package generator

import (
	"testing"

	"mxl-pattern-generator/kernels"
)

func TestWGPUSMPTEPattern(t *testing.T) {
	const width, height = 1920, 1080
	shader, err := kernels.Read("static/smpteBars.wgsl")
	if err != nil {
		t.Fatalf("read shader: %v", err)
	}
	g, err := NewWGPUGenerator(width, height, string(shader))
	if err != nil {
		t.Fatalf("init: %v", err)
	}
	defer g.Close()

	buf := make([]byte, width*height*8/3)
	if err := g.GenerateFrame(buf, 0); err != nil {
		t.Fatalf("GenerateFrame: %v", err)
	}
	if err := g.GenerateFrame(buf, 1); err != nil {
		t.Fatalf("GenerateFrame 2: %v", err)
	}

	tests := []struct {
		name                  string
		x, y                  int
		wantY, wantCb, wantCr uint32
	}{
		{"top left gray flank", 100, 100, 414, 512, 512},
		{"top white bar", 300, 100, 721, 512, 512},
		{"top green bar", 960, 100, 534, 253, 207},
		{"top right gray flank", 1800, 100, 414, 512, 512},
		{"section 2 cyan flank", 100, 650, 754, 615, 64},
		{"section 2 minus I", 300, 650, 244, 612, 395},
		{"section 2 white", 600, 650, 721, 512, 512},
		{"section 2 blue flank", 1800, 650, 127, 960, 471},
		{"section 3 yellow flank", 100, 750, 877, 64, 553},
		{"section 3 plus Q", 300, 750, 141, 697, 606},
		{"section 3 red flank", 1800, 750, 250, 409, 960},
		{"bottom gray flank", 100, 900, 195, 512, 512},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			y, cb, cr := sampleV210(buf, width, tt.x, tt.y)
			if y != tt.wantY || cb != tt.wantCb || cr != tt.wantCr {
				t.Fatalf("pixel (%d,%d): got %d/%d/%d, want %d/%d/%d",
					tt.x, tt.y, y, cb, cr, tt.wantY, tt.wantCb, tt.wantCr)
			}
		})
	}
}

func TestWGPUGeneratorUsesPaddedV210Rows(t *testing.T) {
	const width, height = 100, 2
	shader, err := kernels.Read("static/ebu75.wgsl")
	if err != nil {
		t.Fatalf("read shader: %v", err)
	}
	g, err := NewWGPUGenerator(width, height, string(shader))
	if err != nil {
		t.Fatalf("init: %v", err)
	}
	defer g.Close()

	buf := make([]byte, V210FrameSize(width, height))
	for i := range buf {
		buf[i] = 0xff
	}
	if err := g.GenerateFrame(buf, 0); err != nil {
		t.Fatalf("GenerateFrame: %v", err)
	}

	for y := 0; y < height; y++ {
		gotY, gotCb, gotCr := sampleV210(buf, width, 0, y)
		if gotY != 721 || gotCb != 512 || gotCr != 512 {
			t.Fatalf("row %d first pixel = %d/%d/%d, want 721/512/512", y, gotY, gotCb, gotCr)
		}
		padding := buf[y*V210LineSize(width)+V210ActiveLineSize(width) : (y+1)*V210LineSize(width)]
		for i, b := range padding {
			if b != 0 {
				t.Fatalf("row %d padding byte %d = %#x, want 0", y, i, b)
			}
		}
	}
}