import readline from 'node:readline';
import is from '@sindresorhus/is';
import { logger } from '../../../logger/index.ts';
import * as fs from '../../../util/fs/index.ts';
import type { ApkPackage } from './types.ts';

function applyApkIndexLine(
  line: string,
  packageInfo: Partial<ApkPackage>,
): void {
  const colonIndex = line.indexOf(':');
  if (colonIndex === -1) {
    return;
  }

  // get fields based on the PKGINFO spec - https://wiki.alpinelinux.org/wiki/Apk_spec
  const key = line.substring(0, colonIndex);
  const value = line.substring(colonIndex + 1).trim();

  switch (key) {
    case 'P':
      packageInfo.name = value;
      break;
    case 'V':
      packageInfo.version = value;
      break;
    case 'U':
      packageInfo.url = value;
      break;
    case 't':
      packageInfo.buildDate = parseInt(value, 10);
      break;
    default:
      break;
  }
}

function flushApkPackage(packageInfo: Partial<ApkPackage>): ApkPackage | null {
  if (packageInfo.name && packageInfo.version) {
    return packageInfo as ApkPackage;
  }
  if (is.nonEmptyObject(packageInfo)) {
    logger.warn(
      { packageInfo },
      'Skipping package entry due to missing required fields',
    );
  }
  return null;
}

/**
 * Parses an APK index file line-by-line to avoid loading large indexes into memory.
 *
 * @param extractedFile - Path to the extracted `APKINDEX` file (relative to Renovate cache).
 */
export async function parseApkIndexFile(
  extractedFile: string,
): Promise<ApkPackage[]> {
  logger.debug(`Parsing APK index file ${extractedFile}`);

  const packages: ApkPackage[] = [];
  const rl = readline.createInterface({
    input: fs.createCacheReadStream(extractedFile),
    terminal: false,
  });

  let packageInfo: Partial<ApkPackage> = {};

  for await (const line of rl) {
    if (line === '') {
      const pkg = flushApkPackage(packageInfo);
      if (pkg) {
        packages.push(pkg);
      }
      packageInfo = {};
    } else {
      applyApkIndexLine(line, packageInfo);
    }
  }

  const last = flushApkPackage(packageInfo);
  if (last) {
    packages.push(last);
  }

  logger.debug(`Parsed ${packages.length} packages from APK index`);
  return packages;
}