Pad/internal/ui/element.go

package ui

import (
	"fmt"
	"image"
	"image/color"
	"strings"

	"gioui.org/font"
	"gioui.org/io/key"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/op/clip"
	"gioui.org/op/paint"
	"gioui.org/unit"
)

// Region defines a screen area in device-independent pixels (Dp).
// All element positions and sizes use Dp for device independence.
type Region struct {
	X, Y Dp
	W, H Dp
}

// String returns a string representation of the Region.
func (r Region) String() string {
	return fmt.Sprintf("Region{x=%g y=%g w=%g h=%g}", r.X, r.Y, r.W, r.H)
}

// Element is the base interface for all UI elements.
// Elements know how to draw themselves when given a Renderer.
type Element interface {
	Region() Region
	Visible() bool
	Draw(gtx layout.Context, r *Renderer)
	String() string
	Type() string
}

// Container holds child elements and draws them within its bounds.
// Children's regions are screen-space; clipping handles containment.
type Container struct {
	id         string
	region     Region
	visible    bool
	background Color
	Children   []Element // Changed to Exported
}

func (c Container) Type() string   { return "container" }
func (c Container) Region() Region { return c.region }
func (c Container) Visible() bool  { return c.visible }
func (c Container) Draw(gtx layout.Context, r *Renderer) {
	// Draw background — children are drawn by drawElement, not here
	if c.background != (Color{}) {
		r.drawBg(gtx, c.region, c.background)
	}
}

// String returns a string representation of the Container and all children.
func (c Container) String() string {
	var sb strings.Builder
	sb.WriteString(fmt.Sprintf("Container[%s] region=%+v bg=%#v children=%d", c.id, c.region, c.background, len(c.Children)))
	for i, child := range c.Children {
		if str, ok := any(child).(fmt.Stringer); ok {
			sb.WriteString(fmt.Sprintf("\n  [%d] %s", i, str.String()))
		} else {
			sb.WriteString(fmt.Sprintf("\n  [%d] %T region=%+v", i, child, child.Region()))
		}
	}
	return sb.String()
}

// NewContainer creates a Container with the given region, background, and children.
func NewContainer(region Region, bg Color, children []Element) Container {
	return Container{
		region:     region,
		visible:    true,
		background: bg,
		Children:   children,
	}
}

// --- Leaf element types (each implements Element and knows how to Draw itself) ---

// Label displays static text.
type Label struct {
	id           string
	region       Region
	visible      bool
	interactions []Interaction
	Text         string
	Align        TextAlign
	FontSize     unit.Sp // 0 = theme default
	Color        Color   // 0 = theme default
	Bold         bool
}

func (l Label) Type() string                { return "label" }
func (l Label) Region() Region              { return l.region }
func (l Label) Visible() bool               { return l.visible }
func (l Label) Interactions() []Interaction { return l.interactions }
func (l Label) Draw(gtx layout.Context, r *Renderer) {
	col := l.Color
	if col == (Color{}) {
		col = Color{R: 0, G: 0, B: 0, A: 255}
	}
	// Click registration is handled by registerInteraction within drawElement,
	// which correctly applies the container offset. No separate RegisterClick needed.
	r.drawText(gtx, l.Text, l.FontSize, l.region, l.Align, col, l.id)
}
func (l Label) ID() string { return l.id }

// String returns a string representation of the Label.
func (l Label) String() string {
	return fmt.Sprintf("Label[%s] text=%q region=%+v align=%d fontSize=%g", l.id, l.Text, l.region, l.Align, l.FontSize)
}

// NewLabel creates a visible Label element.
func NewLabel(text string, fontSize unit.Sp, region Region, align TextAlign, id string, interactions []Interaction) Label {
	return Label{
		id:           id,
		region:       region,
		visible:      true,
		interactions: interactions,
		Text:         text,
		FontSize:     fontSize,
		Align:        align,
	}
}

// Icon displays a named icon image.
type Icon struct {
	id           string
	region       Region
	visible      bool
	interactions []Interaction
	Name         string // icon name, e.g. "cut"
	Size         Dp     // 0 = default icon size
}

func (i Icon) Type() string                { return "icon" }
func (i Icon) Region() Region              { return i.region }
func (i Icon) Visible() bool               { return i.visible }
func (i Icon) Interactions() []Interaction { return i.interactions }
func (i Icon) Draw(gtx layout.Context, r *Renderer) {
	img := r.icon(i.Name)
	if img == nil {
		return
	}
	// Click registration is handled by registerInteraction within drawElement,
	// which correctly applies the container offset. No separate RegisterClick needed.
	// Auto-scale: if Size is 0, use region dimensions so the icon fills its region
	w, h := Dp(0), Dp(0)
	if i.Size == 0 {
		w, h = i.region.W, i.region.H
	}
	r.drawPng(gtx, img, i.region, w, h)
}
func (i Icon) ID() string { return i.id }

// String returns a string representation of the Icon.
func (i Icon) String() string {
	return fmt.Sprintf("Icon[%s] name=%q region=%+v size=%g", i.id, i.Name, i.region, i.Size)
}

// NewIcon creates a visible Icon element.
func NewIcon(name string, region Region, size Dp, interactions []Interaction) Icon {
	return Icon{
		id:           name,
		region:       region,
		visible:      true,
		interactions: interactions,
		Name:         name,
		Size:         size,
	}
}

// TextField accepts text input or displays multiline text.
type TextField struct {
	id             string
	region         Region
	visible        bool
	interactions   []Interaction
	Value          string
	Placeholder    string
	Focused        bool
	Multiline      bool
	CursorPosition int
	// SelectionStart/SelectionEnd are byte offsets into Value (the visible
	// window); -1 means no selection. Used for the IME selection push and the
	// in-app highlight.
	SelectionStart int
	SelectionEnd   int
	// MatchRanges are byte ranges [start,end) into Value (the visible
	// window) of in-file search matches; the renderer draws them as yellow
	// highlights. CurrentMatch is the index into MatchRanges of the match the
	// user has navigated to (it is also the active selection); it gets the
	// stronger highlight so it stands out among the others. -1 = none.
	MatchRanges  [][2]int
	CurrentMatch int
	// CaretDrag is set after a long press on blank space: a single caret
	// handle is shown and can be dragged to move the caret.
	CaretDrag    bool
	ScrollOffset Dp
	VisibleLines []Line
	WordWrap     bool
	WrapWidth    Dp
	// ShowIMESeq is a monotonically increasing pulse from the logic layer
	// (incremented on focus gain, file open, and editor taps). The renderer
	// issues SoftKeyboardCmd{Show:true} only when it changes, never every
	// frame: a per-frame show re-shows the keyboard while its hide animation
	// is running (the IME insets dispatches redraw the app), so the keyboard
	// could not be dismissed. See TextField.Draw.
	ShowIMESeq uint64
}

func (tf TextField) Type() string                { return "textfield" }
func (tf TextField) Region() Region              { return tf.region }
func (tf TextField) Visible() bool               { return tf.visible }
func (tf TextField) ID() string                  { return tf.id }
func (tf TextField) Interactions() []Interaction { return tf.interactions }
func (tf TextField) NeedsClip() bool             { return true }

// String returns a string representation of the TextField.
func (tf TextField) String() string {
	return fmt.Sprintf("TextField[%s] region=%+v len=%d multiline=%v", tf.id, tf.region, len(tf.Value), tf.Multiline)
}

// Draw renders the TextField. For multiline text, it shapes with word wrap
// and draws display lines inline — one LayoutString call, no double-shaping.
func (tf TextField) Draw(gtx layout.Context, r *Renderer) {
	if tf.Focused {
		// (Re-)gained focus for this field (or a different field than the one the
		// dedup state currently tracks): force a fresh snippet/selection push so
		// the IME starts from a known state.
		if r.lastIMEField != tf.id || !r.lastWasFocused {
			r.lastSnippet = key.Snippet{}
			r.lastSelStart = -1
			r.lastSelCaret = -1
		}
		r.lastIMEField = tf.id
		r.lastWasFocused = true
		// Issue key.FocusCmd only on a focus transition (see
		// Renderer.lastFocusCmdID): a per-frame no-op FocusCmd still triggers
		// the router's immediate-command path, which re-queues the frame's
		// pointer events and replays every touch event into every gesture.
		r.focusSeenThisFrame = true
		if r.lastFocusCmdID != tf.id {
			r.lastFocusCmdID = tf.id
			gtx.Execute(key.FocusCmd{Tag: tf.id})
		}
		// Raise the soft keyboard only when the logic layer pulses it (focus
		// gain, file open, editor tap), not every frame. A per-frame show was
		// harmless while the app only redrew on user events, but the IME
		// insets now redraw the app during the keyboard's hide animation; a
		// per-frame show re-shows the keyboard mid-animation, so BACK/chevron
		// could never dismiss it (matches widget.Editor, which shows on focus
		// gain and click only).
		if tf.ShowIMESeq != r.lastIMEShowSeq {
			r.lastIMEShowSeq = tf.ShowIMESeq
			gtx.Execute(key.SoftKeyboardCmd{Show: true})
		}
		// IME wiring. The visible window (tf.Value) is pushed as the snippet
		// with Range {0, len}, so the IME treats the window as the document and
		// reports EditEvent.Range window-relative. This lets swipe/autocorrect
		// operate on the visible text without shipping the whole file to the IME.
		//
		// Item 4: tell the IME this is a text field (enables the text keyboard,
		// autocorrect, and suggestions).
		key.InputHintOp{Tag: tf.id, Hint: key.HintText}.Add(gtx.Ops)
		// Item 2: push the snippet (the visible window) for swipe/autocorrect,
		// but only when it changed. Re-pushing an unchanged snippet every frame
		// resets the IME's composition/cursor, which desyncs fast commits (see
		// widget.Editor's updateSnippet dedup).
		snippet := key.Snippet{
			Range: key.Range{Start: 0, End: runeCount(tf.Value, len(tf.Value))},
			Text:  tf.Value,
		}
		if snippet != r.lastSnippet {
			r.lastSnippet = snippet
			gtx.Execute(key.SnippetCmd{Tag: tf.id, Snippet: snippet})
		}
		// Item 1: sync the caret/selection so the IME's selection matches.
		// Window-relative rune indices (tf.CursorPosition and the selection
		// bounds are byte offsets into tf.Value). With a selection, push the
		// full range so the IME highlights it and a commit replaces it (the
		// logic side unions the commit range with the selection, so the
		// replacement is deterministic regardless of what the IME reports).
		// Push only when the (start, end) pair changes, so a static selection
		// does not reset the IME every frame.
		var selStart, selEnd int
		if tf.SelectionStart >= 0 && tf.SelectionEnd > tf.SelectionStart {
			// Clamp to the window (the element may be built from a window that
			// does not fully contain the selection).
			s := tf.SelectionStart
			if s < 0 {
				s = 0
			}
			e := tf.SelectionEnd
			if e > len(tf.Value) {
				e = len(tf.Value)
			}
			selStart = runeCount(tf.Value, s)
			selEnd = runeCount(tf.Value, e)
		} else {
			selStart = -1
			selEnd = runeCount(tf.Value, tf.CursorPosition)
		}
		if selStart != r.lastSelStart || selEnd != r.lastSelCaret {
			// While a selection/caret handle drag is in progress, defer the
			// IME selection sync (see Renderer.selDragActive): pushing a
			// SelectionCmd every frame the drag moves the selection triggers the
			// input router's immediate-command replay of the frame's pointer
			// events, which re-injects the drag into every gesture and makes the
			// selection jump. The final selection is pushed on the first frame
			// after the drag ends (lastSelStart/lastSelCaret were not updated,
			// so the mismatch persists until then).
			if !r.selDragActive {
				r.lastSelStart = selStart
				r.lastSelCaret = selEnd
				rng := key.Range{Start: selStart, End: selEnd}
				if selStart < 0 {
					rng = key.Range{Start: selEnd, End: selEnd}
				}
				gtx.Execute(key.SelectionCmd{Tag: tf.id, Range: rng, Caret: key.Caret{}})
			}
		}
	} else if r.lastIMEField == tf.id {
		// This (previously-focused) field lost focus: forget it so the next focus
		// pushes a fresh snippet/selection. Resetting lastIMEShowSeq makes the
		// next focus re-raise the keyboard even without a fresh pulse.
		r.lastIMEField = ""
		r.lastWasFocused = false
		r.lastSnippet = key.Snippet{}
		r.lastSelStart = -1
		r.lastSelCaret = -1
		r.lastIMEShowSeq = 0
	}
	r.drawWrappedText(gtx, tf.Value, tf.region, tf.WordWrap, tf.WrapWidth, tf.ScrollOffset, tf.CursorPosition, tf.SelectionStart, tf.SelectionEnd, tf.CaretDrag, tf.MatchRanges, tf.CurrentMatch, tf.Focused)
}

// runeCount returns the number of UTF-8 runes in s[:bytePos] (bytePos is a
// byte offset, clamped to len(s)). A rune starts at an ASCII byte (<0x80) or a
// multi-byte lead byte (>=0xC0); 0x80-0xBF are continuation bytes.
func runeCount(s string, bytePos int) int {
	if bytePos > len(s) {
		bytePos = len(s)
	}
	n := 0
	for i := 0; i < bytePos; i++ {
		b := s[i]
		if b < 0x80 || b >= 0xC0 {
			n++
		}
	}
	return n
}

// NewTextField creates a visible multiline TextField.
func NewTextField(id string, value string, region Region, wordWrap bool, wrapWidth Dp, scrollOffset Dp, cursorPos int, selStart, selEnd int, interactions []Interaction) TextField {
	return TextField{
		id:             id,
		region:         region,
		visible:        true,
		interactions:   interactions,
		Value:          value,
		Multiline:      true,
		WordWrap:       wordWrap,
		WrapWidth:      wrapWidth,
		ScrollOffset:   scrollOffset,
		CursorPosition: cursorPos,
		SelectionStart: selStart,
		SelectionEnd:   selEnd,
	}
}

// Line represents a single line of text in a multiline TextField.
type Line struct {
	Text       string
	LineNumber int // 1-indexed, for display
}

// ListView displays a scrollable list of items.
type ListView struct {
	id            string
	region        Region
	visible       bool
	interactions  []Interaction
	Items         []ListItem
	ScrollOffset  Dp // pixel-level scroll offset
	Selected      int
	RowTapHandler func(any) // handler for row taps, receives index as any
}

func (lv ListView) Type() string    { return "listview" }
func (lv ListView) Region() Region  { return lv.region }
func (lv ListView) Visible() bool   { return lv.visible }
func (lv ListView) ID() string      { return lv.id }
func (lv ListView) NeedsClip() bool { return true }
func (lv ListView) Interactions() []Interaction {
	// ListView registers its scroll in Draw, not via registerInteraction.
	// Filter out Scroll so registerInteraction only handles Tap.
	var filtered []Interaction
	for _, interaction := range lv.interactions {
		if interaction.Gesture != Scroll {
			filtered = append(filtered, interaction)
		}
	}
	return filtered
}

// String returns a string representation of the ListView.
func (lv ListView) String() string {
	var sb strings.Builder
	sb.WriteString(fmt.Sprintf("ListView[%s] region=%+v items=%d selected=%d", lv.id, lv.region, len(lv.Items), lv.Selected))
	for i, item := range lv.Items {
		sb.WriteString(fmt.Sprintf("\n  [%d] %s", i, item.String()))
	}
	return sb.String()
}

// Draw renders each list item as a row of text.
// The scroll gesture is registered via the normal interaction path so it
// is clipped to the list region by the element's clip context.
func (lv ListView) Draw(gtx layout.Context, r *Renderer) {
	// Register scroll gesture - clip is already active from drawElement
	if len(lv.interactions) > 0 {
		var scrollHandler func(any)
		for _, interaction := range lv.interactions {
			if interaction.Gesture == Scroll {
				scrollHandler = interaction.Handler
				break
			}
		}
		if scrollHandler != nil {
			r.RegisterScroll(gtx, lv.id, lv.region, scrollHandler)
		}
	}
	rowHeight := Dp(48)
	firstVisibleRow := int(lv.ScrollOffset / rowHeight)
	for i, item := range lv.Items {
		// Account for scroll offset: row Y is shifted up by scroll amount
		rowGlobalIndex := firstVisibleRow + i
		y := lv.region.Y + Dp(rowGlobalIndex)*rowHeight - lv.ScrollOffset
		// Only draw visible rows (virtualized)
		if y+rowHeight < lv.region.Y || y > lv.region.Y+lv.region.H {
			continue
		}
		// Draw background for selected item (removed as per request)
		/*
			if item.Selected || (lv.Selected == i) {
				r.drawBg(gtx, Region{
					X: lv.region.X, Y: y,
					W: lv.region.W, H: rowHeight,
				}, Color{R: 200, G: 220, B: 255, A: 255})
			}
		*/
		// Register click area for this row
		rowID := fmt.Sprintf("list_row_%d", rowGlobalIndex)
		r.RegisterClick(gtx, rowID, Region{
			X: lv.region.X, Y: y,
			W: lv.region.W, H: rowHeight,
		}, func(data any) {
			// ListView clicks are simple taps, not coordinate-based.
			if lv.RowTapHandler != nil {
				lv.RowTapHandler(rowGlobalIndex)
			} else {
				OpenFile(item.Text)
			}
		})
		// Draw main text
		textRegion := Region{
			X: lv.region.X + Dp(8),
			Y: y + Dp(4),
			W: lv.region.W - Dp(32),
			H: rowHeight - Dp(8),
		}
		r.drawText(gtx, item.Text, 14, textRegion, AlignStart, Color{R: 0, G: 0, B: 0, A: 255}, "")
		// Draw subtext
		if item.Subtext != "" {
			subRegion := Region{
				X: lv.region.X + Dp(8),
				Y: y + rowHeight - Dp(22),
				W: lv.region.W - Dp(32),
				H: Dp(16),
			}
			r.drawText(gtx, item.Subtext, 12, subRegion, AlignStart, Color{R: 128, G: 128, B: 128, A: 255}, "")
		}
	}
}

// NewListView creates a visible ListView element.
func NewListView(id string, items []ListItem, region Region, scrollOffset Dp, selected int, interactions []Interaction, rowTapHandler func(any)) ListView {
	return ListView{
		id:            id,
		region:        region,
		visible:       true,
		interactions:  interactions,
		Items:         items,
		ScrollOffset:  scrollOffset,
		Selected:      selected,
		RowTapHandler: rowTapHandler,
	}
}

// ListItem is a single entry in a ListView.
type ListItem struct {
	Text     string
	Subtext  string
	Selected bool
}

// String returns a string representation of the ListItem.
func (li ListItem) String() string {
	selected := ""
	if li.Selected {
		selected = " *"
	}
	return fmt.Sprintf("ListItem text=%q subtext=%q%s", li.Text, li.Subtext, selected)
}

// AlphaIndex displays an alphabetical index for quick navigation.
type AlphaIndex struct {
	id           string
	region       Region
	visible      bool
	interactions []Interaction
	Letters      []string
	ActiveLetter string
}

func (ai AlphaIndex) Type() string                { return "alphaindex" }
func (ai AlphaIndex) Region() Region              { return ai.region }
func (ai AlphaIndex) Visible() bool               { return ai.visible }
func (ai AlphaIndex) ID() string                  { return ai.id }
func (ai AlphaIndex) Interactions() []Interaction { return ai.interactions }

// String returns a string representation of the AlphaIndex.
func (ai AlphaIndex) String() string {
	return fmt.Sprintf("AlphaIndex[%s] region=%+v letters=%v active=%q", ai.id, ai.region, ai.Letters, ai.ActiveLetter)
}

// NewAlphaIndex creates a visible AlphaIndex element.
func NewAlphaIndex(region Region, letters []string) AlphaIndex {
	return AlphaIndex{
		region:  region,
		visible: true,
		Letters: letters,
	}
}

// Button is an interactive button element.
type Button struct {
	id           string
	region       Region
	visible      bool
	interactions []Interaction
	Text         string
	Enabled      bool
	Primary      bool
}

func (b Button) Type() string                { return "button" }
func (b Button) Region() Region              { return b.region }
func (b Button) Visible() bool               { return b.visible }
func (b Button) Interactions() []Interaction { return b.interactions }
func (b Button) Draw(gtx layout.Context, r *Renderer) {
	col := Color{R: 0, G: 0, B: 0, A: 255}
	r.drawText(gtx, b.Text, r.theme.FontSize, b.region, AlignStart, col, b.id)
}
func (b Button) ID() string { return b.id }

// String returns a string representation of the Button.
func (b Button) String() string {
	return fmt.Sprintf("Button[%s] text=%q region=%+v enabled=%v", b.id, b.Text, b.region, b.Enabled)
}

// NewButton creates a visible Button element.
func NewButton(text string, enabled bool, primary bool, region Region) Button {
	return Button{
		region:  region,
		visible: true,
		Text:    text,
		Enabled: enabled,
		Primary: primary,
	}
}

// SearchBar displays an in-editor search interface.
type SearchBar struct {
	id           string
	region       Region
	visible      bool
	interactions []Interaction
	Query        string
	Match        int
	Total        int
	Forward      bool
}

func (sb SearchBar) Type() string                { return "searchbar" }
func (sb SearchBar) Region() Region              { return sb.region }
func (sb SearchBar) Visible() bool               { return sb.visible }
func (sb SearchBar) ID() string                  { return sb.id }
func (sb SearchBar) Interactions() []Interaction { return sb.interactions }

// String returns a string representation of the SearchBar.
func (sb SearchBar) String() string {
	return fmt.Sprintf("SearchBar[%s] region=%+v query=%q match=%d/%d", sb.id, sb.region, sb.Query, sb.Match, sb.Total)
}

// NewSearchBar creates a visible SearchBar element.
func NewSearchBar(region Region, query string, match, total int, forward bool) SearchBar {
	return SearchBar{
		region:  region,
		visible: true,
		Query:   query,
		Match:   match,
		Total:   total,
		Forward: forward,
	}
}

// Cursor displays the text cursor and optional selection highlight.
type Cursor struct {
	id           string
	region       Region
	ClipRegion   Region // Region to clip drawing
	visible      bool
	interactions []Interaction
	Line         int
	Column       int
	Blinking     bool
	Selection    *Selection
}

func (c Cursor) NeedsClip() bool             { return true }
func (c Cursor) Type() string                { return "cursor" }
func (c Cursor) Region() Region              { return c.region }
func (c Cursor) Visible() bool               { return c.visible }
func (c Cursor) ID() string                  { return c.id }
func (c Cursor) Interactions() []Interaction { return c.interactions }

// String returns a string representation of the Cursor.
func (c Cursor) String() string {
	return fmt.Sprintf("Cursor[%s] region=%+v line=%d col=%d", c.id, c.region, c.Line, c.Column)
}
func (c Cursor) Draw(gtx layout.Context, r *Renderer) {
	// Clip to the cursor's allocated clip region (e.g., the editor text field)
	// to prevent drawing over status bars.
	var stack *clip.Stack
	if c.ClipRegion.W > 0 && c.ClipRegion.H > 0 {
		stack = new(clip.Stack)
		*stack = clip.Rect{
			Min: image.Point{X: int(r.toPx(c.ClipRegion.X)), Y: int(r.toPx(c.ClipRegion.Y))},
			Max: image.Point{X: int(r.toPx(c.ClipRegion.X + c.ClipRegion.W)), Y: int(r.toPx(c.ClipRegion.Y + c.ClipRegion.H))},
		}.Op().Push(gtx.Ops)
	}

	// Draw a thin vertical bar (e.g., width 2dp, height 18dp) at the cursor's top-left position
	// instead of filling the entire region, which covers the text editor.
	cursorRegion := Region{
		X: c.region.X,
		Y: c.region.Y,
		W: Dp(2),
		H: Dp(18),
	}
	r.drawBg(gtx, cursorRegion, Color{R: 0, G: 0, B: 0, A: 255})

	if stack != nil {
		stack.Pop()
	}
}

func NewCursor(id string, region Region, line, col int, blinking bool) Cursor {
	return Cursor{
		id:       id,
		region:   region,
		visible:  true,
		Line:     line,
		Column:   col,
		Blinking: blinking,
	}
}

// Selection represents a text selection range.
type Selection struct {
	StartLine, StartCol int
	EndLine, EndCol     int
}

// MergeHunk displays a conflict resolution hunk.
type MergeHunk struct {
	id           string
	region       Region
	visible      bool
	interactions []Interaction
	HunkNumber   int
	TotalHunks   int
	LineRange    string
	ContextLines []string
	OurLines     []string
	TheirLines   []string
	Resolution   HunkResolution
}

func (mh MergeHunk) Type() string                { return "mergehunk" }
func (mh MergeHunk) Region() Region              { return mh.region }
func (mh MergeHunk) Visible() bool               { return mh.visible }
func (mh MergeHunk) ID() string                  { return mh.id }
func (mh MergeHunk) Interactions() []Interaction { return mh.interactions }

// String returns a string representation of the MergeHunk.
func (mh MergeHunk) String() string {
	return fmt.Sprintf("MergeHunk[%s] region=%+v hunk=%d/%d lineRange=%s resolution=%d", mh.id, mh.region, mh.HunkNumber, mh.TotalHunks, mh.LineRange, mh.Resolution)
}

// HunkResolution represents the resolution state of a merge hunk.
type HunkResolution int

const (
	Unresolved HunkResolution = iota
	KeepOurs
	KeepTheirs
	MergeBoth
)

// Toast displays a temporary notification.
type Toast struct {
	id           string
	region       Region
	visible      bool
	interactions []Interaction
	Text         string
	Timeout      int // milliseconds
}

func (t Toast) Type() string                { return "toast" }
func (t Toast) Region() Region              { return t.region }
func (t Toast) Visible() bool               { return t.visible }
func (t Toast) ID() string                  { return t.id }
func (t Toast) Interactions() []Interaction { return t.interactions }

// String returns a string representation of the Toast.
func (t Toast) String() string {
	return fmt.Sprintf("Toast[%s] text=%q region=%+v timeout=%d", t.id, t.Text, t.region, t.Timeout)
}

// NewToast creates a visible Toast element.
func NewToast(region Region, text string, timeout int) Toast {
	return Toast{
		region:  region,
		visible: true,
		Text:    text,
		Timeout: timeout,
	}
}

// Spacer adds vertical or horizontal space.
type Spacer struct {
	id           string
	region       Region
	visible      bool
	interactions []Interaction
}

func (s Spacer) Type() string                { return "spacer" }
func (s Spacer) Region() Region              { return s.region }
func (s Spacer) Visible() bool               { return s.visible }
func (s Spacer) ID() string                  { return s.id }
func (s Spacer) Interactions() []Interaction { return s.interactions }

// String returns a string representation of the Spacer.
func (s Spacer) String() string {
	return fmt.Sprintf("Spacer[%s] region=%+v", s.id, s.region)
}

// NewSpacer creates a visible Spacer element.
func NewSpacer(height Dp) Spacer {
	return Spacer{
		region:  Region{H: height},
		visible: true,
	}
}

// GioEditor is a reference to a main-owned widget.Editor (see
// Renderer.RegisterGioEditor). The element itself is pure data: the mutable
// widget state lives in the renderer, which is owned by the main goroutine.
type GioEditor struct {
	id           string
	region       Region
	visible      bool
	interactions []Interaction
}

func (ge GioEditor) Type() string                { return "gioeditor" }
func (ge GioEditor) Region() Region              { return ge.region }
func (ge GioEditor) Visible() bool               { return ge.visible }
func (ge GioEditor) ID() string                  { return ge.id }
func (ge GioEditor) Interactions() []Interaction { return ge.interactions }

// String returns a string representation of the GioEditor.
func (ge GioEditor) String() string {
	return fmt.Sprintf("GioEditor[%s] region=%+v", ge.id, ge.region)
}

// Draw renders the Gio Editor widget registered for this element's ID.
func (ge GioEditor) Draw(gtx layout.Context, r *Renderer) {
	ed, ok := r.GioEditor(ge.id)
	if !ok {
		return
	}
	ed.SingleLine = true

	// Position and clip to the editor's region
	stack := op.Offset(image.Pt(int(r.toPx(ge.region.X)), int(r.toPx(ge.region.Y)))).Push(gtx.Ops)
	defer stack.Pop()

	// Draw a simple background for the search bar
	rect := image.Rectangle{Max: image.Pt(int(r.toPx(ge.region.W)), int(r.toPx(ge.region.H)))}
	paint.FillShape(gtx.Ops, color.NRGBA{R: 245, G: 245, B: 245, A: 255}, clip.Rect(rect).Op())

	// Create paint color macros for text and selection colors
	textMacro := op.Record(gtx.Ops)
	paint.ColorOp{Color: color.NRGBA{R: 0, G: 0, B: 0, A: 255}}.Add(gtx.Ops)
	textColor := textMacro.Stop()
	selectionMacro := op.Record(gtx.Ops)
	paint.ColorOp{Color: color.NRGBA{R: 200, G: 220, B: 255, A: 255}}.Add(gtx.Ops)
	selectionColor := selectionMacro.Stop()

	// Set constraints so the editor knows its size for hit-testing
	gtx.Constraints = layout.Exact(rect.Size())

	// Use our RegisterClick to ensure the full region is clickable
	// NOTE: We pass the tap handler to RegisterClick which uses coordinates.
	var tapHandler func(any)
	for _, interaction := range ge.interactions {
		if interaction.Gesture == Tap {
			tapHandler = interaction.Handler
			break
		}
	}
	r.RegisterClick(gtx, ge.id, ge.region, tapHandler)

	ed.Layout(gtx, r.shp, font.Font{}, r.theme.FontSize, textColor, selectionColor)
}

// NewGioEditor creates a GioEditor element referencing the widget.Editor
// registered with the renderer under id.
func NewGioEditor(id string, region Region) GioEditor {
	return GioEditor{
		id:      id,
		region:  region,
		visible: true,
	}
}

// --- Utility types ---

// OpenFile is called by the browser list when a file row is tapped.
// Set by the editor package after initialization.
var OpenFile func(string)

// Color is an RGBA color.
type Color struct {
	R, G, B, A uint8
}

// String returns a string representation of the Color.
func (c Color) String() string {
	return fmt.Sprintf("Color{R:%d G:%d B:%d A:%d}", c.R, c.G, c.B, c.A)
}

// Theme holds styling defaults for the UI.
type Theme struct {
	FontSize unit.Sp // Gio's shaper requires unit.Sp for font sizes
}

// TextAlign specifies horizontal text alignment.
type TextAlign int

const (
	AlignStart TextAlign = iota
	AlignCenter
	AlignEnd
)

// InputType specifies the type of user input event.
type InputType int

const (
	Tap InputType = iota
	DoubleTap
	LongPress
	Scroll
	KeyDown
	KeyUp
	// SelDrag is a selection-handle / selection-body / caret-handle drag.
	// The renderer registers the underlying gesture.Drag ops itself (it owns
	// the handle geometry); this interaction just delivers the logic handler.
	SelDrag
	// Pinch is a two-finger pinch inside the element's text region. The
	// renderer owns the probe (it needs raw two-pointer geometry that no
	// single gesture primitive in Gio v0.10 provides); this interaction just
	// delivers the logic handler, which receives FontPinchEvent.
	Pinch
)

// Interaction pairs a gesture type with a handler function.
type Interaction struct {
	Gesture InputType
	Handler func(any)
}

// Interactive is implemented by elements that respond to input events.
type Interactive interface {
	ID() string
	Interactions() []Interaction
}

// Point defines a 2D coordinate in device-independent pixels (Dp).
// KeyEvent is a key press with its modifier state, delivered as the Data of
// an InputEvent to a ui.KeyDown handler. It replaces passing a bare key.Name
// (which discarded modifier state) so handlers can distinguish e.g.
// shift+arrow (extend selection) from plain arrow (move cursor).
type KeyEvent struct {
	Name  key.Name
	Shift bool
}

type Point struct {
	X, Y Dp
}

// LongPressPoint is a touch that was held still for the long-press duration.
// Coordinates are app-local window Dp (the same space as Point from a tap).
type LongPressPoint struct {
	X, Y Dp
}

// DoubleTapPoint is the second tap of a double tap. App-local window Dp.
type DoubleTapPoint struct {
	X, Y Dp
}

// SelectionDragEvent is emitted while a selection handle (Which 0 = start,
// 1 = end), the selection body (Which 2 = move whole selection) or the
// caret drag handle (Which 3) is being dragged. X/Y are app-local window Dp.
type SelectionDragEvent struct {
	Which int
	X, Y  Dp
}

// SelectionDragEnd is emitted when a selection/caret drag is released.
type SelectionDragEnd struct{}

// FontPinchEvent carries one frame's relative two-finger pinch factor
// (current inter-finger distance / previous frame's distance, both in px).
// The logic applies it as a multiplier to the app-local font scale; the
// value is a plain float32 ratio with no rounding, so the font size is
// continuous, never snapped to whole points. Center is the pinch midpoint
// (the average of the two fingers) in app-local window Dp — the same space
// as Point; the logic anchors the content under this point so it stays put
// while the font scales.
type FontPinchEvent struct {
	Scale  float32
	Center Point
}

// MenuItem is one button in the selection menu.
// X/Y/W/H are relative to the Menu region.
type MenuItem struct {
	Icon       string // "copy", "cut", "paste"
	Label      string
	X, Y, W, H Dp
}

// Menu is the floating selection menu (Copy / Cut / Paste). The logic goroutine
// positions it and decides the items; the renderer draws it and routes a tap
// to the element's Tap interaction with the tapped Point, which the logic
// hit-tests against its own items (single source of truth for geometry).
type Menu struct {
	id      string
	region  Region
	visible bool
	items   []MenuItem
	tap     []Interaction
}

func NewMenu(id string, region Region, items []MenuItem, tapHandler func(any)) Menu {
	return Menu{
		id:      id,
		region:  region,
		visible: true,
		items:   items,
		tap:     []Interaction{{Gesture: Tap, Handler: tapHandler}},
	}
}

func (m Menu) Type() string                { return "menu" }
func (m Menu) Region() Region              { return m.region }
func (m Menu) Visible() bool               { return m.visible }
func (m Menu) ID() string                  { return m.id }
func (m Menu) Interactions() []Interaction { return m.tap }
func (m Menu) Items() []MenuItem           { return m.items }

func (m Menu) String() string {
	return fmt.Sprintf("Menu[%s] region=%+v items=%d", m.id, m.region, len(m.items))
}

// Draw renders the menu panel and its items. Click registration happens in
// the renderer's leaf-element path (Tap over the whole panel).
func (m Menu) Draw(gtx layout.Context, r *Renderer) {
	// Panel background (light, like an Android floating menu).
	r.drawBg(gtx, m.region, Color{R: 245, G: 245, B: 245, A: 255})
	for _, it := range m.items {
		// Item X/Y are relative to the menu region; offset to app coordinates.
		ofx, ofy := m.region.X, m.region.Y
		img := r.icon(it.Icon)
		iconSize := it.H / 2
		iconX := ofx + it.X + (it.W-iconSize)/2
		iconY := ofy + it.Y + 2
		r.drawPng(gtx, img, Region{X: iconX, Y: iconY, W: iconSize, H: iconSize}, iconSize, iconSize)
		r.drawText(gtx, it.Label, unit.Sp(10), Region{X: ofx + it.X, Y: ofy + it.Y + iconSize + 3, W: it.W, H: 12}, AlignCenter, Color{R: 30, G: 30, B: 30, A: 255}, "")
	}
}

// InputEvent represents a user input event with its handler.
type InputEvent struct {
	Handler func(any)
	Data    any
}

// ConfigEvent represents a window configuration change (resize, orientation).
// Width and Height are in device-independent pixels (Dp).
type ConfigEvent struct {
	Width  Dp
	Height Dp
}