package world

import (
	"image/color"
	"testing"

	"github.com/fogleman/gg"
	"github.com/stretchr/testify/require"
)

func BenchmarkDrawPlanSinglePass_Lines_GG(b *testing.B) {
	w := NewWorld(600, 600)
	w.IndexOnViewportChange(1000, 700, 1.0)

	// Make a lot of lines, including ones that likely wrap.
	for i := 0; i < 4000; i++ {
		x1 := float64(i % 600)
		y1 := float64((i * 7) % 600)
		x2 := float64((i*13 + 500) % 600) // shift to create various deltas
		y2 := float64((i*17 + 300) % 600)
		_, _ = w.AddLine(x1, y1, x2, y2)
	}
	w.Reindex()

	params := RenderParams{
		ViewportWidthPx:  1000,
		ViewportHeightPx: 700,
		MarginXPx:        250,
		MarginYPx:        175,
		CameraXWorldFp:   300 * SCALE,
		CameraYWorldFp:   300 * SCALE,
		CameraZoom:       1.0,
		Options: &RenderOptions{
			BackgroundColor: color.RGBA{A: 255},
		},
	}

	plan, err := w.buildRenderPlanStageA(params)
	if err != nil {
		b.Fatalf("build plan: %v", err)
	}

	dc := gg.NewContext(params.CanvasWidthPx(), params.CanvasHeightPx())
	drawer := &GGDrawer{DC: dc}

	b.ReportAllocs()
	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		w.drawPlanSinglePass(drawer, plan, true, drawPlanSinglePassClipEnabled, false)
	}
}

func BenchmarkDrawPlanSinglePass_Lines_Fake(b *testing.B) {
	w := NewWorld(600, 600)
	w.IndexOnViewportChange(1000, 700, 1.0)

	for i := 0; i < 4000; i++ {
		x1 := float64(i % 600)
		y1 := float64((i * 7) % 600)
		x2 := float64((i*13 + 500) % 600)
		y2 := float64((i*17 + 300) % 600)
		_, _ = w.AddLine(x1, y1, x2, y2)
	}
	w.Reindex()

	params := RenderParams{
		ViewportWidthPx:  1000,
		ViewportHeightPx: 700,
		MarginXPx:        250,
		MarginYPx:        175,
		CameraXWorldFp:   300 * SCALE,
		CameraYWorldFp:   300 * SCALE,
		CameraZoom:       1.0,
		Options: &RenderOptions{
			BackgroundColor: color.RGBA{A: 255},
		},
	}

	plan, err := w.buildRenderPlanStageA(params)
	if err != nil {
		b.Fatalf("build plan: %v", err)
	}

	drawer := &fakePrimitiveDrawer{}

	b.ReportAllocs()
	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		// Reset command log so it doesn't grow forever and dominate allocations.
		drawer.Reset()
		w.drawPlanSinglePass(drawer, plan, true, drawPlanSinglePassClipEnabled, false)
	}
}

func TestRender_IncrementalShift_UsesOuterClip_NotPerTileClips(t *testing.T) {
	t.Parallel()

	w := NewWorld(10, 10)
	w.IndexOnViewportChange(100, 80, 1.0)
	w.resetGrid(2 * SCALE)

	_, _ = w.AddPoint(5, 5)
	w.Reindex()

	params := RenderParams{
		ViewportWidthPx:  100,
		ViewportHeightPx: 80,
		MarginXPx:        25,
		MarginYPx:        20,
		CameraXWorldFp:   5 * SCALE,
		CameraYWorldFp:   5 * SCALE,
		CameraZoom:       1.0,
		Options: &RenderOptions{
			Incremental: &IncrementalPolicy{AllowShiftOnly: false},
		},
	}

	// First render initializes state.
	d1 := &fakePrimitiveDrawer{}
	require.NoError(t, w.Render(d1, params))

	// Small pan.
	params2 := params
	params2.CameraXWorldFp += 1 * SCALE

	d2 := &fakePrimitiveDrawer{}
	require.NoError(t, w.Render(d2, params2))

	// Expect very few ClipRect calls (dirty strips count), not per tile.
	clipCmds := d2.CommandsByName("ClipRect")
	require.NotEmpty(t, clipCmds)
	require.LessOrEqual(t, len(clipCmds), 4)
}

func TestRender_BatchesConsecutiveLinesByStyleID(t *testing.T) {
	t.Parallel()

	w := NewWorld(10, 10)
	w.IndexOnViewportChange(100, 80, 1.0)

	// Two lines with default style, same priority.
	_, _ = w.AddLine(1, 1, 8, 1)
	_, _ = w.AddLine(1, 2, 8, 2)
	w.Reindex()

	params := RenderParams{
		ViewportWidthPx:  100,
		ViewportHeightPx: 80,
		MarginXPx:        25,
		MarginYPx:        20,
		CameraXWorldFp:   5 * SCALE,
		CameraYWorldFp:   5 * SCALE,
		CameraZoom:       1.0,
	}

	d := &fakePrimitiveDrawer{}
	require.NoError(t, w.Render(d, params))

	// We expect at least two AddLine, but only 1 Stroke for that run in a tile.
	adds := d.CommandsByName("AddLine")
	strokes := d.CommandsByName("Stroke")
	require.GreaterOrEqual(t, len(adds), 2)
	require.GreaterOrEqual(t, len(strokes), 1)

	// Stronger: within any consecutive group of AddLine commands, count strokes <= 1.
	// (Keep it loose to avoid depending on tile partitioning.)
}