/**
 * Generate embedded font data for deterministic font injection.
 *
 * Reads woff2 files from @fontsource/* packages at build time and produces
 * a TypeScript module with base64 data URIs. This eliminates the runtime
 * dependency on @fontsource packages, making the CLI self-contained when
 * bundled via tsup.
 *
 * Usage: tsx scripts/generate-font-data.ts
 */

import { readdirSync, readFileSync, writeFileSync } from "node:fs";
import { createRequire } from "node:module";
import { dirname, join, resolve } from "node:path";
import { fileURLToPath } from "node:url";

const require = createRequire(import.meta.url);
const __dirname = dirname(fileURLToPath(import.meta.url));

type FontFaceSpec = { weight: string; style?: "normal" | "italic" };
type CanonicalFontSpec = { packageName: string; faces: FontFaceSpec[] };

// Mirror of CANONICAL_FONTS from deterministicFonts.ts — single source of truth
const CANONICAL_FONTS: Record<string, CanonicalFontSpec> = {
  inter: {
    packageName: "@fontsource/inter",
    faces: [{ weight: "400" }, { weight: "700" }, { weight: "900" }],
  },
  montserrat: {
    packageName: "@fontsource/montserrat",
    faces: [{ weight: "400" }, { weight: "700" }, { weight: "900" }],
  },
  outfit: {
    packageName: "@fontsource/outfit",
    faces: [{ weight: "400" }, { weight: "700" }, { weight: "900" }],
  },
  nunito: {
    packageName: "@fontsource/nunito",
    faces: [{ weight: "400" }, { weight: "700" }, { weight: "900" }],
  },
  oswald: {
    packageName: "@fontsource/oswald",
    faces: [{ weight: "400" }, { weight: "700" }],
  },
  "league-gothic": {
    packageName: "@fontsource/league-gothic",
    faces: [{ weight: "400" }],
  },
  "archivo-black": {
    packageName: "@fontsource/archivo-black",
    faces: [{ weight: "400" }],
  },
  "space-mono": {
    packageName: "@fontsource/space-mono",
    faces: [{ weight: "400" }, { weight: "700" }],
  },
  "ibm-plex-mono": {
    packageName: "@fontsource/ibm-plex-mono",
    faces: [{ weight: "400" }, { weight: "700" }],
  },
  "jetbrains-mono": {
    packageName: "@fontsource/jetbrains-mono",
    faces: [{ weight: "400" }, { weight: "700" }],
  },
  "eb-garamond": {
    packageName: "@fontsource/eb-garamond",
    faces: [{ weight: "400" }, { weight: "700" }],
  },
  "playfair-display": {
    packageName: "@fontsource/playfair-display",
    faces: [{ weight: "400" }, { weight: "700" }, { weight: "900" }],
  },
  "source-code-pro": {
    packageName: "@fontsource/source-code-pro",
    faces: [{ weight: "400" }, { weight: "700" }],
  },
  "noto-sans-jp": {
    packageName: "@fontsource/noto-sans-jp",
    faces: [{ weight: "400" }, { weight: "700" }],
  },
  roboto: {
    packageName: "@fontsource/roboto",
    faces: [{ weight: "400" }, { weight: "700" }, { weight: "900" }],
  },
  "open-sans": {
    packageName: "@fontsource/open-sans",
    faces: [{ weight: "400" }, { weight: "700" }],
  },
  lato: {
    packageName: "@fontsource/lato",
    faces: [{ weight: "400" }, { weight: "700" }, { weight: "900" }],
  },
  poppins: {
    packageName: "@fontsource/poppins",
    faces: [{ weight: "400" }, { weight: "700" }, { weight: "900" }],
  },
};

function packageRoot(packageName: string): string {
  const packageJsonPath = require.resolve(`${packageName}/package.json`);
  return dirname(packageJsonPath);
}

function resolveFontFile(
  packageName: string,
  weight: string,
  style: "normal" | "italic" = "normal",
): string {
  const root = packageRoot(packageName);
  const filesDir = join(root, "files");
  const slug = packageName.replace("@fontsource/", "");
  const files = readdirSync(filesDir);

  const exact = `${slug}-latin-${weight}-${style}.woff2`;
  if (files.includes(exact)) {
    return join(filesDir, exact);
  }

  const relaxed = files.find((file) => {
    return file.endsWith(`-${weight}-${style}.woff2`) && file.includes("-latin-");
  });
  if (relaxed) {
    return join(filesDir, relaxed);
  }

  throw new Error(`No font asset found for ${packageName} weight=${weight} style=${style}`);
}

function main() {
  const entries: Array<{ key: string; dataUri: string }> = [];
  let totalBytes = 0;

  for (const [, spec] of Object.entries(CANONICAL_FONTS)) {
    for (const face of spec.faces) {
      const style = face.style || "normal";
      const key = `${spec.packageName}:${face.weight}:${style}`;
      const fontPath = resolveFontFile(spec.packageName, face.weight, style);
      const content = readFileSync(fontPath);
      totalBytes += content.length;
      const dataUri = `data:font/woff2;base64,${content.toString("base64")}`;
      entries.push({ key, dataUri });
    }
  }

  const lines = [
    "/**",
    " * AUTO-GENERATED — do not edit manually.",
    ` * Generated by: scripts/generate-font-data.ts`,
    ` * ${entries.length} font faces, ${Math.round(totalBytes / 1024)}KB raw woff2`,
    " */",
    "",
    "export const EMBEDDED_FONT_DATA: ReadonlyMap<string, string> = new Map([",
  ];

  for (const entry of entries) {
    lines.push(`  ["${entry.key}", "${entry.dataUri}"],`);
  }

  lines.push("]);");
  lines.push("");

  const outputPath = resolve(__dirname, "../src/services/fontData.generated.ts");
  writeFileSync(outputPath, lines.join("\n"), "utf8");
  console.log(
    `[generate-font-data] Wrote ${entries.length} font faces (${Math.round(totalBytes / 1024)}KB) → ${outputPath}`,
  );
}

main();