package main

import (
	"context"
	"errors"
	"log"
	"net/http"
	"time"

	"github.com/coder/websocket"
	"github.com/coder/websocket/wsjson"
)

func ServeWsConnection(responseWriter http.ResponseWriter, request *http.Request) {
	connection, err := websocket.Accept(responseWriter, request, &websocket.AcceptOptions{
		InsecureSkipVerify: true,
	})
	if err != nil {
		log.Printf("websocket accept error: %v", err)
		return
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	var user = User{WsConn: connection}
	var isAuthenticated bool
	var ignoreCache bool

	defer closeConnection(&user, ignoreCache)
	for {
		var userMessage map[string]any
		err = wsjson.Read(ctx, connection, &userMessage)
		if err != nil {
			log.Printf("read error: %v", err)
			return
		}

		if len(userMessage) > 0 {
			if isAuthenticated {
				if !handleAuthenticatedMessage(&user, &userMessage) {
					return
				}
			} else {
				if !handleUnauthenticatedMessage(ctx, &user, &userMessage) {
					ignoreCache = true
					return
				}
				isAuthenticated = true
			}
		}
	}
}

func sendMessageCloseIfTimeout(user *User, message *map[string]any) {
	if user.WsConn == nil {
		return
	}

	ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
	defer cancel()

	err := wsjson.Write(ctx, user.WsConn, message)
	if err != nil {
		if errors.Is(err, context.DeadlineExceeded) {
			closeConnection(user, false)
		}
		log.Printf("write error: %v", err)
	}
}

func sendToAllMessageCloseIfTimeout(message *map[string]any) {
	mu.RLock()
	defer mu.RUnlock()
	for _, user := range CacheUsers {
		sendMessageCloseIfTimeout(user, message)
	}
}

func WsSendToGroup(ctx context.Context, groupId uint32, senderId uint32, message string) error {
	group, err := CacheGetGroup(groupId)
	if err != nil {
		return errors.New("group invalid")
	}

	sender, err := CacheGetUserById(senderId)
	if err != nil {
		sender = &User{Id: senderId}
		err = DbUserSetById(ctx, sender)
		if err != nil {
			return errors.New("non existing sender")
		}
	}

	for groupUserId := range group.Users {
		groupUser, err := CacheGetUserById(groupUserId)
		if err != nil || groupUser.Id == sender.Id {
			continue
		}

		var msg = map[string]any{
			"from":    "group",
			"group":   group.Id,
			"sender":  sender.Name,
			"content": message,
		}
		sendMessageCloseIfTimeout(groupUser, &msg)
	}
	return nil
}

func handleAuthenticatedMessage(user *User, userMessage *map[string]any) bool {
	sendMessageCloseIfTimeout(user, userMessage)
	return true
}

func handleUnauthenticatedMessage(ctx context.Context, user *User, userMessage *map[string]any) bool {
	token, ok := (*userMessage)["token"].(string)
	if !ok {
		var msg = map[string]any{
			"from":  "server",
			"error": "no token in message",
		}
		sendMessageCloseIfTimeout(user, &msg)
		return false
	}

	userId, err := TokenValidateGetId(token)
	if err != nil {
		var msg = map[string]any{
			"from":  "server",
			"error": "invalid token",
		}
		sendMessageCloseIfTimeout(user, &msg)
		return false
	}

	userFromCache, err := CacheGetUserById(userId)
	if err != nil {
		dbUser := &User{Id: userId}
		err = DbUserSetByIdWithoutGroups(ctx, dbUser)
		if err != nil {
			var msg = map[string]any{
				"from":  "server",
				"error": "invalid user data",
			}
			sendMessageCloseIfTimeout(user, &msg)
			return false
		}
		err = DbUserSetGroups(ctx, dbUser)
		if err != nil {
			var msg = map[string]any{
				"from":  "server",
				"error": "invalid user data",
			}
			sendMessageCloseIfTimeout(user, &msg)
			return false
		}
		dbUser.WsConn = user.WsConn
		CacheSaveUser(dbUser)
		userFromCache = dbUser
	}

	userFromCache.WsConn = user.WsConn
	*user = *userFromCache

	for groupId, _ := range userFromCache.Groups {
		_, err = CacheGetGroup(groupId)
		if err != nil {
			dbGroup := &Group{Id: groupId}

			err = DbGroupSetById(ctx, dbGroup)
			if err != nil {
				var msg = map[string]any{
					"from":  "server",
					"error": "invalid user data",
				}
				sendMessageCloseIfTimeout(user, &msg)
				return false
			}
			CacheSaveGroup(dbGroup)
		}
	}
	return true
}

func closeConnection(user *User, ignoreCache bool) {
	if !ignoreCache {
		CacheDeleteUser(user.Id)
	}
	user.WsConn.CloseNow()
}