import fontFaces from './font-faces.json';

export interface FontOption {
  name: string;
  category: 'serif' | 'sans';
  google: boolean; // true = a Google Font we host ourselves in public/fonts; false = system font
  fallback: string;
}

/**
 * Curated font list for the admin "Design" editor. Kept in sync by hand with
 * admin/lib/fonts.js (duplicated rather than shared because the Astro site
 * is ESM/TS and the admin backend is CommonJS).
 */
export const FONT_OPTIONS: FontOption[] = [
  { name: 'Playfair Display', category: 'serif', google: true, fallback: "Georgia, 'Times New Roman', serif" },
  { name: 'Lora', category: 'serif', google: true, fallback: "Georgia, 'Times New Roman', serif" },
  { name: 'Merriweather', category: 'serif', google: true, fallback: "Georgia, 'Times New Roman', serif" },
  { name: 'Libre Baskerville', category: 'serif', google: true, fallback: "Georgia, 'Times New Roman', serif" },
  { name: 'DM Serif Display', category: 'serif', google: true, fallback: "Georgia, 'Times New Roman', serif" },
  { name: 'Georgia (Systemschrift)', category: 'serif', google: false, fallback: "Georgia, 'Times New Roman', serif" },
  { name: 'Inter', category: 'sans', google: true, fallback: "system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif" },
  { name: 'Roboto', category: 'sans', google: true, fallback: "system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif" },
  { name: 'Open Sans', category: 'sans', google: true, fallback: "system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif" },
  { name: 'Poppins', category: 'sans', google: true, fallback: "system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif" },
  { name: 'Montserrat', category: 'sans', google: true, fallback: "system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif" },
  { name: 'Nunito', category: 'sans', google: true, fallback: "system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif" },
  { name: 'Work Sans', category: 'sans', google: true, fallback: "system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif" },
  { name: 'Source Sans 3', category: 'sans', google: true, fallback: "system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif" },
  { name: 'System UI (Systemschrift)', category: 'sans', google: false, fallback: "system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif" },
];

export function findFont(name: string): FontOption {
  return FONT_OPTIONS.find((f) => f.name === name) || FONT_OPTIONS[0];
}

export function fontFamilyCss(name: string): string {
  const font = findFont(name);
  return font.google ? `'${font.name}', ${font.fallback}` : font.fallback;
}

/** Builds the @font-face rules for the given font names from the files in
 * public/fonts (see font-faces.json). The fonts are served from our own
 * server so a page view never contacts Google. System fonts are skipped. */
export function localFontFacesCss(fontNames: string[]): string {
  const faces = fontFaces as Record<string, { file: string; weight: string; unicodeRange: string }[]>;
  return fontNames
    .map(findFont)
    .filter((f) => f.google)
    .filter((f, i, arr) => arr.findIndex((g) => g.name === f.name) === i)
    .flatMap((f) =>
      (faces[f.name] || []).map(
        (face) =>
          `@font-face { font-family: '${f.name}'; font-style: normal; font-weight: ${face.weight}; ` +
          `font-display: swap; src: url('${face.file}') format('woff2'); unicode-range: ${face.unicodeRange}; }`,
      ),
    )
    .join('\n');
}

/** Builds `[data-font="Name"] { font-family: ...; }` rules for fonts used
 * inline via the rich-text editor's per-selection font picker. */
export function inlineFontFacesCss(fontNames: string[]): string {
  return fontNames.map((name) => `[data-font="${name}"] { font-family: ${fontFamilyCss(name)}; }`).join('\n');
}