package discord

import (
	"fmt"
	"strings"
	"time"

	"git.birbmc.com/canopeas/config"
	"git.birbmc.com/canopeas/database"

	"git.birbmc.com/Etzelia/go-serverapi"
	"github.com/bwmarrin/discordgo"
	"github.com/dghubble/go-twitter/twitter"
	"github.com/dghubble/oauth1"
	"go.jolheiser.com/beaver"
)

// Register commands to this map
var (
	commands       = make([]*command, 0)
	commandMap     = make(map[string]*command)
	messageRoleMap = make(map[string]map[string]string)

	memeRateLimit *rateLimit
	embedColor    = 0x007D96
)

type commandInit struct {
	session       *discordgo.Session
	message       *discordgo.Message
	config        *config.Config
	database      *database.Database
	sapiClient    *serverapi.Client
	twitterClient *twitter.Client
}

type command struct {
	staffOnly        bool
	deleteInvocation bool
	echo             bool
	album            bool
	// TODO Does this really need to exist separately?
	validate func(cmd commandInit) bool
	run      func(cmd commandInit) (string, error)
	name     string
	aliases  []string
	help     string
}

func Bot(cfg *config.Config, db *database.Database) (*discordgo.Session, error) {
	bot, err := discordgo.New("Bot " + cfg.Token)
	if err != nil {
		return nil, err
	}

	// Init rand
	rand.Seed(time.Now().UnixNano())

	// Init ServerAPI
	sapi := serverapi.NewClient(cfg.ServerAPI.Endpoint, serverapi.WithToken(cfg.ServerAPI.Token))

	// Init Twitter
	twitterConfig := oauth1.NewConfig(cfg.Twitter.ConsumerKey, cfg.Twitter.ConsumerSecret)
	twitterToken := oauth1.NewToken(cfg.Twitter.AccessToken, cfg.Twitter.AccessSecret)
	twitterHttpClient := twitterConfig.Client(oauth1.NoContext, twitterToken)
	twitterClient := twitter.NewClient(twitterHttpClient)

	// Init Unban Schedule
	sched := &unbanSchedule{
		db:   db,
		sapi: sapi,
	}
	go sched.Run()

	for _, messageRole := range cfg.MessageRoles {
		if messageRoleMap[messageRole.MessageID] == nil {
			messageRoleMap[messageRole.MessageID] = make(map[string]string)
		}
		for _, reaction := range messageRole.Reactions {
			_ = bot.MessageReactionAdd(messageRole.ChannelID, messageRole.MessageID, reaction.Emoji)
			messageRoleMap[messageRole.MessageID][reaction.Emoji] = reaction.RoleID
		}
	}

	// Init commandMap
	if err := Album(cfg); err != nil {
		return nil, err
	}
	Echo(cfg)
	for _, c := range commands {
		if c.name == "" {
			beaver.Errorf("command is missing a name: %s", c.help)
			continue
		}
		commandMap[c.name] = c
		for _, a := range c.aliases {
			commandMap[a] = c
		}
	}

	bot.AddHandler(readyHandler())
	bot.AddHandler(leaveHandler(cfg))
	bot.AddHandler(commandHandler(cfg, db, sapi, twitterClient))
	bot.AddHandler(messageHandler(cfg, db))
	bot.AddHandler(reactionAddHandler())
	bot.AddHandler(reactionRemoveHandler())

	// Rate limits
	d, err := time.ParseDuration(cfg.MemeRate)
	if err != nil {
		return nil, err
	}
	memeRateLimit = NewRateLimit(d)

	// Intents
	bot.Identify.Intents = discordgo.MakeIntent(discordgo.IntentsAll)

	return bot, nil
}

func sendTyping(s *discordgo.Session, channelID string) {
	if err := s.ChannelTyping(channelID); err != nil {
		beaver.Errorf("could not send typing status: %v", err)
	}
}

func sendMessage(s *discordgo.Session, channelID, content string, scrub bool) *discordgo.Message {
	var msg *discordgo.Message
	var err error
	if scrub {
		msg, err = s.ChannelMessageSendComplex(channelID, &discordgo.MessageSend{
			Content:         content,
			AllowedMentions: &discordgo.MessageAllowedMentions{},
		})
	} else {
		msg, err = s.ChannelMessageSend(channelID, content)
	}
	if err != nil {
		beaver.Errorf("could not send message: %v", err)
		return nil
	}
	return msg
}

func sendEmbed(s *discordgo.Session, channelID string, embed *discordgo.MessageEmbed) *discordgo.Message {
	embed.Color = embedColor
	msg, err := s.ChannelMessageSendEmbed(channelID, embed)
	if err != nil {
		beaver.Errorf("could not send embed: %v", err)
		return nil
	}
	return msg
}

func isStaff(authorRoleIDs, staffRoleIDs []string) bool {
	for _, aRole := range authorRoleIDs {
		for _, sRole := range staffRoleIDs {
			if aRole == sRole {
				return true
			}
		}
	}
	return false
}

func readyHandler() func(s *discordgo.Session, m *discordgo.Ready) {
	return func(s *discordgo.Session, r *discordgo.Ready) {
		beaver.Infof("https://discord.com/api/oauth2/authorize?client_id=%s&permissions=0&redirect_uri=https://birbmc.com&scope=bot", r.User.ID)
	}
}

func commandHandler(cfg *config.Config, db *database.Database, sapi *serverapi.Client, twitterClient *twitter.Client) func(s *discordgo.Session, m *discordgo.MessageCreate) {
	return func(s *discordgo.Session, m *discordgo.MessageCreate) {
		// Ignore bots
		if m.Author.Bot {
			return
		}

		// Check prefix
		if !strings.HasPrefix(m.Content, cfg.Prefix) {
			return
		}

		content := m.Content[1:]
		args := strings.Fields(content)
		if len(args) == 0 {
			return
		}

		cmdArg := strings.ToLower(args[0])

		cmd, ok := commandMap[cmdArg]
		if !ok {
			return
		}

		if cmd.staffOnly && !isStaff(m.Member.Roles, cfg.StaffRoles) {
			return
		}

		cmdInit := commandInit{
			session:       s,
			message:       m.Message,
			config:        cfg,
			database:      db,
			sapiClient:    sapi,
			twitterClient: twitterClient,
		}
		if !cmd.validate(cmdInit) {
			sendMessage(s, m.ChannelID, "You cannot run this command.", false)
			return
		}
		if cmd.deleteInvocation {
			if err := s.ChannelMessageDelete(m.Message.ChannelID, m.Message.ID); err != nil {
				beaver.Warnf("could not remove invocation for %s: %v", m.Content, err)
			}
		}
		feedback, err := cmd.run(cmdInit)
		if err != nil {
			feedback = "Internal error"
			beaver.Errorf("error while running %s: %v", cmdArg, err)
		}
		if len(feedback) > 0 {
			sendMessage(s, m.ChannelID, feedback, false)
		}
	}
}

func messageHandler(cfg *config.Config, db *database.Database) func(s *discordgo.Session, m *discordgo.MessageCreate) {
	return func(s *discordgo.Session, m *discordgo.MessageCreate) {
		// Ignore bots
		if m.Author.Bot {
			return
		}

		// [FIRED] increment
		for _, role := range m.MentionRoles {
			if cfg.FiredRole == role {
				if err := db.IncrementPing(cfg.FiredRole); err != nil {
					beaver.Errorf("could not increment ping for %s: %v", cfg.FiredRole, err)
				}
			}
		}
	}
}

func reactionAddHandler() func(s *discordgo.Session, m *discordgo.MessageReactionAdd) {
	return func(s *discordgo.Session, m *discordgo.MessageReactionAdd) {
		reactionHandler(true, s, m.MessageReaction)
	}
}

func reactionRemoveHandler() func(s *discordgo.Session, m *discordgo.MessageReactionRemove) {
	return func(s *discordgo.Session, m *discordgo.MessageReactionRemove) {
		reactionHandler(false, s, m.MessageReaction)
	}
}

func reactionHandler(add bool, s *discordgo.Session, m *discordgo.MessageReaction) {
	if _, ok := messageRoleMap[m.MessageID]; ok {
		if r, ok := messageRoleMap[m.MessageID][m.Emoji.APIName()]; ok {
			var roleCmd func(guildID, userID, roleID string) (err error)
			if add {
				roleCmd = s.GuildMemberRoleAdd
			} else {
				roleCmd = s.GuildMemberRoleRemove
			}
			if err := roleCmd(m.GuildID, m.UserID, r); err != nil {
				beaver.Errorf("could not modify role %s for user %s", r, m.UserID)
			}
		}
	}
}

func leaveHandler(cfg *config.Config) func(s *discordgo.Session, m *discordgo.GuildMemberRemove) {
	return func(s *discordgo.Session, m *discordgo.GuildMemberRemove) {
		sendMessage(s, cfg.LeaveChannel, fmt.Sprintf("%s (%s) left the server. :sob:", m.Mention(), m.User.String()), true)
	}
}