Merge pull request #4 from shokinn/codex/implement-phase-3-and-perform-interactive-testing

Add edit mode toggle with entry activation

cmd/hosts/main.go

@@ -1,137 +1,22 @@
 package main
 
 import (
-	"fmt"
 	"log"
-	"strings"
 
 	"hosts-go/internal/core"
+	"hosts-go/internal/tui"
+
+	tea "github.com/charmbracelet/bubbletea"
 )
 
 func main() {
-	fmt.Println("hosts-go - Phase 1: Core Functionality (Parser)")
-	fmt.Println("===============================================")
-
-	// Demonstrate hosts file parsing with sample content
-	sampleHostsContent := `# Sample hosts file content
-127.0.0.1	localhost	# Local loopback
-::1		ip6-localhost	# IPv6 loopback
-192.168.1.100	dev.example.com	www.dev.example.com	api.dev.example.com	# Development server
-# 10.0.0.50	staging.example.com	# Disabled staging server
-203.0.113.10	prod.example.com	# Production server
-
-# Another comment
-::ffff:192.168.1.200	test.example.com	# Test server`
-
-	fmt.Println("Sample hosts file content:")
-	fmt.Println(strings.Repeat("-", 50))
-	fmt.Println(sampleHostsContent)
-	fmt.Println(strings.Repeat("-", 50))
-	fmt.Println()
-
-	// Parse the sample content
-	lines := strings.Split(sampleHostsContent, "\n")
-	hostsFile, warnings, err := core.ParseHostsContent(lines)
+	hostsFile, _, err := core.ParseHostsFile("/etc/hosts")
 	if err != nil {
-		log.Fatalf("Failed to parse hosts content: %v", err)
+		log.Fatalf("failed to parse hosts file: %v", err)
 	}
 
-	// Display parsing results
-	fmt.Printf("✅ Parsing successful!\n")
-	fmt.Printf("   Total entries: %d\n", len(hostsFile.Entries))
-	fmt.Printf("   Active entries: %d\n", len(hostsFile.ActiveEntries()))
-	fmt.Printf("   Standalone comments: %d\n", len(hostsFile.Comments))
-	fmt.Printf("   Warnings: %d\n", len(warnings))
-	fmt.Println()
-
-	// Show warnings if any
-	if len(warnings) > 0 {
-		fmt.Println("Parsing warnings:")
-		for _, warning := range warnings {
-			fmt.Printf("  Line %d: %s\n", warning.Line, warning.Message)
+	p := tea.NewProgram(tui.NewModel(hostsFile))
+	if err := p.Start(); err != nil {
+		log.Fatalf("failed to start TUI: %v", err)
 	}
-		fmt.Println()
-	}
-
-	// Show standalone comments
-	if len(hostsFile.Comments) > 0 {
-		fmt.Println("Standalone comments found:")
-		for i, comment := range hostsFile.Comments {
-			fmt.Printf("%d. %s\n", i+1, comment)
-		}
-		fmt.Println()
-	}
-
-	// Show parsed entries
-	fmt.Println("Parsed entries:")
-	for i, entry := range hostsFile.Entries {
-		status := "✅ Active"
-		if !entry.Active {
-			status = "❌ Disabled"
-		}
-		fmt.Printf("%d. [%s] %s -> %s", i+1, status, entry.IP, entry.Hostname)
-		if len(entry.Aliases) > 0 {
-			fmt.Printf(" (aliases: %s)", strings.Join(entry.Aliases, ", "))
-		}
-		if entry.Comment != "" {
-			fmt.Printf(" # %s", entry.Comment)
-		}
-		fmt.Println()
-	}
-	fmt.Println()
-
-	// Demonstrate intelligent formatting
-	fmt.Println("Intelligent formatting output:")
-	fmt.Println(strings.Repeat("-", 50))
-	formattedLines := core.FormatHostsFile(hostsFile)
-	for _, line := range formattedLines {
-		fmt.Println(line)
-	}
-	fmt.Println(strings.Repeat("-", 50))
-	fmt.Println()
-
-	// Demonstrate formatting style detection
-	fmt.Println("Formatting style detection:")
-	style := core.DetectFormattingStyle(lines)
-	if style.UseTabs {
-		fmt.Printf("  Detected style: Tabs\n")
-	} else {
-		fmt.Printf("  Detected style: Spaces (%d per tab)\n", style.SpacesPerTab)
-	}
-	fmt.Printf("  Column widths: IP=%d, Host=%d\n", style.IPWidth, style.HostWidth)
-	fmt.Println()
-
-	// Demonstrate search functionality
-	fmt.Println("Search demonstrations:")
-	if found := hostsFile.FindEntry("localhost"); found != nil {
-		fmt.Printf("✅ Found 'localhost': %s -> %s\n", found.IP, found.Hostname)
-	}
-
-	if found := hostsFile.FindEntry("www.dev.example.com"); found != nil {
-		fmt.Printf("✅ Found alias 'www.dev.example.com': %s -> %s\n", found.IP, found.Hostname)
-	}
-
-	if found := hostsFile.FindEntry("staging.example.com"); found != nil {
-		status := "active"
-		if !found.Active {
-			status = "disabled"
-		}
-		fmt.Printf("✅ Found 'staging.example.com': %s -> %s (%s)\n", found.IP, found.Hostname, status)
-	}
-
-	if found := hostsFile.FindEntry("notfound.com"); found == nil {
-		fmt.Printf("❌ 'notfound.com' not found (as expected)\n")
-	}
-	fmt.Println()
-
-	fmt.Println("🎉 Phase 1 Complete: Core Functionality (Parser)")
-	fmt.Println("✅ Hosts file parsing with format preservation")
-	fmt.Println("✅ Comment and disabled entry handling")
-	fmt.Println("✅ Intelligent formatting with column alignment")
-	fmt.Println("✅ Malformed line handling with warnings")
-	fmt.Println("✅ Round-trip parsing (parse → format → parse)")
-	fmt.Println("✅ Backup functionality")
-	fmt.Println("✅ Search and entry management")
-	fmt.Println()
-	fmt.Println("Ready for Phase 2: TUI Implementation!")
 }

go.mod

@@ -2,20 +2,22 @@ module hosts-go
 
 go 1.24.5
 
-require github.com/stretchr/testify v1.10.0
+require (
+	github.com/charmbracelet/bubbles v0.21.0
+	github.com/charmbracelet/bubbletea v1.3.6
+	github.com/charmbracelet/lipgloss v1.1.0
+	github.com/stretchr/testify v1.10.0
+)
 
 require (
+	github.com/atotto/clipboard v0.1.4 // indirect
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
-	github.com/charmbracelet/bubbles v0.21.0 // indirect
-	github.com/charmbracelet/bubbletea v1.3.6 // indirect
 	github.com/charmbracelet/colorprofile v0.3.1 // indirect
-	github.com/charmbracelet/lipgloss v1.1.0 // indirect
 	github.com/charmbracelet/x/ansi v0.9.3 // indirect
 	github.com/charmbracelet/x/cellbuf v0.0.13 // indirect
 	github.com/charmbracelet/x/term v0.2.1 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
-	github.com/lrstanley/bubblezone v1.0.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-localereader v0.0.1 // indirect
@@ -25,6 +27,7 @@ require (
 	github.com/muesli/termenv v0.16.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
+	github.com/sahilm/fuzzy v0.1.1 // indirect
 	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
 	golang.org/x/sync v0.15.0 // indirect
 	golang.org/x/sys v0.33.0 // indirect

go.sum

@@ -1,5 +1,9 @@
+github.com/atotto/clipboard v0.1.4 h1:EH0zSVneZPSuFR11BlR9YppQTVDbh5+16AmcJi4g1z4=
+github.com/atotto/clipboard v0.1.4/go.mod h1:ZY9tmq7sm5xIbd9bOK4onWV4S6X0u6GY7Vn0Yu86PYI=
 github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
 github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
+github.com/aymanbagabas/go-udiff v0.2.0 h1:TK0fH4MteXUDspT88n8CKzvK0X9O2xu9yQjWpi6yML8=
+github.com/aymanbagabas/go-udiff v0.2.0/go.mod h1:RE4Ex0qsGkTAJoQdQQCA0uG+nAzJO/pI/QwceO5fgrA=
 github.com/charmbracelet/bubbles v0.21.0 h1:9TdC97SdRVg/1aaXNVWfFH3nnLAwOXr8Fn6u6mfQdFs=
 github.com/charmbracelet/bubbles v0.21.0/go.mod h1:HF+v6QUR4HkEpz62dx7ym2xc71/KBHg+zKwJtMw+qtg=
 github.com/charmbracelet/bubbletea v1.3.6 h1:VkHIxPJQeDt0aFJIsVxw8BQdh/F/L2KKZGsK6et5taU=
@@ -12,14 +16,16 @@ github.com/charmbracelet/x/ansi v0.9.3 h1:BXt5DHS/MKF+LjuK4huWrC6NCvHtexww7dMayh
 github.com/charmbracelet/x/ansi v0.9.3/go.mod h1:3RQDQ6lDnROptfpWuUVIUG64bD2g2BgntdxH0Ya5TeE=
 github.com/charmbracelet/x/cellbuf v0.0.13 h1:/KBBKHuVRbq1lYx5BzEHBAFBP8VcQzJejZ/IA3iR28k=
 github.com/charmbracelet/x/cellbuf v0.0.13/go.mod h1:xe0nKWGd3eJgtqZRaN9RjMtK7xUYchjzPr7q6kcvCCs=
+github.com/charmbracelet/x/exp/golden v0.0.0-20241011142426-46044092ad91 h1:payRxjMjKgx2PaCWLZ4p3ro9y97+TVLZNaRZgJwSVDQ=
+github.com/charmbracelet/x/exp/golden v0.0.0-20241011142426-46044092ad91/go.mod h1:wDlXFlCrmJ8J+swcL/MnGUuYnqgQdW9rhSD61oNMb6U=
 github.com/charmbracelet/x/term v0.2.1 h1:AQeHeLZ1OqSXhrAWpYUtZyX1T3zVxfpZuEQMIQaGIAQ=
 github.com/charmbracelet/x/term v0.2.1/go.mod h1:oQ4enTYFV7QN4m0i9mzHrViD7TQKvNEEkHUMCmsxdUg=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f h1:Y/CXytFA4m6baUTXGLOoWe4PQhGxaX0KpnayAqC48p4=
 github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f/go.mod h1:vw97MGsxSvLiUE2X8qFplwetxpGLQrlU1Q9AUEIzCaM=
-github.com/lrstanley/bubblezone v1.0.0 h1:bIpUaBilD42rAQwlg/4u5aTqVAt6DSRKYZuSdmkr8UA=
-github.com/lrstanley/bubblezone v1.0.0/go.mod h1:kcTekA8HE/0Ll2bWzqHlhA2c513KDNLW7uDfDP4Mly8=
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
 github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
@@ -39,10 +45,14 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
 github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
+github.com/sahilm/fuzzy v0.1.1 h1:ceu5RHF8DGgoi+/dR5PsECjCDH1BE3Fnmpo7aVXOdRA=
+github.com/sahilm/fuzzy v0.1.1/go.mod h1:VFvziUEIMCrT6A6tw2RFIXPXXmzXbOsSHF0DOI8ZK9Y=
 github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavMF/ppJZNG9ZpyihvCd0w101no=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e/go.mod h1:RbqR21r5mrJuqunuUZ/Dhy/avygyECGrLceyNeo4LiM=
+golang.org/x/exp v0.0.0-20220909182711-5c715a9e8561 h1:MDc5xs78ZrZr3HMQugiXOAkSZtfTpbJLDr/lwfgO53E=
+golang.org/x/exp v0.0.0-20220909182711-5c715a9e8561/go.mod h1:cyybsKvd6eL0RnXn6p/Grxp8F5bW7iYuBgsNCOHpMYE=
 golang.org/x/sync v0.15.0 h1:KWH3jNZsfyT6xfAfKiz6MRNmd46ByHDYaZ7KSkCtdW8=
 golang.org/x/sync v0.15.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
 golang.org/x/sys v0.0.0-20210809222454-d867a43fc93e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

internal/tui/model.go

@@ -0,0 +1,118 @@
+package tui
+
+import (
+	"fmt"
+	"hosts-go/internal/core"
+	"strings"
+
+	list "github.com/charmbracelet/bubbles/list"
+	viewport "github.com/charmbracelet/bubbles/viewport"
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+// entryItem wraps a HostEntry for display in a list component.
+type entryItem struct{ entry *core.HostEntry }
+
+func (e entryItem) Title() string {
+	prefix := "[ ]"
+	if e.entry.Active {
+		prefix = "[✓]"
+	}
+	return fmt.Sprintf("%s %s", prefix, e.entry.Hostname)
+}
+
+func (e entryItem) Description() string { return e.entry.IP }
+func (e entryItem) FilterValue() string { return e.entry.Hostname }
+
+// Model is the main Bubble Tea model for the application.
+type Mode int
+
+const (
+	ViewMode Mode = iota
+	EditMode
+)
+
+type pane int
+
+const (
+	listPane pane = iota
+	detailPane
+)
+
+type Model struct {
+	list   list.Model
+	detail viewport.Model
+	hosts  *core.HostsFile
+	width  int
+	height int
+	mode   Mode
+	focus  pane
+}
+
+// NewModel constructs the TUI model from a parsed HostsFile.
+func NewModel(hf *core.HostsFile) Model {
+	items := make([]list.Item, len(hf.Entries))
+	for i, e := range hf.Entries {
+		items[i] = entryItem{entry: e}
+	}
+
+	l := list.New(items, list.NewDefaultDelegate(), 0, 0)
+	l.SetShowStatusBar(false)
+	l.SetFilteringEnabled(false)
+	l.SetShowHelp(false)
+	l.SetShowPagination(false)
+
+	m := Model{
+		list:   l,
+		detail: viewport.New(0, 0),
+		hosts:  hf,
+		mode:   ViewMode,
+		focus:  listPane,
+	}
+	m.refreshDetail()
+	return m
+}
+
+func (m *Model) refreshDetail() {
+	if len(m.hosts.Entries) == 0 {
+		m.detail.SetContent("")
+		return
+	}
+	entry := m.hosts.Entries[m.list.Index()]
+	var b strings.Builder
+	status := "active"
+	if !entry.Active {
+		status = "inactive"
+	}
+	fmt.Fprintf(&b, "IP: %s\n", entry.IP)
+	fmt.Fprintf(&b, "Host: %s\n", entry.Hostname)
+	if len(entry.Aliases) > 0 {
+		fmt.Fprintf(&b, "Aliases: %s\n", strings.Join(entry.Aliases, ", "))
+	}
+	if entry.Comment != "" {
+		fmt.Fprintf(&b, "Comment: %s\n", entry.Comment)
+	}
+	fmt.Fprintf(&b, "Status: %s", status)
+	m.detail.SetContent(b.String())
+	m.detail.YOffset = 0
+}
+
+// Init satisfies tea.Model.
+func (m Model) Init() tea.Cmd { return nil }
+
+// SelectedEntry returns the currently selected host entry.
+func (m Model) SelectedEntry() *core.HostEntry {
+	if len(m.hosts.Entries) == 0 {
+		return nil
+	}
+	idx := m.list.Index()
+	if idx < 0 || idx >= len(m.hosts.Entries) {
+		return nil
+	}
+	return m.hosts.Entries[idx]
+}
+
+// Mode returns the current operating mode of the TUI.
+func (m Model) Mode() Mode {
+	return m.mode
+}

internal/tui/update.go

@@ -0,0 +1,90 @@
+package tui
+
+import (
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+// Update handles all messages for the TUI.
+func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	var cmd tea.Cmd
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "q", "ctrl+c":
+			return m, tea.Quit
+		case "tab":
+			if m.focus == listPane {
+				m.focus = detailPane
+			} else {
+				m.focus = listPane
+			}
+		case "e":
+			if m.mode == ViewMode {
+				m.mode = EditMode
+			} else {
+				m.mode = ViewMode
+			}
+		case "a":
+			if m.mode == EditMode {
+				if entry := m.SelectedEntry(); entry != nil {
+					entry.Active = !entry.Active
+					m.list.SetItem(m.list.Index(), entryItem{entry})
+					m.refreshDetail()
+				}
+			}
+		case "up", "k":
+			if m.focus == detailPane {
+				m.detail.LineUp(1)
+			} else {
+				m.list, cmd = m.list.Update(msg)
+				m.refreshDetail()
+			}
+			return m, cmd
+		case "down", "j":
+			if m.focus == detailPane {
+				m.detail.LineDown(1)
+			} else {
+				m.list, cmd = m.list.Update(msg)
+				m.refreshDetail()
+			}
+			return m, cmd
+		}
+		if m.focus == listPane {
+			m.list, cmd = m.list.Update(msg)
+			m.refreshDetail()
+		}
+	case tea.WindowSizeMsg:
+		m.width = msg.Width
+		m.height = msg.Height - 1
+
+		leftWidth := msg.Width / 2
+		rightWidth := msg.Width - leftWidth
+		leftHeight := m.height
+		rightHeight := m.height
+
+		if m.focus == listPane {
+			leftWidth -= 2
+			leftHeight -= 2
+		} else {
+			rightWidth -= 2
+			rightHeight -= 2
+		}
+
+		leftWidth -= 2
+		rightWidth -= 2
+
+		m.list.SetSize(leftWidth, leftHeight)
+		m.detail.Width = rightWidth
+		m.detail.Height = rightHeight
+
+		if m.focus == listPane {
+			m.list, cmd = m.list.Update(msg)
+		}
+	default:
+		if m.focus == listPane {
+			m.list, cmd = m.list.Update(msg)
+			m.refreshDetail()
+		}
+	}
+	return m, cmd
+}

internal/tui/view.go

@@ -0,0 +1,57 @@
+package tui
+
+import (
+	"fmt"
+
+	"github.com/charmbracelet/lipgloss"
+)
+
+var (
+	listStyle    = lipgloss.NewStyle().Padding(0, 1)
+	detailStyle  = lipgloss.NewStyle().Padding(0, 1)
+	focusedStyle = lipgloss.NewStyle().BorderStyle(lipgloss.RoundedBorder()).BorderForeground(lipgloss.Color("62"))
+	statusStyle  = lipgloss.NewStyle().Padding(0, 1).Foreground(lipgloss.Color("240")).Background(lipgloss.Color("236"))
+)
+
+// View renders the two-pane layout.
+func (m Model) View() string {
+	listView := m.list.View()
+	detailView := m.detail.View()
+
+	// compute dimensions for each pane accounting for padding and focus border
+	leftWidth := m.width / 2
+	rightWidth := m.width - leftWidth
+	leftHeight := m.height
+	rightHeight := m.height
+
+	if m.focus == listPane {
+		leftWidth -= 2 // border
+		leftHeight -= 2
+	} else {
+		rightWidth -= 2
+		rightHeight -= 2
+	}
+
+	// account for horizontal padding
+	leftWidth -= 2
+	rightWidth -= 2
+
+	left := listStyle.Width(leftWidth).Height(leftHeight).Render(listView)
+	right := detailStyle.Width(rightWidth).Height(rightHeight).Render(detailView)
+
+	if m.focus == listPane {
+		left = focusedStyle.Render(left)
+	} else {
+		right = focusedStyle.Render(right)
+	}
+
+	// join panes and status bar
+	panes := lipgloss.JoinHorizontal(lipgloss.Top, left, right)
+	modeLabel := "VIEW"
+	if m.mode == EditMode {
+		modeLabel = "EDIT"
+	}
+	status := fmt.Sprintf("%s MODE • %d entries", modeLabel, len(m.hosts.Entries))
+	bar := statusStyle.Width(m.width).Render(status)
+	return lipgloss.JoinVertical(lipgloss.Left, panes, bar)
+}

memory-bank/activeContext.md

@@ -2,8 +2,8 @@
 
 ## Current Work Focus
 
-**Status**: Phase 1 Complete - Ready for Phase 2 (TUI Implementation)
-**Priority**: Implementing Bubble Tea TUI with two-pane layout
+**Status**: Phase 3 In Progress - Edit mode basics implemented
+**Priority**: Expand Phase 3 with file integration and advanced editing
 
 ## Recent Changes
 
@@ -17,6 +17,17 @@
 - ✅ **Comprehensive testing**: 54 comprehensive tests covering all parser functionality (100% passing)
 - ✅ **Demo application**: Full showcase of parser capabilities with real-world examples
 
+### Phase 2: TUI Prototype (COMPLETED) ✅
+- ✅ **Two-pane layout** with list and detail panes
+- ✅ **Navigation system** with pane switching and detail scrolling
+- ✅ **View mode** showing entry details and status bar
+- ✅ **Parser integration** loading `/etc/hosts` into the UI
+
+### Phase 3: Edit Mode (IN PROGRESS)
+- 🔄 **Edit mode toggle** via 'e' key with status bar indication
+- 🔄 **Entry activation toggle** using 'a' key
+- 🔄 **Model tests** covering edit mode behavior
+
 ### Parser Capabilities Achieved
 - ✅ **Standard entries**: IPv4, IPv6, multiple aliases, inline comments
 - ✅ **Disabled entries**: Commented lines with `# IP hostname` format detection
@@ -35,42 +46,21 @@
 
 ## Next Steps
 
-### Immediate (Phase 2 - Current Priority)
-1. **TUI Architecture Design**
-   - Design main Bubble Tea model structure following MVU pattern
-   - Plan state management for entries, selection, and modes
-   - Define component hierarchy (main → list → detail → modal)
-
-2. **Two-Pane Layout Implementation**
-   - Create left pane: entry list with status indicators
-   - Create right pane: detailed entry view with editing capabilities
-   - Implement responsive layout with proper sizing
-
-3. **Navigation System**
-   - Keyboard navigation between panes and entries
-   - Selection highlighting and status indicators
-   - Scroll handling for large hosts files
-
-4. **View Mode Implementation**
-   - Safe browsing without modification capability
-   - Display parsed entries with active/inactive status
-   - Show entry details in right pane when selected
-
-### Medium-term (Phase 3)
+### Immediate (Phase 3 - Current Priority)
 1. **Edit Mode Implementation**
-   - Explicit mode transition with visual indicators
-   - Permission handling with sudo request
-   - Entry modification forms with validation
+   - ✅ Explicit mode transition with visual indicators
+   - 🔄 Permission handling with sudo request
+   - 🔄 Entry modification forms with validation
 
 2. **File Integration**
-   - Connect TUI with existing parser functionality
-   - Real-time display of actual `/etc/hosts` content
-   - Live validation and formatting preview
+   - 🔄 Connect TUI with existing parser functionality for writes
+   - 🔄 Real-time display of actual `/etc/hosts` content
+   - 🔄 Live validation and formatting preview
 
 3. **Advanced Features**
-   - Entry toggle (activate/deactivate)
-   - Add/edit/delete operations
-   - Sorting and filtering capabilities
+   - ✅ Entry toggle (activate/deactivate)
+   - 🔄 Add/edit/delete operations
+   - 🔄 Sorting and filtering capabilities
 
 ## Active Decisions and Considerations
 

memory-bank/progress.md

@@ -44,18 +44,19 @@
 
 ## What's Left to Build
 
-### 🎨 Basic TUI (Phase 2 - Current Priority)  
-- [ ] **Main Bubble Tea model**: Core application state and structure
-- [ ] **Two-pane layout**: Left list + right detail view
-- [ ] **Entry list display**: Show active status, IP, hostname columns
-- [ ] **Entry selection**: Navigate and select entries with keyboard
-- [ ] **View mode**: Safe browsing without modification capability
-- [ ] **Integration**: Connect TUI with existing parser functionality
+### 🎨 Basic TUI (Phase 2 - Completed)
+- [x] **Main Bubble Tea model**: Core application state and structure
+- [x] **Two-pane layout**: Left list + right detail view
+- [x] **Entry list display**: Show IP and hostname columns
+- [x] **Entry selection**: Navigate and select entries with keyboard
+- [x] **View mode**: Safe browsing with status bar and active/inactive indicators
+- [x] **Integration**: Connect TUI with existing parser functionality
 
 ### 🔧 Edit Functionality (Phase 3)
-- [ ] **Edit mode transition**: Explicit mode switching with visual indicators
+- [x] **Edit mode transition**: Explicit mode switching with visual indicators
 - [ ] **Permission handling**: Request sudo access when entering edit mode
-- [ ] **Entry modification**: Add, edit, delete, toggle active status
+- [x] **Entry modification**: Toggle active status
+- [ ] **Entry modification**: Add, edit, delete operations
 - [ ] **File writing**: Atomic updates with backup and rollback
 - [ ] **Input validation**: Real-time validation of IP and hostname inputs
 
@@ -67,16 +68,16 @@
 - [ ] **Search/filter**: Find entries quickly in large files
 
 ### 🧪 Testing & Quality (Ongoing)
-- [ ] **TUI tests**: User interactions, state transitions
+- [x] **TUI tests**: User interactions, state transitions
 - [ ] **Integration tests**: Complete TUI workflows with file operations
 - [ ] **Permission tests**: sudo scenarios, graceful degradation
 - [ ] **End-to-end tests**: Full application workflows
 
 ## Current Status
 
-### Project Phase: **Phase 1 Complete → Phase 2 (TUI Implementation)**
-- **Completion**: ~65% (foundation and complete core parser functionality implemented)
-- **Active work**: Ready to implement Bubble Tea TUI with two-pane layout (Phase 2)
+### Project Phase: **Phase 2 Complete → Phase 3 (Edit Mode Implementation)**
+- **Completion**: ~80% (parser, TUI, and basic edit mode implemented)
+- **Active work**: Expand edit mode with file integration and advanced editing
 - **Blockers**: None - comprehensive parser foundation with 54 tests completed
 - **Parser status**: Production-ready with all safety features implemented
 
@@ -132,10 +133,10 @@
 ## Success Metrics & Milestones
 
 ### Milestone 1: Basic Functionality (Target: Week 1)
-- [ ] Parse and display existing hosts file entries
-- [ ] Navigate entries with keyboard
-- [ ] View entry details in right pane
-- **Success criteria**: Can safely browse hosts file without editing
+- [x] Parse and display existing hosts file entries
+- [x] Navigate entries with keyboard
+- [x] View entry details in right pane
+- **Success criteria**: Can safely browse hosts file without editing (achieved)
 
 ### Milestone 2: Core Editing (Target: Week 2)  
 - [ ] Toggle entries active/inactive
@@ -179,15 +180,14 @@
 19. ✅ **Verify atomic operations** (temp files with rollback for safe writes)
 20. ✅ **Complete parser documentation** (comprehensive demo showing all capabilities)
 
-### 🚧 NEXT Phase 2 Actions (TUI Implementation)
-1. **Design TUI architecture** following Bubble Tea MVU pattern
-2. **Create main application model** with state management
-3. **Implement two-pane layout** (entry list + detail view)
-4. **Add navigation controls** (keyboard-driven interaction)
-5. **Integrate parser functionality** with TUI display
-6. **Implement view mode** (safe browsing without modifications)
+### 🚧 NEXT Phase 3 Actions (Edit Mode & File Integration)
+1. **Edit mode transition** with explicit mode switching
+2. **Permission handling** requesting sudo when entering edit mode
+3. **Entry modification** forms for add/edit/delete/toggle
+4. **File writing** with backups and atomic updates
+5. **Input validation** in real time
 
-**Phase 1 is fully complete with a production-ready parser foundation.**
+**Phase 2 delivered a functional view-only TUI.**
 
 ### Parser Achievement Summary
 - **54 comprehensive tests** covering all hosts file variations and edge cases
@@ -197,4 +197,4 @@
 - **Search and management** capabilities for finding and manipulating entries
 - **Demo application** showcasing all functionality with realistic examples
 
-The foundation is robust, tested, and ready for TUI implementation in Phase 2.
+The foundation is robust, tested, and ready for edit mode implementation in Phase 3.

tests/tui_test.go

@@ -0,0 +1,87 @@
+package tests
+
+import (
+	"strings"
+	"testing"
+
+	"hosts-go/internal/core"
+	"hosts-go/internal/tui"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestModelSelection(t *testing.T) {
+	sample := `127.0.0.1 localhost
+192.168.1.10 example.com`
+	lines := strings.Split(sample, "\n")
+	hf, _, err := core.ParseHostsContent(lines)
+	require.NoError(t, err)
+
+	m := tui.NewModel(hf)
+	require.NotNil(t, m.SelectedEntry())
+	assert.Equal(t, "localhost", m.SelectedEntry().Hostname)
+
+	// Move selection down
+	nm, _ := m.Update(tea.KeyMsg{Type: tea.KeyDown})
+	m = nm.(tui.Model)
+	assert.Equal(t, "example.com", m.SelectedEntry().Hostname)
+}
+
+func TestViewModeStatusBar(t *testing.T) {
+	sample := `127.0.0.1 localhost
+# 192.168.1.10 example.com`
+	lines := strings.Split(sample, "\n")
+	hf, _, err := core.ParseHostsContent(lines)
+	require.NoError(t, err)
+
+	m := tui.NewModel(hf)
+	nm, _ := m.Update(tea.WindowSizeMsg{Width: 80, Height: 20})
+	m = nm.(tui.Model)
+	view := m.View()
+
+	assert.Contains(t, view, "VIEW MODE")
+	assert.Contains(t, view, "[✓] localhost")
+	assert.Contains(t, view, "[ ] example.com")
+}
+
+func TestPaneSwitching(t *testing.T) {
+	sample := "127.0.0.1 localhost\n192.168.1.10 example.com"
+	lines := strings.Split(sample, "\n")
+	hf, _, err := core.ParseHostsContent(lines)
+	require.NoError(t, err)
+
+	m := tui.NewModel(hf)
+	// Switch focus to detail pane
+	nm, _ := m.Update(tea.KeyMsg{Type: tea.KeyTab})
+	m = nm.(tui.Model)
+
+	// Attempt to move down; selection should remain on first entry
+	nm, _ = m.Update(tea.KeyMsg{Type: tea.KeyDown})
+	m = nm.(tui.Model)
+	assert.Equal(t, "localhost", m.SelectedEntry().Hostname)
+}
+
+func TestEditModeToggleAndActivation(t *testing.T) {
+	sample := "127.0.0.1 localhost\n192.168.1.10 example.com"
+	lines := strings.Split(sample, "\n")
+	hf, _, err := core.ParseHostsContent(lines)
+	require.NoError(t, err)
+
+	m := tui.NewModel(hf)
+
+	// enter edit mode
+	nm, _ := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'e'}})
+	m = nm.(tui.Model)
+	assert.Equal(t, tui.EditMode, m.Mode())
+
+	// toggle active state of first entry
+	nm, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'a'}})
+	m = nm.(tui.Model)
+	assert.False(t, m.SelectedEntry().Active)
+
+	// status bar should reflect edit mode
+	view := m.View()
+	assert.Contains(t, view, "EDIT MODE")
+}