import { readFile, writeFile } from 'fs/promises';

import { getArg } from './lib/args.js';
import { getMany } from './lib/dl.js';
import { error, log } from './lib/log.js';
import { createDb, userSchema } from './lib/schema.js';

const ctx = 'downloadDb.js';

/**
 * Downloads all media possible for the users stored in db.json at the specified `--path`.
 * Useful for first run or for augmenting existing media
 * if it may be only partially archived in an uncertain state.
 *
 * If the db.json is missing, it will be automatically created,
 * as this depends on users being defined in the db.json and not the folders present
 * (as there could be some users whose accounts no longer exist
 * or otherwise may not be maintained by the db.json anymore)
 */
const downloadDb = async () => {
  log(ctx, 'Grabbing db');
  let directory = '', threadMax = 1, db;
  try {
    directory = getArg('path');
  } catch (err) {
    error(ctx, err);
    return;
  }
  try {
    threadMax = getArg('threads');
    log(ctx, `Using ${threadMax} threads`);
  } catch (err) {
    log(ctx, 'Using 1 thread');
  }
  const tryReadDb = async () => {
    let file = await readFile(`${directory}/db.json`, { encoding: 'utf8' });
    db = JSON.parse(file);
  }
  try {
    await tryReadDb();
  } catch (err) {
    if (err.toString().includes('ENOENT')) {
      try {
        log(ctx, 'Database was not yet present. Creating it now.');
        await createDb();
        await tryReadDb();
      } catch (err2) {
        error(ctx, err2);
        return;
      }
    } else {
      error(ctx, err);
      return;
    }
  }

  let processes = [];
  Object.keys(db.userList).forEach(user => {
    processes.push({
      ...db.userList[user],
      user,
      lastUpdated: Date.now(),
      lastError: undefined,
      logs: [],
    })
  });

  log(ctx, `Downloading media using /<user>/media for ${processes.length} users`);
  await getMany(processes, threadMax, directory, 'media');

  const errorReadout = [];
  processes.forEach(entry => {
    entry.logs.forEach(log => {
      if (log.includes('NotFoundError')) {
        const strOut = `${entry.user} wasn't found: "${log.replace('\n', '')}". You may want to remove them from the db.json file or update their username.`;
        errorReadout.push(strOut);
        entry.lastError = strOut;
      } else if (log.includes('AuthorizationError')) {
        const strOut = `There was an authorization error for user ${entry.user}: "${log.replace('\n', '')}"`;
        errorReadout.push(strOut);
        entry.lastError = strOut;
      }
    });
  });

  log(ctx, 'Downloading media using /search');
  await getMany(processes, threadMax, directory, 'search');

  log(ctx, 'Updating the db');
  try {
    let updated = {
      ...db,
      userList: {
        ...db.userList,
        ...Object.fromEntries(processes.map(e => [e.user, userSchema(e)])),
      },
    }
    await writeFile(`${directory}/db.json`, JSON.stringify(updated, null, 2));
  } catch (err) {
    error(ctx, err);
    return;
  }

  log(ctx, 'Collecting errors');
  errorReadout.forEach(err => error(ctx, err));
  log(ctx, 'Done');
}

downloadDb();