter := NewHTMLExporter(htmlCleaner)
+		exporter := NewHTMLExporter(htmlCleaner, nil)
 		tempDir := b.TempDir()
 
 		b.ResetTimer()
@@ -101,100 +102,3 @@ func BenchmarkExporters_LargeCourse(b *testing.B) {
 		}
 	})
 }
-
-// createBenchmarkCourse creates a standard-sized course for benchmarking.
-func createBenchmarkCourse() *models.Course {
-	return &models.Course{
-		ShareID: "benchmark-id",
-		Author:  "Benchmark Author",
-		Course: models.CourseInfo{
-			ID:             "bench-course",
-			Title:          "Benchmark Course",
-			Description:    "Performance testing course",
-			NavigationMode: "menu",
-			Lessons: []models.Lesson{
-				{
-					ID:    "lesson1",
-					Title: "Introduction",
-					Type:  "lesson",
-					Items: []models.Item{
-						{
-							Type: "text",
-							Items: []models.SubItem{
-								{
-									Heading:   "Welcome",
-									Paragraph: "<p>This is a test paragraph with <strong>HTML</strong> content.</p>",
-								},
-							},
-						},
-						{
-							Type: "list",
-							Items: []models.SubItem{
-								{Paragraph: "Item 1"},
-								{Paragraph: "Item 2"},
-								{Paragraph: "Item 3"},
-							},
-						},
-					},
-				},
-			},
-		},
-	}
-}
-
-// createLargeBenchmarkCourse creates a large course for stress testing.
-func createLargeBenchmarkCourse() *models.Course {
-	lessons := make([]models.Lesson, 50)
-	for i := range 50 {
-		lessons[i] = models.Lesson{
-			ID:          string(rune(i)),
-			Title:       "Lesson " + string(rune(i)),
-			Type:        "lesson",
-			Description: "<p>This is lesson description with <em>formatting</em>.</p>",
-			Items: []models.Item{
-				{
-					Type: "text",
-					Items: []models.SubItem{
-						{
-							Heading:   "Section Heading",
-							Paragraph: "<p>Content with <strong>bold</strong> and <em>italic</em> text.</p>",
-						},
-					},
-				},
-				{
-					Type: "list",
-					Items: []models.SubItem{
-						{Paragraph: "Point 1"},
-						{Paragraph: "Point 2"},
-						{Paragraph: "Point 3"},
-					},
-				},
-				{
-					Type: "knowledgeCheck",
-					Items: []models.SubItem{
-						{
-							Title: "Quiz Question",
-							Answers: []models.Answer{
-								{Title: "Answer A", Correct: false},
-								{Title: "Answer B", Correct: true},
-								{Title: "Answer C", Correct: false},
-							},
-							Feedback: "Good job!",
-						},
-					},
-				},
-			},
-		}
-	}
-
-	return &models.Course{
-		ShareID: "large-benchmark-id",
-		Author:  "Benchmark Author",
-		Course: models.CourseInfo{
-			ID:          "large-bench-course",
-			Title:       "Large Benchmark Course",
-			Description: "Large performance testing course",
-			Lessons:     lessons,
-		},
-	}
-}

internal/exporters/docx.go

@@ -29,19 +29,23 @@ const (
 type DocxExporter struct {
 	// htmlCleaner is used to convert HTML content to plain text
 	htmlCleaner *services.HTMLCleaner
+	// logger is used for logging warnings and errors
+	logger interfaces.Logger
 }
 
 // NewDocxExporter creates a new DocxExporter instance.
-// It takes an HTMLCleaner to handle HTML content conversion.
+// It takes an HTMLCleaner to handle HTML content conversion and a logger for logging.
 //
 // Parameters:
 //   - htmlCleaner: Service for cleaning HTML content in course data
+//   - logger: Logger instance for warnings and errors
 //
 // Returns:
 //   - An implementation of the Exporter interface for DOCX format
-func NewDocxExporter(htmlCleaner *services.HTMLCleaner) interfaces.Exporter {
+func NewDocxExporter(htmlCleaner *services.HTMLCleaner, logger interfaces.Logger) interfaces.Exporter {
 	return &DocxExporter{
 		htmlCleaner: htmlCleaner,
+		logger:      logger,
 	}
 }
 
@@ -91,7 +95,7 @@ func (e *DocxExporter) Export(course *models.Course, outputPath string) error {
 	// affect the validity of the exported file.
 	defer func() {
 		if err := file.Close(); err != nil {
-			fmt.Fprintf(os.Stderr, "warning: failed to close output file: %v\n", err)
+			e.logger.Warn("failed to close output file", "error", err)
 		}
 	}()
 

internal/exporters/docx_test.go

@@ -12,7 +12,7 @@ import (
 // TestNewDocxExporter tests the NewDocxExporter constructor.
 func TestNewDocxExporter(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	if exporter == nil {
 		t.Fatal("NewDocxExporter() returned nil")
@@ -32,7 +32,7 @@ func TestNewDocxExporter(t *testing.T) {
 // TestDocxExporter_SupportedFormat tests the SupportedFormat method.
 func TestDocxExporter_SupportedFormat(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	expected := "docx"
 	result := exporter.SupportedFormat()
@@ -45,7 +45,7 @@ func TestDocxExporter_SupportedFormat(t *testing.T) {
 // TestDocxExporter_Export tests the Export method.
 func TestDocxExporter_Export(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	// Create test course
 	testCourse := createTestCourseForDocx()
@@ -79,7 +79,7 @@ func TestDocxExporter_Export(t *testing.T) {
 // TestDocxExporter_Export_AddDocxExtension tests that the .docx extension is added automatically.
 func TestDocxExporter_Export_AddDocxExtension(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	testCourse := createTestCourseForDocx()
 
@@ -102,7 +102,7 @@ func TestDocxExporter_Export_AddDocxExtension(t *testing.T) {
 // TestDocxExporter_Export_InvalidPath tests export with invalid output path.
 func TestDocxExporter_Export_InvalidPath(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	testCourse := createTestCourseForDocx()
 
@@ -118,7 +118,7 @@ func TestDocxExporter_Export_InvalidPath(t *testing.T) {
 // TestDocxExporter_ExportLesson tests the exportLesson method indirectly through Export.
 func TestDocxExporter_ExportLesson(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	// Create course with specific lesson content
 	course := &models.Course{
@@ -165,7 +165,7 @@ func TestDocxExporter_ExportLesson(t *testing.T) {
 // TestDocxExporter_ExportItem tests the exportItem method indirectly through Export.
 func TestDocxExporter_ExportItem(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	// Create course with different item types
 	course := &models.Course{
@@ -231,7 +231,7 @@ func TestDocxExporter_ExportItem(t *testing.T) {
 // TestDocxExporter_ExportSubItem tests the exportSubItem method indirectly through Export.
 func TestDocxExporter_ExportSubItem(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	// Create course with sub-item containing all possible fields
 	course := &models.Course{
@@ -284,7 +284,7 @@ func TestDocxExporter_ExportSubItem(t *testing.T) {
 // TestDocxExporter_ComplexCourse tests export of a complex course structure.
 func TestDocxExporter_ComplexCourse(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	// Create complex test course
 	course := &models.Course{
@@ -421,7 +421,7 @@ func TestDocxExporter_ComplexCourse(t *testing.T) {
 // TestDocxExporter_EmptyCourse tests export of an empty course.
 func TestDocxExporter_EmptyCourse(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	// Create minimal course
 	course := &models.Course{
@@ -450,7 +450,7 @@ func TestDocxExporter_EmptyCourse(t *testing.T) {
 // TestDocxExporter_HTMLCleaning tests that HTML content is properly cleaned.
 func TestDocxExporter_HTMLCleaning(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	// Create course with HTML content that needs cleaning
 	course := &models.Course{
@@ -498,7 +498,7 @@ func TestDocxExporter_HTMLCleaning(t *testing.T) {
 // TestDocxExporter_ExistingDocxExtension tests that existing .docx extension is preserved.
 func TestDocxExporter_ExistingDocxExtension(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	testCourse := createTestCourseForDocx()
 
@@ -526,7 +526,7 @@ func TestDocxExporter_ExistingDocxExtension(t *testing.T) {
 // TestDocxExporter_CaseInsensitiveExtension tests that extension checking is case-insensitive.
 func TestDocxExporter_CaseInsensitiveExtension(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	testCourse := createTestCourseForDocx()
 
@@ -599,7 +599,7 @@ func createTestCourseForDocx() *models.Course {
 // BenchmarkDocxExporter_Export benchmarks the Export method.
 func BenchmarkDocxExporter_Export(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 	course := createTestCourseForDocx()
 
 	// Create temporary directory
@@ -618,7 +618,7 @@ func BenchmarkDocxExporter_Export(b *testing.B) {
 // BenchmarkDocxExporter_ComplexCourse benchmarks export of a complex course.
 func BenchmarkDocxExporter_ComplexCourse(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewDocxExporter(htmlCleaner)
+	exporter := NewDocxExporter(htmlCleaner, nil)
 
 	// Create complex course for benchmarking
 	course := &models.Course{

internal/exporters/example_test.go

@@ -13,7 +13,7 @@ import (
 // ExampleNewFactory demonstrates creating an exporter factory.
 func ExampleNewFactory() {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := exporters.NewFactory(htmlCleaner)
+	factory := exporters.NewFactory(htmlCleaner, nil)
 
 	// Get supported formats
 	formats := factory.SupportedFormats()
@@ -24,7 +24,7 @@ func ExampleNewFactory() {
 // ExampleFactory_CreateExporter demonstrates creating exporters.
 func ExampleFactory_CreateExporter() {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := exporters.NewFactory(htmlCleaner)
+	factory := exporters.NewFactory(htmlCleaner, nil)
 
 	// Create a markdown exporter
 	exporter, err := factory.CreateExporter("markdown")
@@ -39,7 +39,7 @@ func ExampleFactory_CreateExporter() {
 // ExampleFactory_CreateExporter_caseInsensitive demonstrates case-insensitive format names.
 func ExampleFactory_CreateExporter_caseInsensitive() {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := exporters.NewFactory(htmlCleaner)
+	factory := exporters.NewFactory(htmlCleaner, nil)
 
 	// All these work (case-insensitive)
 	formats := []string{"MARKDOWN", "Markdown", "markdown", "MD"}
@@ -58,7 +58,7 @@ func ExampleFactory_CreateExporter_caseInsensitive() {
 // ExampleMarkdownExporter_Export demonstrates exporting to Markdown.
 func ExampleMarkdownExporter_Export() {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := exporters.NewMarkdownExporter(htmlCleaner)
+	exporter := exporters.NewMarkdownExporter(htmlCleaner, nil)
 
 	course := &models.Course{
 		ShareID: "example-id",
@@ -81,7 +81,7 @@ func ExampleMarkdownExporter_Export() {
 // ExampleDocxExporter_Export demonstrates exporting to DOCX.
 func ExampleDocxExporter_Export() {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := exporters.NewDocxExporter(htmlCleaner)
+	exporter := exporters.NewDocxExporter(htmlCleaner, nil)
 
 	course := &models.Course{
 		ShareID: "example-id",
@@ -99,3 +99,33 @@ func ExampleDocxExporter_Export() {
 	fmt.Println("DOCX export complete")
 	// Output: DOCX export complete
 }
+
+// ExampleHTMLExporter_Export demonstrates exporting to HTML.
+func ExampleHTMLExporter_Export() {
+	htmlCleaner := services.NewHTMLCleaner()
+	exporter := exporters.NewHTMLExporter(htmlCleaner, nil)
+
+	course := &models.Course{
+		ShareID: "example-id",
+		Course: models.CourseInfo{
+			Title:       "Example Course",
+			Description: "<p>A sample course</p>",
+			Lessons: []models.Lesson{
+				{
+					ID:    "lesson-1",
+					Title: "Introduction",
+					Type:  "lesson",
+				},
+			},
+		},
+	}
+
+	// Export to HTML file
+	err := exporter.Export(course, "output.html")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println("HTML export complete")
+	// Output: HTML export complete
+}

internal/exporters/factory.go

@@ -25,20 +25,24 @@ const (
 type Factory struct {
 	// htmlCleaner is used by exporters to convert HTML content to plain text
 	htmlCleaner *services.HTMLCleaner
+	// logger is used by exporters for logging
+	logger interfaces.Logger
 }
 
 // NewFactory creates a new exporter factory.
-// It takes an HTMLCleaner instance that will be passed to the exporters
+// It takes an HTMLCleaner instance and a logger that will be passed to the exporters
 // created by this factory.
 //
 // Parameters:
 //   - htmlCleaner: Service for cleaning HTML content in course data
+//   - logger: Logger instance for exporter logging
 //
 // Returns:
 //   - An implementation of the ExporterFactory interface
-func NewFactory(htmlCleaner *services.HTMLCleaner) interfaces.ExporterFactory {
+func NewFactory(htmlCleaner *services.HTMLCleaner, logger interfaces.Logger) interfaces.ExporterFactory {
 	return &Factory{
 		htmlCleaner: htmlCleaner,
+		logger:      logger,
 	}
 }
 
@@ -47,11 +51,11 @@ func NewFactory(htmlCleaner *services.HTMLCleaner) interfaces.ExporterFactory {
 func (f *Factory) CreateExporter(format string) (interfaces.Exporter, error) {
 	switch strings.ToLower(format) {
 	case FormatMarkdown, formatAliasMarkdown:
-		return NewMarkdownExporter(f.htmlCleaner), nil
+		return NewMarkdownExporter(f.htmlCleaner, f.logger), nil
 	case FormatDocx, formatAliasDocx:
-		return NewDocxExporter(f.htmlCleaner), nil
+		return NewDocxExporter(f.htmlCleaner, f.logger), nil
 	case FormatHTML, formatAliasHTML:
-		return NewHTMLExporter(f.htmlCleaner), nil
+		return NewHTMLExporter(f.htmlCleaner, f.logger), nil
 	default:
 		return nil, fmt.Errorf("unsupported export format: %s", format)
 	}

internal/exporters/factory_test.go

@@ -12,7 +12,7 @@ import (
 // TestNewFactory tests the NewFactory constructor.
 func TestNewFactory(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	if factory == nil {
 		t.Fatal("NewFactory() returned nil")
@@ -32,7 +32,7 @@ func TestNewFactory(t *testing.T) {
 // TestFactory_CreateExporter tests the CreateExporter method for all supported formats.
 func TestFactory_CreateExporter(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	testCases := []struct {
 		name           string
@@ -135,7 +135,7 @@ func TestFactory_CreateExporter(t *testing.T) {
 // TestFactory_CreateExporter_CaseInsensitive tests that format strings are case-insensitive.
 func TestFactory_CreateExporter_CaseInsensitive(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	testCases := []struct {
 		format         string
@@ -182,7 +182,7 @@ func TestFactory_CreateExporter_CaseInsensitive(t *testing.T) {
 // TestFactory_CreateExporter_ErrorMessages tests error messages for unsupported formats.
 func TestFactory_CreateExporter_ErrorMessages(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	testCases := []string{
 		"pdf",
@@ -222,7 +222,7 @@ func TestFactory_CreateExporter_ErrorMessages(t *testing.T) {
 // TestFactory_SupportedFormats tests the SupportedFormats method.
 func TestFactory_SupportedFormats(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	formats := factory.SupportedFormats()
 
@@ -255,7 +255,7 @@ func TestFactory_SupportedFormats(t *testing.T) {
 // TestFactory_SupportedFormats_Immutable tests that the returned slice is safe to modify.
 func TestFactory_SupportedFormats_Immutable(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	// Get formats twice
 	formats1 := factory.SupportedFormats()
@@ -281,7 +281,7 @@ func TestFactory_SupportedFormats_Immutable(t *testing.T) {
 // TestFactory_ExporterTypes tests that created exporters are of correct types.
 func TestFactory_ExporterTypes(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	// Test markdown exporter
 	markdownExporter, err := factory.CreateExporter("markdown")
@@ -307,7 +307,7 @@ func TestFactory_ExporterTypes(t *testing.T) {
 // TestFactory_HTMLCleanerPropagation tests that HTMLCleaner is properly passed to exporters.
 func TestFactory_HTMLCleanerPropagation(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	// Test with markdown exporter
 	markdownExporter, err := factory.CreateExporter("markdown")
@@ -358,7 +358,7 @@ func TestFactory_HTMLCleanerPropagation(t *testing.T) {
 // TestFactory_MultipleExporterCreation tests creating multiple exporters of same type.
 func TestFactory_MultipleExporterCreation(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	// Create multiple markdown exporters
 	exporter1, err := factory.CreateExporter("markdown")
@@ -395,7 +395,7 @@ func TestFactory_WithNilHTMLCleaner(t *testing.T) {
 		}
 	}()
 
-	factory := NewFactory(nil)
+	factory := NewFactory(nil, nil)
 
 	if factory == nil {
 		t.Fatal("NewFactory(nil) returned nil")
@@ -412,7 +412,7 @@ func TestFactory_WithNilHTMLCleaner(t *testing.T) {
 // TestFactory_FormatNormalization tests that format strings are properly normalized.
 func TestFactory_FormatNormalization(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	// Test formats with extra whitespace
 	testCases := []struct {
@@ -445,7 +445,7 @@ func TestFactory_FormatNormalization(t *testing.T) {
 // BenchmarkFactory_CreateExporter benchmarks the CreateExporter method.
 func BenchmarkFactory_CreateExporter(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	for b.Loop() {
 		_, _ = factory.CreateExporter("markdown")
@@ -455,7 +455,7 @@ func BenchmarkFactory_CreateExporter(b *testing.B) {
 // BenchmarkFactory_CreateExporter_Docx benchmarks creating DOCX exporters.
 func BenchmarkFactory_CreateExporter_Docx(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	for b.Loop() {
 		_, _ = factory.CreateExporter("docx")
@@ -465,7 +465,7 @@ func BenchmarkFactory_CreateExporter_Docx(b *testing.B) {
 // BenchmarkFactory_SupportedFormats benchmarks the SupportedFormats method.
 func BenchmarkFactory_SupportedFormats(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	factory := NewFactory(htmlCleaner)
+	factory := NewFactory(htmlCleaner, nil)
 
 	for b.Loop() {
 		_ = factory.SupportedFormats()

internal/exporters/html.go

@@ -25,17 +25,21 @@ type HTMLExporter struct {
 	htmlCleaner *services.HTMLCleaner
 	// tmpl holds the parsed HTML template
 	tmpl *template.Template
+	// logger is used for logging warnings and errors
+	logger interfaces.Logger
 }
 
 // NewHTMLExporter creates a new HTMLExporter instance.
-// It takes an HTMLCleaner to handle HTML content conversion when plain text is needed.
+// It takes an HTMLCleaner to handle HTML content conversion when plain text is needed
+// and a logger for logging.
 //
 // Parameters:
 //   - htmlCleaner: Service for cleaning HTML content in course data
+//   - logger: Logger instance for warnings and errors
 //
 // Returns:
 //   - An implementation of the Exporter interface for HTML format
-func NewHTMLExporter(htmlCleaner *services.HTMLCleaner) interfaces.Exporter {
+func NewHTMLExporter(htmlCleaner *services.HTMLCleaner, logger interfaces.Logger) interfaces.Exporter {
 	// Parse the template with custom functions
 	funcMap := template.FuncMap{
 		"safeHTML": func(s string) template.HTML {
@@ -51,6 +55,7 @@ func NewHTMLExporter(htmlCleaner *services.HTMLCleaner) interfaces.Exporter {
 	return &HTMLExporter{
 		htmlCleaner: htmlCleaner,
 		tmpl:        tmpl,
+		logger:      logger,
 	}
 }
 

internal/exporters/html_test.go

@@ -13,7 +13,7 @@ import (
 // TestNewHTMLExporter tests the NewHTMLExporter constructor.
 func TestNewHTMLExporter(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewHTMLExporter(htmlCleaner)
+	exporter := NewHTMLExporter(htmlCleaner, nil)
 
 	if exporter == nil {
 		t.Fatal("NewHTMLExporter() returned nil")
@@ -37,7 +37,7 @@ func TestNewHTMLExporter(t *testing.T) {
 // TestHTMLExporter_SupportedFormat tests the SupportedFormat method.
 func TestHTMLExporter_SupportedFormat(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewHTMLExporter(htmlCleaner)
+	exporter := NewHTMLExporter(htmlCleaner, nil)
 
 	expected := "html"
 	result := exporter.SupportedFormat()
@@ -50,7 +50,7 @@ func TestHTMLExporter_SupportedFormat(t *testing.T) {
 // TestHTMLExporter_Export tests the Export method.
 func TestHTMLExporter_Export(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewHTMLExporter(htmlCleaner)
+	exporter := NewHTMLExporter(htmlCleaner, nil)
 
 	// Create test course
 	testCourse := createTestCourseForHTML()
@@ -129,7 +129,7 @@ func TestHTMLExporter_Export(t *testing.T) {
 // TestHTMLExporter_Export_InvalidPath tests export with invalid output path.
 func TestHTMLExporter_Export_InvalidPath(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewHTMLExporter(htmlCleaner)
+	exporter := NewHTMLExporter(htmlCleaner, nil)
 
 	testCourse := createTestCourseForHTML()
 
@@ -145,7 +145,7 @@ func TestHTMLExporter_Export_InvalidPath(t *testing.T) {
 // TestHTMLExporter_ComplexCourse tests export of a course with complex content.
 func TestHTMLExporter_ComplexCourse(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewHTMLExporter(htmlCleaner)
+	exporter := NewHTMLExporter(htmlCleaner, nil)
 
 	// Create complex test course
 	course := &models.Course{
@@ -276,7 +276,7 @@ func TestHTMLExporter_ComplexCourse(t *testing.T) {
 // TestHTMLExporter_EmptyCourse tests export of an empty course.
 func TestHTMLExporter_EmptyCourse(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewHTMLExporter(htmlCleaner)
+	exporter := NewHTMLExporter(htmlCleaner, nil)
 
 	// Create minimal course
 	course := &models.Course{
@@ -324,7 +324,7 @@ func TestHTMLExporter_EmptyCourse(t *testing.T) {
 // TestHTMLExporter_HTMLCleaning tests that HTML content is properly handled.
 func TestHTMLExporter_HTMLCleaning(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewHTMLExporter(htmlCleaner)
+	exporter := NewHTMLExporter(htmlCleaner, nil)
 
 	// Create course with HTML content that needs cleaning in some places
 	course := &models.Course{
@@ -392,6 +392,227 @@ func TestHTMLExporter_HTMLCleaning(t *testing.T) {
 	}
 }
 
+// TestHTMLExporter_Export_ErrorPaths tests various error conditions for the HTML exporter.
+func TestHTMLExporter_Export_ErrorPaths(t *testing.T) {
+	htmlCleaner := services.NewHTMLCleaner()
+	exporter := NewHTMLExporter(htmlCleaner, nil)
+
+	tests := []struct {
+		name        string
+		course      *models.Course
+		outputPath  string
+		wantErr     bool
+		errContains string
+	}{
+		{
+			name:        "non-existent directory",
+			course:      createTestCourseForHTML(),
+			outputPath:  "/nonexistent/deeply/nested/path/output.html",
+			wantErr:     true,
+			errContains: "failed to create file",
+		},
+		{
+			name:        "empty output path",
+			course:      createTestCourseForHTML(),
+			outputPath:  "",
+			wantErr:     true,
+			errContains: "failed to create file",
+		},
+		{
+			name:        "output path is directory",
+			course:      createTestCourseForHTML(),
+			outputPath:  t.TempDir(), // directory, not a file
+			wantErr:     true,
+			errContains: "failed to create file",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := exporter.Export(tt.course, tt.outputPath)
+
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("Export() expected error containing %q, got nil", tt.errContains)
+					return
+				}
+				if tt.errContains != "" && !strings.Contains(err.Error(), tt.errContains) {
+					t.Errorf("Export() error = %v, want error containing %q", err, tt.errContains)
+				}
+			} else if err != nil {
+				t.Errorf("Export() unexpected error = %v", err)
+			}
+		})
+	}
+}
+
+// TestHTMLExporter_WriteHTML_ErrorPaths tests WriteHTML error conditions.
+func TestHTMLExporter_WriteHTML_ErrorPaths(t *testing.T) {
+	htmlCleaner := services.NewHTMLCleaner()
+	exporter := NewHTMLExporter(htmlCleaner, nil)
+	htmlExporter := exporter.(*HTMLExporter)
+
+	tests := []struct {
+		name        string
+		course      *models.Course
+		writer      *failingWriter
+		wantErr     bool
+		errContains string
+	}{
+		{
+			name:        "writer fails immediately",
+			course:      createTestCourseForHTML(),
+			writer:      &failingWriter{failAfter: 0},
+			wantErr:     true,
+			errContains: "failed to execute template",
+		},
+		{
+			name:        "writer fails mid-write",
+			course:      createTestCourseForHTML(),
+			writer:      &failingWriter{failAfter: 100},
+			wantErr:     true,
+			errContains: "failed to execute template",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := htmlExporter.WriteHTML(tt.writer, tt.course)
+
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("WriteHTML() expected error containing %q, got nil", tt.errContains)
+					return
+				}
+				if tt.errContains != "" && !strings.Contains(err.Error(), tt.errContains) {
+					t.Errorf("WriteHTML() error = %v, want error containing %q", err, tt.errContains)
+				}
+			} else if err != nil {
+				t.Errorf("WriteHTML() unexpected error = %v", err)
+			}
+		})
+	}
+}
+
+// TestHTMLExporter_Export_NilCourse verifies that exporting a nil course panics.
+// This documents the current behavior - nil course is not a supported input.
+func TestHTMLExporter_Export_NilCourse(t *testing.T) {
+	htmlCleaner := services.NewHTMLCleaner()
+	exporter := NewHTMLExporter(htmlCleaner, nil)
+
+	tempDir := t.TempDir()
+	outputPath := filepath.Join(tempDir, "nil-course.html")
+
+	defer func() {
+		if r := recover(); r == nil {
+			t.Error("Export(nil) expected panic, got none")
+		}
+	}()
+
+	// Export nil course - should panic
+	_ = exporter.Export(nil, outputPath)
+}
+
+// TestHTMLExporter_WriteHTML_NilCourse verifies that WriteHTML with nil course panics.
+func TestHTMLExporter_WriteHTML_NilCourse(t *testing.T) {
+	htmlCleaner := services.NewHTMLCleaner()
+	exporter := NewHTMLExporter(htmlCleaner, nil)
+	htmlExporter := exporter.(*HTMLExporter)
+
+	defer func() {
+		if r := recover(); r == nil {
+			t.Error("WriteHTML(nil) expected panic, got none")
+		}
+	}()
+
+	var buf strings.Builder
+	_ = htmlExporter.WriteHTML(&buf, nil)
+}
+
+// TestHTMLExporter_WriteHTML_SuccessWithBuffer tests WriteHTML with a buffer.
+func TestHTMLExporter_WriteHTML_SuccessWithBuffer(t *testing.T) {
+	htmlCleaner := services.NewHTMLCleaner()
+	exporter := NewHTMLExporter(htmlCleaner, nil)
+	htmlExporter := exporter.(*HTMLExporter)
+
+	tests := []struct {
+		name     string
+		course   *models.Course
+		contains []string
+	}{
+		{
+			name:   "basic course",
+			course: createTestCourseForHTML(),
+			contains: []string{
+				"<!DOCTYPE html>",
+				"<html lang=\"en\">",
+				"Test Course",
+			},
+		},
+		{
+			name: "course with special characters",
+			course: &models.Course{
+				ShareID: "special-chars-id",
+				Course: models.CourseInfo{
+					ID:          "special-course",
+					Title:       "Course with <special> & \"characters\"",
+					Description: "<p>Description with &amp; entities</p>",
+					Lessons:     []models.Lesson{},
+				},
+			},
+			contains: []string{
+				"<!DOCTYPE html>",
+				"Course with",
+				"special",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var buf strings.Builder
+			err := htmlExporter.WriteHTML(&buf, tt.course)
+			if err != nil {
+				t.Fatalf("WriteHTML() unexpected error: %v", err)
+			}
+
+			output := buf.String()
+			for _, want := range tt.contains {
+				if !strings.Contains(output, want) {
+					t.Errorf("WriteHTML() output missing %q", want)
+				}
+			}
+		})
+	}
+}
+
+// failingWriter is a test helper that fails after writing a certain number of bytes.
+type failingWriter struct {
+	written   int
+	failAfter int
+}
+
+func (w *failingWriter) Write(p []byte) (n int, err error) {
+	if w.written >= w.failAfter {
+		return 0, errWriteFailed
+	}
+	w.written += len(p)
+	if w.written > w.failAfter {
+		return 0, errWriteFailed
+	}
+	return len(p), nil
+}
+
+var errWriteFailed = &writeError{msg: "simulated write failure"}
+
+type writeError struct {
+	msg string
+}
+
+func (e *writeError) Error() string {
+	return e.msg
+}
+
 // createTestCourseForHTML creates a test course for HTML export tests.
 func createTestCourseForHTML() *models.Course {
 	return &models.Course{
@@ -439,7 +660,7 @@ func createTestCourseForHTML() *models.Course {
 // BenchmarkHTMLExporter_Export benchmarks the Export method.
 func BenchmarkHTMLExporter_Export(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewHTMLExporter(htmlCleaner)
+	exporter := NewHTMLExporter(htmlCleaner, nil)
 	course := createTestCourseForHTML()
 
 	tempDir := b.TempDir()
@@ -455,7 +676,7 @@ func BenchmarkHTMLExporter_Export(b *testing.B) {
 // BenchmarkHTMLExporter_ComplexCourse benchmarks export of a complex course.
 func BenchmarkHTMLExporter_ComplexCourse(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewHTMLExporter(htmlCleaner)
+	exporter := NewHTMLExporter(htmlCleaner, nil)
 
 	// Create complex course for benchmarking
 	course := &models.Course{

internal/exporters/markdown.go

@@ -19,19 +19,23 @@ import (
 type MarkdownExporter struct {
 	// htmlCleaner is used to convert HTML content to plain text
 	htmlCleaner *services.HTMLCleaner
+	// logger is used for logging warnings and errors
+	logger interfaces.Logger
 }
 
 // NewMarkdownExporter creates a new MarkdownExporter instance.
-// It takes an HTMLCleaner to handle HTML content conversion.
+// It takes an HTMLCleaner to handle HTML content conversion and a logger for logging.
 //
 // Parameters:
 //   - htmlCleaner: Service for cleaning HTML content in course data
+//   - logger: Logger instance for warnings and errors
 //
 // Returns:
 //   - An implementation of the Exporter interface for Markdown format
-func NewMarkdownExporter(htmlCleaner *services.HTMLCleaner) interfaces.Exporter {
+func NewMarkdownExporter(htmlCleaner *services.HTMLCleaner, logger interfaces.Logger) interfaces.Exporter {
 	return &MarkdownExporter{
 		htmlCleaner: htmlCleaner,
+		logger:      logger,
 	}
 }
 
@@ -40,19 +44,22 @@ func (e *MarkdownExporter) Export(course *models.Course, outputPath string) erro
 	var buf bytes.Buffer
 
 	// Write course header
-	fmt.Fprintf(&buf, "# %s\n\n", course.Course.Title)
+	fmt.Fprintf(&buf, "# %s\n\n", strings.TrimSpace(course.Course.Title))
 
 	if course.Course.Description != "" {
-		fmt.Fprintf(&buf, "%s\n\n", e.htmlCleaner.CleanHTML(course.Course.Description))
+		desc := strings.TrimSpace(e.htmlCleaner.CleanHTML(course.Course.Description))
+		if desc != "" {
+			fmt.Fprintf(&buf, "%s\n\n", desc)
+		}
 	}
 
 	// Add metadata
 	buf.WriteString("## Course Information\n\n")
-	fmt.Fprintf(&buf, "- **Course ID**: %s\n", course.Course.ID)
+	fmt.Fprintf(&buf, "- **Course ID**: %s\n", strings.TrimSpace(course.Course.ID))
-	fmt.Fprintf(&buf, "- **Share ID**: %s\n", course.ShareID)
+	fmt.Fprintf(&buf, "- **Share ID**: %s\n", strings.TrimSpace(course.ShareID))
-	fmt.Fprintf(&buf, "- **Navigation Mode**: %s\n", course.Course.NavigationMode)
+	fmt.Fprintf(&buf, "- **Navigation Mode**: %s\n", strings.TrimSpace(course.Course.NavigationMode))
 	if course.Course.ExportSettings != nil {
-		fmt.Fprintf(&buf, "- **Export Format**: %s\n", course.Course.ExportSettings.Format)
+		fmt.Fprintf(&buf, "- **Export Format**: %s\n", strings.TrimSpace(course.Course.ExportSettings.Format))
 	}
 	buf.WriteString("\n---\n\n")
 
@@ -60,15 +67,18 @@ func (e *MarkdownExporter) Export(course *models.Course, outputPath string) erro
 	lessonCounter := 0
 	for _, lesson := range course.Course.Lessons {
 		if lesson.Type == lessonTypeSection {
-			fmt.Fprintf(&buf, "# %s\n\n", lesson.Title)
+			fmt.Fprintf(&buf, "# %s\n\n", strings.TrimSpace(lesson.Title))
 			continue
 		}
 
 		lessonCounter++
-		fmt.Fprintf(&buf, "## Lesson %d: %s\n\n", lessonCounter, lesson.Title)
+		fmt.Fprintf(&buf, "## Lesson %d: %s\n\n", lessonCounter, strings.TrimSpace(lesson.Title))
 
 		if lesson.Description != "" {
-			fmt.Fprintf(&buf, "%s\n\n", e.htmlCleaner.CleanHTML(lesson.Description))
+			desc := strings.TrimSpace(e.htmlCleaner.CleanHTML(lesson.Description))
+			if desc != "" {
+				fmt.Fprintf(&buf, "%s\n\n", desc)
+			}
 		}
 
 		// Process lesson items
@@ -76,16 +86,49 @@ func (e *MarkdownExporter) Export(course *models.Course, outputPath string) erro
 			e.processItemToMarkdown(&buf, item, 3)
 		}
 
-		buf.WriteString("\n---\n\n")
+		buf.WriteString("---\n\n")
 	}
 
+	// Clean up multiple consecutive blank lines before writing
+	output := cleanMarkdownWhitespace(buf.Bytes())
+
 	// #nosec G306 - 0644 is appropriate for export files that should be readable by others
-	if err := os.WriteFile(outputPath, buf.Bytes(), 0o644); err != nil {
+	if err := os.WriteFile(outputPath, output, 0o644); err != nil {
 		return fmt.Errorf("failed to write markdown file: %w", err)
 	}
 	return nil
 }
 
+// cleanMarkdownWhitespace normalizes whitespace in markdown output.
+// It removes trailing whitespace from lines and collapses multiple blank lines into one.
+func cleanMarkdownWhitespace(data []byte) []byte {
+	lines := strings.Split(string(data), "\n")
+	result := make([]string, 0, len(lines))
+	prevBlank := false
+
+	for _, line := range lines {
+		// Trim trailing whitespace from each line
+		trimmed := strings.TrimRight(line, " \t")
+
+		// Collapse multiple consecutive blank lines
+		isBlank := trimmed == ""
+		if isBlank && prevBlank {
+			continue
+		}
+
+		result = append(result, trimmed)
+		prevBlank = isBlank
+	}
+
+	// Remove trailing blank lines
+	for len(result) > 0 && result[len(result)-1] == "" {
+		result = result[:len(result)-1]
+	}
+
+	// Ensure file ends with newline
+	return []byte(strings.Join(result, "\n") + "\n")
+}
+
 // SupportedFormat returns "markdown".
 func (e *MarkdownExporter) SupportedFormat() string {
 	return FormatMarkdown
@@ -123,13 +166,13 @@ func (e *MarkdownExporter) processItemToMarkdown(buf *bytes.Buffer, item models.
 func (e *MarkdownExporter) processTextItem(buf *bytes.Buffer, item models.Item, headingPrefix string) {
 	for _, subItem := range item.Items {
 		if subItem.Heading != "" {
-			heading := e.htmlCleaner.CleanHTML(subItem.Heading)
+			heading := strings.TrimSpace(e.htmlCleaner.CleanHTML(subItem.Heading))
 			if heading != "" {
 				fmt.Fprintf(buf, "%s %s\n\n", headingPrefix, heading)
 			}
 		}
 		if subItem.Paragraph != "" {
-			paragraph := e.htmlCleaner.CleanHTML(subItem.Paragraph)
+			paragraph := strings.TrimSpace(e.htmlCleaner.CleanHTML(subItem.Paragraph))
 			if paragraph != "" {
 				fmt.Fprintf(buf, "%s\n\n", paragraph)
 			}
@@ -141,7 +184,7 @@ func (e *MarkdownExporter) processTextItem(buf *bytes.Buffer, item models.Item,
 func (e *MarkdownExporter) processListItem(buf *bytes.Buffer, item models.Item) {
 	for _, subItem := range item.Items {
 		if subItem.Paragraph != "" {
-			paragraph := e.htmlCleaner.CleanHTML(subItem.Paragraph)
+			paragraph := strings.TrimSpace(e.htmlCleaner.CleanHTML(subItem.Paragraph))
 			if paragraph != "" {
 				fmt.Fprintf(buf, "- %s\n", paragraph)
 			}
@@ -166,10 +209,12 @@ func (e *MarkdownExporter) processMediaSubItem(buf *bytes.Buffer, subItem models
 		e.processImageMedia(buf, subItem.Media)
 	}
 	if subItem.Caption != "" {
-		caption := e.htmlCleaner.CleanHTML(subItem.Caption)
+		caption := strings.TrimSpace(e.htmlCleaner.CleanHTML(subItem.Caption))
+		if caption != "" {
 			fmt.Fprintf(buf, "*%s*\n", caption)
 		}
 	}
+}
 
 // processVideoMedia processes video media content.
 func (e *MarkdownExporter) processVideoMedia(buf *bytes.Buffer, media *models.Media) {
@@ -196,10 +241,12 @@ func (e *MarkdownExporter) processImageItem(buf *bytes.Buffer, item models.Item,
 			fmt.Fprintf(buf, "**Image**: %s\n", subItem.Media.Image.OriginalURL)
 		}
 		if subItem.Caption != "" {
-			caption := e.htmlCleaner.CleanHTML(subItem.Caption)
+			caption := strings.TrimSpace(e.htmlCleaner.CleanHTML(subItem.Caption))
+			if caption != "" {
 				fmt.Fprintf(buf, "*%s*\n", caption)
 			}
 		}
+	}
 	buf.WriteString("\n")
 }
 
@@ -215,27 +262,35 @@ func (e *MarkdownExporter) processKnowledgeCheckItem(buf *bytes.Buffer, item mod
 // processQuestionSubItem processes individual question items.
 func (e *MarkdownExporter) processQuestionSubItem(buf *bytes.Buffer, subItem models.SubItem) {
 	if subItem.Title != "" {
-		title := e.htmlCleaner.CleanHTML(subItem.Title)
+		title := strings.TrimSpace(e.htmlCleaner.CleanHTML(subItem.Title))
+		if title != "" {
 			fmt.Fprintf(buf, "**Question**: %s\n\n", title)
 		}
+	}
 
 	e.processAnswers(buf, subItem.Answers)
 
 	if subItem.Feedback != "" {
-		feedback := e.htmlCleaner.CleanHTML(subItem.Feedback)
+		feedback := strings.TrimSpace(e.htmlCleaner.CleanHTML(subItem.Feedback))
+		if feedback != "" {
 			fmt.Fprintf(buf, "\n**Feedback**: %s\n", feedback)
 		}
 	}
+}
 
 // processAnswers processes answer choices for quiz questions.
 func (e *MarkdownExporter) processAnswers(buf *bytes.Buffer, answers []models.Answer) {
+	if len(answers) == 0 {
+		return
+	}
 	buf.WriteString("**Answers**:\n")
 	for i, answer := range answers {
 		correctMark := ""
 		if answer.Correct {
-			correctMark = " ✓"
+			correctMark = " [correct]"
 		}
-		fmt.Fprintf(buf, "%d. %s%s\n", i+1, answer.Title, correctMark)
+		title := strings.TrimSpace(answer.Title)
+		fmt.Fprintf(buf, "%d. %s%s\n", i+1, title, correctMark)
 	}
 }
 
@@ -244,11 +299,13 @@ func (e *MarkdownExporter) processInteractiveItem(buf *bytes.Buffer, item models
 	fmt.Fprintf(buf, "%s Interactive Content\n\n", headingPrefix)
 	for _, subItem := range item.Items {
 		if subItem.Title != "" {
-			title := e.htmlCleaner.CleanHTML(subItem.Title)
+			title := strings.TrimSpace(e.htmlCleaner.CleanHTML(subItem.Title))
+			if title != "" {
 				fmt.Fprintf(buf, "**%s**\n\n", title)
 			}
 		}
 	}
+}
 
 // processDividerItem handles divider elements.
 func (e *MarkdownExporter) processDividerItem(buf *bytes.Buffer) {
@@ -269,11 +326,15 @@ func (e *MarkdownExporter) processUnknownItem(buf *bytes.Buffer, item models.Ite
 // processGenericSubItem processes sub-items for unknown types.
 func (e *MarkdownExporter) processGenericSubItem(buf *bytes.Buffer, subItem models.SubItem) {
 	if subItem.Title != "" {
-		title := e.htmlCleaner.CleanHTML(subItem.Title)
+		title := strings.TrimSpace(e.htmlCleaner.CleanHTML(subItem.Title))
+		if title != "" {
 			fmt.Fprintf(buf, "**%s**\n\n", title)
 		}
+	}
 	if subItem.Paragraph != "" {
-		paragraph := e.htmlCleaner.CleanHTML(subItem.Paragraph)
+		paragraph := strings.TrimSpace(e.htmlCleaner.CleanHTML(subItem.Paragraph))
+		if paragraph != "" {
 			fmt.Fprintf(buf, "%s\n\n", paragraph)
 		}
 	}
+}

internal/exporters/markdown_test.go

@@ -14,7 +14,7 @@ import (
 // TestNewMarkdownExporter tests the NewMarkdownExporter constructor.
 func TestNewMarkdownExporter(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewMarkdownExporter(htmlCleaner)
+	exporter := NewMarkdownExporter(htmlCleaner, nil)
 
 	if exporter == nil {
 		t.Fatal("NewMarkdownExporter() returned nil")
@@ -34,7 +34,7 @@ func TestNewMarkdownExporter(t *testing.T) {
 // TestMarkdownExporter_SupportedFormat tests the SupportedFormat method.
 func TestMarkdownExporter_SupportedFormat(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewMarkdownExporter(htmlCleaner)
+	exporter := NewMarkdownExporter(htmlCleaner, nil)
 
 	expected := "markdown"
 	result := exporter.SupportedFormat()
@@ -47,7 +47,7 @@ func TestMarkdownExporter_SupportedFormat(t *testing.T) {
 // TestMarkdownExporter_Export tests the Export method.
 func TestMarkdownExporter_Export(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewMarkdownExporter(htmlCleaner)
+	exporter := NewMarkdownExporter(htmlCleaner, nil)
 
 	// Create test course
 	testCourse := createTestCourseForMarkdown()
@@ -108,7 +108,7 @@ func TestMarkdownExporter_Export(t *testing.T) {
 // TestMarkdownExporter_Export_InvalidPath tests export with invalid output path.
 func TestMarkdownExporter_Export_InvalidPath(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewMarkdownExporter(htmlCleaner)
+	exporter := NewMarkdownExporter(htmlCleaner, nil)
 
 	testCourse := createTestCourseForMarkdown()
 
@@ -283,7 +283,7 @@ func TestMarkdownExporter_ProcessKnowledgeCheckItem(t *testing.T) {
 	if !strings.Contains(result, "**Answers**:") {
 		t.Error("Should contain answers heading")
 	}
-	if !strings.Contains(result, "2. Paris ✓") {
+	if !strings.Contains(result, "2. Paris [correct]") {
 		t.Error("Should mark correct answer")
 	}
 	if !strings.Contains(result, "**Feedback**: Paris is the capital of France.") {
@@ -432,7 +432,7 @@ func TestMarkdownExporter_ProcessAnswers(t *testing.T) {
 	if !strings.Contains(result, "1. Answer 1") {
 		t.Error("Should contain first answer")
 	}
-	if !strings.Contains(result, "2. Answer 2 ✓") {
+	if !strings.Contains(result, "2. Answer 2 [correct]") {
 		t.Error("Should mark correct answer")
 	}
 	if !strings.Contains(result, "3. Answer 3") {
@@ -510,7 +510,7 @@ func TestMarkdownExporter_ProcessItemToMarkdown_AllTypes(t *testing.T) {
 // TestMarkdownExporter_ComplexCourse tests export of a complex course structure.
 func TestMarkdownExporter_ComplexCourse(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewMarkdownExporter(htmlCleaner)
+	exporter := NewMarkdownExporter(htmlCleaner, nil)
 
 	// Create complex test course
 	course := &models.Course{
@@ -603,7 +603,7 @@ func TestMarkdownExporter_ComplexCourse(t *testing.T) {
 		"- Second objective",
 		"### Knowledge Check",
 		"**Question**: What will you learn?",
-		"2. Everything ✓",
+		"2. Everything [correct]",
 		"**Feedback**: Great choice!",
 	}
 
@@ -654,7 +654,7 @@ func createTestCourseForMarkdown() *models.Course {
 // BenchmarkMarkdownExporter_Export benchmarks the Export method.
 func BenchmarkMarkdownExporter_Export(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := NewMarkdownExporter(htmlCleaner)
+	exporter := NewMarkdownExporter(htmlCleaner, nil)
 	course := createTestCourseForMarkdown()
 
 	// Create temporary directory

internal/exporters/output.md

@@ -1,12 +0,0 @@
-# Example Course
-
-Course description
-
-## Course Information
-
-- **Course ID**: 
-- **Share ID**: example-id
-- **Navigation Mode**: 
-
----
-

internal/models/course.go

@@ -2,6 +2,8 @@
 // These structures closely match the JSON format used by Articulate Rise.
 package models
 
+import "fmt"
+
 // Course represents the top-level structure of an Articulate Rise course.
 // It contains metadata and the actual course content.
 type Course struct {
@@ -53,3 +55,46 @@ type LabelSet struct {
 	// Labels is a mapping of label keys to their customized values
 	Labels map[string]string `json:"labels"`
 }
+
+// Validate checks whether the Course structure contains valid data.
+// It returns an error describing the first validation failure found,
+// or nil if the course is valid.
+//
+// Validation rules:
+//   - ShareID must not be empty
+//   - Course.ID must not be empty
+//   - Course.Title must not be empty
+//   - Each Lesson must have a non-empty ID and Title
+func (c *Course) Validate() error {
+	if c.ShareID == "" {
+		return &ValidationError{Field: "ShareID", Message: "share ID is required"}
+	}
+	if c.Course.ID == "" {
+		return &ValidationError{Field: "Course.ID", Message: "course ID is required"}
+	}
+	if c.Course.Title == "" {
+		return &ValidationError{Field: "Course.Title", Message: "course title is required"}
+	}
+	for i, lesson := range c.Course.Lessons {
+		if lesson.ID == "" {
+			return &ValidationError{Field: "Course.Lessons", Message: fmt.Sprintf("lesson at index %d has empty ID", i)}
+		}
+		if lesson.Title == "" {
+			return &ValidationError{Field: "Course.Lessons", Message: fmt.Sprintf("lesson at index %d has empty title", i)}
+		}
+	}
+	return nil
+}
+
+// ValidationError represents a validation failure for a specific field.
+type ValidationError struct {
+	// Field is the name of the field that failed validation
+	Field string
+	// Message describes the validation failure
+	Message string
+}
+
+// Error implements the error interface for ValidationError.
+func (e *ValidationError) Error() string {
+	return fmt.Sprintf("validation error on %s: %s", e.Field, e.Message)
+}

internal/models/models_test.go

@@ -2,6 +2,7 @@ package models
 
 import (
 	"encoding/json"
+	"errors"
 	"reflect"
 	"testing"
 )
@@ -664,6 +665,161 @@ func BenchmarkCourse_JSONUnmarshal(b *testing.B) {
 	}
 }
 
+// TestCourse_Validate tests the Course.Validate method.
+func TestCourse_Validate(t *testing.T) {
+	tests := []struct {
+		name      string
+		course    Course
+		wantErr   bool
+		errField  string
+		errSubstr string
+	}{
+		{
+			name: "valid course",
+			course: Course{
+				ShareID: "test-share-id",
+				Course: CourseInfo{
+					ID:    "course-123",
+					Title: "Test Course",
+					Lessons: []Lesson{
+						{ID: "lesson-1", Title: "First Lesson"},
+					},
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "valid course with no lessons",
+			course: Course{
+				ShareID: "test-share-id",
+				Course: CourseInfo{
+					ID:      "course-123",
+					Title:   "Test Course",
+					Lessons: []Lesson{},
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "missing share ID",
+			course: Course{
+				Course: CourseInfo{
+					ID:    "course-123",
+					Title: "Test Course",
+				},
+			},
+			wantErr:   true,
+			errField:  "ShareID",
+			errSubstr: "share ID is required",
+		},
+		{
+			name: "missing course ID",
+			course: Course{
+				ShareID: "test-share-id",
+				Course: CourseInfo{
+					Title: "Test Course",
+				},
+			},
+			wantErr:   true,
+			errField:  "Course.ID",
+			errSubstr: "course ID is required",
+		},
+		{
+			name: "missing course title",
+			course: Course{
+				ShareID: "test-share-id",
+				Course: CourseInfo{
+					ID: "course-123",
+				},
+			},
+			wantErr:   true,
+			errField:  "Course.Title",
+			errSubstr: "course title is required",
+		},
+		{
+			name: "lesson with empty ID",
+			course: Course{
+				ShareID: "test-share-id",
+				Course: CourseInfo{
+					ID:    "course-123",
+					Title: "Test Course",
+					Lessons: []Lesson{
+						{ID: "", Title: "First Lesson"},
+					},
+				},
+			},
+			wantErr:   true,
+			errField:  "Course.Lessons",
+			errSubstr: "lesson at index 0 has empty ID",
+		},
+		{
+			name: "lesson with empty title",
+			course: Course{
+				ShareID: "test-share-id",
+				Course: CourseInfo{
+					ID:    "course-123",
+					Title: "Test Course",
+					Lessons: []Lesson{
+						{ID: "lesson-1", Title: ""},
+					},
+				},
+			},
+			wantErr:   true,
+			errField:  "Course.Lessons",
+			errSubstr: "lesson at index 0 has empty title",
+		},
+		{
+			name: "second lesson invalid",
+			course: Course{
+				ShareID: "test-share-id",
+				Course: CourseInfo{
+					ID:    "course-123",
+					Title: "Test Course",
+					Lessons: []Lesson{
+						{ID: "lesson-1", Title: "First Lesson"},
+						{ID: "lesson-2", Title: ""},
+					},
+				},
+			},
+			wantErr:   true,
+			errField:  "Course.Lessons",
+			errSubstr: "lesson at index 1 has empty title",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := tt.course.Validate()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Course.Validate() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if tt.wantErr {
+				var valErr *ValidationError
+				if ok := errors.As(err, &valErr); !ok {
+					t.Errorf("Expected ValidationError, got %T", err)
+					return
+				}
+				if valErr.Field != tt.errField {
+					t.Errorf("ValidationError.Field = %q, want %q", valErr.Field, tt.errField)
+				}
+				if valErr.Message != tt.errSubstr {
+					t.Errorf("ValidationError.Message = %q, want %q", valErr.Message, tt.errSubstr)
+				}
+			}
+		})
+	}
+}
+
+// TestValidationError_Error tests the ValidationError.Error method.
+func TestValidationError_Error(t *testing.T) {
+	err := &ValidationError{Field: "TestField", Message: "test message"}
+	expected := "validation error on TestField: test message"
+	if err.Error() != expected {
+		t.Errorf("ValidationError.Error() = %q, want %q", err.Error(), expected)
+	}
+}
+
 // compareMaps compares two any values that should be maps.
 func compareMaps(original, unmarshaled any) bool {
 	origMap, origOk := original.(map[string]any)

internal/services/app.go

@@ -31,33 +31,46 @@ func NewApp(parser interfaces.CourseParser, exporterFactory interfaces.ExporterF
 }
 
 // ProcessCourseFromFile loads a course from a local file and exports it to the specified format.
-// It takes the path to the course file, the desired export format, and the output file path.
+// It takes a context for cancellation, the path to the course file, the desired export format,
-// Returns an error if loading or exporting fails.
+// and the output file path. Returns an error if loading or exporting fails, or if the context
-func (a *App) ProcessCourseFromFile(filePath, format, outputPath string) error {
+// is canceled.
+func (a *App) ProcessCourseFromFile(ctx context.Context, filePath, format, outputPath string) error {
+	// Check for cancellation before loading
+	if err := ctx.Err(); err != nil {
+		return fmt.Errorf("operation canceled: %w", err)
+	}
+
 	course, err := a.parser.LoadCourseFromFile(filePath)
 	if err != nil {
 		return fmt.Errorf("failed to load course from file: %w", err)
 	}
 
-	return a.exportCourse(course, format, outputPath)
+	return a.exportCourse(ctx, course, format, outputPath)
 }
 
 // ProcessCourseFromURI fetches a course from the provided URI and exports it to the specified format.
-// It takes the URI to fetch the course from, the desired export format, and the output file path.
+// It takes a context for cancellation, the URI to fetch the course from, the desired export format,
-// Returns an error if fetching or exporting fails.
+// and the output file path. Returns an error if fetching or exporting fails, or if the context
+// is canceled.
 func (a *App) ProcessCourseFromURI(ctx context.Context, uri, format, outputPath string) error {
 	course, err := a.parser.FetchCourse(ctx, uri)
 	if err != nil {
 		return fmt.Errorf("failed to fetch course: %w", err)
 	}
 
-	return a.exportCourse(course, format, outputPath)
+	return a.exportCourse(ctx, course, format, outputPath)
 }
 
 // exportCourse exports a course to the specified format and output path.
 // It's a helper method that creates the appropriate exporter and performs the export.
-// Returns an error if creating the exporter or exporting the course fails.
+// Returns an error if creating the exporter or exporting the course fails, or if the
-func (a *App) exportCourse(course *models.Course, format, outputPath string) error {
+// context is canceled.
+func (a *App) exportCourse(ctx context.Context, course *models.Course, format, outputPath string) error {
+	// Check for cancellation before export
+	if err := ctx.Err(); err != nil {
+		return fmt.Errorf("operation canceled: %w", err)
+	}
+
 	exporter, err := a.exporterFactory.CreateExporter(format)
 	if err != nil {
 		return fmt.Errorf("failed to create exporter: %w", err)

internal/services/app_test.go

@@ -207,7 +207,7 @@ func TestApp_ProcessCourseFromFile(t *testing.T) {
 			tt.setupMocks(parser, factory, exporter)
 
 			app := NewApp(parser, factory)
-			err := app.ProcessCourseFromFile(tt.filePath, tt.format, tt.outputPath)
+			err := app.ProcessCourseFromFile(context.Background(), tt.filePath, tt.format, tt.outputPath)
 
 			if tt.expectedError != "" {
 				if err == nil {

internal/services/example_test.go

@@ -5,7 +5,10 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"log/slog"
+	"time"
 
+	"github.com/kjanat/articulate-parser/internal/config"
 	"github.com/kjanat/articulate-parser/internal/services"
 )
 
@@ -14,8 +17,8 @@ func ExampleNewArticulateParser() {
 	// Create a no-op logger for this example
 	logger := services.NewNoOpLogger()
 
-	// Create parser with defaults
+	// Create parser with defaults (nil config uses defaults)
-	parser := services.NewArticulateParser(logger, "", 0)
+	parser := services.NewArticulateParser(logger, nil)
 
 	fmt.Printf("Parser created: %T\n", parser)
 	// Output: Parser created: *services.ArticulateParser
@@ -26,11 +29,11 @@ func ExampleNewArticulateParser_custom() {
 	logger := services.NewNoOpLogger()
 
 	// Create parser with custom base URL and timeout
-	parser := services.NewArticulateParser(
+	cfg := &config.Config{
-		logger,
+		BaseURL:        "https://custom.articulate.com",
-		"https://custom.articulate.com",
+		RequestTimeout: 60 * time.Second,
-		60_000_000_000, // 60 seconds in nanoseconds
+	}
-	)
+	parser := services.NewArticulateParser(logger, cfg)
 
 	fmt.Printf("Parser configured: %T\n", parser)
 	// Output: Parser configured: *services.ArticulateParser
@@ -39,7 +42,7 @@ func ExampleNewArticulateParser_custom() {
 // ExampleArticulateParser_LoadCourseFromFile demonstrates loading a course from a file.
 func ExampleArticulateParser_LoadCourseFromFile() {
 	logger := services.NewNoOpLogger()
-	parser := services.NewArticulateParser(logger, "", 0)
+	parser := services.NewArticulateParser(logger, nil)
 
 	// In a real scenario, you'd have an actual file
 	// This example shows the API usage
@@ -52,7 +55,7 @@ func ExampleArticulateParser_LoadCourseFromFile() {
 // ExampleArticulateParser_FetchCourse demonstrates fetching a course from a URI.
 func ExampleArticulateParser_FetchCourse() {
 	logger := services.NewNoOpLogger()
-	parser := services.NewArticulateParser(logger, "", 0)
+	parser := services.NewArticulateParser(logger, nil)
 
 	// Create a context with timeout
 	ctx := context.Background()
@@ -64,6 +67,54 @@ func ExampleArticulateParser_FetchCourse() {
 	}
 }
 
+// ExampleNewSlogLogger demonstrates creating a JSON logger.
+func ExampleNewSlogLogger() {
+	// Create a JSON structured logger at Info level
+	// Output goes to stdout in JSON format
+	logger := services.NewSlogLogger(slog.LevelInfo)
+
+	// Logger is ready to use - calls like logger.Info("msg") output JSON
+	fmt.Printf("Logger type: %T\n", logger)
+	// Output: Logger type: *services.SlogLogger
+}
+
+// ExampleNewTextLogger demonstrates creating a human-readable text logger.
+func ExampleNewTextLogger() {
+	// Create a text logger, more readable for development
+	logger := services.NewTextLogger(slog.LevelDebug)
+
+	// Logger is ready - calls like logger.Debug("msg") output text
+	fmt.Printf("Logger type: %T\n", logger)
+	// Output: Logger type: *services.SlogLogger
+}
+
+// ExampleNewNoOpLogger demonstrates creating a no-op logger for testing.
+func ExampleNewNoOpLogger() {
+	logger := services.NewNoOpLogger()
+
+	// All log calls are silently discarded
+	logger.Debug("this won't appear")
+	logger.Info("neither will this")
+	logger.Error("or this")
+
+	fmt.Println("Logging silently completed")
+	// Output: Logging silently completed
+}
+
+// ExampleSlogLogger_With demonstrates creating a child logger with context.
+func ExampleSlogLogger_With() {
+	logger := services.NewNoOpLogger()
+
+	// Create a child logger with additional context
+	requestLogger := logger.With("request_id", "abc123", "user", "john")
+
+	// All logs from requestLogger will include request_id and user
+	requestLogger.Info("processing request")
+
+	fmt.Printf("Child logger type: %T\n", requestLogger)
+	// Output: Child logger type: *services.NoOpLogger
+}
+
 // ExampleHTMLCleaner demonstrates cleaning HTML content.
 func ExampleHTMLCleaner() {
 	cleaner := services.NewHTMLCleaner()

internal/services/logger_factory.go

@@ -0,0 +1,15 @@
+package services
+
+import (
+	"github.com/kjanat/articulate-parser/internal/config"
+	"github.com/kjanat/articulate-parser/internal/interfaces"
+)
+
+// NewLoggerFromConfig creates a logger based on the configuration.
+// Returns a JSON logger if cfg.LogFormat is "json", otherwise returns a text logger.
+func NewLoggerFromConfig(cfg *config.Config) interfaces.Logger {
+	if cfg.LogFormat == "json" {
+		return NewSlogLogger(cfg.LogLevel)
+	}
+	return NewTextLogger(cfg.LogLevel)
+}

internal/services/parser.go

@@ -9,17 +9,14 @@ import (
 	"net/url"
 	"os"
 	"regexp"
-	"time"
 
+	"github.com/kjanat/articulate-parser/internal/config"
 	"github.com/kjanat/articulate-parser/internal/interfaces"
 	"github.com/kjanat/articulate-parser/internal/models"
 )
 
-// Default endpoint configuration for the Articulate Rise API.
+// riseHost is the only host accepted in Articulate Rise share URIs.
-const (
+const riseHost = "rise.articulate.com"
-	riseHost       = "rise.articulate.com"
-	defaultBaseURL = "https://" + riseHost
-)
 
 // shareIDRegex is compiled once at package init for extracting share IDs from URIs.
 var shareIDRegex = regexp.MustCompile(`/share/([a-zA-Z0-9_-]+)`)
@@ -35,23 +32,19 @@ type ArticulateParser struct {
 	Logger interfaces.Logger
 }
 
-// NewArticulateParser creates a new ArticulateParser instance.
+// NewArticulateParser creates a new ArticulateParser instance using the provided configuration.
-// If baseURL is empty, uses the default Articulate Rise API URL.
+// If cfg is nil, a default configuration will be used.
-// If timeout is zero, uses a 30-second timeout.
+func NewArticulateParser(logger interfaces.Logger, cfg *config.Config) interfaces.CourseParser {
-func NewArticulateParser(logger interfaces.Logger, baseURL string, timeout time.Duration) interfaces.CourseParser {
 	if logger == nil {
 		logger = NewNoOpLogger()
 	}
-	if baseURL == "" {
+	if cfg == nil {
-		baseURL = defaultBaseURL
+		cfg = config.Load()
-	}
-	if timeout == 0 {
-		timeout = 30 * time.Second
 	}
 	return &ArticulateParser{
-		BaseURL: baseURL,
+		BaseURL: cfg.BaseURL,
 		Client: &http.Client{
-			Timeout: timeout,
+			Timeout: cfg.RequestTimeout,
 		},
 		Logger: logger,
 	}

internal/services/parser_bench_test.go

@@ -8,7 +8,9 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+	"time"
 
+	"github.com/kjanat/articulate-parser/internal/config"
 	"github.com/kjanat/articulate-parser/internal/models"
 )
 
@@ -133,7 +135,11 @@ func BenchmarkArticulateParser_LoadCourseFromFile(b *testing.B) {
 		b.Fatalf("Failed to write file: %v", err)
 	}
 
-	parser := NewArticulateParser(nil, "", 0)
+	cfg := &config.Config{
+		BaseURL:        "https://rise.articulate.com",
+		RequestTimeout: 30 * time.Second,
+	}
+	parser := NewArticulateParser(nil, cfg)
 
 	b.ResetTimer()
 	for b.Loop() {
@@ -180,7 +186,11 @@ func BenchmarkArticulateParser_LoadCourseFromFile_Large(b *testing.B) {
 		b.Fatalf("Failed to write file: %v", err)
 	}
 
-	parser := NewArticulateParser(nil, "", 0)
+	cfg := &config.Config{
+		BaseURL:        "https://rise.articulate.com",
+		RequestTimeout: 30 * time.Second,
+	}
+	parser := NewArticulateParser(nil, cfg)
 
 	b.ResetTimer()
 	for b.Loop() {

internal/services/parser_fuzz_test.go

@@ -0,0 +1,207 @@
+package services
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/kjanat/articulate-parser/internal/models"
+)
+
+// FuzzArticulateParser_ParseJSON fuzzes JSON parsing to ensure no panics on malformed input.
+// It tests that the parser gracefully handles any byte sequence without crashing.
+func FuzzArticulateParser_ParseJSON(f *testing.F) {
+	// Add seed corpus with valid JSON structures
+	f.Add([]byte(`{"shareId":"test","course":{"id":"1","title":"Test"}}`))
+	f.Add([]byte(`{"shareId":"abc123","author":"John Doe","course":{"id":"c1","title":"Course Title","description":"A test course"}}`))
+	f.Add([]byte(`{}`))
+	f.Add([]byte(`{"course":{}}`))
+	f.Add([]byte(`{"shareId":"","course":{"id":"","title":"","lessons":[]}}`))
+
+	// Add seed corpus with invalid/edge case inputs
+	f.Add([]byte(`invalid`))
+	f.Add([]byte(``))
+	f.Add([]byte(`null`))
+	f.Add([]byte(`[]`))
+	f.Add([]byte(`"string"`))
+	f.Add([]byte(`123`))
+	f.Add([]byte(`true`))
+	f.Add([]byte(`{`))
+	f.Add([]byte(`}`))
+	f.Add([]byte(`{"unclosed": `))
+	f.Add([]byte(`{"key": "value with \x00 null byte"}`))
+
+	// Add seed corpus with nested structures
+	f.Add([]byte(`{"course":{"lessons":[{"id":"l1","title":"Lesson 1","items":[{"id":"i1","type":"text","data":"content"}]}]}}`))
+	f.Add([]byte(`{"course":{"lessons":[{},{},{}]}}`))
+
+	// Add seed corpus with special characters
+	f.Add([]byte(`{"shareId":"test<script>alert('xss')</script>"}`))
+	f.Add([]byte(`{"course":{"title":"Test\n\r\t\u0000Title"}}`))
+	f.Add([]byte(`{"course":{"description":"<p>HTML content</p>"}}`))
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		// Test that unmarshaling doesn't panic
+		var course models.Course
+		_ = json.Unmarshal(data, &course)
+
+		// Also test that re-marshaling doesn't panic
+		_, _ = json.Marshal(&course)
+
+		// Test accessing fields doesn't panic
+		_ = course.ShareID
+		_ = course.Author
+		_ = course.Course.ID
+		_ = course.Course.Title
+		_ = course.Course.Description
+
+		// Test iterating over lessons doesn't panic
+		for _, lesson := range course.Course.Lessons {
+			_ = lesson.ID
+			_ = lesson.Title
+			for _, item := range lesson.Items {
+				_ = item.ID
+				_ = item.Type
+			}
+		}
+	})
+}
+
+// FuzzArticulateParser_LoadCourseFromFile_JSON tests JSON parsing behavior used by LoadCourseFromFile.
+// This fuzz test ensures the JSON unmarshaling logic handles arbitrary input gracefully.
+func FuzzArticulateParser_LoadCourseFromFile_JSON(f *testing.F) {
+	// Seed corpus mimicking file contents
+	f.Add([]byte(`{"shareId":"file-test","course":{"id":"1","title":"From File"}}`))
+	f.Add([]byte(`{
+		"shareId": "multiline",
+		"course": {
+			"id": "2",
+			"title": "Multiline JSON"
+		}
+	}`))
+	f.Add([]byte("\xef\xbb\xbf{\"shareId\":\"bom\"}")) // UTF-8 BOM prefix
+	f.Add([]byte(`{"shareId": "spaces",  "course":  {}}`))
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		var course models.Course
+		err := json.Unmarshal(data, &course)
+
+		// If unmarshaling succeeded, verify the result is usable
+		if err == nil {
+			// Access all fields to ensure no panics on zero values
+			_ = course.ShareID
+			_ = course.Author
+			_ = course.Course.ID
+			_ = course.Course.Title
+
+			// Iterate through nested structures
+			for _, lesson := range course.Course.Lessons {
+				_ = lesson.ID
+				_ = lesson.Title
+				_ = lesson.Type
+				for _, item := range lesson.Items {
+					_ = item.ID
+					_ = item.Type
+					_ = item.Data
+				}
+			}
+		}
+	})
+}
+
+// FuzzHTMLCleaner_CleanHTML fuzzes the HTML cleaner to ensure no panics on malformed HTML.
+// It tests that arbitrary HTML-like input is handled gracefully.
+func FuzzHTMLCleaner_CleanHTML(f *testing.F) {
+	cleaner := NewHTMLCleaner()
+
+	// Add seed corpus with valid HTML patterns
+	f.Add("<p>Simple paragraph</p>")
+	f.Add("<div><p>Nested</p></div>")
+	f.Add("<h1>Title</h1><p>Content</p>")
+	f.Add("<strong>Bold</strong> and <em>italic</em>")
+	f.Add("<a href=\"https://example.com\">Link</a>")
+	f.Add("<img src=\"image.png\" alt=\"Image\"/>")
+	f.Add("<br/><hr/>")
+	f.Add("<ul><li>Item 1</li><li>Item 2</li></ul>")
+	f.Add("<table><tr><td>Cell</td></tr></table>")
+
+	// Add seed corpus with HTML entities
+	f.Add("AT&amp;T")
+	f.Add("&lt;script&gt;alert('xss')&lt;/script&gt;")
+	f.Add("&nbsp;&nbsp;&nbsp;")
+	f.Add("&#39;apostrophe&#39;")
+	f.Add("&quot;quoted&quot;")
+	f.Add("&eacute;&iuml;&ouml;")
+	f.Add("&#x27;hex entity&#x27;")
+	f.Add("&#8217;numeric entity&#8217;")
+
+	// Add seed corpus with malformed/edge case HTML
+	f.Add("")
+	f.Add("plain text no HTML")
+	f.Add("<p>Unclosed paragraph")
+	f.Add("</p>Close tag first<p>")
+	f.Add("<div><div><div>Deep nesting")
+	f.Add("<script>alert('xss')</script>")
+	f.Add("<style>body{color:red}</style>")
+	f.Add("<!--comment-->")
+	f.Add("<!DOCTYPE html>")
+	f.Add("<![CDATA[data]]>")
+	f.Add("<p class=\"test\" id='test' data-attr=unquoted>Attributes</p>")
+	f.Add("<p\n\t>Whitespace in tag</p\n>")
+	f.Add("<>empty tag</>")
+	f.Add("<<<nested angles>>>")
+	f.Add("<p onclick=\"evil()\">Event handler</p>")
+
+	// Add seed corpus with special characters
+	f.Add("<p>\x00null byte</p>")
+	f.Add("<p>\xffhigh byte</p>")
+	f.Add("<p>emoji: \xf0\x9f\x98\x80</p>")
+	f.Add("<p>unicode: \u2603</p>")
+	f.Add("<p>newlines\n\r\nand\rtabs\there</p>")
+
+	// Add seed corpus with potentially problematic patterns
+	f.Add(string(make([]byte, 0)))                     // Empty
+	f.Add(string(make([]byte, 1)))                     // Single null byte
+	f.Add("<" + string(make([]byte, 100)) + ">")       // Tag with null bytes
+	f.Add("<p>" + string(make([]byte, 1000)) + "</p>") // Large content
+
+	f.Fuzz(func(t *testing.T, input string) {
+		// Test that CleanHTML doesn't panic on any input
+		result := cleaner.CleanHTML(input)
+
+		// Verify the result is a valid string (doesn't panic on access)
+		_ = len(result)
+
+		// Test that the result can be used in common string operations without panic
+		_ = result == ""
+		_ = result == input
+
+		// Test that calling CleanHTML on its own output doesn't panic (idempotency check)
+		_ = cleaner.CleanHTML(result)
+	})
+}
+
+// FuzzHTMLCleaner_CleanHTML_Bytes tests HTML cleaner with raw byte sequences.
+// This catches issues with invalid UTF-8 and binary data in HTML content.
+func FuzzHTMLCleaner_CleanHTML_Bytes(f *testing.F) {
+	cleaner := NewHTMLCleaner()
+
+	// Add seed corpus with byte sequences
+	f.Add([]byte("<p>normal</p>"))
+	f.Add([]byte{0x3c, 0x70, 0x3e, 0xff, 0xfe, 0x3c, 0x2f, 0x70, 0x3e})       // <p>..invalid..</p>
+	f.Add([]byte{0x00})                                                       // Null byte
+	f.Add([]byte{0xff, 0xfe})                                                 // Invalid UTF-8
+	f.Add([]byte{0xef, 0xbb, 0xbf, 0x3c, 0x70, 0x3e, 0x3c, 0x2f, 0x70, 0x3e}) // UTF-8 BOM + <p></p>
+	f.Add([]byte("<p>\xc0\xaf</p>"))                                          // Overlong UTF-8
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		// Convert bytes to string and test
+		input := string(data)
+
+		// Test that CleanHTML doesn't panic
+		result := cleaner.CleanHTML(input)
+
+		// Verify result is usable
+		_ = len(result)
+		_ = []byte(result)
+	})
+}

internal/services/parser_test.go

@@ -11,12 +11,14 @@ import (
 	"testing"
 	"time"
 
+	"github.com/kjanat/articulate-parser/internal/config"
 	"github.com/kjanat/articulate-parser/internal/models"
 )
 
 // TestNewArticulateParser tests the NewArticulateParser constructor.
 func TestNewArticulateParser(t *testing.T) {
-	parser := NewArticulateParser(nil, "", 0)
+	// Test with nil config (should use defaults)
+	parser := NewArticulateParser(nil, nil)
 
 	if parser == nil {
 		t.Fatal("NewArticulateParser() returned nil")
@@ -212,7 +214,11 @@ func TestArticulateParser_LoadCourseFromFile(t *testing.T) {
 		t.Fatalf("Failed to write test file: %v", err)
 	}
 
-	parser := NewArticulateParser(nil, "", 0)
+	cfg := &config.Config{
+		BaseURL:        "https://rise.articulate.com",
+		RequestTimeout: 30 * time.Second,
+	}
+	parser := NewArticulateParser(nil, cfg)
 
 	tests := []struct {
 		name          string
@@ -271,7 +277,11 @@ func TestArticulateParser_LoadCourseFromFile_InvalidJSON(t *testing.T) {
 		t.Fatalf("Failed to write test file: %v", err)
 	}
 
-	parser := NewArticulateParser(nil, "", 0)
+	cfg := &config.Config{
+		BaseURL:        "https://rise.articulate.com",
+		RequestTimeout: 30 * time.Second,
+	}
+	parser := NewArticulateParser(nil, cfg)
 	_, err := parser.LoadCourseFromFile(tempFile)
 
 	if err == nil {

internal/testdata/fixtures.go

@@ -0,0 +1,467 @@
+// Package testdata provides shared test fixtures for Articulate Rise course testing.
+// It contains builders for creating Course, Lesson, and Item structures with various
+// configurations to support unit tests, integration tests, and benchmarks.
+package testdata
+
+import (
+	"fmt"
+
+	"github.com/kjanat/articulate-parser/internal/models"
+)
+
+// SampleAnswers provides a reusable set of quiz answers for testing.
+var SampleAnswers = []models.Answer{
+	{ID: "ans-1", Title: "Option A", Correct: false},
+	{ID: "ans-2", Title: "Option B", Correct: true},
+	{ID: "ans-3", Title: "Option C", Correct: false},
+	{ID: "ans-4", Title: "Option D", Correct: false},
+}
+
+// SampleSubItems provides a reusable set of sub-items for testing.
+var SampleSubItems = []models.SubItem{
+	{
+		ID:        "sub-1",
+		Heading:   "Sample Heading",
+		Paragraph: "<p>Sample paragraph with <strong>formatting</strong>.</p>",
+	},
+	{
+		ID:        "sub-2",
+		Paragraph: "<p>Another paragraph with <em>emphasis</em>.</p>",
+	},
+}
+
+// MinimalCourse returns a course with just ShareID and Title set.
+// Useful for testing edge cases with minimal data.
+func MinimalCourse() *models.Course {
+	return &models.Course{
+		ShareID: "minimal-share-id",
+		Course: models.CourseInfo{
+			Title: "Minimal Course",
+		},
+	}
+}
+
+// BasicCourse returns a course with 1 section, 1 lesson, and 1 text item.
+// Suitable for basic functionality tests.
+func BasicCourse() *models.Course {
+	return &models.Course{
+		ShareID: "basic-share-id",
+		Author:  "Test Author",
+		Course: models.CourseInfo{
+			ID:             "basic-course-id",
+			Title:          "Basic Test Course",
+			Description:    "<p>A basic course for testing.</p>",
+			NavigationMode: "menu",
+			Lessons: []models.Lesson{
+				{
+					ID:    "section-1",
+					Title: "Introduction Section",
+					Type:  "section",
+				},
+				{
+					ID:          "lesson-1",
+					Title:       "First Lesson",
+					Type:        "lesson",
+					Description: "<p>Lesson introduction text.</p>",
+					Items: []models.Item{
+						TextItem("Welcome", "<p>Welcome to the course!</p>"),
+					},
+				},
+			},
+		},
+	}
+}
+
+// CompleteCourse returns a course with all item types represented.
+// Useful for comprehensive export and parsing tests.
+func CompleteCourse() *models.Course {
+	return &models.Course{
+		ShareID: "complete-share-id",
+		Author:  "Complete Test Author",
+		Course: models.CourseInfo{
+			ID:             "complete-course-id",
+			Title:          "Complete Test Course",
+			Description:    "<p>A comprehensive course with <strong>all</strong> item types.</p>",
+			Color:          "#3366CC",
+			NavigationMode: "menu",
+			ExportSettings: &models.ExportSettings{
+				Title:  "Exported Complete Course",
+				Format: "scorm",
+			},
+			CoverImage: &models.Media{
+				Image: &models.ImageMedia{
+					Key:         "cover-img-key",
+					Type:        "jpg",
+					Width:       1920,
+					Height:      1080,
+					OriginalURL: "https://example.com/cover.jpg",
+				},
+			},
+			Lessons: []models.Lesson{
+				{
+					ID:    "section-1",
+					Title: "Course Overview",
+					Type:  "section",
+				},
+				{
+					ID:          "lesson-1",
+					Title:       "Introduction",
+					Type:        "lesson",
+					Description: "<p>Introduction to the course content.</p>",
+					Icon:        "book",
+					Items: []models.Item{
+						TextItem("Welcome", "<p>Welcome to this comprehensive course!</p>"),
+						TextItem("Objectives", "<p>In this course you will learn:</p>"),
+						ListItem("First objective", "Second objective", "Third objective"),
+						DividerItem(),
+						MediaItem("video", "https://example.com/intro.mp4"),
+						MediaItem("image", "https://example.com/diagram.png"),
+					},
+				},
+				{
+					ID:          "lesson-2",
+					Title:       "Core Concepts",
+					Type:        "lesson",
+					Description: "<p>Core concepts and fundamentals.</p>",
+					Items: []models.Item{
+						TextItem("Key Concepts", "<p>Let's explore the key concepts.</p>"),
+						KnowledgeCheckItem("What is the primary purpose of this course?", []models.Answer{
+							{ID: "kc-1-a", Title: "Learning basics", Correct: false},
+							{ID: "kc-1-b", Title: "Comprehensive understanding", Correct: true},
+							{ID: "kc-1-c", Title: "Quick overview", Correct: false},
+						}),
+						InteractiveItem("Interactive Exercise"),
+					},
+				},
+				{
+					ID:          "lesson-3",
+					Title:       "Advanced Topics",
+					Type:        "lesson",
+					Description: "<p>Deep dive into advanced topics.</p>",
+					Items: []models.Item{
+						TextItem("Advanced Section", "<p>This section covers advanced material.</p>"),
+						FlipCardItem("Front content", "Back content"),
+						QuoteItem("Learning is not attained by chance.", "Abigail Adams"),
+					},
+				},
+				{
+					ID:    "section-2",
+					Title: "Summary",
+					Type:  "section",
+				},
+				{
+					ID:          "lesson-4",
+					Title:       "Conclusion",
+					Type:        "lesson",
+					Description: "<p>Course wrap-up and next steps.</p>",
+					Items: []models.Item{
+						TextItem("Summary", "<p>Thank you for completing this course!</p>"),
+						ListItem("Review materials regularly", "Practice learned skills", "Share knowledge"),
+					},
+				},
+			},
+		},
+		LabelSet: models.LabelSet{
+			ID:   "default-labels",
+			Name: "Default",
+			Labels: map[string]string{
+				"next":     "Next",
+				"previous": "Previous",
+				"complete": "Mark Complete",
+			},
+		},
+	}
+}
+
+// LargeCourse returns a parameterized course for benchmarking with the specified number of lessons.
+// Each lesson contains multiple item types for realistic performance testing.
+func LargeCourse(lessons int) *models.Course {
+	courseLessons := make([]models.Lesson, 0, lessons+lessons/5) // +sections
+
+	for i := range lessons {
+		// Add section header every 5 lessons
+		if i%5 == 0 {
+			courseLessons = append(courseLessons, models.Lesson{
+				ID:    fmt.Sprintf("section-%d", i/5+1),
+				Title: fmt.Sprintf("Section %d", i/5+1),
+				Type:  "section",
+			})
+		}
+
+		lesson := models.Lesson{
+			ID:          fmt.Sprintf("lesson-%d", i+1),
+			Title:       fmt.Sprintf("Lesson %d", i+1),
+			Type:        "lesson",
+			Description: fmt.Sprintf("<p>Description for lesson %d with <em>formatting</em>.</p>", i+1),
+			Items: []models.Item{
+				TextItem(
+					fmt.Sprintf("Heading %d", i+1),
+					fmt.Sprintf("<p>Content for lesson %d with <strong>bold</strong> and <em>italic</em> text.</p>", i+1),
+				),
+				ListItem("Point 1", "Point 2", "Point 3"),
+				KnowledgeCheckItem(
+					fmt.Sprintf("Quiz Question %d", i+1),
+					[]models.Answer{
+						{ID: fmt.Sprintf("q%d-a", i), Title: "Answer A", Correct: false},
+						{ID: fmt.Sprintf("q%d-b", i), Title: "Answer B", Correct: true},
+						{ID: fmt.Sprintf("q%d-c", i), Title: "Answer C", Correct: false},
+					},
+				),
+			},
+		}
+		courseLessons = append(courseLessons, lesson)
+	}
+
+	return &models.Course{
+		ShareID: "large-benchmark-id",
+		Author:  "Benchmark Author",
+		Course: models.CourseInfo{
+			ID:             "large-benchmark-course",
+			Title:          fmt.Sprintf("Large Benchmark Course (%d lessons)", lessons),
+			Description:    "<p>Large course for performance testing.</p>",
+			NavigationMode: "menu",
+			Lessons:        courseLessons,
+		},
+	}
+}
+
+// TextItem creates a text item with the specified heading and paragraph content.
+func TextItem(heading, paragraph string) models.Item {
+	return models.Item{
+		Type:   "text",
+		Family: "text",
+		Items: []models.SubItem{
+			{
+				ID:        "text-sub-1",
+				Heading:   heading,
+				Paragraph: paragraph,
+			},
+		},
+	}
+}
+
+// ListItem creates a list item with the specified items as list entries.
+func ListItem(items ...string) models.Item {
+	subItems := make([]models.SubItem, len(items))
+	for i, item := range items {
+		subItems[i] = models.SubItem{
+			ID:        fmt.Sprintf("list-sub-%d", i+1),
+			Paragraph: fmt.Sprintf("<p>%s</p>", item),
+		}
+	}
+
+	return models.Item{
+		Type:   "list",
+		Family: "list",
+		Items:  subItems,
+	}
+}
+
+// KnowledgeCheckItem creates a knowledge check item with the specified question and answers.
+func KnowledgeCheckItem(question string, answers []models.Answer) models.Item {
+	return models.Item{
+		Type:   "knowledgeCheck",
+		Family: "knowledge",
+		Items: []models.SubItem{
+			{
+				ID:       "kc-sub-1",
+				Title:    fmt.Sprintf("<p>%s</p>", question),
+				Answers:  answers,
+				Feedback: "<p>Thank you for your response.</p>",
+			},
+		},
+	}
+}
+
+// MediaItem creates a media item (video or image) with the specified type and URL.
+// The mediaType should be "video" or "image".
+func MediaItem(mediaType, url string) models.Item {
+	var media *models.Media
+
+	switch mediaType {
+	case "video":
+		media = &models.Media{
+			Video: &models.VideoMedia{
+				Key:         "video-key",
+				URL:         url,
+				Type:        "mp4",
+				Duration:    120,
+				OriginalURL: url,
+			},
+		}
+	case "image":
+		media = &models.Media{
+			Image: &models.ImageMedia{
+				Key:         "image-key",
+				Type:        "png",
+				Width:       800,
+				Height:      600,
+				OriginalURL: url,
+			},
+		}
+	default:
+		media = &models.Media{}
+	}
+
+	return models.Item{
+		Type:   "multimedia",
+		Family: "media",
+		Items: []models.SubItem{
+			{
+				ID:      "media-sub-1",
+				Title:   fmt.Sprintf("<p>%s content</p>", mediaType),
+				Caption: fmt.Sprintf("<p>Caption for %s</p>", mediaType),
+				Media:   media,
+			},
+		},
+	}
+}
+
+// InteractiveItem creates an interactive content item with the specified title.
+func InteractiveItem(title string) models.Item {
+	return models.Item{
+		Type:   "interactive",
+		Family: "interactive",
+		Items: []models.SubItem{
+			{
+				ID:    "interactive-sub-1",
+				Title: fmt.Sprintf("<p>%s</p>", title),
+			},
+		},
+	}
+}
+
+// DividerItem creates a divider/separator item.
+func DividerItem() models.Item {
+	return models.Item{
+		Type:   "divider",
+		Family: "divider",
+	}
+}
+
+// FlipCardItem creates a flashcard-style item with front and back content.
+func FlipCardItem(front, back string) models.Item {
+	return models.Item{
+		Type:   "flashcard",
+		Family: "interactive",
+		Items: []models.SubItem{
+			{
+				ID: "flipcard-sub-1",
+				Front: &models.CardSide{
+					Description: fmt.Sprintf("<p>%s</p>", front),
+				},
+				Back: &models.CardSide{
+					Description: fmt.Sprintf("<p>%s</p>", back),
+				},
+			},
+		},
+	}
+}
+
+// QuoteItem creates a quote/blockquote item with text and attribution.
+func QuoteItem(quote, author string) models.Item {
+	return models.Item{
+		Type:   "quote",
+		Family: "text",
+		Items: []models.SubItem{
+			{
+				ID:        "quote-sub-1",
+				Paragraph: fmt.Sprintf("<blockquote>%s</blockquote>", quote),
+				Title:     author,
+			},
+		},
+	}
+}
+
+// ImageItem creates a standalone image item with caption.
+func ImageItem(url, caption string) models.Item {
+	return models.Item{
+		Type:   "image",
+		Family: "media",
+		Items: []models.SubItem{
+			{
+				ID:      "image-sub-1",
+				Caption: fmt.Sprintf("<p>%s</p>", caption),
+				Media: &models.Media{
+					Image: &models.ImageMedia{
+						Key:         "standalone-img-key",
+						Type:        "jpg",
+						Width:       1200,
+						Height:      800,
+						OriginalURL: url,
+					},
+				},
+			},
+		},
+	}
+}
+
+// VideoItem creates a standalone video item with caption.
+func VideoItem(url string, duration int, caption string) models.Item {
+	return models.Item{
+		Type:   "video",
+		Family: "media",
+		Items: []models.SubItem{
+			{
+				ID:      "video-sub-1",
+				Caption: fmt.Sprintf("<p>%s</p>", caption),
+				Media: &models.Media{
+					Video: &models.VideoMedia{
+						Key:         "standalone-video-key",
+						URL:         url,
+						Type:        "mp4",
+						Duration:    duration,
+						OriginalURL: url,
+					},
+				},
+			},
+		},
+	}
+}
+
+// MatchingItem creates a matching/pairing knowledge check item.
+func MatchingItem(pairs map[string]string) models.Item {
+	answers := make([]models.Answer, 0, len(pairs))
+	i := 0
+	for term, match := range pairs {
+		answers = append(answers, models.Answer{
+			ID:         fmt.Sprintf("match-%d", i),
+			Title:      term,
+			MatchTitle: match,
+			Correct:    true,
+		})
+		i++
+	}
+
+	return models.Item{
+		Type:   "matching",
+		Family: "knowledge",
+		Items: []models.SubItem{
+			{
+				ID:       "matching-sub-1",
+				Title:    "<p>Match the following items:</p>",
+				Answers:  answers,
+				Feedback: "<p>Check your matches!</p>",
+			},
+		},
+	}
+}
+
+// EmptyLesson returns a lesson with no items for edge case testing.
+func EmptyLesson(id, title string) models.Lesson {
+	return models.Lesson{
+		ID:    id,
+		Title: title,
+		Type:  "lesson",
+		Items: []models.Item{},
+	}
+}
+
+// SectionLesson returns a section header (not a content lesson).
+func SectionLesson(id, title string) models.Lesson {
+	return models.Lesson{
+		ID:    id,
+		Title: title,
+		Type:  "section",
+	}
+}

internal/testdata/fixtures_test.go

@@ -0,0 +1,273 @@
+package testdata
+
+import (
+	"testing"
+
+	"github.com/kjanat/articulate-parser/internal/models"
+)
+
+func TestMinimalCourse(t *testing.T) {
+	course := MinimalCourse()
+	if course == nil {
+		t.Fatal("MinimalCourse() returned nil")
+	}
+	if course.ShareID == "" {
+		t.Error("MinimalCourse() should have ShareID set")
+	}
+	if course.Course.Title == "" {
+		t.Error("MinimalCourse() should have Title set")
+	}
+}
+
+func TestBasicCourse(t *testing.T) {
+	course := BasicCourse()
+	if course == nil {
+		t.Fatal("BasicCourse() returned nil")
+	}
+	if len(course.Course.Lessons) != 2 {
+		t.Errorf("BasicCourse() should have 2 lessons, got %d", len(course.Course.Lessons))
+	}
+	if course.Course.Lessons[0].Type != "section" {
+		t.Error("First lesson should be a section")
+	}
+	if course.Course.Lessons[1].Type != "lesson" {
+		t.Error("Second lesson should be a lesson")
+	}
+	if len(course.Course.Lessons[1].Items) != 1 {
+		t.Errorf("Lesson should have 1 item, got %d", len(course.Course.Lessons[1].Items))
+	}
+}
+
+func TestCompleteCourse(t *testing.T) {
+	course := CompleteCourse()
+	if course == nil {
+		t.Fatal("CompleteCourse() returned nil")
+	}
+	if len(course.Course.Lessons) == 0 {
+		t.Error("CompleteCourse() should have lessons")
+	}
+
+	// Verify all expected item types exist
+	itemTypes := make(map[string]bool)
+	for _, lesson := range course.Course.Lessons {
+		for _, item := range lesson.Items {
+			itemTypes[item.Type] = true
+		}
+	}
+
+	expectedTypes := []string{"text", "list", "divider", "multimedia", "knowledgeCheck", "interactive", "flashcard", "quote"}
+	for _, et := range expectedTypes {
+		if !itemTypes[et] {
+			t.Errorf("CompleteCourse() should have item type %q", et)
+		}
+	}
+}
+
+func TestLargeCourse(t *testing.T) {
+	tests := []struct {
+		lessons  int
+		expected int
+	}{
+		{1, 2},   // 1 lesson + 1 section
+		{5, 6},   // 5 lessons + 1 section
+		{10, 12}, // 10 lessons + 2 sections
+		{50, 60}, // 50 lessons + 10 sections
+	}
+
+	for _, tt := range tests {
+		course := LargeCourse(tt.lessons)
+		if course == nil {
+			t.Fatalf("LargeCourse(%d) returned nil", tt.lessons)
+		}
+		if len(course.Course.Lessons) != tt.expected {
+			t.Errorf("LargeCourse(%d) should have %d lessons+sections, got %d",
+				tt.lessons, tt.expected, len(course.Course.Lessons))
+		}
+	}
+}
+
+func TestTextItem(t *testing.T) {
+	item := TextItem("Test Heading", "<p>Test paragraph</p>")
+	if item.Type != "text" {
+		t.Errorf("TextItem Type should be 'text', got %q", item.Type)
+	}
+	if len(item.Items) != 1 {
+		t.Fatalf("TextItem should have 1 sub-item, got %d", len(item.Items))
+	}
+	if item.Items[0].Heading != "Test Heading" {
+		t.Errorf("TextItem heading mismatch: got %q", item.Items[0].Heading)
+	}
+}
+
+func TestListItem(t *testing.T) {
+	item := ListItem("Item 1", "Item 2", "Item 3")
+	if item.Type != "list" {
+		t.Errorf("ListItem Type should be 'list', got %q", item.Type)
+	}
+	if len(item.Items) != 3 {
+		t.Errorf("ListItem should have 3 sub-items, got %d", len(item.Items))
+	}
+}
+
+func TestKnowledgeCheckItem(t *testing.T) {
+	answers := []models.Answer{
+		{Title: "A", Correct: false},
+		{Title: "B", Correct: true},
+	}
+	item := KnowledgeCheckItem("Test question?", answers)
+	if item.Type != "knowledgeCheck" {
+		t.Errorf("KnowledgeCheckItem Type should be 'knowledgeCheck', got %q", item.Type)
+	}
+	if len(item.Items) != 1 {
+		t.Fatalf("KnowledgeCheckItem should have 1 sub-item, got %d", len(item.Items))
+	}
+	if len(item.Items[0].Answers) != 2 {
+		t.Errorf("KnowledgeCheckItem should have 2 answers, got %d", len(item.Items[0].Answers))
+	}
+}
+
+func TestMediaItem(t *testing.T) {
+	tests := []struct {
+		name      string
+		mediaType string
+		hasVideo  bool
+		hasImage  bool
+	}{
+		{"video", "video", true, false},
+		{"image", "image", false, true},
+		{"unknown", "unknown", false, false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			item := MediaItem(tt.mediaType, "https://example.com/media")
+			if item.Type != "multimedia" {
+				t.Errorf("MediaItem Type should be 'multimedia', got %q", item.Type)
+			}
+			if len(item.Items) != 1 {
+				t.Fatalf("MediaItem should have 1 sub-item, got %d", len(item.Items))
+			}
+			if tt.hasVideo && item.Items[0].Media.Video == nil {
+				t.Error("Expected video media to be set")
+			}
+			if tt.hasImage && item.Items[0].Media.Image == nil {
+				t.Error("Expected image media to be set")
+			}
+		})
+	}
+}
+
+func TestInteractiveItem(t *testing.T) {
+	item := InteractiveItem("Interactive Title")
+	if item.Type != "interactive" {
+		t.Errorf("InteractiveItem Type should be 'interactive', got %q", item.Type)
+	}
+}
+
+func TestDividerItem(t *testing.T) {
+	item := DividerItem()
+	if item.Type != "divider" {
+		t.Errorf("DividerItem Type should be 'divider', got %q", item.Type)
+	}
+}
+
+func TestFlipCardItem(t *testing.T) {
+	item := FlipCardItem("Front text", "Back text")
+	if item.Type != "flashcard" {
+		t.Errorf("FlipCardItem Type should be 'flashcard', got %q", item.Type)
+	}
+	if len(item.Items) != 1 {
+		t.Fatalf("FlipCardItem should have 1 sub-item, got %d", len(item.Items))
+	}
+	if item.Items[0].Front == nil || item.Items[0].Back == nil {
+		t.Error("FlipCardItem should have Front and Back set")
+	}
+}
+
+func TestQuoteItem(t *testing.T) {
+	item := QuoteItem("Test quote", "Test author")
+	if item.Type != "quote" {
+		t.Errorf("QuoteItem Type should be 'quote', got %q", item.Type)
+	}
+}
+
+func TestImageItem(t *testing.T) {
+	item := ImageItem("https://example.com/img.jpg", "Image caption")
+	if item.Type != "image" {
+		t.Errorf("ImageItem Type should be 'image', got %q", item.Type)
+	}
+	if len(item.Items) != 1 || item.Items[0].Media == nil || item.Items[0].Media.Image == nil {
+		t.Error("ImageItem should have image media set")
+	}
+}
+
+func TestVideoItem(t *testing.T) {
+	item := VideoItem("https://example.com/video.mp4", 120, "Video caption")
+	if item.Type != "video" {
+		t.Errorf("VideoItem Type should be 'video', got %q", item.Type)
+	}
+	if len(item.Items) != 1 || item.Items[0].Media == nil || item.Items[0].Media.Video == nil {
+		t.Error("VideoItem should have video media set")
+	}
+	if item.Items[0].Media.Video.Duration != 120 {
+		t.Errorf("VideoItem duration should be 120, got %d", item.Items[0].Media.Video.Duration)
+	}
+}
+
+func TestMatchingItem(t *testing.T) {
+	pairs := map[string]string{
+		"Term 1": "Match 1",
+		"Term 2": "Match 2",
+	}
+	item := MatchingItem(pairs)
+	if item.Type != "matching" {
+		t.Errorf("MatchingItem Type should be 'matching', got %q", item.Type)
+	}
+	if len(item.Items) != 1 {
+		t.Fatalf("MatchingItem should have 1 sub-item, got %d", len(item.Items))
+	}
+	if len(item.Items[0].Answers) != 2 {
+		t.Errorf("MatchingItem should have 2 answers, got %d", len(item.Items[0].Answers))
+	}
+}
+
+func TestEmptyLesson(t *testing.T) {
+	lesson := EmptyLesson("test-id", "Test Title")
+	if lesson.ID != "test-id" {
+		t.Errorf("EmptyLesson ID mismatch: got %q", lesson.ID)
+	}
+	if lesson.Type != "lesson" {
+		t.Errorf("EmptyLesson Type should be 'lesson', got %q", lesson.Type)
+	}
+	if len(lesson.Items) != 0 {
+		t.Errorf("EmptyLesson should have no items, got %d", len(lesson.Items))
+	}
+}
+
+func TestSectionLesson(t *testing.T) {
+	lesson := SectionLesson("section-id", "Section Title")
+	if lesson.Type != "section" {
+		t.Errorf("SectionLesson Type should be 'section', got %q", lesson.Type)
+	}
+}
+
+func TestSampleVariables(t *testing.T) {
+	if len(SampleAnswers) == 0 {
+		t.Error("SampleAnswers should not be empty")
+	}
+	if len(SampleSubItems) == 0 {
+		t.Error("SampleSubItems should not be empty")
+	}
+
+	// Verify one correct answer exists in SampleAnswers
+	hasCorrect := false
+	for _, a := range SampleAnswers {
+		if a.Correct {
+			hasCorrect = true
+			break
+		}
+	}
+	if !hasCorrect {
+		t.Error("SampleAnswers should have at least one correct answer")
+	}
+}

main.go

@@ -7,11 +7,12 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"os/signal"
 	"strings"
+	"syscall"
 
 	"github.com/kjanat/articulate-parser/internal/config"
 	"github.com/kjanat/articulate-parser/internal/exporters"
-	"github.com/kjanat/articulate-parser/internal/interfaces"
 	"github.com/kjanat/articulate-parser/internal/services"
 	"github.com/kjanat/articulate-parser/internal/version"
 )
@@ -26,20 +27,19 @@ func main() {
 // run contains the main application logic and returns an exit code.
 // This function is testable as it doesn't call os.Exit directly.
 func run(args []string) int {
+	// Create context that cancels on interrupt signals (SIGINT, SIGTERM)
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer cancel()
+
 	// Load configuration
 	cfg := config.Load()
 
 	// Dependency injection setup with configuration
-	var logger interfaces.Logger
+	logger := services.NewLoggerFromConfig(cfg)
-	if cfg.LogFormat == "json" {
-		logger = services.NewSlogLogger(cfg.LogLevel)
-	} else {
-		logger = services.NewTextLogger(cfg.LogLevel)
-	}
 
 	htmlCleaner := services.NewHTMLCleaner()
-	parser := services.NewArticulateParser(logger, cfg.BaseURL, cfg.RequestTimeout)
+	parser := services.NewArticulateParser(logger, cfg)
-	exporterFactory := exporters.NewFactory(htmlCleaner)
+	exporterFactory := exporters.NewFactory(htmlCleaner, logger)
 	app := services.NewApp(parser, exporterFactory)
 
 	// Check for version flag
@@ -70,9 +70,9 @@ func run(args []string) int {
 
 	// Determine if source is a URI or file path
 	if isURI(source) {
-		err = app.ProcessCourseFromURI(context.Background(), source, format, output)
+		err = app.ProcessCourseFromURI(ctx, source, format, output)
 	} else {
-		err = app.ProcessCourseFromFile(source, format, output)
+		err = app.ProcessCourseFromFile(ctx, source, format, output)
 	}
 
 	if err != nil {