const DataResolver = require('../util/DataResolver');
const Channel = require('./Channel');
const APIMessage = require('./APIMessage');

/**
 * Represents a webhook.
 */
class Webhook {
  constructor(client, data) {
    /**
     * The client that instantiated the webhook
     * @name Webhook#client
     * @type {Client}
     * @readonly
     */
    Object.defineProperty(this, 'client', { value: client });
    if (data) this._patch(data);
  }

  _patch(data) {
    /**
     * The name of the webhook
     * @type {string}
     */
    this.name = data.name;

    /**
     * The token for the webhook
     * @type {string}
     */
    Object.defineProperty(this, 'token', { value: data.token, writable: true, configurable: true });

    /**
     * The avatar for the webhook
     * @type {?string}
     */
    this.avatar = data.avatar;

    /**
     * The ID of the webhook
     * @type {Snowflake}
     */
    this.id = data.id;

    /**
     * The guild the webhook belongs to
     * @type {Snowflake}
     */
    this.guildID = data.guild_id;

    /**
     * The channel the webhook belongs to
     * @type {Snowflake}
     */
    this.channelID = data.channel_id;

    if (data.user) {
      /**
       * The owner of the webhook
       * @type {?User|Object}
       */
      this.owner = this.client.users ? this.client.users.get(data.user.id) : data.user;
    } else {
      this.owner = null;
    }
  }

  /**
   * Options that can be passed into send.
   * @typedef {Object} WebhookMessageOptions
   * @property {string} [username=this.name] Username override for the message
   * @property {string} [avatarURL] Avatar URL override for the message
   * @property {boolean} [tts=false] Whether or not the message should be spoken aloud
   * @property {string} [nonce=''] The nonce for the message
   * @property {Object[]} [embeds] An array of embeds for the message
   * (see [here](https://discordapp.com/developers/docs/resources/channel#embed-object) for more details)
   * @property {boolean} [disableEveryone=this.client.options.disableEveryone] Whether or not @everyone and @here
   * should be replaced with plain-text
   * @property {FileOptions[]|string[]} [files] Files to send with the message
   * @property {string|boolean} [code] Language for optional codeblock formatting to apply
   * @property {boolean|SplitOptions} [split=false] Whether or not the message should be split into multiple messages if
   * it exceeds the character limit. If an object is provided, these are the options for splitting the message.
   */

  /**
   * Sends a message with this webhook.
   * @param {StringResolvable|APIMessage} [content=''] The content to send
   * @param {WebhookMessageOptions|MessageAdditions} [options={}] The options to provide
   * @returns {Promise<Message|Object>}
   * @example
   * // Send a basic message
   * webhook.send('hello!')
   *   .then(message => console.log(`Sent message: ${message.content}`))
   *   .catch(console.error);
   * @example
   * // Send a remote file
   * webhook.send({
   *   files: ['https://cdn.discordapp.com/icons/222078108977594368/6e1019b3179d71046e463a75915e7244.png?size=2048']
   * })
   *   .then(console.log)
   *   .catch(console.error);
   * @example
   * // Send a local file
   * webhook.send({
   *   files: [{
   *     attachment: 'entire/path/to/file.jpg',
   *     name: 'file.jpg'
   *   }]
   * })
   *   .then(console.log)
   *   .catch(console.error);
   * @example
   * // Send an embed with a local image inside
   * webhook.send('This is an embed', {
   *   embeds: [{
   *     thumbnail: {
   *          url: 'attachment://file.jpg'
   *       }
   *    }],
   *    files: [{
   *       attachment: 'entire/path/to/file.jpg',
   *       name: 'file.jpg'
   *    }]
   * })
   *   .then(console.log)
   *   .catch(console.error);
   */
  async send(content, options) {
    let apiMessage;

    if (content instanceof apiMessage) {
      apiMessage = content.resolveData();
    } else {
      apiMessage = APIMessage.create(this, content, options).resolveData();
      if (apiMessage.data.content instanceof Array) {
        return Promise.all(apiMessage.split().map(this.send.bind(this)));
      }
    }

    const { data, files } = await apiMessage.resolveFiles();
    return this.client.api.webhooks(this.id, this.token).post({
      data, files,
      query: { wait: true },
      auth: false,
    }).then(d => {
      if (!this.client.channels) return d;
      return this.client.channels.get(d.channel_id).messages.add(d, false);
    });
  }

  /**
   * Sends a raw slack message with this webhook.
   * @param {Object} body The raw body to send
   * @returns {Promise<Message|Object>}
   * @example
   * // Send a slack message
   * webhook.sendSlackMessage({
   *   'username': 'Wumpus',
   *   'attachments': [{
   *     'pretext': 'this looks pretty cool',
   *     'color': '#F0F',
   *     'footer_icon': 'http://snek.s3.amazonaws.com/topSnek.png',
   *     'footer': 'Powered by sneks',
   *     'ts': Date.now() / 1000
   *   }]
   * }).catch(console.error);
   */
  sendSlackMessage(body) {
    return this.client.api.webhooks(this.id, this.token).slack.post({
      query: { wait: true },
      auth: false,
      data: body,
    }).then(data => {
      if (!this.client.channels) return data;
      return this.client.channels.get(data.channel_id).messages.add(data, false);
    });
  }

  /**
   * Edits the webhook.
   * @param {Object} options Options
   * @param {string} [options.name=this.name] New name for this webhook
   * @param {BufferResolvable} [options.avatar] New avatar for this webhook
   * @param {ChannelResolvable} [options.channel] New channel for this webhook
   * @param {string} [reason] Reason for editing this webhook
   * @returns {Promise<Webhook>}
   */
  edit({ name = this.name, avatar, channel }, reason) {
    if (avatar && (typeof avatar === 'string' && !avatar.startsWith('data:'))) {
      return DataResolver.resolveImage(avatar).then(image => this.edit({ name, avatar: image }, reason));
    }
    if (channel) channel = channel instanceof Channel ? channel.id : channel;
    return this.client.api.webhooks(this.id, channel ? undefined : this.token).patch({
      data: { name, avatar, channel_id: channel },
      reason,
    }).then(data => {
      this.name = data.name;
      this.avatar = data.avatar;
      this.channelID = data.channel_id;
      return this;
    });
  }

  /**
   * Deletes the webhook.
   * @param {string} [reason] Reason for deleting this webhook
   * @returns {Promise}
   */
  delete(reason) {
    return this.client.api.webhooks(this.id, this.token).delete({ reason });
  }

  static applyToClass(structure) {
    for (const prop of [
      'send',
      'sendSlackMessage',
      'edit',
      'delete',
    ]) {
      Object.defineProperty(structure.prototype, prop,
        Object.getOwnPropertyDescriptor(Webhook.prototype, prop));
    }
  }
}

module.exports = Webhook;