Revert "feat: enhance split diff viewer (#40)"

This reverts commit c2b20c1.

Author: bakayu

internal/tui/update.go

@@ -499,10 +499,6 @@ func (m *Model) updateMainPanel() tea.Cmd {
 		if content == "" {
 			content = "Select an item to see details."
 		}
-		// Apply adaptive visual styling: split-view for wide terminals, unified for narrow ones
-		// Calculate right panel width (approximately 65% of total width minus borders)
-		rightPanelWidth := int(float64(m.width)*(1-leftPanelWidthRatio)) - borderWidth - 2
-		content = renderAdaptiveDiffView(content, rightPanelWidth, m.theme)
 		return mainContentUpdatedMsg{content: content}
 	}
 }

internal/tui/view.go

@@ -19,274 +19,6 @@ func stripAnsi(str string) string {
 	return ansiRegex.ReplaceAllString(str, "")
 }
 
-// diffLineType represents the type of a diff line.
-type diffLineType int
-
-const (
-	lineTypeContext diffLineType = iota
-	lineTypeAdded
-	lineTypeRemoved
-	lineTypeHeader
-	lineTypeFileHeader
-	lineTypeHunkHeader
-)
-
-// diffRow represents a single row in the structured diff.
-type diffRow struct {
-	lineType diffLineType
-	oldLine  string
-	newLine  string
-	rawLine  string // Original line for fallback
-}
-
-// parseDiffStructure transforms a unified diff into structured rows suitable for split-view rendering.
-func parseDiffStructure(content string) []diffRow {
-	lines := strings.Split(content, "\n")
-	var rows []diffRow
-
-	for _, line := range lines {
-		if len(line) == 0 {
-			rows = append(rows, diffRow{lineType: lineTypeContext, oldLine: "", newLine: "", rawLine: ""})
-			continue
-		}
-
-		// Always strip ANSI codes first before any parsing logic
-		cleanedLine := stripAnsi(line)
-
-		if len(cleanedLine) == 0 {
-			rows = append(rows, diffRow{lineType: lineTypeContext, oldLine: "", newLine: "", rawLine: line})
-			continue
-		}
-
-		firstChar := cleanedLine[0]
-
-		// File headers
-		if strings.HasPrefix(cleanedLine, "diff --git") ||
-			strings.HasPrefix(cleanedLine, "index ") {
-			rows = append(rows, diffRow{lineType: lineTypeFileHeader, rawLine: line})
-			continue
-		}
-
-		// --- and +++ headers (but not as content)
-		if strings.HasPrefix(cleanedLine, "---") && len(cleanedLine) > 3 && cleanedLine[3] == ' ' {
-			rows = append(rows, diffRow{lineType: lineTypeFileHeader, rawLine: line})
-			continue
-		}
-		if strings.HasPrefix(cleanedLine, "+++") && len(cleanedLine) > 3 && cleanedLine[3] == ' ' {
-			rows = append(rows, diffRow{lineType: lineTypeFileHeader, rawLine: line})
-			continue
-		}
-
-		// Hunk headers
-		if strings.HasPrefix(cleanedLine, "@@") {
-			rows = append(rows, diffRow{lineType: lineTypeHunkHeader, rawLine: line})
-			continue
-		}
-
-		// Newline marker
-		if strings.HasPrefix(cleanedLine, "\\ No newline") {
-			rows = append(rows, diffRow{lineType: lineTypeFileHeader, rawLine: line})
-			continue
-		}
-
-		// Added lines (but not +++ headers)
-		if firstChar == '+' {
-			// Store content without the "+" prefix for rendering
-			contentWithoutPrefix := cleanedLine[1:]
-			rows = append(rows, diffRow{lineType: lineTypeAdded, newLine: contentWithoutPrefix, rawLine: line})
-			continue
-		}
-
-		// Removed lines (but not --- headers)
-		if firstChar == '-' {
-			// Store content without the "-" prefix for rendering
-			contentWithoutPrefix := cleanedLine[1:]
-			rows = append(rows, diffRow{lineType: lineTypeRemoved, oldLine: contentWithoutPrefix, rawLine: line})
-			continue
-		}
-
-		// Context lines (start with space)
-		if firstChar == ' ' {
-			// Store content without the space prefix
-			contentWithoutSpace := cleanedLine[1:]
-			rows = append(rows, diffRow{lineType: lineTypeContext, oldLine: contentWithoutSpace, newLine: contentWithoutSpace, rawLine: line})
-			continue
-		}
-
-		// Fallback for any other lines
-		rows = append(rows, diffRow{lineType: lineTypeContext, oldLine: cleanedLine, newLine: cleanedLine, rawLine: line})
-	}
-
-	return rows
-}
-
-// renderSplitDiffView renders a GitHub-style split-view diff.
-// columnWidth should be roughly half the viewport width minus some padding.
-func renderSplitDiffView(rows []diffRow, columnWidth int, theme Theme) string {
-	if columnWidth < 20 {
-		// Column too narrow for split view
-		return ""
-	}
-
-	// Create themed styles
-	headerStyle := lipgloss.NewStyle().Bold(true)
-
-	// Use theme's added/removed colors for backgrounds
-	addedStyle := theme.GitStaged.
-		Width(columnWidth).
-		Padding(0, 1)
-
-	removedStyle := theme.GitUnstaged.
-		Width(columnWidth).
-		Padding(0, 1)
-
-	contextStyle := lipgloss.NewStyle().
-		Width(columnWidth).
-		Padding(0, 1)
-
-	emptyStyle := lipgloss.NewStyle().
-		Width(columnWidth).
-		Padding(0, 1)
-
-	var renderedRows []string
-
-	for _, row := range rows {
-		var left, right string
-
-		switch row.lineType {
-		case lineTypeFileHeader:
-			// File headers span full width
-			fullLine := headerStyle.Width(columnWidth * 2).Render(row.rawLine)
-			renderedRows = append(renderedRows, fullLine)
-
-		case lineTypeHunkHeader:
-			// Hunk headers span full width
-			fullLine := headerStyle.Width(columnWidth * 2).Render(row.rawLine)
-			renderedRows = append(renderedRows, fullLine)
-
-		case lineTypeRemoved:
-			// Removed line on left (oldLine is already without "-" prefix), empty on right
-			left = removedStyle.Render(row.oldLine)
-			right = emptyStyle.Render("")
-			renderedRows = append(renderedRows, lipgloss.JoinHorizontal(lipgloss.Top, left, right))
-
-		case lineTypeAdded:
-			// Empty on left, added line on right (newLine is already without "+" prefix)
-			left = emptyStyle.Render("")
-			right = addedStyle.Render(row.newLine)
-			renderedRows = append(renderedRows, lipgloss.JoinHorizontal(lipgloss.Top, left, right))
-
-		case lineTypeContext:
-			// Context lines on both sides (oldLine and newLine are already without space prefix and identical)
-			left = contextStyle.Render(row.oldLine)
-			right = contextStyle.Render(row.newLine)
-			renderedRows = append(renderedRows, lipgloss.JoinHorizontal(lipgloss.Top, left, right))
-
-		default:
-			// Fallback: show on both sides
-			left = contextStyle.Render(row.oldLine)
-			right = contextStyle.Render(row.newLine)
-			renderedRows = append(renderedRows, lipgloss.JoinHorizontal(lipgloss.Top, left, right))
-		}
-	}
-
-	return strings.Join(renderedRows, "\n")
-}
-
-// renderAdaptiveDiffView returns the appropriately formatted diff based on viewport width.
-// If width >= 80, uses split-view; otherwise falls back to unified diff.
-func renderAdaptiveDiffView(content string, width int, theme Theme) string {
-	// Quick check: if content doesn't look like a diff, return as-is
-	if !strings.Contains(content, "diff --git") && !strings.Contains(content, "@@") {
-		return content
-	}
-
-	// Threshold for split-view: 80 chars available
-	const splitViewThreshold = 80
-
-	if width >= splitViewThreshold && width > 60 {
-		// Use split-view mode
-		columnWidth := (width - 1) / 2
-		rows := parseDiffStructure(content)
-		splitView := renderSplitDiffView(rows, columnWidth, theme)
-		if splitView != "" {
-			return splitView
-		}
-	}
-
-	// Fallback to unified diff styling
-	return styleDiffContent(content, theme)
-}
-
-// styleDiffContent applies visual highlighting to diff lines for better readability.
-// It detects and styles:
-// - Diff headers (diff --git, index, ---, +++, @@) with bold magenta
-// - Added lines (+) with green
-// - Removed lines (-) with red
-// - Context lines with normal or dimmed styling
-// It also adds visual separation before hunk markers for improved scanability.
-func styleDiffContent(content string, theme Theme) string {
-	// Quick check: if content doesn't look like a diff, return as-is
-	if !strings.Contains(content, "diff --git") && !strings.Contains(content, "@@") {
-		return content
-	}
-
-	lines := strings.Split(content, "\n")
-
-	// Create styles for different diff elements
-	headerStyle := lipgloss.NewStyle().Bold(true)
-
-	// Use theme colors for added/removed lines (aligns with git status colors)
-	addedStyle := theme.GitStaged     // Green
-	removedStyle := theme.GitUnstaged // Red
-
-	var result []string
-	for i, line := range lines {
-		if len(line) == 0 {
-			result = append(result, line)
-			continue
-		}
-
-		// Strip ANSI codes before checking prefixes
-		cleanedLine := stripAnsi(line)
-
-		if len(cleanedLine) == 0 {
-			result = append(result, line)
-			continue
-		}
-
-		firstChar := cleanedLine[0]
-
-		// Add spacing before hunk markers (visual separation of hunks)
-		if strings.HasPrefix(cleanedLine, "@@") && i > 0 && result[len(result)-1] != "" {
-			result = append(result, "") // Add blank line for visual separation
-		}
-
-		// Handle diff headers
-		if strings.HasPrefix(cleanedLine, "diff --git") ||
-			strings.HasPrefix(cleanedLine, "index ") ||
-			strings.HasPrefix(cleanedLine, "---") ||
-			strings.HasPrefix(cleanedLine, "+++") ||
-			strings.HasPrefix(cleanedLine, "@@") {
-			result = append(result, headerStyle.Render(line))
-		} else if firstChar == '+' && !strings.HasPrefix(cleanedLine, "+++") {
-			// Added line: apply green styling
-			result = append(result, addedStyle.Render(line))
-		} else if firstChar == '-' && !strings.HasPrefix(cleanedLine, "---") {
-			// Removed line: apply red styling
-			result = append(result, removedStyle.Render(line))
-		} else if firstChar == '\\' {
-			// "\ No newline at end of file" marker - treat as metadata
-			result = append(result, headerStyle.Render(line))
-		} else {
-			// Context line (starts with space) - keep as-is
-			result = append(result, line)
-		}
-	}
-
-	return strings.Join(result, "\n")
-}
-
 // View is the main render function for the application.
 func (m Model) View() string {