package ui

import (
	"image"

	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/op/clip"
	"gioui.org/text"
	"gioui.org/unit"
	"gioui.org/widget/material"
)

// Renderer consumes a slice of elements and draws them.
type Renderer struct {
	theme Theme
	shp   *text.Shaper
}

// New creates a new Renderer.
func New(th Theme, shp *text.Shaper) *Renderer {
	return &Renderer{theme: th, shp: shp}
}

// Draw iterates elements and draws each in slice order (back-to-front).
func (r *Renderer) Draw(gtx layout.Context, elems []Element) {
	for _, e := range elems {
		if !e.Visible() {
			continue
		}
		switch v := e.(type) {
		case Label:
			r.drawLabel(gtx, v)
		case ListView:
			r.drawListView(gtx, v)
		case StatusBar:
			r.drawStatusBar(gtx, v)
		case BottomBar:
			r.drawBottomBar(gtx, v)
		case Button:
			r.drawButton(gtx, v)
		default:
			// unknown element type, skip
		}
	}
}

func (r *Renderer) drawLabel(gtx layout.Context, l Label) {
	reg := l.Region()
	th := material.NewTheme()
	th.Shaper = r.shp
	size := l.FontSize
	if size == 0 {
		size = r.theme.FontSize
	}

	// Position label at region origin
	gtx.Constraints.Min.X = int(reg.X)
	gtx.Constraints.Min.Y = int(reg.Y)
	material.Label(th, size, l.Text).Layout(gtx)
}

func (r *Renderer) drawListView(gtx layout.Context, lv ListView) {
	reg := lv.Region()
	th := material.NewTheme()
	th.Shaper = r.shp

	// Position list view at region origin
	gtx.Constraints.Min.X = int(reg.X)
	gtx.Constraints.Min.Y = int(reg.Y)
	for _, item := range lv.Items {
		material.Label(th, r.theme.FontSize, item.Text).Layout(gtx)
	}
}

func (r *Renderer) drawStatusBar(gtx layout.Context, sb StatusBar) {
	reg := sb.Region()
	th := material.NewTheme()
	th.Shaper = r.shp

	// Clip to status bar region
	c := clip.Rect{
		Min: image.Point{X: int(reg.X), Y: int(reg.Y)},
		Max: image.Point{X: int(reg.X + reg.W), Y: int(reg.Y + reg.H)},
	}.Push(gtx.Ops)

	// Line 1: Filename (truncated with ellipsis if needed)
	filenameLineY := reg.Y
	filenameLineH := unit.Dp(24)

	// Truncate filename if needed
	displayFilename := sb.Filename
	// Simple truncation: if filename is too long, truncate it
	if len(displayFilename) > 30 {
		displayFilename = displayFilename[:27] + "..."
	}

	// Position filename at (reg.X + 8, filenameLineY)
	gtx.Constraints.Min.X = int(reg.X + unit.Dp(8))
	gtx.Constraints.Min.Y = int(filenameLineY)
	material.Label(th, r.theme.FontSize, displayFilename).Layout(gtx)

	// Line 2: Icons
	iconsLineY := filenameLineY + filenameLineH

	// Left side: Cut, Copy, Paste icons
	leftX := reg.X + unit.Dp(8)
	iconY := iconsLineY

	if sb.CutCopy {
		r.drawIconButton(gtx, th, "✂", leftX, iconY)
		leftX += unit.Dp(36)
	}
	if sb.Copy {
		r.drawIconButton(gtx, th, "⎘", leftX, iconY)
		leftX += unit.Dp(36)
	}
	if sb.Paste {
		r.drawIconButton(gtx, th, "⎘", leftX, iconY)
		leftX += unit.Dp(36)
	}

	// Right side: Conflict, Search icons
	rightX := reg.X + reg.W - unit.Dp(8)
	if sb.Search {
		rightX -= unit.Dp(36)
		r.drawIconButton(gtx, th, "🔍", rightX, iconY)
	}
	if sb.ConflictIcon {
		rightX -= unit.Dp(36)
		r.drawIconButton(gtx, th, "⚠", rightX, iconY)
	}

	c.Pop()
}

func (r *Renderer) drawBottomBar(gtx layout.Context, bb BottomBar) {
	reg := bb.Region()
	th := material.NewTheme()
	th.Shaper = r.shp

	// Clip to bottom bar region
	c := clip.Rect{
		Min: image.Point{X: int(reg.X), Y: int(reg.Y)},
		Max: image.Point{X: int(reg.X + reg.W), Y: int(reg.Y + reg.H)},
	}.Push(gtx.Ops)

	// Left: Cursor position
	cursorX := reg.X + unit.Dp(8)
	call1 := op.Offset(image.Point{X: int(cursorX), Y: int(reg.Y)}).Push(gtx.Ops)
	material.Label(th, r.theme.FontSize, bb.CursorPos).Layout(gtx)
	call1.Pop()

	// Center: Byte position
	byteX := reg.X + reg.W/2 - unit.Dp(60) // approximate center
	call2 := op.Offset(image.Point{X: int(byteX), Y: int(reg.Y)}).Push(gtx.Ops)
	material.Label(th, r.theme.FontSize, bb.BytePos).Layout(gtx)
	call2.Pop()

	// Right: Word wrap button
	wordWrapX := reg.X + reg.W - unit.Dp(120)
	call3 := op.Offset(image.Point{X: int(wordWrapX), Y: int(reg.Y)}).Push(gtx.Ops)
	material.Label(th, r.theme.FontSize, "[Word Wrap: "+boolToString(bb.WordWrap)+"]").Layout(gtx)
	call3.Pop()

	c.Pop()
}

func (r *Renderer) drawButton(gtx layout.Context, btn Button) {
	reg := btn.Region()
	th := material.NewTheme()
	th.Shaper = r.shp

	// Position button at region origin
	gtx.Constraints.Min.X = int(reg.X)
	gtx.Constraints.Min.Y = int(reg.Y)
	material.Label(th, r.theme.FontSize, btn.Text).Layout(gtx)
}

func (r *Renderer) drawIconButton(gtx layout.Context, th *material.Theme, icon string, x, y unit.Dp) {
	// Position icon button at (x, y)
	gtx.Constraints.Min.X = int(x)
	gtx.Constraints.Min.Y = int(y)
	material.Label(th, r.theme.FontSize, icon).Layout(gtx)
}

func boolToString(b bool) string {
	if b {
		return "On"
	}
	return "Off"
}