package features

import (
	"bytes"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"strings"

	"github.com/disgoorg/disgo/discord"
	"github.com/disgoorg/disgo/events"
	"github.com/disgoorg/disgo/rest"
	"github.com/disgoorg/disgo/webhook"
	"github.com/disgoorg/snowflake/v2"

	"github.com/elisiei/unbot/db"
)

type Starboard struct {
	db      *db.DB
	config  StarboardConfig
	webhook *webhook.Client
}

type StarboardConfig struct {
	Enabled    bool
	WebhookURL string
	ChannelID  uint64
	Threshold  int
}

func NewStarboard(database *db.DB, webhookURL string, channelID uint64, threshold int, enabled bool) (*Starboard, error) {
	var wh *webhook.Client
	if webhookURL != "" {
		var err error
		wh, err = webhook.NewWithURL(webhookURL)
		if err != nil {
			return nil, fmt.Errorf("failed to create webhook: %w", err)
		}
	}
	return &Starboard{
		db:      database,
		webhook: wh,
		config: StarboardConfig{
			Enabled:    enabled,
			WebhookURL: webhookURL,
			ChannelID:  channelID,
			Threshold:  threshold,
		},
	}, nil
}

func (s *Starboard) HandleReactionAdd(e *events.GuildMessageReactionAdd) {
	if !s.config.Enabled || s.webhook == nil {
		return
	}

	if e.ChannelID == snowflake.ID(s.config.ChannelID) {
		return
	}

	originalMsgID := e.MessageID.String()

	msg, err := e.Client().Rest.GetMessage(e.ChannelID, e.MessageID)
	if err != nil {
		slog.Error("failed to get message for starboard", slog.Any("err", err))
		return
	}

	totalReactions := 0
	for _, r := range msg.Reactions {
		totalReactions += r.Count
	}

	starboardMsgIDStr, err := s.db.GetStarboardMessageID(originalMsgID)
	if err != nil {
		slog.Error("failed to check starboard entry", slog.Any("err", err))
		return
	}

	if starboardMsgIDStr != "" {
		if totalReactions >= s.config.Threshold {
			s.updateStarboardEntry(starboardMsgIDStr, msg, e.ChannelID, e.GuildID, e.MessageID)
		} else {
			s.removeStarboardEntry(starboardMsgIDStr, originalMsgID)
		}
		return
	}

	if totalReactions < s.config.Threshold {
		return
	}

	content, embeds, files := s.buildStarboardMessage(msg, e.ChannelID, e.GuildID, e.MessageID)

	msgCreate := discord.WebhookMessageCreate{
		Content:   content,
		Embeds:    embeds,
		Files:     files,
		Username:  msg.Author.EffectiveName(),
		AvatarURL: msg.Author.EffectiveAvatarURL(),
	}

	webhookMsg, err := s.webhook.CreateMessage(msgCreate, rest.CreateWebhookMessageParams{Wait: true})
	if err != nil {
		slog.Error("failed to send starboard webhook", slog.Any("err", err))
		return
	}
	if webhookMsg == nil {
		slog.Error("starboard webhook returned nil message")
		return
	}

	if err := s.db.AddStarboardEntry(originalMsgID, webhookMsg.ID.String()); err != nil {
		slog.Error("failed to save starboard entry", slog.Any("err", err))
	}
}

func (s *Starboard) HandleReactionRemove(e *events.GuildMessageReactionRemove) {
	if !s.config.Enabled || s.webhook == nil {
		return
	}

	if e.ChannelID == snowflake.ID(s.config.ChannelID) {
		return
	}

	originalMsgID := e.MessageID.String()

	starboardMsgIDStr, err := s.db.GetStarboardMessageID(originalMsgID)
	if err != nil {
		slog.Error("failed to check starboard entry", slog.Any("err", err))
		return
	}

	if starboardMsgIDStr == "" {
		return
	}

	msg, err := e.Client().Rest.GetMessage(e.ChannelID, e.MessageID)
	if err != nil {
		slog.Warn("original message gone, removing starboard entry", slog.Any("err", err))
		s.removeStarboardEntry(starboardMsgIDStr, originalMsgID)
		return
	}

	totalReactions := 0
	for _, r := range msg.Reactions {
		totalReactions += r.Count
	}

	if totalReactions >= s.config.Threshold {
		s.updateStarboardEntry(starboardMsgIDStr, msg, e.ChannelID, e.GuildID, e.MessageID)
	} else {
		s.removeStarboardEntry(starboardMsgIDStr, originalMsgID)
	}
}

func (s *Starboard) buildStarboardMessage(msg *discord.Message, channelID, guildID, messageID snowflake.ID) (content string, embeds []discord.Embed, files []*discord.File) {
	content = msg.Content
	if content == "" {
		content = "*(no text content)*"
	}
	if len(content) > 2000 {
		content = content[:1997] + "..."
	}

	jumpURL := fmt.Sprintf("https://discord.com/channels/%s/%s/%s", guildID, channelID, messageID)

	for _, a := range msg.Attachments {
		resp, err := http.Get(a.URL)
		if err != nil {
			slog.Warn("failed to download attachment for starboard", slog.Any("err", err), slog.String("url", a.URL))
			continue
		}
		data, err := io.ReadAll(resp.Body)
		resp.Body.Close()
		if err != nil {
			slog.Warn("failed to read attachment for starboard", slog.Any("err", err), slog.String("url", a.URL))
			continue
		}
		files = append(files, discord.NewFile(a.Filename, "", bytes.NewReader(data)))
	}

	if len(msg.Reactions) > 0 {
		var parts []string
		for _, r := range msg.Reactions {
			var e string
			if r.Emoji.ID == 0 {
				e = r.Emoji.Name
			} else if r.Emoji.Animated {
				e = fmt.Sprintf("<a:%s:%d>", r.Emoji.Name, r.Emoji.ID)
			} else {
				e = fmt.Sprintf("<:%s:%d>", r.Emoji.Name, r.Emoji.ID)
			}
			parts = append(parts, fmt.Sprintf("%s %d", e, r.Count))
		}
		parts = append(parts, fmt.Sprintf("\n[[ jump to message ]](%s)", jumpURL))
		embeds = append(embeds, discord.Embed{
			Description: strings.Join(parts, "  "),
		})
	}

	return
}

func (s *Starboard) updateStarboardEntry(starboardMsgIDStr string, msg *discord.Message, channelID, guildID, messageID snowflake.ID) {
	content, embeds, files := s.buildStarboardMessage(msg, channelID, guildID, messageID)

	starboardMsgID, err := snowflake.Parse(starboardMsgIDStr)
	if err != nil {
		slog.Error("failed to parse starboard message ID", slog.Any("err", err))
		return
	}

	emptyAttachments := []discord.AttachmentUpdate{}
	update := discord.WebhookMessageUpdate{
		Content:     &content,
		Embeds:      &embeds,
		Attachments: &emptyAttachments,
		Files:       files,
	}

	if _, err := s.webhook.UpdateMessage(starboardMsgID, update, rest.UpdateWebhookMessageParams{}); err != nil {
		slog.Error("failed to update starboard webhook", slog.Any("err", err))
	}
}

func (s *Starboard) removeStarboardEntry(starboardMsgIDStr, originalMsgID string) {
	starboardMsgID, err := snowflake.Parse(starboardMsgIDStr)
	if err == nil {
		if err := s.webhook.Rest.DeleteWebhookMessage(s.webhook.ID, s.webhook.Token, starboardMsgID, 0); err != nil {
			slog.Error("failed to delete starboard webhook message", slog.Any("err", err))
		}
	} else {
		slog.Error("failed to parse starboard message ID for deletion", slog.Any("err", err))
	}

	if err := s.db.RemoveStarboardEntry(originalMsgID); err != nil {
		slog.Error("failed to remove starboard entry", slog.Any("err", err))
	}
}