package telegram

import (
	"fmt"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"sync"

	"dev.narayana.im/narayana/telegabber/telegram/formatter"
	"dev.narayana.im/narayana/telegabber/xmpp/gateway"

	log "github.com/sirupsen/logrus"
	"github.com/zelenin/go-tdlib/client"
)

func uhOh() {
	log.Fatal("Update type mismatch")
}

func int64SliceToStringSlice(ints []int64) []string {
	strings := make([]string, len(ints))
	wg := sync.WaitGroup{}

	for i, xi := range ints {
		wg.Add(1)
		go func(i int, xi int64) {
			strings[i] = strconv.FormatInt(xi, 10)
			wg.Done()
		}(i, xi)
	}
	wg.Wait()

	return strings
}

func (c *Client) getChatMessageLock(chatID int64) *sync.Mutex {
	lock, ok := c.locks.chatMessageLocks[chatID]
	if !ok {
		lock = &sync.Mutex{}
		c.locks.chatMessageLocks[chatID] = lock
	}

	return lock
}

func (c *Client) cleanTempFile(path string) {
	os.Remove(path)

	dir := filepath.Dir(path)
	dirName := filepath.Base(dir)
	if strings.HasPrefix(dirName, "telegabber-") {
		os.Remove(dir)
	}
}

func (c *Client) sendMarker(chatId, messageId int64, typ gateway.MarkerType) {
	xmppId, err := gateway.IdsDB.GetByTgIds(c.Session.Login, c.jid, chatId, messageId)
	if err != nil {
		xmppId = strconv.FormatInt(messageId, 10)
	}

	var stringType string
	if typ == gateway.MarkerTypeReceived {
		stringType = "received"
	} else if typ == gateway.MarkerTypeDisplayed {
		stringType = "displayed"
	}
	log.WithFields(log.Fields{
		"xmppId": xmppId,
	}).Debugf("marker: %s", stringType)

	gateway.SendMessageMarker(
		c.jid,
		strconv.FormatInt(chatId, 10),
		c.xmpp,
		typ,
		xmppId,
	)
}

func (c *Client) updateHandler() {
	listener := c.client.GetListener()
	defer listener.Close()

	for update := range listener.Updates {
		if update.GetClass() == client.ClassUpdate {
			switch update.GetType() {
			case client.TypeUpdateUser:
				typedUpdate, ok := update.(*client.UpdateUser)
				if !ok {
					uhOh()
				}
				c.updateUser(typedUpdate)
				log.Debugf("%#v", typedUpdate.User)
			case client.TypeUpdateUserStatus:
				typedUpdate, ok := update.(*client.UpdateUserStatus)
				if !ok {
					uhOh()
				}
				c.updateUserStatus(typedUpdate)
				log.Debugf("%#v", typedUpdate.Status)
			case client.TypeUpdateNewChat:
				typedUpdate, ok := update.(*client.UpdateNewChat)
				if !ok {
					uhOh()
				}
				c.updateNewChat(typedUpdate)
				log.Debugf("%#v", typedUpdate.Chat)
			case client.TypeUpdateChatPosition:
				typedUpdate, ok := update.(*client.UpdateChatPosition)
				if !ok {
					uhOh()
				}
				c.updateChatPosition(typedUpdate)
				log.Debugf("%#v", typedUpdate)
			case client.TypeUpdateChatLastMessage:
				typedUpdate, ok := update.(*client.UpdateChatLastMessage)
				if !ok {
					uhOh()
				}
				c.updateChatLastMessage(typedUpdate)
				log.Debugf("%#v", typedUpdate)
			case client.TypeUpdateNewMessage:
				typedUpdate, ok := update.(*client.UpdateNewMessage)
				if !ok {
					uhOh()
				}
				c.updateNewMessage(typedUpdate)
				log.Debugf("%#v", typedUpdate.Message)
			case client.TypeUpdateMessageContent:
				typedUpdate, ok := update.(*client.UpdateMessageContent)
				if !ok {
					uhOh()
				}
				c.updateMessageContent(typedUpdate)
				log.Debugf("%#v", typedUpdate.NewContent)
			case client.TypeUpdateDeleteMessages:
				typedUpdate, ok := update.(*client.UpdateDeleteMessages)
				if !ok {
					uhOh()
				}
				c.updateDeleteMessages(typedUpdate)
			case client.TypeUpdateAuthorizationState:
				typedUpdate, ok := update.(*client.UpdateAuthorizationState)
				if !ok {
					uhOh()
				}
				c.updateAuthorizationState(typedUpdate)
			case client.TypeUpdateMessageSendSucceeded:
				typedUpdate, ok := update.(*client.UpdateMessageSendSucceeded)
				if !ok {
					uhOh()
				}
				c.updateMessageSendSucceeded(typedUpdate)
			case client.TypeUpdateMessageSendFailed:
				typedUpdate, ok := update.(*client.UpdateMessageSendFailed)
				if !ok {
					uhOh()
				}
				c.updateMessageSendFailed(typedUpdate)
			case client.TypeUpdateChatTitle:
				typedUpdate, ok := update.(*client.UpdateChatTitle)
				if !ok {
					uhOh()
				}
				c.updateChatTitle(typedUpdate)
			case client.TypeUpdateChatReadOutbox:
				typedUpdate, ok := update.(*client.UpdateChatReadOutbox)
				if !ok {
					uhOh()
				}
				c.updateChatReadOutbox(typedUpdate)
			default:
				// log only handled types
				continue
			}

			log.Debugf("%#v", update)
		}
	}
}

// new user discovered
func (c *Client) updateUser(update *client.UpdateUser) {
	c.cache.SetUser(update.User.Id, update.User)
	show, status, presenceType := c.userStatusToText(update.User.Status, update.User.Id)
	go c.ProcessStatusUpdate(update.User.Id, status, show, gateway.SPType(presenceType))
}

// user status changed
func (c *Client) updateUserStatus(update *client.UpdateUserStatus) {
	show, status, presenceType := c.userStatusToText(update.Status, update.UserId)
	go c.ProcessStatusUpdate(update.UserId, status, show, gateway.SPImmed(false), gateway.SPType(presenceType))
}

// new chat discovered
func (c *Client) updateNewChat(update *client.UpdateNewChat) {
	go func() {
		if update.Chat != nil && update.Chat.Photo != nil && update.Chat.Photo.Small != nil {
			_, err := c.DownloadFile(update.Chat.Photo.Small.Id, 10, true)

			if err != nil {
				log.Error("Failed to download the chat photo")
			}
		}

		c.cache.SetChat(update.Chat.Id, update.Chat)

		if update.Chat.Positions != nil && len(update.Chat.Positions) > 0 {
			c.subscribeToID(update.Chat.Id, update.Chat)
		}

		if update.Chat.Id < 0 {
			c.ProcessStatusUpdate(update.Chat.Id, update.Chat.Title, "chat")
		}
	}()
}

// chat position is updated
func (c *Client) updateChatPosition(update *client.UpdateChatPosition) {
	if update.Position != nil && update.Position.Order != 0 {
		go c.subscribeToID(update.ChatId, nil)
	}
}

// chat last message is updated
func (c *Client) updateChatLastMessage(update *client.UpdateChatLastMessage) {
	if update.Positions != nil && len(update.Positions) > 0 {
		go c.subscribeToID(update.ChatId, nil)
	}
}

// message received
func (c *Client) updateNewMessage(update *client.UpdateNewMessage) {
	chatId := update.Message.ChatId

	// guarantee sequential message delivering per chat
	lock := c.getChatMessageLock(chatId)
	go func() {
		lock.Lock()
		defer lock.Unlock()

		c.updateLastMessageHash(update.Message.ChatId, update.Message.Id, update.Message.Content)

		// ignore self outgoing messages
		if update.Message.IsOutgoing &&
			update.Message.SendingState != nil &&
			update.Message.SendingState.MessageSendingStateType() == client.TypeMessageSendingStatePending {
			return
		}

		log.WithFields(log.Fields{
			"chat_id": chatId,
		}).Warn("New message from chat")

		c.ProcessIncomingMessage(chatId, update.Message)
	}()
}

// message content updated
func (c *Client) updateMessageContent(update *client.UpdateMessageContent) {
	markupFunction := c.getFormatter()

	defer c.updateLastMessageHash(update.ChatId, update.MessageId, update.NewContent)

	log.Debugf("newContent: %#v", update.NewContent)

	lock := c.getChatMessageLock(update.ChatId)
	lock.Lock()
	lock.Unlock()
	c.SendMessageLock.Lock()
	c.SendMessageLock.Unlock()

	xmppId, xmppIdErr := gateway.IdsDB.GetByTgIds(c.Session.Login, c.jid, update.ChatId, update.MessageId)
	var ignoredResource string
	if xmppIdErr == nil {
		ignoredResource = c.popFromEditOutbox(xmppId)
	} else {
		log.Infof("Couldn't retrieve XMPP message ids for %v, an echo may happen", update.MessageId)
	}
	log.Infof("ignoredResource: %v", ignoredResource)

	jids := c.getCarbonFullJids(true, ignoredResource)
	if len(jids) == 0 {
		log.Info("The only resource is ignored, aborting")
		return
	}

	if update.NewContent.MessageContentType() == client.TypeMessageText && c.hasLastMessageHashChanged(update.ChatId, update.MessageId, update.NewContent) {
		textContent := update.NewContent.(*client.MessageText)
		log.Debugf("textContent: %#v", textContent.Text)

		var replaceId string
		sId := strconv.FormatInt(update.MessageId, 10)
		var isCarbon bool

		// use XEP-0308 edits only if the last message is edited for sure, fallback otherwise
		if c.Session.NativeEdits {
			lastXmppId, ok := c.getLastChatMessageId(update.ChatId)
			if xmppIdErr != nil {
				xmppId = sId
			}
			if ok && lastXmppId == xmppId {
				replaceId = xmppId
			} else {
				log.Infof("Mismatching message ids: %v %v, falling back to separate edit message", lastXmppId, xmppId)
			}
		}

		message, messageErr := c.client.GetMessage(&client.GetMessageRequest{
			ChatId:    update.ChatId,
			MessageId: update.MessageId,
		})
		var prefix string
		if messageErr == nil {
			isCarbon = c.isCarbonsEnabled() && message.IsOutgoing
			// reply correction support in clients is suboptimal yet, so cut them out for now
			prefix, _ = c.messageToPrefix(message, "", "", true)
		} else {
			log.Errorf("No message %v/%v found, cannot reliably determine if it's a carbon", update.ChatId, update.MessageId)
		}

		var text strings.Builder

		if replaceId == "" {
			var editChar string
			if c.Session.AsciiArrows {
				editChar = "e"
			} else {
				editChar = "✎"
			}
			text.WriteString(fmt.Sprintf("%s %v | ", editChar, update.MessageId))
		} else if prefix != "" {
			text.WriteString(prefix)
			text.WriteString(c.getPrefixSeparator(update.ChatId))
		}

		text.WriteString(formatter.Format(
			textContent.Text.Text,
			textContent.Text.Entities,
			markupFunction,
		))

		sChatId := strconv.FormatInt(update.ChatId, 10)
		for _, jid := range jids {
			gateway.SendMessage(jid, sChatId, text.String(), "e"+sId, c.xmpp, nil, replaceId, isCarbon, false)
		}
	}
}

// message(s) deleted
func (c *Client) updateDeleteMessages(update *client.UpdateDeleteMessages) {
	if update.IsPermanent {
		var deleteChar string
		if c.Session.AsciiArrows {
			deleteChar = "X "
		} else {
			deleteChar = "✗ "
		}
		text := deleteChar + strings.Join(int64SliceToStringSlice(update.MessageIds), ",")
		gateway.SendTextMessage(c.jid, strconv.FormatInt(update.ChatId, 10), text, c.xmpp)
	}
}

func (c *Client) updateAuthorizationState(update *client.UpdateAuthorizationState) {
	switch update.AuthorizationState.AuthorizationStateType() {
	case client.TypeAuthorizationStateClosing:
		log.Warn("Closing the updates listener")
	case client.TypeAuthorizationStateClosed:
		log.Warn("Closed the updates listener")
		c.forceClose()
	}
}

func (c *Client) updateMessageSendSucceeded(update *client.UpdateMessageSendSucceeded) {
	// replace message ID in local database
	log.Debugf("replace message %v with %v", update.OldMessageId, update.Message.Id)
	if err := gateway.IdsDB.ReplaceTgId(c.Session.Login, c.jid, update.Message.ChatId, update.OldMessageId, update.Message.Id); err != nil {
		log.Errorf("failed to replace %v with %v: %v", update.OldMessageId, update.Message.Id, err.Error())
	}

	c.updateLastMessageHash(update.Message.ChatId, update.Message.Id, update.Message.Content)

	c.sendMarker(update.Message.ChatId, update.Message.Id, gateway.MarkerTypeReceived)

	// clean uploaded files
	file, _ := c.contentToFile(update.Message.Content)
	if file != nil && file.Local != nil {
		c.cleanTempFile(file.Local.Path)
	}
}
func (c *Client) updateMessageSendFailed(update *client.UpdateMessageSendFailed) {
	// clean uploaded files
	file, _ := c.contentToFile(update.Message.Content)
	if file != nil && file.Local != nil {
		c.cleanTempFile(file.Local.Path)
	}
}

// chat title changed
func (c *Client) updateChatTitle(update *client.UpdateChatTitle) {
	gateway.SetNickname(c.jid, strconv.FormatInt(update.ChatId, 10), update.Title, c.xmpp)

	// set also the status (for group chats only)
	chat, user, _ := c.GetContactByID(update.ChatId, nil)
	if user == nil {
		c.ProcessStatusUpdate(update.ChatId, update.Title, "chat", gateway.SPImmed(true))
	}

	// update chat title in the cache
	if chat != nil {
		chat.Title = update.Title
	}
}

func (c *Client) updateChatReadOutbox(update *client.UpdateChatReadOutbox) {
	c.sendMarker(update.ChatId, update.LastReadOutboxMessageId, gateway.MarkerTypeDisplayed)
}