package main

import (
	"bytes"
	"database/sql"
	"encoding/base64"
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"slices"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/gorilla/websocket"
	_ "github.com/mattn/go-sqlite3"
)

const CONFIGFILE = "./config.json"

type Client struct {
	Conn *websocket.Conn
	Name string
	Mu   sync.Mutex
}

type Server struct {
	Mu      sync.Mutex
	Clients []*Client
	Db      *sql.DB
	Cef     *CEF
}

type CEF struct {
	Conn       *websocket.Conn
	FromServer chan string
	ToServer   chan string
	Kill       chan error
}

type Message struct {
	Type    string `json:"type"`
	User    string `json:"user"`
	Content string `json:"content"`
}

type Config struct {
	Listen  string `json:"listen"`
	Webhook string `json:"webhook"`
	Cef     struct {
		Channel  string `json:"channel"`
		Username string `json:"username"`
		Password string `json:"password"`
	} `json:"cef"`
	Users []string `json:"users"`
}

var config Config
var server = Server{
	Clients: make([]*Client, 0),
}

func (s *Server) KillClient(client *Client) {
	s.Mu.Lock()
	defer s.Mu.Unlock()
	for i, _ := range s.Clients {
		if client == s.Clients[i] {
			s.Clients = append(s.Clients[:i], s.Clients[i+1:]...)
			return
		}
	}
}

func (c *Client) Send(struc any) {
	c.Mu.Lock()
	defer c.Mu.Unlock()
	err := c.Conn.WriteJSON(struc)
	if err != nil {
		server.KillClient(c)
	}
}

func Webhook(message Message) {
	jsonValue, _ := json.Marshal(struct {
		Content  string `json:"content"`
		Username string `json:"username"`
	}{
		Content:  message.Content,
		Username: message.User,
	})
	_, err := http.Post(config.Webhook, "application/json", bytes.NewBuffer(jsonValue))
	if err != nil {
		log.Println("webhook", err)
	}
}

func (s *Server) BroadcastMessage(from string, content string) {
	message := Message{
		Type:    "message",
		User:    from,
		Content: content,
	}
	for _, c := range s.Clients {
		c.Send(message)
	}
	tx, err := s.Db.Begin()
	stmt, err := tx.Prepare("insert into messages(`type`, `user`, `content`) values(?, ?, ?)")
	if err != nil {
		log.Fatal(err)
		return
	}
	_, err = stmt.Exec("message", from, content)
	if err != nil {
		log.Println(stmt)
		return
	}
	tx.Commit()
	go Webhook(message)
	go s.CEFSend(message)
}

func (s *Server) CEFSend(message Message) {
	msg := fmt.Sprintf("NPC %s %s :%s", config.Cef.Channel, message.User, message.Content)
	select {
	case s.Cef.ToServer <- msg:
	default:
	}
}

func (s *Server) SendHistory(client *Client) {
	// Blast
	rows, err := s.Db.Query("SELECT `user`, `content` FROM messages ORDER BY rowid ASC")
	if err != nil {
		log.Println(err)
		return
	}
	defer rows.Close()
	var user, content string

	for rows.Next() {
		err = rows.Scan(&user, &content)
		if err != nil {
			log.Panicln(err)
		}
		client.Send(Message{
			Type:    "history",
			User:    user,
			Content: content,
		})

	}

	client.Send(Message{
		Type:    "ready",
		User:    strconv.Itoa(len(server.Clients)),
		Content: "Welcome back, " + client.Name,
	})

}

func loadConfig() {
	data, err := os.ReadFile(CONFIGFILE)
	if err != nil {
		log.Panicln("Could not read config, ", err)
	}
	err = json.Unmarshal(data, &config)
	if err != nil {
		log.Panicln("Could not load config, ", err)
	}
}

func watchConfig() {
	initialStat, _ := os.Stat(CONFIGFILE)

	for {
		stat, _ := os.Stat(CONFIGFILE)

		if stat.Size() != initialStat.Size() || stat.ModTime() != initialStat.ModTime() {
			loadConfig()
		}

		time.Sleep(1 * time.Second)
	}
}

func (c *CEF) Send(m string) {
	log.Println("[CEF-O]", m)
	err := c.Conn.WriteMessage(websocket.TextMessage, []byte(m))
	if err != nil {
		log.Println("[CEF-S]", err)
		c.Kill <- err
		return
	}
}

func (c *CEF) Loop() {
	for {
		_, message, err := c.Conn.ReadMessage()
		log.Println("[CEF]", string(message), err)
		if err != nil {
			c.Kill <- err
			return
		}
		c.FromServer <- string(message)
	}
}

func BasicCef() {
	c, _, err := websocket.DefaultDialer.Dial("wss://cef.icu/chat", nil)
	defer c.Close()
	if err != nil {
		return
	}
	cef := &CEF{
		Conn:       c,
		FromServer: make(chan string),
		ToServer:   make(chan string),
		Kill:       make(chan error),
	}
	defer close(cef.FromServer)
	defer close(cef.ToServer)
	defer close(cef.Kill)
	server.Cef = cef
	cef.Send("CAP REQ :account-notify account-tag away-notify batch chghost cef/extended-names draft/chathistory draft/multiline draft/event-playback draft/relaymsg echo-message extended-join invite-notify labeled-response message-tags multi-prefix sasl server-time setname userhost-in-names")
	cef.Send("NICK " + config.Cef.Username)
	cef.Send("USER " + config.Cef.Username + " . . :cool dude")
	cef.Send("AUTHENTICATE PLAIN")
	auth := fmt.Sprintf("%s\000%s\000%s", config.Cef.Username, config.Cef.Username, config.Cef.Password)
	cef.Send("AUTHENTICATE " + base64.StdEncoding.EncodeToString([]byte(auth)))
	cef.Send("CAP END")
	// cef.Send("JOIN " + config.Cef.Channel)

	go cef.Loop()
	for {
		select {
		case msg := <-cef.FromServer:
			split := strings.Split(msg, " ")
			if len(split) > 2 {
				if split[1] == "PING" {
					cef.Send("PONG " + split[2])
				}
			}
		case msg := <-cef.ToServer:
			cef.Send(msg)
		case killError := <-cef.Kill:
			log.Println("[CEF]", killError)
			break
		}
	}

}

var upgrader = websocket.Upgrader{} // use default options

func comm(w http.ResponseWriter, r *http.Request) {
	c, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Print("upgrade:", err)
		return
	}
	defer c.Close()
	var client = &Client{
		Conn: c,
		Name: "",
	}
	setup := false
	var inbound struct {
		Msg string `json:"msg"`
	}
	for {
		_, message, err := c.ReadMessage()
		if err != nil {
			log.Println("read:", err)
			break
		}
		err = json.Unmarshal(message, &inbound)
		if err != nil {
			log.Println("unmarshal", err)
			return
		}
		log.Printf("recv: %s", message)
		if !setup {
			if slices.Contains(config.Users, inbound.Msg) {
				server.Mu.Lock()
				server.Clients = append(server.Clients, client)
				server.Mu.Unlock()
				defer server.KillClient(client)
				setup = true
				client.Name = inbound.Msg
				server.SendHistory(client)
			} else {
				err := c.WriteJSON(Message{
					Type:    "error",
					User:    "",
					Content: "LANCER NOT FOUND",
				})
				if err != nil {
					log.Println("writejson", err)
					return
				}
			}
		} else {
			server.BroadcastMessage(client.Name, inbound.Msg)
		}
	}
}

func CefDaemon() {
	for {
		BasicCef()
		time.Sleep(60)
	}
}

func main() {
	loadConfig()
	go watchConfig()
	var addr = flag.String("addr", config.Listen, "http service address")
	db, err := sql.Open("sqlite3", "./messages.db")
	if err != nil {
		log.Fatal(err)
	}
	server.Db = db
	db.Exec("CREATE TABLE messages(`type` text, `user` text, `content` text)")
	defer db.Close()
	go CefDaemon()

	flag.Parse()
	log.SetFlags(0)
	fs := http.FileServer(http.Dir("./assets"))
	http.Handle("/", fs)
	http.HandleFunc("/comm", comm)
	log.Fatal(http.ListenAndServe(*addr, nil))
}