import { NeedlescriptError } from './errors.ts';
import { didYouMean } from './suggestions.ts';

export const DEFAULT_PALETTE = [
  '#c8472f',
  '#31604f',
  '#3a4e8c',
  '#d9a441',
  '#8c4a6b',
  '#2b2b2b',
  '#5e8f8c',
  '#b8651b',
] as const;

export const DEFAULT_BACKGROUND = '#f5efe4';

const COLOR_RGB: Record<string, readonly [number, number, number]> = {
  aliceblue: [240, 248, 255],
  antiquewhite: [250, 235, 215],
  aqua: [0, 255, 255],
  aquamarine: [127, 255, 212],
  azure: [240, 255, 255],
  beige: [245, 245, 220],
  bisque: [255, 228, 196],
  black: [0, 0, 0],
  blanchedalmond: [255, 235, 205],
  blue: [0, 0, 255],
  blueviolet: [138, 43, 226],
  brown: [165, 42, 42],
  burlywood: [222, 184, 135],
  cadetblue: [95, 158, 160],
  chartreuse: [127, 255, 0],
  chocolate: [210, 105, 30],
  coral: [255, 127, 80],
  cornflowerblue: [100, 149, 237],
  cornsilk: [255, 248, 220],
  crimson: [220, 20, 60],
  cyan: [0, 255, 255],
  darkblue: [0, 0, 139],
  darkcyan: [0, 139, 139],
  darkgoldenrod: [184, 134, 11],
  darkgray: [169, 169, 169],
  darkgreen: [0, 100, 0],
  darkgrey: [169, 169, 169],
  darkkhaki: [189, 183, 107],
  darkmagenta: [139, 0, 139],
  darkolivegreen: [85, 107, 47],
  darkorange: [255, 140, 0],
  darkorchid: [153, 50, 204],
  darkred: [139, 0, 0],
  darksalmon: [233, 150, 122],
  darkseagreen: [143, 188, 143],
  darkslateblue: [72, 61, 139],
  darkslategray: [47, 79, 79],
  darkslategrey: [47, 79, 79],
  darkturquoise: [0, 206, 209],
  darkviolet: [148, 0, 211],
  deeppink: [255, 20, 147],
  deepskyblue: [0, 191, 255],
  dimgray: [105, 105, 105],
  dimgrey: [105, 105, 105],
  dodgerblue: [30, 144, 255],
  firebrick: [178, 34, 34],
  floralwhite: [255, 250, 240],
  forestgreen: [34, 139, 34],
  fuchsia: [255, 0, 255],
  gainsboro: [220, 220, 220],
  ghostwhite: [248, 248, 255],
  gold: [255, 215, 0],
  goldenrod: [218, 165, 32],
  gray: [128, 128, 128],
  green: [0, 128, 0],
  greenyellow: [173, 255, 47],
  grey: [128, 128, 128],
  honeydew: [240, 255, 240],
  hotpink: [255, 105, 180],
  indianred: [205, 92, 92],
  indigo: [75, 0, 130],
  ivory: [255, 255, 240],
  khaki: [240, 230, 140],
  lavender: [230, 230, 250],
  lavenderblush: [255, 240, 245],
  lawngreen: [124, 252, 0],
  lemonchiffon: [255, 250, 205],
  lightblue: [173, 216, 230],
  lightcoral: [240, 128, 128],
  lightcyan: [224, 255, 255],
  lightgoldenrodyellow: [250, 250, 210],
  lightgray: [211, 211, 211],
  lightgreen: [144, 238, 144],
  lightgrey: [211, 211, 211],
  lightpink: [255, 182, 193],
  lightsalmon: [255, 160, 122],
  lightseagreen: [32, 178, 170],
  lightskyblue: [135, 206, 250],
  lightslategray: [119, 136, 153],
  lightslategrey: [119, 136, 153],
  lightsteelblue: [176, 196, 222],
  lightyellow: [255, 255, 224],
  lime: [0, 255, 0],
  limegreen: [50, 205, 50],
  linen: [250, 240, 230],
  magenta: [255, 0, 255],
  maroon: [128, 0, 0],
  mediumaquamarine: [102, 205, 170],
  mediumblue: [0, 0, 205],
  mediumorchid: [186, 85, 211],
  mediumpurple: [147, 112, 219],
  mediumseagreen: [60, 179, 113],
  mediumslateblue: [123, 104, 238],
  mediumspringgreen: [0, 250, 154],
  mediumturquoise: [72, 209, 204],
  mediumvioletred: [199, 21, 133],
  midnightblue: [25, 25, 112],
  mintcream: [245, 255, 250],
  mistyrose: [255, 228, 225],
  moccasin: [255, 228, 181],
  navajowhite: [255, 222, 173],
  navy: [0, 0, 128],
  oldlace: [253, 245, 230],
  olive: [128, 128, 0],
  olivedrab: [107, 142, 35],
  orange: [255, 165, 0],
  orangered: [255, 69, 0],
  orchid: [218, 112, 214],
  palegoldenrod: [238, 232, 170],
  palegreen: [152, 251, 152],
  paleturquoise: [175, 238, 238],
  palevioletred: [219, 112, 147],
  papayawhip: [255, 239, 213],
  peachpuff: [255, 218, 185],
  peru: [205, 133, 63],
  pink: [255, 192, 203],
  plum: [221, 160, 221],
  powderblue: [176, 224, 230],
  purple: [128, 0, 128],
  rebeccapurple: [102, 51, 153],
  red: [255, 0, 0],
  rosybrown: [188, 143, 143],
  royalblue: [65, 105, 225],
  saddlebrown: [139, 69, 19],
  salmon: [250, 128, 114],
  sandybrown: [244, 164, 96],
  seagreen: [46, 139, 87],
  seashell: [255, 245, 238],
  sienna: [160, 82, 45],
  silver: [192, 192, 192],
  skyblue: [135, 206, 235],
  slateblue: [106, 90, 205],
  slategray: [112, 128, 144],
  slategrey: [112, 128, 144],
  snow: [255, 250, 250],
  springgreen: [0, 255, 127],
  steelblue: [70, 130, 180],
  tan: [210, 180, 140],
  teal: [0, 128, 128],
  thistle: [216, 191, 216],
  tomato: [255, 99, 71],
  turquoise: [64, 224, 208],
  violet: [238, 130, 238],
  wheat: [245, 222, 179],
  white: [255, 255, 255],
  whitesmoke: [245, 245, 245],
  yellow: [255, 255, 0],
  yellowgreen: [154, 205, 50],
};

const channelHex = (n: number) =>
  Math.round(Math.min(255, Math.max(0, n)))
    .toString(16)
    .padStart(2, '0');
const fromRgb = ([r, g, b]: readonly number[]) =>
  `#${channelHex(r)}${channelHex(g)}${channelHex(b)}`;

export const COLOR_NAMES: Readonly<Record<string, string>> = Object.fromEntries(
  Object.entries(COLOR_RGB).map(([name, channels]) => [name, fromRgb(channels)]),
);

export interface ParsedColor {
  hex: string;
  name?: string;
}

export function parseColor(value: string, line?: number): string {
  return parseColorDetails(value, line).hex;
}

export function parseColorDetails(value: string, line?: number): ParsedColor {
  if (value.startsWith('#')) {
    if (/^#[0-9a-f]{8}$/i.test(value))
      throw new NeedlescriptError(
        `Color '${value}' has an alpha channel, but thread is opaque`,
        line,
      );
    if (!/^#[0-9a-f]{3}(?:[0-9a-f]{3})?$/i.test(value))
      throw new NeedlescriptError(
        `Malformed color '${value}' — use #rgb or #rrggbb (no alpha)`,
        line,
      );
    const raw = value.slice(1).toLowerCase();
    return { hex: raw.length === 3 ? `#${[...raw].map((c) => c + c).join('')}` : `#${raw}` };
  }
  const name = value.toLowerCase();
  const hex = COLOR_NAMES[name];
  if (!hex)
    throw new NeedlescriptError(
      `Unknown color '${value}'${didYouMean(name, Object.keys(COLOR_NAMES))} — hex colors start with #`,
      line,
    );
  return { hex, name };
}

export function hexParts(color: string, line?: number): [number, number, number] {
  const hex = parseColor(color, line);
  return [1, 3, 5].map((i) => parseInt(hex.slice(i, i + 2), 16)) as [number, number, number];
}

export function rgb(r: number, g: number, b: number): string {
  return fromRgb([r, g, b]);
}

export function hsl(h: number, s: number, l: number): string {
  h = ((h % 360) + 360) % 360;
  s = Math.min(1, Math.max(0, s));
  l = Math.min(1, Math.max(0, l));
  const c = (1 - Math.abs(2 * l - 1)) * s;
  const x = c * (1 - Math.abs(((h / 60) % 2) - 1));
  const m = l - c / 2;
  const [r, g, b] =
    h < 60
      ? [c, x, 0]
      : h < 120
        ? [x, c, 0]
        : h < 180
          ? [0, c, x]
          : h < 240
            ? [0, x, c]
            : h < 300
              ? [x, 0, c]
              : [c, 0, x];
  return rgb((r + m) * 255, (g + m) * 255, (b + m) * 255);
}

export type OKLab = [number, number, number];
const linear = (v: number) => (v <= 0.04045 ? v / 12.92 : Math.pow((v + 0.055) / 1.055, 2.4));
const gamma = (v: number) => (v <= 0.0031308 ? 12.92 * v : 1.055 * Math.pow(v, 1 / 2.4) - 0.055);

export function oklab(color: string, line?: number): OKLab {
  const [r8, g8, b8] = hexParts(color, line);
  const r = linear(r8 / 255),
    g = linear(g8 / 255),
    b = linear(b8 / 255);
  const l = Math.cbrt(0.4122214708 * r + 0.5363325363 * g + 0.0514459929 * b);
  const m = Math.cbrt(0.2119034982 * r + 0.6806995451 * g + 0.1073969566 * b);
  const s = Math.cbrt(0.0883024619 * r + 0.2817188376 * g + 0.6299787005 * b);
  return [
    0.2104542553 * l + 0.793617785 * m - 0.0040720468 * s,
    1.9779984951 * l - 2.428592205 * m + 0.4505937099 * s,
    0.0259040371 * l + 0.7827717662 * m - 0.808675766 * s,
  ];
}

export function unoklab([L, a, b]: OKLab): string {
  const l = Math.pow(L + 0.3963377774 * a + 0.2158037573 * b, 3);
  const m = Math.pow(L - 0.1055613458 * a - 0.0638541728 * b, 3);
  const s = Math.pow(L - 0.0894841775 * a - 1.291485548 * b, 3);
  return rgb(
    gamma(4.0767416621 * l - 3.3077115913 * m + 0.2309699292 * s) * 255,
    gamma(-1.2684380046 * l + 2.6097574011 * m - 0.3413193965 * s) * 255,
    gamma(-0.0041960863 * l - 0.7034186147 * m + 1.707614701 * s) * 255,
  );
}

export function colorDist(a: string, b: string, line?: number): number {
  const x = oklab(a, line),
    y = oklab(b, line);
  return Math.hypot(x[0] - y[0], x[1] - y[1], x[2] - y[2]);
}

export function lerpColor(a: string, b: string, t: number, mode = 'oklab', line?: number): string {
  t = Math.min(1, Math.max(0, t));
  if (mode === 'rgb') {
    const x = hexParts(a, line),
      y = hexParts(b, line);
    return rgb(x[0] + (y[0] - x[0]) * t, x[1] + (y[1] - x[1]) * t, x[2] + (y[2] - x[2]) * t);
  }
  if (mode !== 'oklab')
    throw new NeedlescriptError(`lerpcolor mode must be 'oklab' or 'rgb'`, line);
  const x = oklab(a, line),
    y = oklab(b, line);
  return unoklab([x[0] + (y[0] - x[0]) * t, x[1] + (y[1] - x[1]) * t, x[2] + (y[2] - x[2]) * t]);
}

export function defaultSlotColor(index: number): string {
  return DEFAULT_PALETTE[
    ((index % DEFAULT_PALETTE.length) + DEFAULT_PALETTE.length) % DEFAULT_PALETTE.length
  ];
}