import path from 'node:path';
import { readJson, writeJson, ensureDir } from '../utils/fs.js';

export interface PageAssetManifest {
  js?: string;
  css?: string;
}

export interface AssetManifest {
  pages: Record<string, PageAssetManifest>;
  shared?: SharedAssets;
}

export interface SharedAssets {
  css?: string;
  js?: string;
}

const MANIFEST_FILENAME = 'manifest.json';

export async function updatePageManifest(
  directory: string,
  pageName: string,
  updater: (value: PageAssetManifest) => void,
): Promise<void> {
  const manifestPath = path.join(directory, MANIFEST_FILENAME);
  await ensureDir(directory);
  const manifest = (await readJson<AssetManifest>(manifestPath)) ?? { pages: {} };
  const pageManifest: PageAssetManifest = manifest.pages[pageName] ?? {};
  updater(pageManifest);
  manifest.pages[pageName] = pageManifest;
  await writeJson(manifestPath, manifest);
}

export async function readPageManifest(
  directory: string,
  pageName: string,
): Promise<PageAssetManifest> {
  const manifestPath = path.join(directory, MANIFEST_FILENAME);
  const manifest = (await readJson<AssetManifest>(manifestPath)) ?? { pages: {} };
  return manifest.pages[pageName] ?? {};
}

export async function updateSharedAssets(
  directory: string,
  updater: (value: SharedAssets) => void,
): Promise<void> {
  const manifestPath = path.join(directory, MANIFEST_FILENAME);
  await ensureDir(directory);
  const manifest = (await readJson<AssetManifest>(manifestPath)) ?? { pages: {} };
  const shared: SharedAssets = manifest.shared ?? {};
  updater(shared);
  manifest.shared = shared;
  await writeJson(manifestPath, manifest);
}

export async function readSharedAssets(directory: string): Promise<SharedAssets | null> {
  const manifestPath = path.join(directory, MANIFEST_FILENAME);
  const manifest = await readJson<AssetManifest>(manifestPath);
  return manifest?.shared ?? null;
}