package generator

import (
	"encoding/binary"
	"fmt"
	"testing"
)

func TestV210Sizes(t *testing.T) {
	tests := []struct {
		width      int
		activeLine int
		line       int
	}{
		{width: 1920, activeLine: 5120, line: 5120},
		{width: 1280, activeLine: 3424, line: 3456},
		{width: 100, activeLine: 272, line: 384},
		{width: 54, activeLine: 144, line: 256},
		{width: 48, activeLine: 128, line: 128},
	}
	for _, tc := range tests {
		if got := V210ActiveLineSize(tc.width); got != tc.activeLine {
			t.Errorf("V210ActiveLineSize(%d) = %d, want %d", tc.width, got, tc.activeLine)
		}
		if got := V210LineSize(tc.width); got != tc.line {
			t.Errorf("V210LineSize(%d) = %d, want %d", tc.width, got, tc.line)
		}
		if got := V210FrameSize(tc.width, 2); got != tc.line*2 {
			t.Errorf("V210FrameSize(%d, 2) = %d, want %d", tc.width, got, tc.line*2)
		}
	}
}

func TestAlphaSizes(t *testing.T) {
	tests := []struct {
		width     int
		height    int
		lineSize  int
		frameSize int
		v210aSize int
	}{
		{
			width: 1920, height: 1080,
			lineSize: 2560, frameSize: 2_764_800, v210aSize: 8_294_400,
		},
		{
			width: 1280, height: 720,
			lineSize: 1708, frameSize: 1_229_760, v210aSize: 3_718_080,
		},
		{
			width: 100, height: 2,
			lineSize: 136, frameSize: 272, v210aSize: 1040,
		},
	}

	for _, tc := range tests {
		t.Run(fmt.Sprintf("%dx%d", tc.width, tc.height), func(t *testing.T) {
			if got := AlphaLineSize(tc.width); got != tc.lineSize {
				t.Errorf("AlphaLineSize(%d) = %d, want %d", tc.width, got, tc.lineSize)
			}
			if got := AlphaFrameSize(tc.width, tc.height); got != tc.frameSize {
				t.Errorf("AlphaFrameSize(%d, %d) = %d, want %d", tc.width, tc.height, got, tc.frameSize)
			}
			if got := V210AFrameSize(tc.width, tc.height); got != tc.v210aSize {
				t.Errorf("V210AFrameSize(%d, %d) = %d, want %d", tc.width, tc.height, got, tc.v210aSize)
			}
			if got := V210AFrameSize(tc.width, tc.height) - AlphaFrameSize(tc.width, tc.height); got != V210FrameSize(tc.width, tc.height) {
				t.Errorf("alpha plane starts at byte %d, want %d", got, V210FrameSize(tc.width, tc.height))
			}
		})
	}
}

func sampleV210(buf []byte, width, x, y int) (yc, cb, cr uint32) {
	offset := y*V210LineSize(width) + x/6*16
	w0 := binary.LittleEndian.Uint32(buf[offset:])
	w1 := binary.LittleEndian.Uint32(buf[offset+4:])
	w2 := binary.LittleEndian.Uint32(buf[offset+8:])
	w3 := binary.LittleEndian.Uint32(buf[offset+12:])

	switch x % 6 {
	case 0:
		return (w0 >> 10) & 0x3FF, w0 & 0x3FF, (w0 >> 20) & 0x3FF
	case 1:
		return w1 & 0x3FF, w0 & 0x3FF, (w0 >> 20) & 0x3FF
	case 2:
		return (w1 >> 20) & 0x3FF, (w1 >> 10) & 0x3FF, w2 & 0x3FF
	case 3:
		return (w2 >> 10) & 0x3FF, (w1 >> 10) & 0x3FF, w2 & 0x3FF
	case 4:
		return w3 & 0x3FF, (w2 >> 20) & 0x3FF, (w3 >> 10) & 0x3FF
	default:
		return (w3 >> 20) & 0x3FF, (w2 >> 20) & 0x3FF, (w3 >> 10) & 0x3FF
	}
}