package generator

import (
	"testing"

	"mxl-pattern-generator/kernels"
)

func TestWGPUMoveSquare(t *testing.T) {
	const width, height = 1920, 1080
	shader, err := kernels.Read("dynamic/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)

	// square center x=960 sits on the green bar (534/253/207):
	// inverted -> Y=1004-534=470, Cb=1024-253=771, Cr=1024-207=817
	const invY, invCb, invCr = 470, 771, 817
	const greenY = 534 // bar 3 covers x in [823,1098)

	// tick 0: offset = 0, square centered at (960,540), half = 75
	if err := g.GenerateFrame(buf, 0); err != nil {
		t.Fatalf("tick 0: %v", err)
	}
	if y, cb, cr := sampleV210(buf, width, 960, 540); y != invY || cb != invCb || cr != invCr {
		t.Fatalf("tick 0 center: got %d/%d/%d, want inverted green 470/771/817", y, cb, cr)
	}
	if y, _, _ := sampleV210(buf, width, 860, 540); y != greenY {
		t.Fatalf("tick 0 left of square: Y=%d, want green %d", y, greenY)
	}

	// amplitude = centerX - half = 885: tick 79 (sin~1) puts the square at
	// the far right, x in [1770,1920), over the gray side panel
	// (414/512/512): inverted -> 590/512/512.
	const invFlankY, invFlankCb, invFlankCr = 590, 512, 512
	if err := g.GenerateFrame(buf, 79); err != nil {
		t.Fatalf("tick 79: %v", err)
	}
	if y, cb, cr := sampleV210(buf, width, 1840, 540); y != invFlankY || cb != invFlankCb || cr != invFlankCr {
		t.Fatalf("tick 79 shifted center: got %d/%d/%d, want inverted gray 590/512/512", y, cb, cr)
	}
	if y, _, _ := sampleV210(buf, width, 960, 540); y != greenY {
		t.Fatalf("tick 79 old center: Y=%d, want green %d (square moved away)", y, greenY)
	}
	// bars untouched far from the square
	if y, _, _ := sampleV210(buf, width, 100, 100); y != 414 {
		t.Fatalf("tick 79 bars: Y=%d, want gray flank 414", y)
	}
}