package main

import (
	"encoding/json"
	"log"
	"net/http"
	"sync"

	"github.com/gorilla/websocket"
	"github.com/nats-io/nats.go"

	"git.zb-server.de/ZB-Server/EscapeFromTeacher/pkg/game"
)

var upgrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool {
		return true // Erlaube alle Origins für Development
	},
}

// WebSocketMessage ist das allgemeine Format für WebSocket-Nachrichten
type WebSocketMessage struct {
	Type    string          `json:"type"`    // "join", "input", "start", "leaderboard_request"
	Payload json.RawMessage `json:"payload"` // Beliebige JSON-Daten
}

// WebSocketClient repräsentiert einen verbundenen WebSocket-Client
type WebSocketClient struct {
	conn         *websocket.Conn
	natsConn     *nats.EncodedConn
	playerID     string
	playerCode   string
	roomID       string
	send         chan []byte
	mutex        sync.Mutex
	subUpdates   *nats.Subscription
	subScoreResp *nats.Subscription
}

// handleWebSocket verwaltet eine WebSocket-Verbindung
func handleWebSocket(w http.ResponseWriter, r *http.Request, ec *nats.EncodedConn) {
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Printf("❌ WebSocket Upgrade Fehler: %v", err)
		return
	}

	client := &WebSocketClient{
		conn:     conn,
		natsConn: ec,
		send:     make(chan []byte, 256),
	}

	log.Printf("🔌 Neuer WebSocket-Client verbunden: %s", conn.RemoteAddr())

	// Goroutinen für Lesen und Schreiben starten
	go client.writePump()
	go client.readPump()
}

// readPump liest Nachrichten vom WebSocket-Client
func (c *WebSocketClient) readPump() {
	defer func() {
		if c.subUpdates != nil {
			c.subUpdates.Unsubscribe()
		}
		if c.subScoreResp != nil {
			c.subScoreResp.Unsubscribe()
		}
		c.conn.Close()
		log.Printf("🔌 WebSocket-Client getrennt: %s", c.conn.RemoteAddr())
	}()

	for {
		var msg WebSocketMessage
		err := c.conn.ReadJSON(&msg)
		if err != nil {
			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
				log.Printf("⚠️ WebSocket Fehler: %v", err)
			}
			break
		}

		// Nachricht basierend auf Typ verarbeiten
		c.handleMessage(msg)
	}
}

// writePump sendet Nachrichten zum WebSocket-Client
func (c *WebSocketClient) writePump() {
	defer c.conn.Close()

	for {
		message, ok := <-c.send
		if !ok {
			c.conn.WriteMessage(websocket.CloseMessage, []byte{})
			return
		}

		err := c.conn.WriteMessage(websocket.TextMessage, message)
		if err != nil {
			log.Printf("⚠️ Fehler beim Senden: %v", err)
			return
		}
	}
}

// handleMessage verarbeitet eingehende Nachrichten vom Client
func (c *WebSocketClient) handleMessage(msg WebSocketMessage) {
	switch msg.Type {
	case "join":
		var req game.JoinRequest
		if err := json.Unmarshal(msg.Payload, &req); err != nil {
			log.Printf("❌ Join-Payload ungültig: %v", err)
			return
		}

		c.playerID = req.Name
		c.roomID = req.RoomID
		if c.roomID == "" {
			c.roomID = "lobby"
		}

		log.Printf("📥 WebSocket JOIN: Name=%s, RoomID=%s", req.Name, req.RoomID)

		// An NATS weiterleiten
		c.natsConn.Publish("game.join", &req)

		// Auf Game-Updates für diesen Raum subscriben
		roomChannel := "game.update." + c.roomID
		sub, err := c.natsConn.Subscribe(roomChannel, func(state *game.GameState) {
			// GameState an WebSocket-Client senden
			data, _ := json.Marshal(map[string]interface{}{
				"type":    "game_update",
				"payload": state,
			})
			select {
			case c.send <- data:
			default:
				log.Printf("⚠️ Send channel voll, Nachricht verworfen")
			}
		})

		if err != nil {
			log.Printf("❌ Fehler beim Subscribe auf %s: %v", roomChannel, err)
		} else {
			c.subUpdates = sub
			log.Printf("👂 WebSocket-Client lauscht auf %s", roomChannel)
		}

	case "input":
		var input game.ClientInput
		if err := json.Unmarshal(msg.Payload, &input); err != nil {
			log.Printf("❌ Input-Payload ungültig: %v", err)
			return
		}

		// PlayerID setzen falls nicht vorhanden
		if input.PlayerID == "" {
			input.PlayerID = c.playerID
		}

		// An NATS weiterleiten
		c.natsConn.Publish("game.input", &input)

	case "start":
		var req game.StartRequest
		if err := json.Unmarshal(msg.Payload, &req); err != nil {
			log.Printf("❌ Start-Payload ungültig: %v", err)
			return
		}

		log.Printf("▶️ WebSocket START: RoomID=%s", req.RoomID)
		c.natsConn.Publish("game.start", &req)

	case "leaderboard_request":
		var req game.LeaderboardRequest
		if err := json.Unmarshal(msg.Payload, &req); err != nil {
			log.Printf("❌ Leaderboard-Request ungültig: %v", err)
			return
		}

		log.Printf("🏆 WebSocket Leaderboard-Request: Mode=%s", req.Mode)

		// Auf Leaderboard-Response subscriben (einmalig)
		responseChannel := "leaderboard.response." + c.playerID
		sub, _ := c.natsConn.Subscribe(responseChannel, func(resp *game.LeaderboardResponse) {
			data, _ := json.Marshal(map[string]interface{}{
				"type":    "leaderboard_response",
				"payload": resp,
			})
			select {
			case c.send <- data:
			default:
			}
		})

		// Nach 5 Sekunden unsubscriben
		go func() {
			<-make(chan struct{})
			sub.Unsubscribe()
		}()

		// Request mit ResponseChannel an NATS senden
		req.ResponseChannel = responseChannel
		c.natsConn.Publish("leaderboard.request", &req)

	case "score_submit":
		var submit game.ScoreSubmission
		if err := json.Unmarshal(msg.Payload, &submit); err != nil {
			log.Printf("❌ Score-Submit ungültig: %v", err)
			return
		}

		log.Printf("📊 WebSocket Score-Submit: Player=%s, Score=%d", submit.PlayerCode, submit.Score)

		// Speichere PlayerCode und subscribe auf Response-Channel
		if c.playerCode == "" && submit.PlayerCode != "" {
			c.playerCode = submit.PlayerCode

			// Subscribe auf Score-Response für diesen Spieler
			responseChannel := "score.response." + submit.PlayerCode
			sub, err := c.natsConn.Subscribe(responseChannel, func(resp *game.ScoreSubmissionResponse) {
				// ScoreSubmissionResponse an WebSocket-Client senden
				data, _ := json.Marshal(map[string]interface{}{
					"type":    "score_response",
					"payload": resp,
				})
				select {
				case c.send <- data:
					log.Printf("📤 Proof-Code an Client gesendet: %s", resp.ProofCode)
				default:
					log.Printf("⚠️ Send channel voll, Proof-Code verworfen")
				}
			})

			if err != nil {
				log.Printf("❌ Fehler beim Subscribe auf %s: %v", responseChannel, err)
			} else {
				c.subScoreResp = sub
				log.Printf("👂 WebSocket-Client lauscht auf Score-Responses: %s", responseChannel)
			}
		}

		c.natsConn.Publish("score.submit", &submit)

	default:
		log.Printf("⚠️ Unbekannter Nachrichtentyp: %s", msg.Type)
	}
}