import discord, {
  CommandInteraction, 
  CommandInteractionOptionResolver,
  SlashCommandBuilder,
  SlashCommandRoleOption,
  SlashCommandStringOption,
  SlashCommandIntegerOption,
  SlashCommandSubcommandBuilder,
  EmbedBuilder,
  InteractionResponse,
  SlashCommandSubcommandsOnlyBuilder,
} from 'discord.js';
import {HydratedDocument} from 'mongoose';

import {Command} from '../../classes/command';
import {logger} from '../../logger';
import {config} from '../../config';
import {Guild, guildModel} from '../../models/Guild';
import {GiveawayMsg, giveawayMsgModel} from '../../models/GiveawayMsg';

type CIOR = CommandInteractionOptionResolver;

async function add(interaction: CommandInteraction): Promise<void>{
  const message: string | null = 
    (interaction.options as CIOR).getString('message'); 
  if(!message)
    throw Error('message not exist');
  const embed = new EmbedBuilder()
    .setTitle('New Giveaway')
    .setDescription(`@everyone\n${message}`);

  if(!interaction.guildId) 
    throw Error('guildId not exist');
  if(!interaction.channelId)
    throw Error('channelId not exist');

  let msg: discord.Message = 
    await (await interaction.reply({embeds: [embed]})).fetch();
  await msg.react(config.giveaway.emoji);
  if(!interaction.guild || !interaction.guild.id)
    throw Error('guild not exist');
  const guild: HydratedDocument<Guild> | null =
    await guildModel.findOneAndUpdate(
      {id: interaction.guild.id}, 
      {$set: {name: interaction.guild.name}}, 
      {upsert: true, new: true}
    );
  if(!guild)
    throw Error('guild not exist');
  const giveawayMsg: HydratedDocument<GiveawayMsg> | null =
    await giveawayMsgModel.findOneAndUpdate(
      {guild: guild, messageId: msg.id, authorId: interaction.user.id},
      {}, {upsert: true, new: true}
    );
  if(!giveawayMsg) 
    throw Error('giveawayMsg not exist');

  await msg.edit({embeds: [new EmbedBuilder()
    .setColor(Math.floor(Math.random()*16777215))
    .setTitle('Giveaway')
    .setDescription(message)
    .setFooter({text: `id: ${msg.id}`})
  ]});
}

async function pick(interaction: CommandInteraction): Promise<void>{
  const messageId: string | null = 
    (interaction.options as CIOR).getString('message'); 
  if(!messageId)
    throw Error('message not exist');
  const num: number | null = 
    (interaction.options as CIOR).getInteger('number'); 
  if(!num)
    throw Error('number not exist');

  const dbGiveawayMsg: HydratedDocument<GiveawayMsg> | null = 
    await giveawayMsgModel.findOneAndDelete({
      messageId: messageId, authorId: interaction.user.id
    });
  if(!dbGiveawayMsg){
    await interaction.reply({
      content: logger.log(`Giveaway didn't exist or the author didn't match.`), 
      ephemeral: true
    });
    return;
  }
  for(let i = dbGiveawayMsg.userIds.length - 1; i > 0; i--){
    let j = Math.floor(Math.random() * (i + 1));
    [dbGiveawayMsg.userIds[i], dbGiveawayMsg.userIds[j]]
     = [dbGiveawayMsg.userIds[j], dbGiveawayMsg.userIds[i]];
  }
  let content: string = '### Giveaway Result\n';
  for(let i = 0; i < num; i++)
    content += `1. ${await interaction.client.users.fetch(dbGiveawayMsg.userIds[i])}\n`;
  content += `will obtain the prize for giveaway, id: ${dbGiveawayMsg.messageId}`;
  await interaction.reply({content: content});
}

class Giveaway extends Command{
  get name(){return 'giveaway';}
  get description(){return 'Setup a Giveaway message.';}
  async execute(interaction: CommandInteraction): Promise<void>{
    try{
      const subcommand: string | null = 
        (interaction.options as CIOR).getSubcommand();
      switch(subcommand){
      case 'add': 
        await add(interaction); break;
      case 'pick':
        await pick(interaction); break;
      default: 
        throw Error('subcommand not exist');
      }
    }catch(err: unknown){
      let message;
      if(err instanceof Error) message = err.message;
      else message = String(message);
      logger.error(`While executing "/giveaway", ${message}`);
      await interaction.reply({content: `While executing "/giveaway", ${message}`});
    }
  }
  override build(): SlashCommandSubcommandsOnlyBuilder{
    return new SlashCommandBuilder()
      .setName(this.name)
      .setDescription(this.description)
      .addSubcommand((subcommand: SlashCommandSubcommandBuilder) => subcommand
        .setName('add')
        .setDescription('Construct a giveaway')
        .addStringOption((option: SlashCommandStringOption) => option
          .setName('message')
          .setDescription('The message displayed with the giveaway message.')
          .setRequired(true)
        )
      )
      .addSubcommand((subcommand: SlashCommandSubcommandBuilder) => subcommand
        .setName('pick')
        .setDescription('Random pick a number of user in a giveaway')
        .addStringOption((option: SlashCommandStringOption) => option
          .setName('message')
          .setDescription('The message id of the giveaway (Shown in the footer)')
          .setRequired(true)
        )
        .addIntegerOption((option: SlashCommandIntegerOption) => option
          .setName('number')
          .setDescription('The number of member to choose.')
          .setRequired(true)
        )
      )
  }
};

export const command = new Giveaway();