package telegram

import (
	"log/slog"

	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"
)

const (
	TextLengthLimit = 4000
)

type TelegramMessageSender struct {
	bot    *tgbotapi.BotAPI
	logger *slog.Logger
}

func NewTelegramMessageSender(botToken string, logger *slog.Logger) (*TelegramMessageSender, error) {
	bot, err := tgbotapi.NewBotAPI(botToken)
	if err != nil {
		return nil, err
	}

	return &TelegramMessageSender{
		bot:    bot,
		logger: logger,
	}, nil
}

func (s *TelegramMessageSender) Send(text string, chatId int64, replyToMessageId *int) error {
	// If message is short enough, send it directly
	if len([]rune(text)) <= TextLengthLimit {
		return s.sendSingleMessage(text, chatId, replyToMessageId)
	}

	// Split long message into parts
	parts := s.splitMessageByWords(text, TextLengthLimit)

	// Send each part
	for i, part := range parts {
		var replyId *int
		// Only use replyToMessageId for the first part
		if i == 0 {
			replyId = replyToMessageId
		}
		err := s.sendSingleMessage(part, chatId, replyId)
		if err != nil {
			return err
		}
	}

	return nil
}

// sendSingleMessage sends a single message
func (s *TelegramMessageSender) sendSingleMessage(text string, chatId int64, replyToMessageId *int) error {
	resultMsg := tgbotapi.NewMessage(chatId, text)
	if replyToMessageId != nil {
		resultMsg.ReplyToMessageID = *replyToMessageId
	}
	_, err := s.bot.Send(resultMsg)
	if err != nil {
		s.logger.Error("Failed to send message to tg bot", "error", err)
		return err
	}
	return nil
}