package telegram

import (
	"fmt"
	"strings"

	"tgchanbot/internal/storage"

	tele "gopkg.in/telebot.v3"
)

const (
	cbPrefixCat     = "cat:"
	cbPrefixConfirm = "confirm:"
	cbCancel        = "cancel"
)

func (b *Bot) handlePost(c tele.Context) error {
	b.states.StartPost(c.Sender().ID)
	return c.Reply("📨 请转发一条来自目标频道的消息")
}

func (b *Bot) handleTextOrForwarded(c tele.Context) error {
	msg := c.Message()
	if msg == nil || msg.OriginalChat == nil {
		return nil
	}
	return b.handleForwarded(c)
}

func (b *Bot) handleForwarded(c tele.Context) error {
	if !b.cfg.IsAdmin(c.Sender().ID) {
		return nil
	}

	state := b.states.Get(c.Sender().ID)
	if state == nil || state.Step != StepAwaitForward {
		return nil
	}

	msg := c.Message()
	if msg.OriginalChat == nil {
		return c.Reply("❌ 这不是一条转发消息，请转发频道消息")
	}

	b.states.SetForwarded(c.Sender().ID, msg)

	categories, err := b.storage.ListCategories()
	if err != nil {
		b.states.Delete(c.Sender().ID)
		return c.Reply(fmt.Sprintf("❌ 获取分类失败: %v", err))
	}

	if len(categories) == 0 {
		b.states.Delete(c.Sender().ID)
		return c.Reply("❌ 暂无分类，请先使用 /cat_add 创建分类")
	}

	keyboard := b.buildCategoryKeyboard(categories)
	return c.Reply("📁 请选择分类:", keyboard)
}

func (b *Bot) buildCategoryKeyboard(categories []storage.Category) *tele.ReplyMarkup {
	menu := &tele.ReplyMarkup{}
	var rows []tele.Row

	var currentRow []tele.Btn
	for _, cat := range categories {
		btn := menu.Data(cat.Name, cbPrefixCat+cat.Name)
		currentRow = append(currentRow, btn)

		if len(currentRow) == 3 {
			rows = append(rows, menu.Row(currentRow...))
			currentRow = nil
		}
	}

	if len(currentRow) > 0 {
		rows = append(rows, menu.Row(currentRow...))
	}

	cancelBtn := menu.Data("❌ 取消", cbCancel)
	rows = append(rows, menu.Row(cancelBtn))

	menu.Inline(rows...)
	return menu
}

func (b *Bot) handleCallback(c tele.Context) error {
	if !b.cfg.IsAdmin(c.Sender().ID) {
		return c.Respond(&tele.CallbackResponse{Text: "无权限"})
	}

	data := c.Callback().Data
	userID := c.Sender().ID

	switch {
	case data == cbCancel:
		return b.handleCancelCallback(c, userID)

	case strings.HasPrefix(data, cbPrefixCat):
		category := strings.TrimPrefix(data, cbPrefixCat)
		return b.handleCategoryCallback(c, userID, category)

	case strings.HasPrefix(data, cbPrefixConfirm):
		action := strings.TrimPrefix(data, cbPrefixConfirm)
		return b.handleConfirmCallback(c, userID, action)
	}

	return c.Respond()
}

func (b *Bot) handleCancelCallback(c tele.Context, userID int64) error {
	b.states.Delete(userID)
	c.Edit("❌ 已取消")
	return c.Respond(&tele.CallbackResponse{Text: "已取消"})
}

func (b *Bot) handleCategoryCallback(c tele.Context, userID int64, category string) error {
	state := b.states.Get(userID)
	if state == nil || state.Step != StepAwaitCategory {
		return c.Respond(&tele.CallbackResponse{Text: "会话已过期"})
	}

	b.states.SetCategory(userID, category)

	channelName := "未知频道"
	if state.ForwardedMsg.OriginalChat != nil {
		channelName = state.ForwardedMsg.OriginalChat.Title
	}

	menu := &tele.ReplyMarkup{}
	confirmBtn := menu.Data("✅ 确认", cbPrefixConfirm+"yes")
	cancelBtn := menu.Data("❌ 取消", cbCancel)
	menu.Inline(menu.Row(confirmBtn, cancelBtn))

	text := fmt.Sprintf("📋 确认添加?\n\n频道: %s\n分类: %s", channelName, category)
	c.Edit(text, menu)
	return c.Respond()
}

func (b *Bot) handleConfirmCallback(c tele.Context, userID int64, action string) error {
	if action != "yes" {
		return b.handleCancelCallback(c, userID)
	}

	state := b.states.Get(userID)
	if state == nil || state.Step != StepAwaitConfirm {
		return c.Respond(&tele.CallbackResponse{Text: "会话已过期"})
	}

	defer b.states.Delete(userID)

	msg := state.ForwardedMsg
	title := extractTitle(msg)
	link := buildMessageLink(msg)

	entry, err := b.storage.CreateEntry(state.SelectedCat, title, link)
	if err != nil {
		c.Edit(fmt.Sprintf("❌ 保存失败: %v", err))
		return c.Respond(&tele.CallbackResponse{Text: "保存失败"})
	}

	b.toc.TriggerUpdate()

	text := fmt.Sprintf("✅ 已添加\n\nID: %s\n分类: %s\n标题: %s", entry.ID, entry.Category, entry.Title)
	c.Edit(text)
	return c.Respond(&tele.CallbackResponse{Text: "添加成功"})
}

func extractTitle(msg *tele.Message) string {
	text := msg.Text
	if text == "" {
		text = msg.Caption
	}

	lines := strings.Split(text, "\n")
	title := strings.TrimSpace(lines[0])

	if len(title) > 50 {
		title = title[:47] + "..."
	}

	if title == "" {
		title = "无标题"
	}

	return title
}

func buildMessageLink(msg *tele.Message) string {
	if msg.OriginalChat == nil {
		return ""
	}

	chat := msg.OriginalChat
	msgID := msg.OriginalMessageID
	if msgID == 0 {
		msgID = msg.ID
	}

	if chat.Username != "" {
		return fmt.Sprintf("https://t.me/%s/%d", chat.Username, msgID)
	}

	chatID := chat.ID
	if chatID < 0 {
		chatID = -chatID - 1000000000000
	}
	return fmt.Sprintf("https://t.me/c/%d/%d", chatID, msgID)
}