package world

import (
	"image"
	"image/color"
	"testing"

	"github.com/fogleman/gg"
)

type benchBgTheme struct {
	img       image.Image
	anchor    BackgroundAnchorMode
	tileMode  BackgroundTileMode
	scaleMode BackgroundScaleMode
}

func (t benchBgTheme) ID() string   { return "benchbg" }
func (t benchBgTheme) Name() string { return "benchbg" }

func (t benchBgTheme) BackgroundColor() color.Color { return color.RGBA{A: 255} }
func (t benchBgTheme) BackgroundImage() image.Image { return t.img }

func (t benchBgTheme) BackgroundTileMode() BackgroundTileMode     { return t.tileMode }
func (t benchBgTheme) BackgroundScaleMode() BackgroundScaleMode   { return t.scaleMode }
func (t benchBgTheme) BackgroundAnchorMode() BackgroundAnchorMode { return t.anchor }

func (t benchBgTheme) PointStyle() Style {
	return Style{FillColor: color.RGBA{A: 255}, PointRadiusPx: 2}
}
func (t benchBgTheme) LineStyle() Style {
	return Style{StrokeColor: color.RGBA{A: 255}, StrokeWidthPx: 1}
}
func (t benchBgTheme) CircleStyle() Style {
	return Style{FillColor: color.RGBA{A: 255}, StrokeColor: color.RGBA{A: 255}, StrokeWidthPx: 1}
}

func (t benchBgTheme) PointClassOverride(PointClassID) (StyleOverride, bool) {
	return StyleOverride{}, false
}
func (t benchBgTheme) LineClassOverride(LineClassID) (StyleOverride, bool) {
	return StyleOverride{}, false
}
func (t benchBgTheme) CircleClassOverride(CircleClassID) (StyleOverride, bool) {
	return StyleOverride{}, false
}

func BenchmarkRender_IncrementalPan_NoBackground(b *testing.B) {
	w := NewWorld(600, 600)
	w.IndexOnViewportChange(1200, 800, 1.0)

	// Some primitives to keep it realistic but not dominant.
	for i := 0; i < 200; i++ {
		_, _ = w.AddPoint(float64(i%600), float64((i*7)%600))
	}
	w.Reindex()

	dc := gg.NewContext(1200, 800)
	drawer := &GGDrawer{DC: dc}

	params := RenderParams{
		ViewportWidthPx:  1000,
		ViewportHeightPx: 700,
		MarginXPx:        250,
		MarginYPx:        175,
		CameraXWorldFp:   300 * SCALE,
		CameraYWorldFp:   300 * SCALE,
		CameraZoom:       1.0,
		Options: &RenderOptions{
			Incremental: &IncrementalPolicy{
				AllowShiftOnly:   false,
				CoalesceUpdates:  false,
				MaxCatchUpAreaPx: 0,
				RenderBudgetMs:   0,
			},
		},
	}

	// Initial render (commit state).
	_ = w.Render(drawer, params)

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		params.CameraXWorldFp += 1 * SCALE
		_ = w.Render(drawer, params)
	}
}

func BenchmarkRender_IncrementalPan_BackgroundRepeat_WorldAnchor_ScaleNone(b *testing.B) {
	benchRenderBg(b, BackgroundAnchorWorld, BackgroundTileRepeat, BackgroundScaleNone)
}

func BenchmarkRender_IncrementalPan_BackgroundRepeat_WorldAnchor_ScaleFit(b *testing.B) {
	benchRenderBg(b, BackgroundAnchorWorld, BackgroundTileRepeat, BackgroundScaleFit)
}

func BenchmarkRender_IncrementalPan_BackgroundRepeat_ViewportAnchor_ScaleNone(b *testing.B) {
	benchRenderBg(b, BackgroundAnchorViewport, BackgroundTileRepeat, BackgroundScaleNone)
}

func benchRenderBg(b *testing.B, anchor BackgroundAnchorMode, tile BackgroundTileMode, scale BackgroundScaleMode) {
	w := NewWorld(600, 600)
	w.IndexOnViewportChange(1200, 800, 1.0)

	for i := 0; i < 200; i++ {
		_, _ = w.AddPoint(float64(i%600), float64((i*7)%600))
	}
	w.Reindex()

	// Background tile (RGBA) — typical texture size.
	bg := image.NewRGBA(image.Rect(0, 0, 96, 96))
	// Make it semi-transparent so draw.Over has real work.
	for y := 0; y < 96; y++ {
		for x := 0; x < 96; x++ {
			bg.SetRGBA(x, y, color.RGBA{R: 255, G: 255, B: 255, A: 18})
		}
	}

	w.SetTheme(benchBgTheme{img: bg, anchor: anchor, tileMode: tile, scaleMode: scale})

	dc := gg.NewContext(1200, 800)
	drawer := &GGDrawer{DC: dc}

	params := RenderParams{
		ViewportWidthPx:  1000,
		ViewportHeightPx: 700,
		MarginXPx:        250,
		MarginYPx:        175,
		CameraXWorldFp:   300 * SCALE,
		CameraYWorldFp:   300 * SCALE,
		CameraZoom:       1.0,
		Options: &RenderOptions{
			Incremental: &IncrementalPolicy{
				AllowShiftOnly:   false,
				CoalesceUpdates:  false,
				MaxCatchUpAreaPx: 0,
				RenderBudgetMs:   0,
			},
		},
	}

	_ = w.Render(drawer, params)

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		params.CameraXWorldFp += 1 * SCALE
		_ = w.Render(drawer, params)
	}
}