Move logic into separate internal/editor package

- Create internal/editor/state.go with State struct and EditorLayout
- Create internal/editor/logic.go with Logic struct and Run method
- Logic owns all state, provides channels for config, frames, input, results
- Main goroutine uses editor.NewLogic() and logic.Run()
- Proper separation for testing later

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

cmd/pad/main.go

@@ -10,6 +10,7 @@ import (
 	"gioui.org/text"
 	"gioui.org/unit"
 
+	"pad/internal/editor"
 	"pad/internal/ui"
 )
 
@@ -32,27 +33,22 @@ func run(w *app.Window) error {
 	shaper := text.NewShaper()
 	renderer := ui.New(ui.Theme{FontSize: 14}, shaper)
 
-	// Channels for communication between goroutines
-	configChan := make(chan ui.ConfigEvent)
-	frameChan := make(chan []ui.Element)
-	inputChan := make(chan []ui.InputEvent)
+	// Initial screen size
+	screenWidth := unit.Dp(390)
+	screenHeight := unit.Dp(844)
+
+	// Create logic instance
+	logic := editor.NewLogic(screenWidth, screenHeight)
 
 	// Shared state protected by mutex
 	var mu sync.Mutex
 	var elems []ui.Element
 
-	// Initial screen size
-	screenWidth := unit.Dp(390)
-	screenHeight := unit.Dp(844)
-
-	// Compute initial elements
-	elems = ui.EditorLayout(screenWidth, screenHeight)
-
 	// Start logic goroutine
-	go logic(w, shaper, screenWidth, screenHeight, configChan, frameChan, inputChan)
+	go logic.Run()
 
 	// Start frame receiver goroutine
-	go frameReceiver(w, &mu, &elems, frameChan)
+	go frameReceiver(w, &mu, &elems, logic.FrameChan())
 
 	// Main event loop
 	for {
@@ -61,7 +57,7 @@ func run(w *app.Window) error {
 			return e.Err
 		case app.ConfigEvent:
 			// Send config event to logic goroutine
-			configChan <- ui.ConfigEvent{
+			logic.ConfigChan() <- editor.ConfigEvent{
 				Width:  unit.Dp(e.Config.Size.X),
 				Height: unit.Dp(e.Config.Size.Y),
 			}
@@ -78,28 +74,6 @@ func run(w *app.Window) error {
 	}
 }
 
-// logic runs in a separate goroutine and owns all application state.
-func logic(w *app.Window, shaper *text.Shaper, screenWidth, screenHeight unit.Dp,
-	configChan <-chan ui.ConfigEvent, frameChan chan<- []ui.Element, inputChan <-chan []ui.InputEvent) {
-
-	// Initial elements
-	elems := ui.EditorLayout(screenWidth, screenHeight)
-
-	for {
-		select {
-		case cfg := <-configChan:
-			// Update screen size and recompute layout
-			screenWidth = cfg.Width
-			screenHeight = cfg.Height
-			elems = ui.EditorLayout(screenWidth, screenHeight)
-			frameChan <- elems
-		case <-inputChan:
-			// Process input (not implemented in mockup)
-			frameChan <- elems
-		}
-	}
-}
-
 // frameReceiver runs in a separate goroutine and bridges frameChan to the main loop.
 func frameReceiver(w *app.Window, mu *sync.Mutex, elems *[]ui.Element, frameChan <-chan []ui.Element) {
 	for {

internal/editor/logic.go

@@ -0,0 +1,90 @@
+package editor
+
+import (
+	"gioui.org/unit"
+
+	"pad/internal/ui"
+)
+
+// ConfigEvent represents a window configuration change (resize, orientation).
+type ConfigEvent struct {
+	Width  unit.Dp
+	Height unit.Dp
+}
+
+// InputEvent represents a user input event routed to an element.
+type InputEvent struct {
+	ElementID string
+	Type      ui.InputType
+	Data      any
+}
+
+// ResultEvent represents a completed async task result.
+type ResultEvent struct {
+	// Future: add result fields here
+}
+
+// Logic runs the logic goroutine and provides channels for communication.
+type Logic struct {
+	state     *State
+	configChan chan ConfigEvent
+	frameChan  chan []ui.Element
+	inputChan  chan []InputEvent
+	resultChan chan ResultEvent
+}
+
+// NewLogic creates a new Logic instance.
+func NewLogic(screenWidth, screenHeight unit.Dp) *Logic {
+	return &Logic{
+		state:      NewState(screenWidth, screenHeight),
+		configChan: make(chan ConfigEvent),
+		frameChan:  make(chan []ui.Element),
+		inputChan:  make(chan []InputEvent),
+		resultChan: make(chan ResultEvent),
+	}
+}
+
+// ConfigChan returns the config channel for the logic goroutine.
+func (l *Logic) ConfigChan() chan<- ConfigEvent {
+	return l.configChan
+}
+
+// FrameChan returns the frame channel for the logic goroutine.
+func (l *Logic) FrameChan() <-chan []ui.Element {
+	return l.frameChan
+}
+
+// InputChan returns the input channel for the logic goroutine.
+func (l *Logic) InputChan() chan<- []InputEvent {
+	return l.inputChan
+}
+
+// ResultChan returns the result channel for the logic goroutine.
+func (l *Logic) ResultChan() <-chan ResultEvent {
+	return l.resultChan
+}
+
+// Run runs the logic goroutine loop.
+func (l *Logic) Run() {
+	for {
+		select {
+		case cfg := <-l.configChan:
+			// Update screen size and recompute layout
+			l.state.ScreenWidth = cfg.Width
+			l.state.ScreenHeight = cfg.Height
+			l.state.Elems = EditorLayout(cfg.Width, cfg.Height)
+			l.frameChan <- l.state.Elems
+		case <-l.inputChan:
+			// Process input (not implemented in mockup)
+			l.frameChan <- l.state.Elems
+		case <-l.resultChan:
+			// Handle result (not implemented in mockup)
+			l.frameChan <- l.state.Elems
+		}
+	}
+}
+
+// State returns the current state.
+func (l *Logic) State() *State {
+	return l.state
+}

internal/editor/state.go

@@ -0,0 +1,70 @@
+package editor
+
+import (
+	"gioui.org/unit"
+
+	"pad/internal/ui"
+)
+
+// State holds all application state owned by the logic goroutine.
+type State struct {
+	ScreenWidth  unit.Dp
+	ScreenHeight unit.Dp
+	Elems        []ui.Element
+}
+
+// NewState creates a new State with initial editor layout.
+func NewState(screenWidth, screenHeight unit.Dp) *State {
+	return &State{
+		ScreenWidth:  screenWidth,
+		ScreenHeight: screenHeight,
+		Elems:        EditorLayout(screenWidth, screenHeight),
+	}
+}
+
+// EditorLayout computes regions for the editor page.
+// It takes screen dimensions and returns []Element.
+func EditorLayout(screenWidth, screenHeight unit.Dp) []ui.Element {
+	// Compute StatusBar region
+	// Line 1: filename (24 DP)
+	// Line 2: icons (24 DP)
+	statusBarHeight := unit.Dp(48)
+	statusBarRegion := ui.Region{
+		X: 0,
+		Y: 0,
+		W: screenWidth,
+		H: statusBarHeight,
+	}
+
+	// Compute BottomBar region (fixed height, at bottom of screen)
+	bottomBarHeight := unit.Dp(24)
+	bottomBarY := screenHeight - bottomBarHeight
+	bottomBarRegion := ui.Region{
+		X: 0,
+		Y: bottomBarY,
+		W: screenWidth,
+		H: bottomBarHeight,
+	}
+
+	// Create StatusBar with mocked filename
+	statusBar := ui.NewStatusBar(
+		statusBarRegion,
+		"very_long_filename_that_does_not_fit_on_a_single_line.txt",
+		false, // FilenameExp
+		true,  // CutCopy
+		false, // Copy
+		true,  // Paste
+		false, // ConflictIcon
+		true,  // Search
+	)
+
+	// Create BottomBar with mocked data
+	bottomBar := ui.NewBottomBar(
+		bottomBarRegion,
+		"Ln 47, Col 12",
+		"1024 / 50000",
+		true, // WordWrap
+	)
+
+	return []ui.Element{statusBar, bottomBar}
+}