/**
 * @file
 * @copyright 2020, Valentin Anger
 * @license ISC
 */

import { Client } from "./client.ts";
import IrcError from "./error.ts";

export default class Message {
  readonly prefix: string | undefined;
  readonly command: string;
  readonly parameters: string[];

  readonly direct: boolean;
  readonly sender:
    | {
      nickname: string;
      user: string;
      host: string;
    }
    | undefined;

  constructor(readonly client: Client, readonly message: string) {
    let base = 0;

    if (message[0] == ":") {
      const prefix_end = message.indexOf(" ");
      this.prefix = message.substring(1, prefix_end);
      base = prefix_end + 1;
    }

    const trailing_colon = message.indexOf(" :", base);

    if (trailing_colon != -1) {
      // There is a trailing parameter
      const trailing = message.substring(
        trailing_colon + 2,
        message.length - 2,
      );

      this.parameters = message.substring(base, trailing_colon).split(" ");
      this.parameters.push(trailing);
    } else {
      this.parameters = message.substring(base, message.length - 2).split(" ");
    }

    const command = this.parameters.shift();

    if (command == undefined) {
      throw new IrcError("Malformed message");
    }

    this.command = command;

    // Basic message parsing done

    if (this.prefix != undefined) {
      const match = this.prefix.match(/([^@!]+)(?:(?:!([^@]+))?@(.*))?/);

      if (match != null) {
        this.sender = {
          nickname: match[1],
          user: match[2],
          host: match[3],
        };
      }
    }

    this.direct = this.parameters[0] == this.client.nickname;
  }

  channel(): string | undefined {
    return this.direct ? undefined : this.parameters[0];
  }

  async replyPrivmsg(
    message: string,
    direct_reply: boolean = false,
  ): Promise<void> {
    if (this.direct || direct_reply) {
      if (this.sender == undefined) {
        throw new IrcError("Cannot reply to unknown sender");
      }
      await this.client.sendPrivmsg(this.sender.nickname, message);
    } else {
      await this.client.sendPrivmsg(this.parameters[0], message);
    }
  }

  async replyNotice(
    message: string,
    direct_reply: boolean = false,
  ): Promise<void> {
    if (this.direct || direct_reply) {
      if (this.sender == undefined) {
        throw new IrcError("Cannot reply to unknown sender");
      }
      await this.client.sendNotice(this.sender.nickname, message);
    } else {
      await this.client.sendNotice(this.parameters[0], message);
    }
  }

  toString(): string {
    return this.message;
  }
}