refactor: extract base exporter, add sentinel errors, document unused fields

internal/apperrors/errors.go

@@ -0,0 +1,28 @@
+// Package apperrors provides sentinel errors for the articulate-parser application.
+package apperrors
+
+import "errors"
+
+// Export errors.
+var (
+	// ErrUnsupportedFormat is returned when an unknown export format is requested.
+	ErrUnsupportedFormat = errors.New("unsupported export format")
+)
+
+// URI parsing errors.
+var (
+	// ErrInvalidURI is returned when a URI cannot be parsed.
+	ErrInvalidURI = errors.New("invalid URI")
+
+	// ErrInvalidDomain is returned when the URI domain is not an Articulate Rise domain.
+	ErrInvalidDomain = errors.New("invalid domain for Articulate Rise URI")
+
+	// ErrNoShareID is returned when a share ID cannot be extracted from the URI.
+	ErrNoShareID = errors.New("could not extract share ID from URI")
+)
+
+// Operation errors.
+var (
+	// ErrOperationCanceled is returned when an operation is canceled via context.
+	ErrOperationCanceled = errors.New("operation canceled")
+)

internal/apperrors/errors_test.go

@@ -0,0 +1,50 @@
+package apperrors
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+)
+
+func TestSentinelErrors_Unwrap(t *testing.T) {
+	tests := []struct {
+		name     string
+		sentinel error
+		wrapped  error
+	}{
+		{"ErrUnsupportedFormat", ErrUnsupportedFormat, fmt.Errorf("%w: xyz", ErrUnsupportedFormat)},
+		{"ErrInvalidURI", ErrInvalidURI, fmt.Errorf("%w: bad", ErrInvalidURI)},
+		{"ErrInvalidDomain", ErrInvalidDomain, fmt.Errorf("%w: evil.com", ErrInvalidDomain)},
+		{"ErrNoShareID", ErrNoShareID, fmt.Errorf("%w: no match", ErrNoShareID)},
+		{"ErrOperationCanceled", ErrOperationCanceled, fmt.Errorf("%w: ctx done", ErrOperationCanceled)},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if !errors.Is(tt.wrapped, tt.sentinel) {
+				t.Errorf("errors.Is(%v, %v) = false, want true", tt.wrapped, tt.sentinel)
+			}
+		})
+	}
+}
+
+func TestSentinelErrors_Message(t *testing.T) {
+	tests := []struct {
+		err      error
+		expected string
+	}{
+		{ErrUnsupportedFormat, "unsupported export format"},
+		{ErrInvalidURI, "invalid URI"},
+		{ErrInvalidDomain, "invalid domain for Articulate Rise URI"},
+		{ErrNoShareID, "could not extract share ID from URI"},
+		{ErrOperationCanceled, "operation canceled"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.expected, func(t *testing.T) {
+			if tt.err.Error() != tt.expected {
+				t.Errorf("got %q, want %q", tt.err.Error(), tt.expected)
+			}
+		})
+	}
+}

internal/exporters/base.go

@@ -0,0 +1,20 @@
+package exporters
+
+import "github.com/kjanat/articulate-parser/internal/interfaces"
+
+// baseExporter contains common fields shared by all exporter implementations.
+// Embed this struct in concrete exporters to inherit HTMLCleaner and Logger.
+type baseExporter struct {
+	// htmlCleaner is used to convert HTML content to plain text.
+	htmlCleaner interfaces.HTMLCleaner
+	// logger is used for logging warnings and errors.
+	logger interfaces.Logger
+}
+
+// newBaseExporter creates a new baseExporter with the given dependencies.
+func newBaseExporter(htmlCleaner interfaces.HTMLCleaner, logger interfaces.Logger) baseExporter {
+	return baseExporter{
+		htmlCleaner: htmlCleaner,
+		logger:      logger,
+	}
+}

internal/exporters/docx.go

@@ -26,10 +26,7 @@ const (
 // It converts Articulate Rise course data into a Microsoft Word document
 // using the go-docx package.
 type DocxExporter struct {
-	// htmlCleaner is used to convert HTML content to plain text
-	htmlCleaner interfaces.HTMLCleaner
-	// logger is used for logging warnings and errors
-	logger interfaces.Logger
+	baseExporter
 }
 
 // NewDocxExporter creates a new DocxExporter instance.
@@ -43,8 +40,7 @@ type DocxExporter struct {
 //   - An implementation of the Exporter interface for DOCX format
 func NewDocxExporter(htmlCleaner interfaces.HTMLCleaner, logger interfaces.Logger) interfaces.Exporter {
 	return &DocxExporter{
-		htmlCleaner: htmlCleaner,
-		logger:      logger,
+		baseExporter: newBaseExporter(htmlCleaner, logger),
 	}
 }
 

internal/exporters/factory.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/kjanat/articulate-parser/internal/apperrors"
 	"github.com/kjanat/articulate-parser/internal/interfaces"
 )
 
@@ -56,7 +57,7 @@ func (f *Factory) CreateExporter(format string) (interfaces.Exporter, error) {
 	case FormatHTML, formatAliasHTML:
 		return NewHTMLExporter(f.htmlCleaner, f.logger), nil
 	default:
-		return nil, fmt.Errorf("unsupported export format: %s", format)
+		return nil, fmt.Errorf("%w: %s", apperrors.ErrUnsupportedFormat, format)
 	}
 }
 

internal/exporters/html.go

@@ -20,12 +20,9 @@ var htmlTemplate string
 // HTMLExporter implements the Exporter interface for HTML format.
 // It converts Articulate Rise course data into a structured HTML document using templates.
 type HTMLExporter struct {
-	// htmlCleaner is used to convert HTML content to plain text when needed
-	htmlCleaner interfaces.HTMLCleaner
-	// tmpl holds the parsed HTML template
+	baseExporter
+	// 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.
@@ -52,9 +49,8 @@ func NewHTMLExporter(htmlCleaner interfaces.HTMLCleaner, logger interfaces.Logge
 	tmpl := template.Must(template.New("html").Funcs(funcMap).Parse(htmlTemplate))
 
 	return &HTMLExporter{
-		htmlCleaner: htmlCleaner,
+		baseExporter: newBaseExporter(htmlCleaner, logger),
 		tmpl:         tmpl,
-		logger:      logger,
 	}
 }
 

internal/exporters/markdown.go

@@ -16,10 +16,7 @@ import (
 // MarkdownExporter implements the Exporter interface for Markdown format.
 // It converts Articulate Rise course data into a structured Markdown document.
 type MarkdownExporter struct {
-	// htmlCleaner is used to convert HTML content to plain text
-	htmlCleaner interfaces.HTMLCleaner
-	// logger is used for logging warnings and errors
-	logger interfaces.Logger
+	baseExporter
 }
 
 // NewMarkdownExporter creates a new MarkdownExporter instance.
@@ -33,8 +30,7 @@ type MarkdownExporter struct {
 //   - An implementation of the Exporter interface for Markdown format
 func NewMarkdownExporter(htmlCleaner interfaces.HTMLCleaner, logger interfaces.Logger) interfaces.Exporter {
 	return &MarkdownExporter{
-		htmlCleaner: htmlCleaner,
-		logger:      logger,
+		baseExporter: newBaseExporter(htmlCleaner, logger),
 	}
 }
 

internal/exporters/markdown_test.go

@@ -124,7 +124,7 @@ func TestMarkdownExporter_Export_InvalidPath(t *testing.T) {
 // TestMarkdownExporter_ProcessTextItem tests the processTextItem method.
 func TestMarkdownExporter_ProcessTextItem(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	item := models.Item{
@@ -153,7 +153,7 @@ func TestMarkdownExporter_ProcessTextItem(t *testing.T) {
 // TestMarkdownExporter_ProcessListItem tests the processListItem method.
 func TestMarkdownExporter_ProcessListItem(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	item := models.Item{
@@ -178,7 +178,7 @@ func TestMarkdownExporter_ProcessListItem(t *testing.T) {
 // TestMarkdownExporter_ProcessMultimediaItem tests the processMultimediaItem method.
 func TestMarkdownExporter_ProcessMultimediaItem(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	item := models.Item{
@@ -217,7 +217,7 @@ func TestMarkdownExporter_ProcessMultimediaItem(t *testing.T) {
 // TestMarkdownExporter_ProcessImageItem tests the processImageItem method.
 func TestMarkdownExporter_ProcessImageItem(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	item := models.Item{
@@ -252,7 +252,7 @@ func TestMarkdownExporter_ProcessImageItem(t *testing.T) {
 // TestMarkdownExporter_ProcessKnowledgeCheckItem tests the processKnowledgeCheckItem method.
 func TestMarkdownExporter_ProcessKnowledgeCheckItem(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	item := models.Item{
@@ -294,7 +294,7 @@ func TestMarkdownExporter_ProcessKnowledgeCheckItem(t *testing.T) {
 // TestMarkdownExporter_ProcessInteractiveItem tests the processInteractiveItem method.
 func TestMarkdownExporter_ProcessInteractiveItem(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	item := models.Item{
@@ -319,7 +319,7 @@ func TestMarkdownExporter_ProcessInteractiveItem(t *testing.T) {
 // TestMarkdownExporter_ProcessDividerItem tests the processDividerItem method.
 func TestMarkdownExporter_ProcessDividerItem(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	exporter.processDividerItem(&buf)
@@ -335,7 +335,7 @@ func TestMarkdownExporter_ProcessDividerItem(t *testing.T) {
 // TestMarkdownExporter_ProcessUnknownItem tests the processUnknownItem method.
 func TestMarkdownExporter_ProcessUnknownItem(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	item := models.Item{
@@ -366,7 +366,7 @@ func TestMarkdownExporter_ProcessUnknownItem(t *testing.T) {
 // TestMarkdownExporter_ProcessVideoMedia tests the processVideoMedia method.
 func TestMarkdownExporter_ProcessVideoMedia(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	media := &models.Media{
@@ -391,7 +391,7 @@ func TestMarkdownExporter_ProcessVideoMedia(t *testing.T) {
 // TestMarkdownExporter_ProcessImageMedia tests the processImageMedia method.
 func TestMarkdownExporter_ProcessImageMedia(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	media := &models.Media{
@@ -413,7 +413,7 @@ func TestMarkdownExporter_ProcessImageMedia(t *testing.T) {
 // TestMarkdownExporter_ProcessAnswers tests the processAnswers method.
 func TestMarkdownExporter_ProcessAnswers(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	var buf bytes.Buffer
 	answers := []models.Answer{
@@ -443,7 +443,7 @@ func TestMarkdownExporter_ProcessAnswers(t *testing.T) {
 // TestMarkdownExporter_ProcessItemToMarkdown_AllTypes tests all item types.
 func TestMarkdownExporter_ProcessItemToMarkdown_AllTypes(t *testing.T) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	tests := []struct {
 		name         string
@@ -673,7 +673,7 @@ func BenchmarkMarkdownExporter_Export(b *testing.B) {
 // BenchmarkMarkdownExporter_ProcessTextItem benchmarks the processTextItem method.
 func BenchmarkMarkdownExporter_ProcessTextItem(b *testing.B) {
 	htmlCleaner := services.NewHTMLCleaner()
-	exporter := &MarkdownExporter{htmlCleaner: htmlCleaner}
+	exporter := &MarkdownExporter{baseExporter: baseExporter{htmlCleaner: htmlCleaner}}
 
 	item := models.Item{
 		Type: "text",

internal/models/course.go

@@ -47,6 +47,8 @@ type ExportSettings struct {
 
 // LabelSet contains customized labels used throughout the course.
 // This allows course creators to modify standard terminology.
+//
+// NOTE: Currently parsed but not used in export logic.
 type LabelSet struct {
 	// ID is the unique identifier for this label set
 	ID string `json:"id"`

internal/models/lesson.go

@@ -15,7 +15,8 @@ type Lesson struct {
 	Icon string `json:"icon"`
 	// Items is an ordered array of content items within the lesson
 	Items []Item `json:"items"`
-	// Position stores the ordering information for the lesson
+	// Position stores the ordering information for the lesson.
+	// NOTE: Currently parsed but not used in export logic.
 	Position any `json:"position"`
 	// Ready indicates whether the lesson is marked as complete
 	Ready bool `json:"ready"`
@@ -38,9 +39,11 @@ type Item struct {
 	Variant string `json:"variant"`
 	// Items contains the actual content elements (sub-items) of this item
 	Items []SubItem `json:"items"`
-	// Settings contains configuration options specific to this item type
+	// Settings contains configuration options specific to this item type.
+	// NOTE: Currently parsed but not used in export logic.
 	Settings any `json:"settings"`
-	// Data contains additional structured data for the item
+	// Data contains additional structured data for the item.
+	// NOTE: Currently parsed but not used in export logic.
 	Data any `json:"data"`
 	// Media contains any associated media for the item
 	Media *Media `json:"media,omitempty"`

internal/services/app.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/kjanat/articulate-parser/internal/apperrors"
 	"github.com/kjanat/articulate-parser/internal/interfaces"
 	"github.com/kjanat/articulate-parser/internal/models"
 )
@@ -37,7 +38,7 @@ func NewApp(parser interfaces.CourseParser, exporterFactory interfaces.ExporterF
 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)
+		return fmt.Errorf("%w: %w", apperrors.ErrOperationCanceled, err)
 	}
 
 	course, err := a.parser.LoadCourseFromFile(filePath)
@@ -68,7 +69,7 @@ func (a *App) ProcessCourseFromURI(ctx context.Context, uri, format, outputPath
 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)
+		return fmt.Errorf("%w: %w", apperrors.ErrOperationCanceled, err)
 	}
 
 	exporter, err := a.exporterFactory.CreateExporter(format)

internal/services/parser.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"regexp"
 
+	"github.com/kjanat/articulate-parser/internal/apperrors"
 	"github.com/kjanat/articulate-parser/internal/config"
 	"github.com/kjanat/articulate-parser/internal/interfaces"
 	"github.com/kjanat/articulate-parser/internal/models"
@@ -127,17 +128,17 @@ func (p *ArticulateParser) extractShareID(uri string) (string, error) {
 	// Parse the URL to validate the domain
 	parsedURL, err := url.Parse(uri)
 	if err != nil {
-		return "", fmt.Errorf("invalid URI: %s", uri)
+		return "", fmt.Errorf("%w: %s", apperrors.ErrInvalidURI, uri)
 	}
 
 	// Validate that it's an Articulate Rise domain
 	if parsedURL.Host != riseHost {
-		return "", fmt.Errorf("invalid domain for Articulate Rise URI: %s", parsedURL.Host)
+		return "", fmt.Errorf("%w: %s", apperrors.ErrInvalidDomain, parsedURL.Host)
 	}
 
 	matches := shareIDRegex.FindStringSubmatch(uri)
 	if len(matches) < 2 {
-		return "", fmt.Errorf("could not extract share ID from URI: %s", uri)
+		return "", fmt.Errorf("%w: %s", apperrors.ErrNoShareID, uri)
 	}
 	return matches[1], nil
 }