Initial commit: terminal file browser & markdown viewer

A beautiful TUI for browsing files and reading markdown/code:
- Two-pane layout with file tree and content viewer
- Markdown rendering via Glamour
- Syntax highlighting via Chroma
- Auto-detects light/dark terminal theme
- Arrow key navigation, Esc to go back
- Page Up/Down, Home/End for scrolling

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

filetree/view.go

@@ -0,0 +1,206 @@
+package filetree
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/charmbracelet/lipgloss"
+)
+
+// Styles (will be set from parent)
+var (
+	DirectoryStyle = lipgloss.NewStyle()
+	FileStyle      = lipgloss.NewStyle()
+	SelectedStyle  = lipgloss.NewStyle()
+)
+
+// View renders the file tree
+func (m Model) View(width, height int, focused bool) string {
+	var b strings.Builder
+
+	// Calculate visible range for scrolling
+	visibleHeight := height - 2 // Account for potential padding
+	if visibleHeight < 1 {
+		visibleHeight = 1
+	}
+
+	startIdx := 0
+	if m.Cursor >= visibleHeight {
+		startIdx = m.Cursor - visibleHeight + 1
+	}
+
+	endIdx := startIdx + visibleHeight
+	if endIdx > len(m.Nodes) {
+		endIdx = len(m.Nodes)
+	}
+
+	for i := startIdx; i < endIdx; i++ {
+		node := m.Nodes[i]
+		line := m.renderNode(node, i == m.Cursor, focused)
+
+		// Truncate line if too long
+		if lipgloss.Width(line) > width-2 {
+			line = truncateString(line, width-2)
+		}
+
+		// Pad to width
+		padding := width - 2 - lipgloss.Width(line)
+		if padding > 0 {
+			line += strings.Repeat(" ", padding)
+		}
+
+		b.WriteString(line)
+		if i < endIdx-1 {
+			b.WriteString("\n")
+		}
+	}
+
+	return b.String()
+}
+
+func (m Model) renderNode(node *Node, selected, focused bool) string {
+	// Build the prefix with tree characters
+	prefix := m.buildPrefix(node)
+
+	// Get icon
+	icon := getIcon(node)
+
+	// Format name
+	name := node.Name
+	if node.IsDir {
+		name += "/"
+	}
+
+	line := fmt.Sprintf("%s%s %s", prefix, icon, name)
+
+	// Apply style
+	if selected && focused {
+		return SelectedStyle.Render(line)
+	} else if selected {
+		return lipgloss.NewStyle().Foreground(lipgloss.Color("#666666")).Render(line)
+	} else if node.IsDir {
+		return DirectoryStyle.Render(line)
+	}
+	return FileStyle.Render(line)
+}
+
+func (m Model) buildPrefix(node *Node) string {
+	if node.Level == 0 {
+		return ""
+	}
+
+	// Build prefix by traversing parents
+	prefixParts := make([]string, node.Level)
+
+	current := node
+	for i := node.Level - 1; i >= 0; i-- {
+		parent := current.Parent
+		if parent == nil {
+			prefixParts[i] = "  "
+			continue
+		}
+
+		isLast := true
+		for j, sibling := range parent.Children {
+			if sibling == current {
+				isLast = j == len(parent.Children)-1
+				break
+			}
+		}
+
+		if i == node.Level-1 {
+			if isLast {
+				prefixParts[i] = "└─"
+			} else {
+				prefixParts[i] = "├─"
+			}
+		} else {
+			if isLast {
+				prefixParts[i] = "  "
+			} else {
+				prefixParts[i] = "│ "
+			}
+		}
+
+		current = parent
+	}
+
+	return strings.Join(prefixParts, "")
+}
+
+func getIcon(node *Node) string {
+	if node.IsDir {
+		if node.IsOpen {
+			return "▼"
+		}
+		return "▶"
+	}
+
+	// Minimal icons using Unicode block/geometric characters
+	// Grouped by file type category
+	ext := node.Ext()
+
+	// Documents
+	docs := map[string]bool{".md": true, ".markdown": true, ".txt": true, ".pdf": true, ".doc": true, ".docx": true}
+	if docs[ext] {
+		return "◔"
+	}
+
+	// Code files
+	code := map[string]bool{
+		".go": true, ".py": true, ".js": true, ".ts": true, ".jsx": true, ".tsx": true,
+		".rs": true, ".c": true, ".cpp": true, ".h": true, ".hpp": true,
+		".java": true, ".rb": true, ".php": true, ".swift": true, ".kt": true,
+		".scala": true, ".ex": true, ".exs": true, ".clj": true, ".zig": true,
+		".nim": true, ".lua": true, ".vim": true, ".el": true,
+	}
+	if code[ext] {
+		return "◇"
+	}
+
+	// Shell/scripts
+	shell := map[string]bool{".sh": true, ".bash": true, ".zsh": true, ".fish": true}
+	if shell[ext] {
+		return "▷"
+	}
+
+	// Data/config
+	data := map[string]bool{
+		".json": true, ".yaml": true, ".yml": true, ".toml": true,
+		".xml": true, ".csv": true, ".sql": true, ".env": true,
+	}
+	if data[ext] {
+		return "◫"
+	}
+
+	// Web
+	web := map[string]bool{".html": true, ".css": true, ".scss": true, ".sass": true, ".less": true}
+	if web[ext] {
+		return "◈"
+	}
+
+	// Images
+	images := map[string]bool{".png": true, ".jpg": true, ".jpeg": true, ".gif": true, ".svg": true, ".webp": true}
+	if images[ext] {
+		return "◐"
+	}
+
+	// Default
+	return "○"
+}
+
+func truncateString(s string, maxWidth int) string {
+	if lipgloss.Width(s) <= maxWidth {
+		return s
+	}
+
+	// Simple truncation - could be improved for unicode
+	runes := []rune(s)
+	for i := len(runes) - 1; i >= 0; i-- {
+		truncated := string(runes[:i]) + "…"
+		if lipgloss.Width(truncated) <= maxWidth {
+			return truncated
+		}
+	}
+	return "…"
+}