package chat

import (
	"fmt"
	"log/slog"
	"strings"

	"github.com/ayn2op/discordo/internal/config"
	"github.com/ayn2op/tview"
	"github.com/ayn2op/tview/help"
	"github.com/ayn2op/tview/keybind"
	"github.com/ayn2op/tview/picker"
	"github.com/diamondburned/arikawa/v3/discord"
	"github.com/gdamore/tcell/v3"
)

const emojiPickerLayerName = "emojiPicker"

type emojiPicker struct {
	*picker.Model
	chatView   *Model
	browseMode bool
	favorites  *emojiFavorites

	// allItems is cached on picker open; only favorites change on toggle.
	allItems []picker.Item

	targetMessageID discord.MessageID
	targetChannelID discord.ChannelID
}

var _ help.KeyMap = (*emojiPicker)(nil)

func newEmojiPicker(cfg *config.Config, chatView *Model) *emojiPicker {
	ep := &emojiPicker{
		Model:     picker.NewModel(),
		chatView:  chatView,
		favorites: loadEmojiFavorites(),
	}
	ConfigurePicker(ep.Model, cfg, "Emoji")
	return ep
}

// resetBrowse starts the emoji picker in browse (scroll) mode by default.
func (ep *emojiPicker) resetBrowse() { ep.browseMode = true }

var commonEmoji = []struct {
	emoji string
	names string
}{
	{"👍", "thumbsup thumbs_up +1 like"},
	{"👎", "thumbsdown thumbs_down -1 dislike"},
	{"❤️", "heart love red_heart"},
	{"😂", "joy laughing tears"},
	{"😭", "sob crying"},
	{"😊", "blush smile happy"},
	{"😍", "heart_eyes love"},
	{"🤣", "rofl rolling"},
	{"🙂", "slightly_smiling_face"},
	{"😔", "pensive sad"},
	{"🔥", "fire lit hot"},
	{"✅", "white_check_mark check yes"},
	{"❌", "x cross no"},
	{"👀", "eyes look"},
	{"🎉", "tada party celebration"},
	{"💀", "skull dead"},
	{"🤔", "thinking hmm"},
	{"😐", "neutral_face"},
	{"🤷", "shrug"},
	{"👋", "wave hello hi"},
	{"🙏", "pray please thanks"},
	{"💯", "100 hundred perfect"},
	{"😎", "sunglasses cool"},
	{"🥳", "partying_face party"},
	{"😢", "cry sad"},
	{"😅", "sweat_smile nervous"},
	{"🤗", "hugs hugging"},
	{"😤", "triumph angry"},
	{"🥺", "pleading_face"},
	{"💪", "muscle strong flex"},
	{"✨", "sparkles stars"},
	{"💜", "purple_heart"},
	{"💙", "blue_heart"},
	{"💚", "green_heart"},
	{"🧡", "orange_heart"},
	{"💛", "yellow_heart"},
	{"🖤", "black_heart"},
	{"🤍", "white_heart"},
	{"⭐", "star"},
	{"🌟", "star2 glowing_star"},
	{"😮", "open_mouth surprised"},
	{"😱", "scream shocked"},
	{"😈", "smiling_imp devil"},
	{"🤡", "clown clown_face"},
	{"🫡", "salute saluting_face"},
	{"🫠", "melting_face"},
	{"💤", "zzz sleep"},
	{"🤝", "handshake"},
	{"🏳️", "white_flag surrender"},
}

// update loads all emoji items (cached) and rebuilds with favorites.
func (ep *emojiPicker) update() {
	if ep.allItems == nil {
		ep.loadItems()
	}
	ep.rebuildWithFavorites()
}

// loadItems builds the static emoji list (common + guild). Called once per picker open.
func (ep *emojiPicker) loadItems() {
	items := make(picker.Items, 0, len(commonEmoji)+50)
	for _, e := range commonEmoji {
		firstName := e.names
		if i := strings.IndexByte(e.names, ' '); i != -1 {
			firstName = e.names[:i]
		}
		items = append(items, picker.Item{
			Text:       e.emoji + " " + firstName,
			FilterText: e.names,
			Reference:  discord.APIEmoji(e.emoji),
		})
	}

	selectedChannel := ep.chatView.SelectedChannel()
	if selectedChannel != nil && selectedChannel.GuildID.IsValid() {
		emojis, err := ep.chatView.state.Cabinet.Emojis(selectedChannel.GuildID)
		if err == nil {
			for _, emoji := range emojis {
				if !emoji.Available {
					continue
				}
				items = append(items, picker.Item{
					Text:       ":" + emoji.Name + ":",
					FilterText: emoji.Name,
					Reference:  emoji.APIString(),
				})
			}
		}
	}
	ep.allItems = items
}

// rebuildWithFavorites prepends favorites to the cached item list.
func (ep *emojiPicker) rebuildWithFavorites() {
	byKey := make(map[string]picker.Item, len(ep.allItems))
	for _, item := range ep.allItems {
		byKey[emojiItemKey(item)] = item
	}

	items := make(picker.Items, 0, maxFavoriteEmoji+len(ep.allItems))
	favSet := make(map[string]struct{})
	for _, key := range ep.favorites.list() {
		if item, ok := byKey[key]; ok {
			items = append(items, picker.Item{
				Text:       "★ " + item.Text,
				FilterText: "favorite " + item.FilterText,
				Reference:  item.Reference,
			})
			favSet[key] = struct{}{}
		}
	}

	for _, item := range ep.allItems {
		if _, isFav := favSet[emojiItemKey(item)]; !isFav {
			items = append(items, item)
		}
	}

	ep.Model.SetItems(items)
}

func emojiItemKey(item picker.Item) string {
	if ref, ok := item.Reference.(discord.APIEmoji); ok {
		return string(ref)
	}
	return ""
}

func (ep *emojiPicker) HandleEvent(event tview.Event) tview.Command {
	switch event := event.(type) {
	case *tview.KeyEvent:
		if cmd, handled := pickerBrowseHandleKey(
			event, &ep.browseMode, ep.Model,
			func() { ep.chatView.closeEmojiPicker() },
			ep.handleFavoriteKey,
		); handled {
			return cmd
		}
	case *picker.SelectedEvent:
		apiEmoji, ok := event.Reference.(discord.APIEmoji)
		if !ok {
			return nil
		}

		channelID := ep.targetChannelID
		messageID := ep.targetMessageID

		// Check if user already reacted with this emoji.
		alreadyReacted := false
		if msg, err := ep.chatView.state.Cabinet.Message(channelID, messageID); err == nil {
			for _, r := range msg.Reactions {
				if r.Me && r.Emoji.APIString() == apiEmoji {
					alreadyReacted = true
					break
				}
			}
		}

		ep.chatView.closeEmojiPicker()

		return func() tview.Event {
			if alreadyReacted {
				if err := ep.chatView.state.Unreact(channelID, messageID, apiEmoji); err != nil {
					slog.Error("failed to remove reaction", "err", err, "emoji", fmt.Sprint(apiEmoji))
				}
			} else {
				if err := ep.chatView.state.React(channelID, messageID, apiEmoji); err != nil {
					slog.Error("failed to add reaction", "err", err, "emoji", fmt.Sprint(apiEmoji))
				}
			}
			if cmd := ep.chatView.focusMessagesList(); cmd != nil {
				return cmd()
			}
			return nil
		}
	case *picker.CancelEvent:
		ep.chatView.closeEmojiPicker()
		return nil
	}
	return ep.Model.HandleEvent(event)
}

func (ep *emojiPicker) handleFavoriteKey(event *tview.KeyEvent) (tview.Command, bool) {
	if event.Key() != tcell.KeyRune || event.Str() != "f" {
		return nil, false
	}

	// Trigger a select to get the highlighted item's reference without
	// dispatching the event through the normal loop.
	cmd := ep.Model.HandleEvent(tcell.NewEventKey(tcell.KeyEnter, "", tcell.ModNone))
	if cmd == nil {
		return nil, true
	}
	if sel, ok := cmd().(*picker.SelectedEvent); ok {
		key := emojiItemKey(sel.Item)
		if key != "" {
			ep.favorites.toggle(key)
			ep.update()
		}
	}
	return nil, true
}

func (ep *emojiPicker) ShortHelp() []keybind.Keybind {
	return pickerShortHelp(ep.chatView.cfg.Keybinds.Picker)
}

func (ep *emojiPicker) FullHelp() [][]keybind.Keybind {
	return pickerFullHelp(ep.chatView.cfg.Keybinds.Picker)
}