import {
  Plugin,
  EventListener,
  Configurable,
  IPluginManifest,
  IPlugin,
} from '@squeebot/core/lib/plugin';

import { IChannel } from '@squeebot/core/lib/channel';
import { IRepoPluginDef, IRepository } from '@squeebot/core/lib/plugin/repository';
import { ISqueebotCore, logger } from '@squeebot/core/lib/core';

import path from 'path';
import fs from 'fs/promises';
import tls, { TLSSocket } from 'tls';
import net, { Server, Socket } from 'net';

interface ControlCommand {
  execute: Function;
  name: string;
  plugin: string;
}

let controlCommands: ControlCommand[] = [
  {
    name: 'loadPlugin',
    plugin: 'control',
    execute: async (p: ControlPlugin, plugin: string): Promise<void> => {
      if (!plugin) {
        throw new Error('This function takes 1 argument.');
      }
      p.stream.emitTo('core', 'pluginLoad', plugin);
    },
  },
  {
    name: 'unloadPlugin',
    plugin: 'control',
    execute: async (p: ControlPlugin, plugin: string): Promise<void> => {
      if (!plugin) {
        throw new Error('This function takes 1 argument.');
      }
      p.stream.emitTo(plugin, 'pluginUnload', plugin);
    },
  },
  {
    name: 'listActivePlugins',
    plugin: 'control',
    execute: async (p: ControlPlugin): Promise<IPluginManifest[]> => {
      return p.core!.pluginManager.getLoaded().map((x: IPlugin) => x.manifest);
    },
  },
  {
    name: 'listInstalledPlugins',
    plugin: 'control',
    execute: async (p: ControlPlugin): Promise<IPluginManifest[]> => {
      return p.core!.pluginManager.availablePlugins;
    },
  },
  {
    name: 'installPlugin',
    plugin: 'control',
    execute: async (p: ControlPlugin, plugin: string): Promise<IPluginManifest> => {
      if (!plugin) {
        throw new Error('This function takes 1 argument.');
      }
      return p.core!.repositoryManager.installPlugin(plugin);
    },
  },
  {
    name: 'uninstallPlugin',
    plugin: 'control',
    execute: async (p: ControlPlugin, plugin: string): Promise<void> => {
      if (!plugin) {
        throw new Error('This function takes 1 argument.');
      }
      return p.core!.repositoryManager.uninstallPlugin(plugin);
    },
  },
  {
    name: 'enablePlugin',
    plugin: 'control',
    execute: async (p: ControlPlugin, plugin: string): Promise<void> => {
      if (!plugin) {
        throw new Error('This function takes 1 argument.');
      }
      if (!p.core!.pluginManager.getAvailableByName(plugin)) {
        throw new Error('No such plugin is available.');
      }

      if (!p.core!.config.config.enabled) {
        p.core!.config.config.enabled = [plugin];
      } else if (p.core!.config.config.enabled.indexOf(plugin) === -1) {
        p.core!.config.config.enabled.push(plugin);
      }

      return p.core!.config.save();
    },
  },
  {
    name: 'disablePlugin',
    plugin: 'control',
    execute: async (p: ControlPlugin, plugin: string): Promise<void> => {
      if (!plugin) {
        throw new Error('This function takes 1 argument.');
      }
      if (!p.core!.pluginManager.getAvailableByName(plugin)) {
        throw new Error('No such plugin is available.');
      }
      if (!p.core!.config.config.enabled) {
        return;
      }
      const indx = p.core!.config.config.enabled.indexOf(plugin);

      if (indx > -1) {
        p.core!.config.config.enabled.splice(indx, 1);
      }

      return p.core!.config.save();
    },
  },
  {
    name: 'installRepository',
    plugin: 'control',
    execute: async (p: ControlPlugin, url: string): Promise<IRepository> => {
      if (!url) {
        throw new Error('This function takes 1 argument.');
      }
      return p.core!.repositoryManager.installRepository(url);
    },
  },
  {
    name: 'uninstallRepository',
    plugin: 'control',
    execute: async (p: ControlPlugin, repo: string): Promise<void> => {
      if (!repo) {
        throw new Error('This function takes 1 argument.');
      }
      return p.core!.repositoryManager.uninstallRepository(repo);
    },
  },
  {
    name: 'listRepositoryPlugins',
    plugin: 'control',
    execute: async (p: ControlPlugin, repo: string): Promise<IRepoPluginDef[]> => {
      if (!repo) {
        throw new Error('This function takes 1 argument.');
      }
      const repoData = p.core!.repositoryManager.getRepoByName(repo);
      if (!repoData) {
        throw new Error('No such repository found.');
      }
      return repoData.plugins;
    },
  },
  {
    name: 'listRepositories',
    plugin: 'control',
    execute: async (p: ControlPlugin): Promise<IRepository[]> => {
      return p.core!.repositoryManager.getAll();
    },
  },
  {
    name: 'updateRepository',
    plugin: 'control',
    execute: async (p: ControlPlugin, repo: string): Promise<IPluginManifest[]> => {
      if (!repo) {
        throw new Error('This function takes 1 argument.');
      }
      const repoData = p.core!.repositoryManager.getRepoByName(repo);
      if (!repoData) {
        throw new Error('No such repository found.');
      }
      return p.core!.repositoryManager.checkForUpdates(repoData);
    },
  },
  {
    name: 'newChannel',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string, plugins?: string[]): Promise<void> => {
      if (!name) {
        throw new Error('This function takes 1 argument.');
      }
      if (p.core!.channelManager.getChannelByName(name)) {
        throw new Error('A channel by that name already exists!');
      }

      p.core!.channelManager.addChannel({
        name,
        plugins: plugins || [],
        enabled: true,
      });
    },
  },
  {
    name: 'removeChannel',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string): Promise<void> => {
      if (!name) {
        throw new Error('This function takes 1 argument.');
      }
      const chan = p.core!.channelManager.getChannelByName(name);
      if (!chan) {
        throw new Error('A channel by that name does not exists!');
      }

      p.core!.channelManager.removeChannel(chan);
    },
  },
  {
    name: 'enableChannel',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string): Promise<void> => {
      if (!name) {
        throw new Error('This function takes 1 argument.');
      }
      const chan = p.core!.channelManager.getChannelByName(name);
      if (!chan) {
        throw new Error('A channel by that name does not exists!');
      }

      chan.enabled = true;
      p.core!.config.config.channels = p.core!.channelManager.getAll();
      await p.core!.config.save();
    },
  },
  {
    name: 'disableChannel',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string): Promise<void> => {
      if (!name) {
        throw new Error('This function takes 1 argument.');
      }
      const chan = p.core!.channelManager.getChannelByName(name);
      if (!chan) {
        throw new Error('A channel by that name does not exists!');
      }

      chan.enabled = false;
      p.core!.config.config.channels = p.core!.channelManager.getAll();
      await p.core!.config.save();
    },
  },
  {
    name: 'addChannelPlugin',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string, plugins: string | string[]): Promise<void> => {
      if (!name || !plugins) {
        throw new Error('This function takes 2 arguments.');
      }
      const chan = p.core!.channelManager.getChannelByName(name);
      if (!chan) {
        throw new Error('A channel by that name does not exists!');
      }
      if (!Array.isArray(plugins)) {
        plugins = [plugins];
      }
      for (const plugin of plugins) {
        if (chan.plugins.indexOf(plugin) === -1) {
          chan.plugins.push(plugin);
        }
      }
    },
  },
  {
    name: 'removeChannelPlugin',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string, plugins: string | string[]): Promise<void> => {
      if (!name || !plugins) {
        throw new Error('This function takes 2 arguments.');
      }
      const chan = p.core!.channelManager.getChannelByName(name);
      if (!chan) {
        throw new Error('A channel by that name does not exists!');
      }
      if (!Array.isArray(plugins)) {
        plugins = [plugins];
      }
      for (const plugin of plugins) {
        const idx = chan.plugins.indexOf(plugin);
        if (idx !== -1) {
          chan.plugins.splice(idx, 1);
        }
      }
    },
  },
  {
    name: 'listChannels',
    plugin: 'control',
    execute: async (p: ControlPlugin): Promise<IChannel[]> => {
      return p.core!.channelManager.getAll();
    },
  },
  {
    name: 'getPluginConfig',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string): Promise<any> => {
      if (!name) {
        throw new Error('This function takes 1 argument.');
      }
      const plugin = p.core!.pluginManager.getLoadedByName(name);
      if (!plugin) {
        throw new Error('No such plugin is currently running!');
      }
      return plugin.config.config;
    },
  },
  {
    name: 'getPluginConfigValue',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string, key: string): Promise<any> => {
      if (!name || !key) {
        throw new Error('This function takes 2 arguments.');
      }
      const plugin = p.core!.pluginManager.getLoadedByName(name);
      if (!plugin) {
        throw new Error('No such plugin is currently running!');
      }
      return plugin.config.get(key);
    },
  },
  {
    name: 'getPluginConfigSchema',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string): Promise<any> => {
      if (!name) {
        throw new Error('This function takes 1 argument.');
      }
      return p.getPluginSchema(name);
    },
  },
  {
    name: 'setPluginConfig',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string, config: any): Promise<any> => {
      if (!name || !config) {
        throw new Error('This function takes 2 arguments.');
      }
      const plugin = p.core!.pluginManager.getLoadedByName(name);
      if (!plugin) {
        throw new Error('No such plugin is currently running!');
      }
      plugin.config.config = config;
      return plugin.config.save();
    },
  },
  {
    name: 'setPluginConfigValue',
    plugin: 'control',
    execute: async (p: ControlPlugin, name: string, key: string, value: string): Promise<any> => {
      if (!name || !key) {
        throw new Error('This function takes 3 arguments.');
      }
      const plugin = p.core!.pluginManager.getLoadedByName(name);
      if (!plugin) {
        throw new Error('No such plugin is currently running!');
      }
      plugin.config.set(key, value);
      return plugin.config.save();
    },
  },
];

declare type StringAny = {[key: string]: any};
const match = ['key', 'cert', 'ca', 'dhparam', 'crl', 'pfx'];
async function parseTLSConfig(tlsconfig: StringAny): Promise<StringAny> {
  const result: StringAny = {};
  for (const key in tlsconfig) {
    if (key === 'enabled') {
      continue;
    }
    if (match.indexOf(key) === -1) {
      result[key] = tlsconfig[key];
      continue;
    }

    const value = path.resolve(tlsconfig[key]);
    const bf = await fs.readFile(value);
    result[key] = bf;
  }
  return result;
}

@Configurable({
  authorizedIPs: [],
  tls: {
    enabled: false,
    key: '',
    cert: '',
    rejectUnauthorized: false,
    requestCert: false,
  },
  bind: null,
})
class ControlPlugin extends Plugin {
  public core: ISqueebotCore | null = null;
  public plugins = new Map<string, any>();
  private server: Server | null = null;
  private sockets = new Set<Socket>();

  public initialize(): void {
    this.addEventListener('core', (core: ISqueebotCore) => this.core = core);
    this.emitTo('core', 'request-core', this.name);
    this.createSocket();
    this.getPluginSchema(this.name).catch(
      () => logger.error('[control] How embarrasing! control could not load it\'s own schema!')
    );
  }

  /**
   * Load a plugin schema from it's schema file, if it exists.
   * @param name Plugin name
   * @returns Plugin schema
   */
  public async loadPluginSchema(name: string): Promise<any> {
    if (!this.core) {
      throw new Error('control could not access the core.');
    }

    const { pluginsPath } = this.core.environment;
    const schemaPath = path.join(pluginsPath, name, 'schema.json');
    let schema: any;

    try {
      const fileRead = await fs.readFile(schemaPath, { encoding: 'utf8' });
      schema = JSON.parse(fileRead);
    } catch (e: any) {
      throw new Error('No schema file found, it is not accessible or is not valid JSON.');
    }

    if (!schema.type) {
      throw new Error('Schema does not specify what type of object it is referencing.');
    }

    this.plugins.set(name, schema);
    return schema;
  }

  /**
   * Register a plugin's configuration schema directly instead of reading from file.
   * @param name Plugin name
   * @param confspec Static schema
   */
  public registerPluginConfigSchema(name: string, confspec?: any): void {
    this.plugins.set(name, confspec);
  }

  /**
   * Load a plugin's configuration schema from memory or from file.
   * @param name Plugin name
   * @returns Schema
   * @throws Error if schema is not found or is invalid
   */
  public async getPluginSchema(name: string): Promise<any> {
    if (this.plugins.has(name)) {
      return this.plugins.get(name);
    }

    return this.loadPluginSchema(name);
  }

  /**
   * Execute a registered control command.
   * @param command Control command
   * @param args Control command arguments
   * @returns Control command response
   */
  public async executeControlCommand(command: string, args: string[]): Promise<any> {
    if (!this.core) {
      throw new Error('The control plugin cannot control the bot right now.');
    }
    const cmdobj = controlCommands.find(k => k.name === command);
    if (!cmdobj || !cmdobj.execute) {
      throw new Error('No such command');
    }
    return cmdobj.execute.call(this, this, ...args);
  }

  /**
   * Register a new custom control command.
   * @param obj ControlCommand object
   */
  public registerControlCommand(obj: ControlCommand): void {
    if (!obj.execute || !obj.name || !obj.plugin) {
      throw new Error('Invalid command object.');
    }
    const exists = controlCommands.find(k => k.name === obj.name);
    if (exists) {
      throw new Error('Control commands should not be overwritten.');
    }
    controlCommands.push(obj);
    logger.log('[%s] registered control command', this.name, obj.name);
  }

  public listControlCommands(): string[] {
    return controlCommands.map((command) => command.name);
  }

  @EventListener('pluginUnload')
  public unloadEventHandler(plugin: string | Plugin): void {
    if (plugin === this.name || plugin === this) {
      logger.debug('[%s]', this.name, 'shutting down..');

      if (this.server) {
        logger.log('[%s] Stopping socket server..', this.name);
        this.server.close();
        for (const sock of this.sockets) {
          sock.destroy();
        }
        this.sockets.clear();
      }

      this.plugins.clear();
      this.emit('pluginUnloaded', this);
    }
  }

  @EventListener('pluginUnloaded')
  public unloadedEventHandler(plugin: string | Plugin): void {
    if (typeof plugin !== 'string') {
      plugin = plugin.manifest.name;
    }
    this.plugins.delete(plugin);
    controlCommands = controlCommands.filter(k => k.plugin !== plugin);
  }

  private errorToClient(socket: TLSSocket | Socket, error: Error): void {
    socket.write(JSON.stringify({
      status: 'ERROR',
      message: error.message,
    }) + '\r\n');
  }

  private handleClientLine(socket: TLSSocket | Socket, req: any): void {
    if (!req.command || req.command === 'status') {
      socket.write(JSON.stringify({
        status: 'OK'
      }) + '\r\n');
      return;
    }

    if (req.command === 'quit') {
      socket.end();
      return;
    }

    let args = [];
    const argField = req.args || req.argument || req.arguments;
    if (argField) {
      if (!Array.isArray(argField)) {
        args = [argField];
      } else {
        args = argField;
      }
    }

    this.executeControlCommand(req.command, args).then((cmdData) => {
      try {
        const response: any = { status: 'OK', command: req.command };
        if (cmdData != null) {
          if (Array.isArray(cmdData)) {
            response.list = cmdData;
          } else {
            response.data = cmdData;
          }
        }
        socket.write(JSON.stringify(response) + '\r\n');
      } catch (e: any) {
        this.errorToClient(socket, e);
      }
    }, (e) => this.errorToClient(socket, e));
  }

  private handleIncoming(socket: TLSSocket | Socket): void {
    const c = this.config.config;
    let addr = socket.remoteAddress;
    if (addr?.indexOf('::ffff:') === 0) {
      addr = addr.substr(7);
    }
    if (c.authorizedIPs &&
        c.authorizedIPs.length &&
        c.authorizedIPs.indexOf(addr) === -1) {
      if (!(c.authorizedIPs.indexOf('localhost') !== -1 &&
        (addr === '::1' || addr === '127.0.0.1'))) {
        logger.warn('[%s] Unauthorized connection made from %s',
          this.name, addr);
        socket.destroy();
        return;
      }
    }

    this.sockets.add(socket);

    socket.once('end', () => {
      logger.log('[%s] Client from %s disconnected.', this.name, addr);
      this.sockets.delete(socket);
    });

    logger.log('[%s] Client from %s connected.', this.name, addr);
    socket.setEncoding('utf8');
    socket.write(JSON.stringify({
      status: 'OK',
      commands: controlCommands.map(k => k.name),
    }) + '\r\n');

    socket.on('data', (data) => {
      try {
        const split = data.split('\r\n');
        for (const chunk of split) {
          if (chunk === '') {
            continue;
          }

          const req = JSON.parse(chunk);
          this.handleClientLine(socket, req);
        }
      } catch (e: any) {
        this.errorToClient(socket, e);
      }
    });
  }

  private createSocket(): void {
    const c = this.config.config;
    if (c.bind == null ||
        c.bind === false) {
      return;
    }

    if (c.tls && c.tls.enabled) {
      if (!c.tls.rejectUnauthorized && (!c.authorizedIPs || !c.authorizedIPs.length)) {
        logger.warn('[%s] [SECURITY WARNING] !!! YOUR CONTROL SOCKET IS (STILL) INSECURE !!!', this.name);
        logger.warn('[%s] [SECURITY WARNING] You have enabled TLS, ' +
          'but you do not have any form of access control configured.', this.name);
        logger.warn('[%s] [SECURITY WARNING] In order to secure your control socket, ' +
          'either enable invalid certificate rejection (rejectUnauthorized) or set a ' +
          'list of authorized IPs.', this.name);
        logger.warn('[%s] [SECURITY WARNING] !!! YOUR CONTROL SOCKET IS (STILL) INSECURE !!!', this.name);
      }
      parseTLSConfig(c.tls).then((options) => {
        this.server = tls.createServer(options,
          (socket) => this.handleIncoming(socket));
        this.server.on('error',
          (e) => logger.error('[%s] Secure socket error:', e.message));
        this.server.listen(c.bind, () => {
          logger.log('[%s] Secure socket listening on %s',
            this.name, c.bind.toString());
        });
      }, (err) => {
        logger.error('[%s] Secure socket listen failed: %s',
            this.name, err.message);
      });
      return;
    }

    if (!c.authorizedIPs || !c.authorizedIPs.length) {
      logger.warn('[%s] [SECURITY WARNING] !!! YOUR CONTROL SOCKET IS INSECURE !!!', this.name);
      logger.warn('[%s] [SECURITY WARNING] You do not have any form of access control configured.', this.name);
      logger.warn('[%s] [SECURITY WARNING] In order to secure your control socket, ' +
        'either enable TLS with certificate verification or set a list of authorized IPs.', this.name);
      logger.warn('[%s] [SECURITY WARNING] !!! YOUR CONTROL SOCKET IS INSECURE !!!', this.name);
    }

    this.server = net.createServer((socket) => this.handleIncoming(socket));
    this.server.on('error', (e) => logger.error('[%s] Socket error:', e.message));
    this.server.listen(c.bind, () => {
      logger.log('[%s] Socket listening on %s',
        this.name, c.bind.toString());
    });
  }
}

module.exports = ControlPlugin;