import * as path from 'path';

import { ChannelManager } from '@squeebot/core/lib/channel';

import { PluginManager, PluginMetaLoader } from '@squeebot/core/lib/plugin';

import { RepositoryManager } from '@squeebot/core/lib/plugin/repository';

import { NPMExecutor } from '@squeebot/core/lib/npm';

import { Configuration, IEnvironment } from '@squeebot/core/lib/types';

import { ScopedEventEmitter } from '@squeebot/core/lib/util';

import { ISqueebotCore, logger } from '@squeebot/core/lib/core';

const defaultConfiguration: {[key: string]: any} = {
  channels: [],
  enabled: [],
  name: 'squeebot',
};

/**
 * Reference implementation of a Squeebot system using core classes.
 */
export class Squeebot implements ISqueebotCore {
  public npm: NPMExecutor = new NPMExecutor(this.environment, '@squeebot/core');

  public stream: ScopedEventEmitter = new ScopedEventEmitter();

  public pluginManager: PluginManager = new PluginManager(
    [],
    this.stream,
    this.environment,
    this.npm);

  public repositoryManager: RepositoryManager = new RepositoryManager(
    this.environment,
    this.pluginManager,
  );

  public channelManager: ChannelManager = new ChannelManager(this.stream);

  public pluginLoader: PluginMetaLoader = new PluginMetaLoader(
    this.environment,
  );

  public config: Configuration = new Configuration(
    this.environment,
    path.join(this.environment.configurationPath, 'squeebot.json'),
    defaultConfiguration,
  );

  private shuttingDown = false;

  constructor(public environment: IEnvironment) {}

  public async initialize(autostart = true): Promise<void> {
    // Load configuration
    await this.config.load();

    // Initialize npm executor
    await this.npm.loadPackageFile();

    // Load all plugins
    const plugins = await this.pluginLoader.loadAll();

    // Give manager all loaded manifests
    this.pluginManager.addAvailable(plugins);

    // Load repositories
    await this.repositoryManager.loadFromFiles();

    // Start channels
    this.channelManager.initialize(this.config.get('channels'));

    // Send core on request
    this.stream.on('core', 'request-core', (pl: string) =>
      this.stream.emitTo(pl, 'core', this));

    // Handle uncaught exceptions to prevent the whole bot from getting bricked
    process.on('uncaughtException', (err) => {
      logger.error('Process caught an unhandled exception:', err.stack);
      this.stream.emit('error', err);
    });

    // Handle uncaught rejections to prevent the whole bot from getting bricked
    process.on('unhandledRejection', (reason, promise) => {
      logger.error('Process caught an unhandled promise rejection:', reason);
      logger.error('In promise:', promise);

      const error = new Error(reason?.toString());
      error.name = 'unhandledRejection';
      this.stream.emit('error', error);
    });

    // Start enabled plugins
    if (autostart) {
      await this.startPlugins();
    }
  }

  public async startPlugins(): Promise<void> {
    for (const pluginName of this.config.get('enabled')) {
      const getManifest = this.pluginManager.getAvailableByName(pluginName);
      if (!getManifest) {
        logger.error(new Error(`Failed to start ${pluginName}: no manifest available. You might not have installed it.`));
        continue;
      }

      try {
        await this.pluginManager.load(getManifest);
      } catch (e: any) {
        logger.error('Failed to start %s:', pluginName, e.stack);
      }
    }
  }

  public attachReadline(rl: any): void {
    // Pass readline to logger
    logger.setReadline(rl);

    // Send readline on request
    this.stream.on('core', 'request-cli', () =>
      this.stream.emit('cli', rl));

    // Handle readline events
    rl.on('line', (l: string) => this.stream.emit('cli-line', l));
    rl.on('SIGINT', () => this.shutdown());
  }

  public shutdown(): void {
    if (this.shuttingDown) {
      return;
    }

    logger.warn('Shutting down..');
    this.shuttingDown = true;

    // Subsystems confirmed shutdown, go ahead and exit.
    this.stream.on('core', 'shutdown', (state: number) => {
      if (state > 0) {
        this.config.save().then((x) => process.exit(0));
      }
    });

    // Prompt subsystems to prepare for shutting down
    this.stream.emitTo('core', 'shutdown', 0);
  }
}