package bot

import (
	"context"
	"log"
	"time"
	"velox-bot/internal/beta"
	"velox-bot/internal/commands"
	"velox-bot/internal/db/repos/musicrepo"
	"velox-bot/internal/db/services"
	"velox-bot/internal/events"
	"velox-bot/internal/music"
	"velox-bot/internal/security"
	"velox-bot/internal/tickets"

	"github.com/bwmarrin/discordgo"
)

type Bot struct {
	Session            *discordgo.Session
	AppID              string
	GuildID            string
	Commands           []*discordgo.ApplicationCommand
	registeredCommands []*discordgo.ApplicationCommand
	Services           *services.Services
	MusicRepo          *musicrepo.Repo
	DBHost             string
	LavalinkHost       string
	LavalinkPass       string
	betaGuild          string // where beta commands are registered right now
}

func NewBot(token, appID, guildID, lavalinkHost, lavalinkPass string, cmds []*discordgo.ApplicationCommand, services *services.Services, musicRepo *musicrepo.Repo, dbHost string) (*Bot, error) {
	session, err := discordgo.New("Bot " + token)
	if err != nil {
		return nil, err
	}

	// Intents needed for:
	// - InteractionCreate (slash commands): Guilds
	// - MessageCreate (leveling): GuildMessages
	// - GuildMemberAdd (welcome messages): GuildMembers
	// - VoiceStateUpdate (meeting lobby): GuildVoiceStates
	session.Identify.Intents = discordgo.IntentsGuilds |
		discordgo.IntentsGuildBans |
		discordgo.IntentsGuildMembers |
		discordgo.IntentsGuildMessages |
		discordgo.IntentsMessageContent |
		discordgo.IntentsGuildVoiceStates |
		discordgo.IntentsDirectMessages

	return &Bot{
		Session:      session,
		AppID:        appID,
		GuildID:      guildID,
		Commands:     cmds,
		Services:     services,
		MusicRepo:    musicRepo,
		DBHost:       dbHost,
		LavalinkHost: lavalinkHost,
		LavalinkPass: lavalinkPass,
	}, nil
}

func (b *Bot) Start() error {
	if err := b.Session.Open(); err != nil {
		return err
	}

	_ = music.Init(b.Session, b.MusicRepo, b.AppID, b.LavalinkHost, b.LavalinkPass)

	go func() {
		if err := music.StartCommandListener(context.Background(), b.DBHost, b.MusicRepo); err != nil {
			log.Printf("music: command listener stopped: %v", err)
		}
	}()

	if st := tickets.Default(); st != nil {
		go func() {
			// The connection can drop (database restart, network blip):
			// reconnect instead of silently ignoring the dashboard from then on.
			for {
				err := tickets.StartCommandListener(context.Background(), b.DBHost, b.Session, st)
				log.Printf("tickets: command listener stopped: %v (retrying in 10s)", err)
				time.Sleep(10 * time.Second)
			}
		}()
	}

	if eng := security.Start(b.Session, b.Session.State.User.ID); eng != nil {
		// Moderators are exempt from heat; their permissions come from the
		// gateway cache so a message never costs an API call.
		eng.ChannelPerms = b.Session.State.UserChannelPermissions
		eng.ResumeRaids(context.Background())
		go eng.WatchRaids(context.Background(), 30*time.Second)
		go eng.WatchSnapshots(context.Background())
		go func() {
			// Reconnect if the database connection drops, instead of
			// silently ignoring the dashboard from then on.
			for {
				err := eng.StartCommandListener(context.Background(), b.DBHost)
				log.Printf("security: command listener stopped: %v (retrying in 10s)", err)
				time.Sleep(10 * time.Second)
			}
		}()
	}

	b.registeredCommands = make([]*discordgo.ApplicationCommand, len(b.Commands))
	for _, cmd := range b.Commands {
		created, err := b.Session.ApplicationCommandCreate(b.AppID, b.GuildID, cmd)
		if err != nil {
			log.Printf("Cannot create '%v' command: %v", cmd.Name, err)
			continue
		}
		b.registeredCommands = append(b.registeredCommands, created)
	}

	b.Session.AddHandler(commands.HandleInteraction)

	b.Session.AddHandler(func(s *discordgo.Session, c *discordgo.ChannelDelete) {
		events.HandleChannelDelete(s, c, b.Services)
	})

	b.Session.AddHandler(func(s *discordgo.Session, m *discordgo.MessageCreate) {
		if eng := security.Default(); eng != nil {
			eng.OnMessage(context.Background(), m)
		}
		events.HandleMessageCreate(s, m, b.Services)
	})

	b.Session.AddHandler(func(s *discordgo.Session, m *discordgo.GuildMemberAdd) {
		events.HandleBotAddedOnGuild(s, m, b.Services)

		// Security runs first: someone it removes (join lock, Join Gate,
		// raid) gets no welcome message or default role.
		if eng := security.Default(); eng != nil && m != nil && m.Member != nil {
			if eng.OnMemberJoin(context.Background(), m.GuildID, m.Member) {
				events.HandleGuildMemberAddLog(s, m, b.Services)
				return
			}
		}

		// Ignore bot members for welcome/log onboarding of normal users.
		if m != nil && m.Member != nil && m.User != nil && m.User.Bot {
			return
		}

		events.HandleGuildMemberAdd(s, m, b.Services)
		events.HandleGuildMemberAddLog(s, m, b.Services)
	})

	// Anti-nuke and unauthorized bot additions read the audit log as it
	// happens (needs the Guild Moderation intent and View Audit Log).
	b.Session.AddHandler(func(s *discordgo.Session, ev *discordgo.GuildAuditLogEntryCreate) {
		if eng := security.Default(); eng != nil && ev.AuditLogEntry != nil {
			eng.OnAuditLogEntry(context.Background(), ev.GuildID, ev.AuditLogEntry)
		}
	})

	b.Session.AddHandler(func(s *discordgo.Session, m *discordgo.GuildMemberRemove) {
		events.HandleGuildMemberRemoveLog(s, m, b.Services)
	})

	b.Session.AddHandler(func(s *discordgo.Session, m *discordgo.GuildMemberUpdate) {
		events.HandleGuildMemberUpdateLog(s, m, b.Services)
	})

	b.Session.AddHandler(func(s *discordgo.Session, m *discordgo.MessageUpdate) {
		events.HandleMessageUpdateLog(s, m, b.Services)
	})

	b.Session.AddHandler(func(s *discordgo.Session, m *discordgo.MessageDelete) {
		events.HandleMessageDeleteLog(s, m, b.Services)
	})

	b.Session.AddHandler(func(s *discordgo.Session, m *discordgo.GuildBanAdd) {
		events.HandleGuildBanAddLog(s, m, b.Services)
	})

	b.Session.AddHandler(func(s *discordgo.Session, m *discordgo.GuildBanRemove) {
		events.HandleGuildBanRemoveLog(s, m, b.Services)
	})

	b.Session.AddHandler(func(s *discordgo.Session, t *discordgo.ThreadDelete) {
		if st := tickets.Default(); st != nil && t.Channel != nil {
			tickets.ThreadDeleted(context.Background(), st, t.ID)
		}
	})

	b.Session.AddHandler(func(s *discordgo.Session, vs *discordgo.VoiceStateUpdate) {
		events.HandleVoiceStateUpdate(s, vs, b.Services)
		music.OnVoiceStateUpdate(vs)
	})

	b.Session.AddHandler(func(s *discordgo.Session, ev *discordgo.VoiceServerUpdate) {
		music.OnVoiceServerUpdate(ev)
	})

	events.StartScheduleReminderLoop(b.Session, b.Services)
	events.StartTwitchLiveLoop(b.Session, b.Services)

	return nil
}

// betaPollEvery is how often the bot looks for a change to the beta settings
// made on the dashboard.
const betaPollEvery = 30 * time.Second

// WatchBeta keeps the bot's idea of who the beta testers are in step with the
// settings the owner saves on the dashboard. When the beta server changes, the
// beta commands move with it. If the settings can't be read, the last known
// ones stay in force (and before the first read, beta stays locked).
func (b *Bot) WatchBeta(ctx context.Context, load func(context.Context) (guildID, roleID string, err error)) {
	sync := func() {
		guildID, roleID, err := load(ctx)
		if err != nil {
			log.Printf("beta: cannot read settings, keeping the last ones: %v", err)
			return
		}
		beta.Configure(guildID, roleID)
		if now := beta.GuildID(); now != b.betaGuild {
			b.registerBetaCommands(b.betaGuild, now)
			b.betaGuild = now
		}
	}
	sync()
	go func() {
		t := time.NewTicker(betaPollEvery)
		defer t.Stop()
		for {
			select {
			case <-ctx.Done():
				return
			case <-t.C:
				sync()
			}
		}
	}()
}

// registerBetaCommands puts the beta commands in the beta server, and only
// there, so nobody else sees them. Commands this bot left there that are no
// longer beta (or no longer exist) are removed. When the beta server is also
// the bot's main server, its regular commands are kept. If the beta server
// changed, the beta commands are taken out of the old one.
func (b *Bot) registerBetaCommands(previous, guildID string) {
	if previous != "" && previous != guildID {
		isBeta := map[string]bool{}
		for _, cmd := range commands.BetaCommands {
			isBeta[cmd.Name] = true
		}
		if old, err := b.Session.ApplicationCommands(b.AppID, previous); err != nil {
			log.Printf("beta: cannot list commands in the previous server: %v", err)
		} else {
			for _, cmd := range old {
				if isBeta[cmd.Name] {
					if err := b.Session.ApplicationCommandDelete(b.AppID, previous, cmd.ID); err != nil {
						log.Printf("beta: cannot remove '%v' from the previous server: %v", cmd.Name, err)
					}
				}
			}
		}
	}
	if guildID == "" {
		return
	}
	keep := map[string]bool{}
	for _, cmd := range b.Commands {
		if b.GuildID == guildID {
			keep[cmd.Name] = true
		}
	}
	for _, cmd := range commands.BetaCommands {
		keep[cmd.Name] = true
		if _, err := b.Session.ApplicationCommandCreate(b.AppID, guildID, cmd); err != nil {
			log.Printf("beta: cannot create '%v' command: %v", cmd.Name, err)
		}
	}
	existing, err := b.Session.ApplicationCommands(b.AppID, guildID)
	if err != nil {
		log.Printf("beta: cannot list commands, leaving stale ones alone: %v", err)
		return
	}
	for _, cmd := range existing {
		if keep[cmd.Name] {
			continue
		}
		if err := b.Session.ApplicationCommandDelete(b.AppID, guildID, cmd.ID); err != nil {
			log.Printf("beta: cannot remove stale '%v' command: %v", cmd.Name, err)
		}
	}
}

func (b *Bot) Close() error {
	for _, cmd := range b.registeredCommands {
		if err := b.Session.ApplicationCommandDelete(b.AppID, b.GuildID, cmd.ID); err != nil {
			log.Printf("cannot delete '%s' command: %v", cmd.Name, err)
		}
	}
	return b.Session.Close()
}