import type { PaletteOptions, PalettePreset } from "./types.js";

/** Built-in foil colour schemes, keyed by {@link PalettePreset}. */
export const PALETTES: Record<PalettePreset, PaletteOptions> = {
  rainbow: {
    sunpillars: [
      "hsl(2, 100%, 73%)",
      "hsl(53, 100%, 69%)",
      "hsl(93, 100%, 69%)",
      "hsl(176, 100%, 76%)",
      "hsl(228, 100%, 74%)",
      "hsl(283, 100%, 73%)",
    ],
    spectrum: ["#f80e35", "#eedf10", "#21e985", "#0dbde9", "#c929f1"],
    cosmos: [
      "hsl(53, 65%, 60%)",
      "hsl(93, 56%, 50%)",
      "hsl(176, 54%, 49%)",
      "hsl(228, 59%, 55%)",
      "hsl(283, 60%, 55%)",
      "hsl(326, 59%, 51%)",
    ],
  },
  gold: {
    sunpillars: [
      "hsl(45, 100%, 80%)",
      "hsl(38, 100%, 68%)",
      "hsl(50, 100%, 78%)",
      "hsl(33, 95%, 62%)",
      "hsl(48, 100%, 85%)",
      "hsl(40, 100%, 70%)",
    ],
    spectrum: ["#8c5a12", "#ffd24a", "#fff0b0", "#e0962a", "#6b3f06"],
    cosmos: [
      "hsl(45, 80%, 65%)",
      "hsl(40, 75%, 58%)",
      "hsl(36, 70%, 52%)",
      "hsl(50, 85%, 70%)",
      "hsl(33, 65%, 48%)",
      "hsl(28, 70%, 55%)",
    ],
    edge: "hsl(45, 100%, 78%)",
    glow: "hsl(45, 100%, 80%)",
  },
  aurora: {
    sunpillars: [
      "hsl(150, 90%, 72%)",
      "hsl(170, 85%, 68%)",
      "hsl(190, 90%, 72%)",
      "hsl(260, 85%, 78%)",
      "hsl(140, 80%, 70%)",
      "hsl(200, 90%, 74%)",
    ],
    spectrum: ["#10b981", "#34d399", "#a7f3d0", "#22d3ee", "#8b5cf6"],
    cosmos: [
      "hsl(160, 60%, 55%)",
      "hsl(180, 55%, 50%)",
      "hsl(200, 60%, 55%)",
      "hsl(260, 55%, 58%)",
      "hsl(150, 55%, 52%)",
      "hsl(290, 50%, 55%)",
    ],
    edge: "hsl(160, 90%, 80%)",
    glow: "hsl(170, 100%, 85%)",
  },
  ruby: {
    sunpillars: [
      "hsl(350, 100%, 75%)",
      "hsl(330, 100%, 72%)",
      "hsl(10, 100%, 72%)",
      "hsl(300, 90%, 72%)",
      "hsl(355, 100%, 80%)",
      "hsl(20, 100%, 70%)",
    ],
    spectrum: ["#e11d48", "#fb7185", "#fecdd3", "#f43f5e", "#9f1239"],
    cosmos: [
      "hsl(350, 65%, 58%)",
      "hsl(330, 60%, 55%)",
      "hsl(10, 65%, 58%)",
      "hsl(300, 55%, 55%)",
      "hsl(355, 60%, 52%)",
      "hsl(20, 60%, 55%)",
    ],
    edge: "hsl(350, 100%, 82%)",
    glow: "hsl(345, 100%, 85%)",
  },
  sapphire: {
    sunpillars: [
      "hsl(210, 100%, 75%)",
      "hsl(190, 100%, 72%)",
      "hsl(230, 100%, 76%)",
      "hsl(170, 90%, 70%)",
      "hsl(250, 90%, 78%)",
      "hsl(200, 100%, 74%)",
    ],
    spectrum: ["#1d4ed8", "#3b82f6", "#bfdbfe", "#06b6d4", "#4338ca"],
    cosmos: [
      "hsl(210, 65%, 58%)",
      "hsl(190, 60%, 55%)",
      "hsl(230, 60%, 58%)",
      "hsl(170, 55%, 52%)",
      "hsl(250, 55%, 58%)",
      "hsl(200, 60%, 55%)",
    ],
    edge: "hsl(205, 100%, 80%)",
    glow: "hsl(200, 100%, 85%)",
  },
  mono: {
    sunpillars: [
      "hsl(0, 0%, 92%)",
      "hsl(0, 0%, 82%)",
      "hsl(0, 0%, 96%)",
      "hsl(0, 0%, 78%)",
      "hsl(0, 0%, 88%)",
      "hsl(0, 0%, 84%)",
    ],
    spectrum: ["#9ca3af", "#e5e7eb", "#ffffff", "#d1d5db", "#6b7280"],
    cosmos: [
      "hsl(0, 0%, 75%)",
      "hsl(0, 0%, 68%)",
      "hsl(0, 0%, 82%)",
      "hsl(0, 0%, 62%)",
      "hsl(0, 0%, 78%)",
      "hsl(0, 0%, 70%)",
    ],
    edge: "hsl(0, 0%, 90%)",
    glow: "hsl(0, 0%, 92%)",
  },
};

/** Merge a palette's `preset` base with its explicit overrides into a flat scheme. */
export const resolvePalette = (palette: PaletteOptions): PaletteOptions => {
  const base = palette.preset ? PALETTES[palette.preset] : undefined;
  const merged: PaletteOptions = { ...base, ...palette };
  delete merged.preset;
  return merged;
};

const SPECTRUM_VARS = ["--red", "--yellow", "--green", "--blue", "--violet"] as const;

/** Every CSS custom property the palette can own — used to clear stale values when swapping palettes. */
export const PALETTE_VARIABLES: string[] = [
  "--sunpillar-1",
  "--sunpillar-2",
  "--sunpillar-3",
  "--sunpillar-4",
  "--sunpillar-5",
  "--sunpillar-6",
  ...SPECTRUM_VARS,
  "--cosmos-clr-1",
  "--cosmos-clr-2",
  "--cosmos-clr-3",
  "--cosmos-clr-4",
  "--cosmos-clr-5",
  "--cosmos-clr-6",
  "--card-edge",
  "--card-back",
  "--card-glow",
];

const cycle = (colors: readonly string[], index: number): string => colors[index % colors.length] as string;

const cycleInto = (vars: Record<string, string>, prefix: string, count: number, colors: readonly string[]): void => {
  if (colors.length === 0) {
    return;
  }
  for (let i = 0; i < count; i += 1) {
    vars[`${prefix}${i + 1}`] = cycle(colors, i);
  }
};

/** Convert a (resolved or raw) palette into the CSS custom properties it drives. */
export const paletteToCssVariables = (palette: PaletteOptions): Record<string, string> => {
  const resolved = resolvePalette(palette);
  const vars: Record<string, string> = {};
  if (resolved.sunpillars) {
    cycleInto(vars, "--sunpillar-", 6, resolved.sunpillars);
  }
  const spectrum = resolved.spectrum;
  if (spectrum && spectrum.length > 0) {
    SPECTRUM_VARS.forEach((name, i) => {
      vars[name] = cycle(spectrum, i);
    });
  }
  if (resolved.cosmos) {
    cycleInto(vars, "--cosmos-clr-", 6, resolved.cosmos);
  }
  if (resolved.edge) {
    vars["--card-edge"] = resolved.edge;
  }
  if (resolved.back) {
    vars["--card-back"] = resolved.back;
  }
  if (resolved.glow) {
    vars["--card-glow"] = resolved.glow;
  }
  return vars;
};