// InnkeeperBot, a bot to create and manage custom channels
// Copyright (C) 2020-2021 Matteo Schiff
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package main

import (
	"github.com/bwmarrin/discordgo"
)

type AutoGuild struct {
	id                 string
	newChannelEndpoint *discordgo.Channel
	createdChannels    map[string][]string
}

var managedGuilds = make(map[string]*AutoGuild)

const CATEGORY_NAME = "Gaming🎮"
const DEFAULT_CHANNEL_NAME = "Stanza"

func initChannels(s *discordgo.Session, guildID string) {
	var guild AutoGuild
	guild.id = guildID
	guild.createdChannels = make(map[string][]string)

	log.Debugf("Preparing guild %s for automatic channel management", guildID)

	category := searchChannel(s, guildID, CATEGORY_NAME, "")
	if category == nil {
		log.Errorf("Cannot find category %s in guild %s", CATEGORY_NAME, guildID)
		return
	}

	deleteAllChannelsUnderCategory(s, guildID, category.ID)
	guild.createNewChannelEndpoint(s, category.ID)

	managedGuilds[guildID] = &guild
}

func (guild *AutoGuild) createNewChannelEndpoint(s *discordgo.Session, channelParent string) {

	newChannelData := discordgo.GuildChannelCreateData{
		Name:     "Crea nuovo canale",
		Type:     discordgo.ChannelTypeGuildVoice,
		ParentID: channelParent}

	var err error
	guild.newChannelEndpoint, err = s.GuildChannelCreateComplex(guild.id, newChannelData)

	if err != nil {
		log.Errorf("Cannot create channel with name %s in guild %s. This guild is in a corrupted state", newChannelData.Name, guild.id)
		return
	}

	log.Debugf("Created channel with name %s in guild %s", newChannelData.Name, guild.id)
}

func (guild *AutoGuild) createNewChannel(s *discordgo.Session, channelID string, userID string) {
	category := searchChannel(s, guild.id, CATEGORY_NAME, "")
	if category == nil {
		log.Errorf("Cannot find category %s in guild %s", CATEGORY_NAME, guild.id)
		return
	}

	channelName := guild.getActivity(s.State, userID)
	editChannelData := discordgo.ChannelEdit{Name: channelName}
	_, err := s.ChannelEdit(channelID, &editChannelData)
	if err != nil {
		log.Errorf("Cannot rename channel %s with new name %s in guild %s", channelID, channelName, guild.id)
		return
	}
	guild.createdChannels[channelID] = []string{userID}
	log.Debugf("Renamed channel %s to %s in guild %s", channelID, channelName, guild.id)

	guild.createNewChannelEndpoint(s, category.ID)
}

func (guild *AutoGuild) removeUserFromChannels(s *discordgo.Session, userID string) {
	for channelID, channel := range guild.createdChannels {
		index := contains(channel, userID)

		if index != -1 {
			if len(channel) == 1 {
				// If this user was the only one left in the channel, delete the channel
				_, err := s.ChannelDelete(channelID)
				if err != nil {
					log.Errorf("Cannot delete channel %s in guild %s", channelID, guild.id)
				} else {
					log.Debugf("Channel %s deleted in guild %s", channelID, guild.id)
					delete(guild.createdChannels, channelID)
				}
			} else {
				// Otherwise update the channel name and remove user from the list
				guild.createdChannels[channelID] = remove(channel, index)
				guild.updateChannelName(s, channelID)
			}
		}
	}
}

func (guild *AutoGuild) trackUserJoinManagedChannel(s *discordgo.Session, channelID string, userID string) {
	guild.createdChannels[channelID] = append(guild.createdChannels[channelID], userID)
	guild.updateChannelName(s, channelID)
}

func (guild *AutoGuild) updateChannelName(s *discordgo.Session, channelID string) {
	programs := make(map[string]int)

	for _, userID := range guild.createdChannels[channelID] {
		programs[guild.getActivity(s.State, userID)] += 1
	}

	max := -1
	name := DEFAULT_CHANNEL_NAME

	for program, count := range programs {
		if program != DEFAULT_CHANNEL_NAME && count > max {
			max = count
			name = program
		}
	}

	channel, err := s.Channel(channelID)
	if err != nil {
		log.Errorf("Channel %s not found in guild %s", channelID, guild.id)
		return
	}

	oldName := channel.Name

	if oldName == name {
		return
	}

	editChannelData := discordgo.ChannelEdit{Name: name}
	_, err = s.ChannelEdit(channelID, &editChannelData)
	if err != nil {
		log.Errorf("Cannot rename channel %s with new name %s in guild %s", channelID, name, guild.id)
	}
	log.Debugf("Renamed channel %s from %s to %s in guild %s", channelID, oldName, name, guild.id)
}

func (guild *AutoGuild) getActivity(st *discordgo.State, userID string) string {
	presence, err := st.Presence(guild.id, userID)

	if err != nil || len(presence.Activities) == 0 {
		return DEFAULT_CHANNEL_NAME
	}

	for _, activity := range presence.Activities {
		if activity.Name != "Hang Status" {
			return activity.Name
		}
	}

	return DEFAULT_CHANNEL_NAME
}