feat: add support for Google Docs tabs

cmd/gdocs-cli/main.go

@@ -81,6 +81,9 @@ func run(docURL, credPath string) error {
 		return fmt.Errorf("invalid URL: %w", err)
 	}
 
+	// Extract tab ID from URL (may be empty)
+	tabID := gdocs.ExtractTabID(docURL)
+
 	// Create authenticator
 	authenticator, err := auth.NewAuthenticator(credPath)
 	if err != nil {
@@ -107,7 +110,26 @@ func run(docURL, credPath string) error {
 	}
 
 	// Convert to markdown
-	converter := markdown.NewConverter(doc)
+	var converter *markdown.Converter
+	if tabID != "" {
+		// Find the specific tab
+		tab := gdocs.FindTab(doc, tabID)
+		if tab == nil {
+			return fmt.Errorf("tab '%s' not found in document", tabID)
+		}
+		if tab.DocumentTab == nil || tab.DocumentTab.Body == nil {
+			return fmt.Errorf("tab '%s' has no document content", tabID)
+		}
+		tabTitle := tabID
+		if tab.TabProperties != nil {
+			tabTitle = tab.TabProperties.Title
+		}
+		log.Printf("Using tab: %s", tabTitle)
+		converter = markdown.NewConverterFromTab(doc, tab)
+	} else {
+		converter = markdown.NewConverter(doc)
+	}
+
 	markdownOutput, err := converter.Convert()
 	if err != nil {
 		return fmt.Errorf("conversion failed: %w", err)

internal/gdocs/client.go

@@ -24,12 +24,55 @@ func NewClient(ctx context.Context, httpClient *http.Client) (*Client, error) {
 	return &Client{service: service}, nil
 }
 
-// FetchDocument retrieves a Google Docs document by its ID.
+// FetchDocument retrieves a Google Docs document by its ID with all tabs included.
 func (c *Client) FetchDocument(docID string) (*docs.Document, error) {
-	doc, err := c.service.Documents.Get(docID).Do()
+	doc, err := c.service.Documents.Get(docID).IncludeTabsContent(true).Do()
 	if err != nil {
 		return nil, fmt.Errorf("unable to retrieve document: %w\n\nThis could mean:\n1. The document is private and you don't have permission\n2. The document doesn't exist\n3. The document ID is incorrect", err)
 	}
 
 	return doc, nil
 }
+
+// FindTab searches for a tab by ID in the document's tab tree.
+// Returns nil if the tab is not found.
+func FindTab(doc *docs.Document, tabID string) *docs.Tab {
+	if doc == nil || doc.Tabs == nil {
+		return nil
+	}
+
+	for _, tab := range doc.Tabs {
+		if found := findTabRecursive(tab, tabID); found != nil {
+			return found
+		}
+	}
+
+	return nil
+}
+
+// findTabRecursive recursively searches for a tab by ID.
+func findTabRecursive(tab *docs.Tab, tabID string) *docs.Tab {
+	if tab == nil {
+		return nil
+	}
+	if tab.TabProperties != nil && tab.TabProperties.TabId == tabID {
+		return tab
+	}
+
+	for _, child := range tab.ChildTabs {
+		if found := findTabRecursive(child, tabID); found != nil {
+			return found
+		}
+	}
+
+	return nil
+}
+
+// GetFirstTab returns the first tab in the document.
+// Returns nil if the document has no tabs.
+func GetFirstTab(doc *docs.Document) *docs.Tab {
+	if doc == nil || doc.Tabs == nil || len(doc.Tabs) == 0 {
+		return nil
+	}
+	return doc.Tabs[0]
+}

internal/gdocs/client_test.go

@@ -0,0 +1,184 @@
+package gdocs
+
+import (
+	"testing"
+
+	"google.golang.org/api/docs/v1"
+)
+
+func TestFindTab(t *testing.T) {
+	// Create a mock document with nested tabs
+	doc := &docs.Document{
+		Title: "Test Document",
+		Tabs: []*docs.Tab{
+			{
+				TabProperties: &docs.TabProperties{
+					TabId: "t.tab1",
+					Title: "Tab 1",
+				},
+				DocumentTab: &docs.DocumentTab{
+					Body: &docs.Body{},
+				},
+				ChildTabs: []*docs.Tab{
+					{
+						TabProperties: &docs.TabProperties{
+							TabId: "t.tab1child1",
+							Title: "Tab 1 Child 1",
+						},
+						DocumentTab: &docs.DocumentTab{
+							Body: &docs.Body{},
+						},
+					},
+				},
+			},
+			{
+				TabProperties: &docs.TabProperties{
+					TabId: "t.tab2",
+					Title: "Tab 2",
+				},
+				DocumentTab: &docs.DocumentTab{
+					Body: &docs.Body{},
+				},
+			},
+		},
+	}
+
+	tests := []struct {
+		name      string
+		tabID     string
+		wantTitle string
+		wantNil   bool
+	}{
+		{
+			name:      "find top-level tab",
+			tabID:     "t.tab1",
+			wantTitle: "Tab 1",
+			wantNil:   false,
+		},
+		{
+			name:      "find second top-level tab",
+			tabID:     "t.tab2",
+			wantTitle: "Tab 2",
+			wantNil:   false,
+		},
+		{
+			name:      "find nested child tab",
+			tabID:     "t.tab1child1",
+			wantTitle: "Tab 1 Child 1",
+			wantNil:   false,
+		},
+		{
+			name:    "tab not found",
+			tabID:   "t.nonexistent",
+			wantNil: true,
+		},
+		{
+			name:    "empty tab ID",
+			tabID:   "",
+			wantNil: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := FindTab(doc, tt.tabID)
+			if tt.wantNil {
+				if got != nil {
+					t.Errorf("FindTab() = %v, want nil", got)
+				}
+				return
+			}
+			if got == nil {
+				t.Errorf("FindTab() = nil, want tab with title %q", tt.wantTitle)
+				return
+			}
+			if got.TabProperties.Title != tt.wantTitle {
+				t.Errorf("FindTab() title = %q, want %q", got.TabProperties.Title, tt.wantTitle)
+			}
+		})
+	}
+}
+
+func TestFindTab_NilTabs(t *testing.T) {
+	doc := &docs.Document{
+		Title: "Test Document",
+		Tabs:  nil,
+	}
+
+	got := FindTab(doc, "t.any")
+	if got != nil {
+		t.Errorf("FindTab() with nil tabs = %v, want nil", got)
+	}
+}
+
+func TestFindTab_NilDocument(t *testing.T) {
+	got := FindTab(nil, "t.any")
+	if got != nil {
+		t.Errorf("FindTab() with nil document = %v, want nil", got)
+	}
+}
+
+func TestGetFirstTab_NilDocument(t *testing.T) {
+	got := GetFirstTab(nil)
+	if got != nil {
+		t.Errorf("GetFirstTab() with nil document = %v, want nil", got)
+	}
+}
+
+func TestGetFirstTab(t *testing.T) {
+	tests := []struct {
+		name      string
+		doc       *docs.Document
+		wantTitle string
+		wantNil   bool
+	}{
+		{
+			name: "document with tabs",
+			doc: &docs.Document{
+				Tabs: []*docs.Tab{
+					{
+						TabProperties: &docs.TabProperties{
+							TabId: "t.first",
+							Title: "First Tab",
+						},
+					},
+				},
+			},
+			wantTitle: "First Tab",
+			wantNil:   false,
+		},
+		{
+			name: "document with no tabs",
+			doc: &docs.Document{
+				Tabs: []*docs.Tab{},
+			},
+			wantNil: true,
+		},
+		{
+			name: "document with nil tabs",
+			doc: &docs.Document{
+				Tabs: nil,
+			},
+			wantNil: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetFirstTab(tt.doc)
+			if tt.wantNil {
+				if got != nil {
+					t.Errorf("GetFirstTab() = %v, want nil", got)
+				}
+				return
+			}
+			if got == nil {
+				t.Errorf("GetFirstTab() = nil, want tab with title %q", tt.wantTitle)
+				return
+			}
+			if got.TabProperties.Title != tt.wantTitle {
+				t.Errorf("GetFirstTab() title = %q, want %q", got.TabProperties.Title, tt.wantTitle)
+			}
+		})
+	}
+}

internal/gdocs/url.go

@@ -23,3 +23,19 @@ func ExtractDocumentID(url string) (string, error) {
 
 	return matches[1], nil
 }
+
+// tabIDPattern matches the tab query parameter in Google Docs URLs.
+// Captures the full tab value without assuming a specific format.
+var tabIDPattern = regexp.MustCompile(`[?&]tab=([^&#]+)`)
+
+// ExtractTabID extracts the tab ID from a Google Docs URL if present.
+// Tab IDs appear in URLs as ?tab={TAB_ID} or &tab={TAB_ID}
+// Returns empty string if no tab ID is found.
+func ExtractTabID(url string) string {
+	matches := tabIDPattern.FindStringSubmatch(url)
+	if len(matches) < 2 {
+		return ""
+	}
+
+	return matches[1]
+}

internal/gdocs/url_test.go

@@ -80,3 +80,66 @@ func TestExtractDocumentID(t *testing.T) {
 		})
 	}
 }
+
+func TestExtractTabID(t *testing.T) {
+	tests := []struct {
+		name string
+		url  string
+		want string
+	}{
+		{
+			name: "URL with tab parameter",
+			url:  "https://docs.google.com/document/d/1abc123xyz/edit?tab=t.v63b7x227gkk",
+			want: "t.v63b7x227gkk",
+		},
+		{
+			name: "URL with tab and other params",
+			url:  "https://docs.google.com/document/d/1abc123xyz/edit?usp=sharing&tab=t.abc123",
+			want: "t.abc123",
+		},
+		{
+			name: "URL with tab and heading anchor",
+			url:  "https://docs.google.com/document/d/1abc123xyz/edit?tab=t.v63b7x227gkk#heading=h.ehdxodmabfmp",
+			want: "t.v63b7x227gkk",
+		},
+		{
+			name: "URL with tab parameter with trailing params",
+			url:  "https://docs.google.com/document/d/1abc123xyz/edit?tab=t.abc123&other=value",
+			want: "t.abc123",
+		},
+		{
+			name: "URL with numeric tab ID",
+			url:  "https://docs.google.com/document/d/1abc123xyz/edit?tab=t.0",
+			want: "t.0",
+		},
+		{
+			name: "URL with non-standard tab format",
+			url:  "https://docs.google.com/document/d/1abc123xyz/edit?tab=custom-tab-id",
+			want: "custom-tab-id",
+		},
+		{
+			name: "URL without tab parameter",
+			url:  "https://docs.google.com/document/d/1abc123xyz/edit",
+			want: "",
+		},
+		{
+			name: "URL with only sharing param",
+			url:  "https://docs.google.com/document/d/1abc123xyz/edit?usp=sharing",
+			want: "",
+		},
+		{
+			name: "empty URL",
+			url:  "",
+			want: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ExtractTabID(tt.url)
+			if got != tt.want {
+				t.Errorf("ExtractTabID() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}