const std = @import("std");
const color = @import("color");

const RGB = color.RGB;
const RGBA = color.RGBA;
const rgb = RGB.from_u24;

test "contrast white/yellow" {
    const a: u24 = 0xFFFFFF; // white
    const b: u24 = 0x00FFFF; // yellow
    const ratio = RGB.contrast(rgb(a), rgb(b));
    try std.testing.expectApproxEqAbs(ratio, 1.25388109, 0.000001);
}

test "contrast white/blue" {
    const a: u24 = 0xFFFFFF; // white
    const b: u24 = 0x0000FF; // blue
    const ratio = RGB.contrast(rgb(a), rgb(b));
    try std.testing.expectApproxEqAbs(ratio, 8.59247135, 0.000001);
}

test "contrast black/yellow" {
    const a: u24 = 0x000000; // black
    const b: u24 = 0x00FFFF; // yellow
    const ratio = RGB.contrast(rgb(a), rgb(b));
    try std.testing.expectApproxEqAbs(ratio, 16.7479991, 0.000001);
}

test "contrast black/blue" {
    const a: u24 = 0x000000; // black
    const b: u24 = 0x0000FF; // blue
    const ratio = RGB.contrast(rgb(a), rgb(b));
    try std.testing.expectApproxEqAbs(ratio, 2.444, 0.000001);
}

test "best contrast black/white to yellow" {
    const best = color.max_contrast(0x00FFFF, 0xFFFFFF, 0x000000);
    try std.testing.expectEqual(best, 0x000000);
}

test "best contrast black/white to blue" {
    const best = color.max_contrast(0x0000FF, 0xFFFFFF, 0x000000);
    try std.testing.expectEqual(best, 0xFFFFFF);
}

test "verify RGBA byte order" {
    const v1: RGBA = .init(0xA, 0xB, 0xC, 0xD);
    const v1_u32: u32 = @bitCast(v1);
    const v2: RGBA = .{
        .r = @truncate(v1_u32 >> 24),
        .g = @truncate(v1_u32 >> 16),
        .b = @truncate(v1_u32 >> 8),
        .a = @truncate(v1_u32),
    };
    const v3: RGBA = @bitCast(v1_u32);

    const testing = @import("std").testing;
    try testing.expectEqual(v1, v2);
    try testing.expectEqual(v1, v3);
}