import { existsSync, readFileSync } from "node:fs";
import { resolve } from "node:path";

// Expose the monorepo-root .env to server-side `process.env.*` reads (see note
// in CLAUDE.md / the original config — never use nextConfig.env for secrets).
const envPath = resolve(import.meta.dirname, "../../.env");
if (existsSync(envPath)) {
  for (const line of readFileSync(envPath, "utf-8").split("\n")) {
    const trimmed = line.trim();
    if (!trimmed || trimmed.startsWith("#")) continue;
    const eq = trimmed.indexOf("=");
    if (eq < 0) continue;
    const key = trimmed.slice(0, eq).trim();
    if (key && process.env[key] === undefined) process.env[key] = trimmed.slice(eq + 1).trim();
  }
}

// Workspace server packages the web service imports in-process. Next's webpack
// must NOT bundle them (they reach @remotion/bundler → esbuild, which webpack
// can't bundle). serverExternalPackages alone does NOT stop Next from following
// workspace symlinks and bundling these, so we also force them external on the
// server build below. At runtime they're required from node_modules as built dist.
const EXTERNALS = [
  "@pipeline/core",
  "@pipeline/text",
  "@pipeline/audio",
  "@pipeline/renderer",
  "@pipeline/tts",
  "@pipeline/collect",
];

/** @type {import('next').NextConfig} */
const nextConfig = {
  transpilePackages: ["@pipeline/shared"],
  serverExternalPackages: [
    "@remotion/bundler",
    "@remotion/renderer",
    "@remotion/media-utils",
    "esbuild",
    "ali-oss",
  ],
  webpack: (config, { isServer }) => {
    if (isServer) {
      // `@pipeline/*` are ESM-only workspace packages (type:module, exports
      // with only `import`/`types` conditions). Next's webpack must NOT bundle
      // them (they reach @remotion/bundler → esbuild). We force them external,
      // but as **module**-type externals so webpack emits a NATIVE `import()`
      // for the lazy `await import("@pipeline/...")` calls. A `commonjs`
      // external would rewrite those to `require()`, which Node's CJS resolver
      // rejects on an ESM-only package ("ERR_PACKAGE_PATH_NOT_EXPORTED: No
      // 'exports' main defined"). `import()` is valid inside the CJS server
      // bundle and resolves the `import` export condition at runtime.
      const prev = config.externals;
      const prevArr = Array.isArray(prev) ? prev : prev ? [prev] : [];
      config.externals = [
        ...prevArr,
        ({ request }, callback) => {
          if (EXTERNALS.some((p) => request === p || request.startsWith(p + "/"))) {
            return callback(null, request, "module");
          }
          callback();
        },
      ];
    }
    return config;
  },
};

export default nextConfig;