import { encodeBase64 } from 'https://deno.land/std@0.224.0/encoding/base64.ts';
import { ensureFile } from 'https://deno.land/std@0.224.0/fs/mod.ts';

/**
 * { [path]: base64EncodedContent }
 */
type StaticFilesRecord = Record<string, string>;

/**
 * Traverse a directory recursively, adding every base64 encoded file content to the record.
 * 
 * @param staticFileRecord the record in which to add base64 encoded file content 
 * @param root the path of the root directory for traversal, that should not be included in the record file path
 * @param subdir the current subdir to traverse
 */
async function traverse(
  staticFileRecord: StaticFilesRecord,
  root: string,
  subdir: string = '',
) {
  for await (const dirEntry of Deno.readDir(`${root}/${subdir}`)) {
    const path = `${subdir}/${dirEntry.name}`.slice(1);
    console.log(`encoding: ${path}`);
    if (dirEntry.isDirectory) {
      await traverse(staticFileRecord, root, `${subdir}/${dirEntry.name}`);
    } else {
      staticFileRecord[path] = encodeBase64(
        await Deno.readFile(
          `${root}/${subdir}/${dirEntry.name}`,
        ),
      );
    }
  }
}

/**
 * Bundle all files of the given directory into a single json file at the given path.
 * 
 * @param sourceDir path of the directory to bundle 
 * @param bundleFilePath path of the json file
 */
async function buildFromDir(
  sourceDir: string,
  bundleFilePath: string,
) {
  const staticFiles: StaticFilesRecord = {};
  await traverse(staticFiles, sourceDir);

  await ensureFile(bundleFilePath);
  await Deno.writeTextFile(bundleFilePath, JSON.stringify(staticFiles));
}

if (Deno.args.length !== 2) {
  console.error('Incorrect usage: Two parameters expected !');
  console.error('<script> view-dist-directory json-bundle-file');
  Deno.exit(1);
}

await buildFromDir(Deno.args[0], Deno.args[1]);