// Copyright 2025 The Casibase Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package object

import (
	"fmt"

	"github.com/beego/beego/logs"
	"github.com/robfig/cron/v3"
)

func getChatMessagesFromMessages(chat string, messages []*Message) []*Message {
	res := []*Message{}
	for _, message := range messages {
		if message.Chat == chat {
			res = append(res, message)
		}
	}
	return res
}

func deleteChatAndMessages(chat string) error {
	_, err := DeleteChat(&Chat{Owner: "admin", Name: chat})
	if err != nil {
		return err
	}

	_, err = DeleteMessagesByChat(&Message{Owner: "admin", Chat: chat})
	if err != nil {
		return err
	}

	return nil
}

func isRedundentMessages(chatMessages []*Message) bool {
	if len(chatMessages) != 2 {
		return false
	}

	var aiMessage *Message
	if chatMessages[0].Author == "AI" && chatMessages[1].Author != "AI" {
		aiMessage = chatMessages[0]
	} else if chatMessages[1].Author == "AI" && chatMessages[0].Author != "AI" {
		aiMessage = chatMessages[1]
	} else {
		return false
	}
	if aiMessage == nil {
		return false
	}

	if aiMessage.Text == "" && aiMessage.ReplyTo == "Welcome" {
		return true
	}
	return false
}

func cleanupChats() error {
	chats, err := GetGlobalChats()
	if err != nil {
		return err
	}

	messages, err := GetGlobalMessages()
	if err != nil {
		return err
	}

	i := 1
	for _, chat := range chats {
		needDelete := false
		chatMessages := getChatMessagesFromMessages(chat.Name, messages)
		if chat.MessageCount == 0 || len(chatMessages) == 0 {
			needDelete = true
		} else if chat.MessageCount == 1 {
			if chatMessages[0].Author == "AI" {
				needDelete = true
			}
		} else if chat.MessageCount == 2 {
			if isRedundentMessages(chatMessages) {
				needDelete = true
			}
		}

		if needDelete {
			err = deleteChatAndMessages(chat.Name)
			if err != nil {
				return err
			}

			logs.Info("[%d] Cleaned up empty chat: [%s], user = [%s], clientIp = [%s], userAgent = [%s]\n", i, chat.Name, chat.User, chat.ClientIp, chat.UserAgent)
			i += 1
		}
	}

	return err
}

func cleanupChatsNoError() {
	err := cleanupChats()
	if err != nil {
		logs.Error("cleanupChatsNoError() error: %s\n", err.Error())
	}
}

func InitCleanupChats() {
	cleanupChatsNoError()

	cronJob := cron.New()
	schedule := fmt.Sprintf("@every %ds", 3600)
	_, err := cronJob.AddFunc(schedule, cleanupChatsNoError)
	if err != nil {
		panic(err)
	}

	cronJob.Start()
}