package labels

import (
	"sync"

	"github.com/diamondburned/arikawa/v2/discord"
	"github.com/diamondburned/arikawa/v2/gateway"
	"github.com/diamondburned/cchat"
	"github.com/diamondburned/ningen/v2"
)

// Repository is a repository containing LabelContainers. It watches for update
// events from the gateway.
//
// If a labeler that is already registered were to be added again, then the
// adder function will do nothing and will return a callback that does nothing.
type Repository struct {
	state   *ningen.State
	detachs []func()
	stopped bool

	mutex  sync.Mutex
	stores labelContainers
}

// NewRepository creates a new repository.
func NewRepository(state *ningen.State) *Repository {
	r := Repository{
		state:  state,
		stores: newLabelContainers(),
	}

	r.detachs = []func(){
		state.AddHandler(r.onGuildUpdate),
		state.AddHandler(r.onMemberUpdate),
		state.AddHandler(r.onMemberRemove),
		state.AddHandler(r.onChannelUpdate),
		state.AddHandler(r.onChannelDelete),
	}

	return &r
}

func (r *Repository) onGuildUpdate(ev *gateway.GuildUpdateEvent) {
	r.mutex.Lock()
	defer r.mutex.Unlock()

	if r.stopped {
		return
	}

	guild, ok := r.stores.guilds[ev.ID]
	if !ok {
		return
	}

	rich := labelGuild(r.state, ev.ID)

	for labeler := range guild.guild {
		labeler.SetLabel(rich)
	}
}

// AddGuildLabel adds a label to display the given guild ID. Refer to Repository
// for more documentation.
func (r *Repository) AddGuildLabel(guildID discord.GuildID, l cchat.LabelContainer) func() {
	l.SetLabel(labelGuild(r.state, guildID))

	r.mutex.Lock()
	defer r.mutex.Unlock()

	guild, _ := r.stores.guilds[guildID]
	guild.guild.Add(l)
	r.stores.guilds[guildID] = guild

	return func() {
		r.mutex.Lock()
		defer r.mutex.Unlock()

		guild, _ := r.stores.guilds[guildID]
		guild.guild.Remove(l)

		if guild.IsEmpty() {
			delete(r.stores.guilds, guildID)
			return
		}

		r.stores.guilds[guildID] = guild
	}
}

func (r *Repository) onMemberRemove(ev *gateway.GuildMemberRemoveEvent) {}

func (r *Repository) onMemberUpdate(ev *gateway.GuildMemberUpdateEvent) {}

// AddMemberLabel adds a label to display the given member live. Refer to
// Repository for more documentation.
func (r *Repository) AddMemberLabel(
	guildID discord.GuildID, userID discord.UserID, l cchat.LabelContainer) func() {

	l.SetLabel(labelMember(r.state, guildID, userID))

	r.mutex.Lock()
	defer r.mutex.Unlock()

	guild, _ := r.stores.guilds[guildID]

	llist := guild.members[userID]
	llist.Add(l)

	if guild.members == nil {
		guild.members = make(map[discord.UserID]labelerList, 1)
	}

	guild.members[userID] = llist
	r.stores.guilds[guildID] = guild

	return func() {
		r.mutex.Lock()
		defer r.mutex.Unlock()

		guild, _ := r.stores.guilds[guildID]

		llist := guild.members[userID]
		llist.Remove(l)

		if guild.IsEmpty() {
			delete(r.stores.guilds, guildID)
			return
		}

		guild.members[userID] = llist
		r.stores.guilds[guildID] = guild
	}
}

func (r *Repository) onChannelUpdate(ev *gateway.ChannelUpdateEvent) {}
func (r *Repository) onChannelDelete(ev *gateway.ChannelDeleteEvent) {}

// AddChannelLabel adds a label to display the given channel live. Refer to
// Repository for more documentation.
func (r *Repository) AddChannelLabel(chID discord.ChannelID, l cchat.LabelContainer) func() {
	l.SetLabel(labelChannel(r.state, chID))

	r.mutex.Lock()
	defer r.mutex.Unlock()

	llist := r.stores.channels[chID]
	llist.Add(l)
	r.stores.channels[chID] = llist

	return func() {
		r.mutex.Lock()
		defer r.mutex.Unlock()

		llist := r.stores.channels[chID]
		llist.Remove(l)

		if len(llist) == 0 {
			delete(r.stores.channels, chID)
			return
		}

		r.stores.channels[chID] = llist
	}
}

// Stop detaches all handlers.
func (r *Repository) Stop() {
	r.mutex.Lock()
	defer r.mutex.Unlock()

	r.stopped = true

	for _, detach := range r.detachs {
		detach()
	}
}