package main

import (
	"context"
	"encoding/json"
	"fmt"
	"html"
	"log"
	"math/rand"
	"net/http"
	"os"
	"strconv"
	"time"

	"github.com/google/uuid"
	"github.com/redis/go-redis/v9"
)

// ==========================================
// 1. KONSTANTEN
// ==========================================
const (
	Gravity      = 0.6
	JumpPower    = -12.0
	GroundY      = 350.0
	PlayerHeight = 50.0
	PlayerYBase  = GroundY - PlayerHeight // 300.0

	GameSpeed = 5.0
	GameWidth = 800.0
)

// ==========================================
// 2. GLOBALE VARIABLEN
// ==========================================
var (
	ctx           = context.Background()
	rdb           *redis.Client
	defaultConfig GameConfig
	adminUser     string
	adminPass     string
)

// ==========================================
// 3. STRUCTS
// ==========================================

type ObstacleDef struct {
	ID          string   `json:"id"`
	Width       float64  `json:"width"`
	Height      float64  `json:"height"`
	Color       string   `json:"color"`
	Image       string   `json:"image"`
	CanTalk     bool     `json:"canTalk"`
	SpeechLines []string `json:"speechLines"`
	YOffset     float64  `json:"yOffset"`
}

type GameConfig struct {
	Obstacles   []ObstacleDef `json:"obstacles"`
	Backgrounds []string      `json:"backgrounds"`
}

type ActiveObstacle struct {
	ID     string  `json:"id"`
	X      float64 `json:"x"`
	Y      float64 `json:"y"`
	Width  float64 `json:"w"`
	Height float64 `json:"h"`
}

type Input struct {
	Tick int    `json:"t"`
	Act  string `json:"act"`
}

type ValidateRequest struct {
	SessionID  string  `json:"sessionId"`
	Inputs     []Input `json:"inputs"`
	TotalTicks int     `json:"totalTicks"`
}

type ValidateResponse struct {
	Status        string           `json:"status"`
	VerifiedScore int              `json:"verifiedScore"`
	ServerObs     []ActiveObstacle `json:"serverObs"`
}

type StartResponse struct {
	SessionID string `json:"sessionId"`
	Seed      uint32 `json:"seed"`
}

type SubmitNameRequest struct {
	SessionID string `json:"sessionId"`
	Name      string `json:"name"`
}

type SubmitResponse struct {
	ClaimCode string `json:"claimCode"`
}

type LeaderboardEntry struct {
	Rank  int64  `json:"rank"`
	Name  string `json:"name"`
	Score int    `json:"score"`
	IsMe  bool   `json:"isMe"`
}

type AdminActionRequest struct {
	SessionID string `json:"sessionId"`
	Action    string `json:"action"`
}

type AdminEntry struct {
	SessionID string `json:"sessionId"`
	Name      string `json:"name"`
	Score     int    `json:"score"`
	Code      string `json:"code"`
	Time      string `json:"time"`
}

type ClaimDeleteRequest struct {
	SessionID string `json:"sessionId"`
	ClaimCode string `json:"claimCode"`
}

// ==========================================
// 4. PSEUDO RNG
// ==========================================
type PseudoRNG struct {
	State uint32
}

func NewRNG(seed int64) *PseudoRNG {
	// DEBUG: RNG Init
	// log.Printf("[RNG] Init mit Seed: %d", seed)
	return &PseudoRNG{State: uint32(seed)}
}

func (r *PseudoRNG) NextFloat() float64 {
	calc := (uint64(r.State)*1664525 + 1013904223) % 4294967296
	r.State = uint32(calc)
	return float64(r.State) / 4294967296.0
}

func (r *PseudoRNG) NextRange(min, max float64) float64 {
	return min + (r.NextFloat() * (max - min))
}

func (r *PseudoRNG) PickDef(defs []ObstacleDef) *ObstacleDef {
	if len(defs) == 0 {
		return nil
	}
	idx := int(r.NextRange(0, float64(len(defs))))
	return &defs[idx]
}

// ==========================================
// 5. HELPER
// ==========================================
func getEnv(key, fallback string) string {
	if value, ok := os.LookupEnv(key); ok {
		return value
	}
	return fallback
}

func parseOr(s string, def float64) float64 {
	if s == "" {
		return def
	}
	v, err := strconv.ParseFloat(s, 64)
	if err != nil {
		return def
	}
	return v
}

func generateClaimCode() string {
	const charset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	b := make([]byte, 8)
	for i := range b {
		b[i] = charset[rand.Intn(len(charset))]
	}
	return string(b)
}

// Middleware für Basic Auth
func BasicAuth(next http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user, pass, ok := r.BasicAuth()
		if !ok || user != adminUser || pass != adminPass {
			w.Header().Set("WWW-Authenticate", `Basic realm="Lehrerzimmer"`)
			http.Error(w, "Unauthorized", 401)
			return
		}
		next(w, r)
	}
}

// Middleware für Request Logging (DAMIT DU SIEHST OB REQUESTS ANKOMMEN)
func LogRequest(next http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		start := time.Now()
		log.Printf("➡ [REQ] %s %s von %s", r.Method, r.URL.Path, r.RemoteAddr)
		next(w, r)
		log.Printf("⬅ [RES] %s %s fertig in %v", r.Method, r.URL.Path, time.Since(start))
	}
}

// ==========================================
// 6. MAIN
// ==========================================
func main() {
	// Config laden
	redisAddr := getEnv("REDIS_ADDR", "localhost:6379")
	adminUser = getEnv("ADMIN_USER", "lehrer")
	adminPass = getEnv("ADMIN_PASS", "geheim123")

	log.Printf("🔧 CONFIG: Redis=%s | AdminUser=%s", redisAddr, adminUser)

	// Redis verbinden
	log.Println("🔌 Verbinde zu Redis...")
	rdb = redis.NewClient(&redis.Options{Addr: redisAddr})

	pong, err := rdb.Ping(ctx).Result()
	if err != nil {
		log.Fatalf("❌ REDIS ERROR: %v", err)
	}
	log.Printf("✅ Redis verbunden: %s", pong)

	initGameConfig()

	// File Server
	fs := http.FileServer(http.Dir("./static"))
	http.Handle("/", fs)

	// API Routes (mit Logging Wrapper)
	http.HandleFunc("/api/config", LogRequest(handleConfig))
	http.HandleFunc("/api/start", LogRequest(handleStart))
	http.HandleFunc("/api/validate", LogRequest(handleValidate)) // Hier passiert die Magie
	http.HandleFunc("/api/submit-name", LogRequest(handleSubmitName))
	http.HandleFunc("/api/leaderboard", LogRequest(handleLeaderboard))
	http.HandleFunc("/api/claim/delete", LogRequest(handleClaimDelete))

	// Admin Routes
	http.HandleFunc("/admin", BasicAuth(handleAdminPage))
	http.HandleFunc("/api/admin/list", BasicAuth(handleAdminList))
	http.HandleFunc("/api/admin/action", BasicAuth(handleAdminAction))

	log.Println("🦖 Server läuft auf Port 8080")
	log.Fatal(http.ListenAndServe(":8080", nil))
}

func initGameConfig() {
	defaultConfig = GameConfig{
		Obstacles: []ObstacleDef{
			{ID: "desk", Width: 40, Height: 30, Color: "#8B4513", Image: "desk.png"},
			{ID: "teacher", Width: 30, Height: 60, Color: "#000080", Image: "teacher.png", CanTalk: true, SpeechLines: []string{"Halt!", "Handy weg!", "Nachsitzen!"}},
			{ID: "trashcan", Width: 25, Height: 35, Color: "#555", Image: "trash.png"},
			{ID: "eraser", Width: 30, Height: 20, Color: "#fff", Image: "eraser.png", YOffset: 45.0},
		},
		Backgrounds: []string{"background.jpg"},
	}
	log.Println("✅ Game Config initialisiert")
}

// ==========================================
// 7. HANDLER (MIT DEBUG LOGS)
// ==========================================

func handleConfig(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(defaultConfig)
}

func handleStart(w http.ResponseWriter, r *http.Request) {
	sessionID := uuid.New().String()

	// Seed erstellen (32-Bit sicher)
	rawSeed := time.Now().UnixNano()
	seed32 := uint32(rawSeed)

	// Initiale Hindernisse (leer)
	emptyObs, _ := json.Marshal([]ActiveObstacle{})

	log.Printf("🆕 START SESSION: %s | Seed: %d", sessionID, seed32)

	// In Redis speichern
	err := rdb.HSet(ctx, "session:"+sessionID, map[string]interface{}{
		"seed":      seed32,
		"rng_state": seed32,
		"score":     0,
		"is_dead":   0,
		"pos_y":     PlayerYBase, // WICHTIG: Start auf dem Boden (300.0)
		"vel_y":     0.0,
		"obstacles": string(emptyObs),
	}).Err()

	if err != nil {
		log.Printf("❌ REDIS WRITE ERROR bei Start: %v", err)
		http.Error(w, "DB Error", 500)
		return
	}

	// Expire setzen
	rdb.Expire(ctx, "session:"+sessionID, 1*time.Hour)

	json.NewEncoder(w).Encode(StartResponse{SessionID: sessionID, Seed: seed32})
}

func handleValidate(w http.ResponseWriter, r *http.Request) {
	var req ValidateRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		log.Printf("⚠️ Validate Decode Error: %v", err)
		http.Error(w, "Bad Request", 400)
		return
	}

	key := "session:" + req.SessionID

	// Alle Daten holen
	vals, err := rdb.HGetAll(ctx, key).Result()
	if err != nil || len(vals) == 0 {
		log.Printf("⚠️ Session nicht gefunden oder leer: %s", req.SessionID)
		http.Error(w, "Session invalid", 401)
		return
	}

	// Check ob schon tot
	if vals["is_dead"] == "1" {
		// log.Printf("💀 Validierung abgelehnt: Spieler %s ist bereits tot.", req.SessionID)
		json.NewEncoder(w).Encode(ValidateResponse{Status: "dead", VerifiedScore: 0})
		return
	}

	// State parsen
	posY := parseOr(vals["pos_y"], PlayerYBase)
	velY := parseOr(vals["vel_y"], 0.0)
	score := int(parseOr(vals["score"], 0))
	rngStateVal, _ := strconv.ParseInt(vals["rng_state"], 10, 64)

	// RNG initialisieren
	rng := NewRNG(rngStateVal)

	// Hindernisse laden
	var obstacles []ActiveObstacle
	if val, ok := vals["obstacles"]; ok && val != "" {
		json.Unmarshal([]byte(val), &obstacles)
	} else {
		obstacles = []ActiveObstacle{}
	}

	// log.Printf("🎮 SIMULATION START (%s) | Ticks: %d | PosY: %.2f | Obstacles: %d", req.SessionID, req.TotalTicks, posY, len(obstacles))

	playerDead := false

	// --- SIMULATION LOOP ---
	for i := 0; i < req.TotalTicks; i++ {

		// A. INPUT
		didJump := false
		isCrouching := false
		for _, inp := range req.Inputs {
			if inp.Tick == i {
				if inp.Act == "JUMP" {
					didJump = true
				}
				if inp.Act == "DUCK" {
					isCrouching = true
				}
			}
		}

		// B. PHYSIK
		// Toleranz 1.0px
		isGrounded := posY >= PlayerYBase-1.0

		currentHeight := PlayerHeight
		if isCrouching {
			currentHeight = PlayerHeight / 2
			if !isGrounded {
				velY += 2.0
			} // Fast fall
		}

		if didJump && isGrounded && !isCrouching {
			velY = JumpPower
		}

		velY += Gravity
		posY += velY

		if posY > PlayerYBase {
			posY = PlayerYBase
			velY = 0
		}

		// Hitbox Y berechnen
		hitboxY := posY
		if isCrouching {
			hitboxY = posY + (PlayerHeight - currentHeight)
		}

		// C. OBSTACLES & KOLLISION
		nextObstacles := []ActiveObstacle{}
		rightmostX := 0.0

		for _, obs := range obstacles {
			obs.X -= GameSpeed

			// Ist Hindernis schon vorbei? (Hinter Spieler)
			if obs.X+obs.Width < 50.0 {
				// log.Printf("🗑️ Obstacle %s passed safely", obs.ID)
				continue // Nicht in nextObstacles aufnehmen -> wird gelöscht
			}

			// Kollisions-Logik
			paddingX := 10.0
			paddingY_Top := 25.0
			paddingY_Bottom := 5.0

			pLeft, pRight := 50.0+paddingX, 50.0+30.0-paddingX
			pTop, pBottom := hitboxY+paddingY_Top, hitboxY+currentHeight-paddingY_Bottom

			oLeft, oRight := obs.X+paddingX, obs.X+obs.Width-paddingX
			oTop, oBottom := obs.Y+paddingY_Top, obs.Y+obs.Height-paddingY_Bottom

			if pRight > oLeft && pLeft < oRight && pBottom > oTop && pTop < oBottom {
				log.Printf("💥 KOLLISION! Session: %s | Obs: %s at %.2f | PlayerY: %.2f | Crouch: %v", req.SessionID, obs.ID, obs.X, posY, isCrouching)
				playerDead = true
			}

			// Behalten wenn noch relevant (sichtbar oder kurz davor)
			// Wir behalten es etwas länger, damit Client Synchronisation nicht springt
			if obs.X+obs.Width > -100 {
				nextObstacles = append(nextObstacles, obs)
				if obs.X+obs.Width > rightmostX {
					rightmostX = obs.X + obs.Width
				}
			}
		}
		obstacles = nextObstacles

		// D. SPAWNING
		if rightmostX < GameWidth-10.0 {
			rawGap := 400.0 + rng.NextRange(0, 500)
			gap := float64(int(rawGap))
			spawnX := rightmostX + gap
			if spawnX < GameWidth {
				spawnX = GameWidth
			}

			var possibleDefs []ObstacleDef
			for _, d := range defaultConfig.Obstacles {
				if d.ID == "eraser" {
					if score >= 500 {
						possibleDefs = append(possibleDefs, d)
					}
				} else {
					possibleDefs = append(possibleDefs, d)
				}
			}

			def := rng.PickDef(possibleDefs)

			if def != nil && def.CanTalk {
				if rng.NextFloat() > 0.7 {
					rng.NextFloat()
				}
			}

			if def != nil {
				spawnY := GroundY - def.Height - def.YOffset
				// log.Printf("✨ SPAWN: %s at %.2f (Y: %.2f)", def.ID, spawnX, spawnY)

				obstacles = append(obstacles, ActiveObstacle{
					ID:     def.ID,
					X:      spawnX,
					Y:      spawnY,
					Width:  def.Width,
					Height: def.Height,
				})
			}
		}

		if !playerDead {
			score++
		} else {
			// Wenn tot, brechen wir die Loop ab, um Rechenzeit zu sparen
			// und senden den Dead-Status zurück
			break
		}
	}

	// --- SPEICHERN ---

	status := "alive"
	if playerDead {
		status = "dead"
		rdb.HSet(ctx, key, "is_dead", 1)
	}

	obsJson, _ := json.Marshal(obstacles)

	err = rdb.HSet(ctx, key, map[string]interface{}{
		"score":     score,
		"pos_y":     fmt.Sprintf("%f", posY),
		"vel_y":     fmt.Sprintf("%f", velY),
		"rng_state": rng.State,
		"obstacles": string(obsJson),
	}).Err()

	if err != nil {
		log.Printf("❌ REDIS SAVE ERROR: %v", err)
	}

	rdb.Expire(ctx, key, 1*time.Hour)

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(ValidateResponse{
		Status:        status,
		VerifiedScore: score,
		ServerObs:     obstacles,
	})
}

func handleSubmitName(w http.ResponseWriter, r *http.Request) {
	var req SubmitNameRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Bad Request", 400)
		return
	}

	log.Printf("📝 SUBMIT NAME: %s für Session %s", req.Name, req.SessionID)

	safeName := html.EscapeString(req.Name)
	sessionKey := "session:" + req.SessionID

	scoreVal, err := rdb.HGet(ctx, sessionKey, "score").Result()
	if err != nil {
		log.Printf("⚠️ Submit fehlgeschlagen: Session nicht gefunden %s", req.SessionID)
		http.Error(w, "Session expired", 404)
		return
	}
	scoreInt, _ := strconv.Atoi(scoreVal)

	claimCode := generateClaimCode()
	timestamp := time.Now().Format("02.01.2006 15:04")

	rdb.HSet(ctx, sessionKey, map[string]interface{}{
		"name":       safeName,
		"claim_code": claimCode,
		"created_at": timestamp,
	})

	rdb.ZAdd(ctx, "leaderboard:unverified", redis.Z{
		Score:  float64(scoreInt),
		Member: req.SessionID,
	})

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(SubmitResponse{ClaimCode: claimCode})
}

func handleLeaderboard(w http.ResponseWriter, r *http.Request) {
	mySessionID := r.URL.Query().Get("sessionId")
	targetKey := "leaderboard:public"

	var entries []LeaderboardEntry

	top3, _ := rdb.ZRevRangeWithScores(ctx, targetKey, 0, 2).Result()

	for i, z := range top3 {
		rank := int64(i + 1)
		sid := z.Member.(string)
		name, _ := rdb.HGet(ctx, "session:"+sid, "name").Result()
		if name == "" {
			name = "Unbekannt"
		}

		entries = append(entries, LeaderboardEntry{
			Rank: rank, Name: name, Score: int(z.Score), IsMe: (sid == mySessionID),
		})
	}

	if mySessionID != "" {
		myRank, err := rdb.ZRevRank(ctx, targetKey, mySessionID).Result()
		if err == nil {
			if myRank > 2 {
				start := myRank - 1
				stop := myRank + 1
				neighbors, _ := rdb.ZRevRangeWithScores(ctx, targetKey, start, stop).Result()

				for i, z := range neighbors {
					rank := start + int64(i) + 1
					sid := z.Member.(string)
					name, _ := rdb.HGet(ctx, "session:"+sid, "name").Result()
					if name == "" {
						name = "Unbekannt"
					}

					entries = append(entries, LeaderboardEntry{
						Rank: rank, Name: name, Score: int(z.Score), IsMe: (sid == mySessionID),
					})
				}
			}
		}
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(entries)
}

func handleAdminPage(w http.ResponseWriter, r *http.Request) {
	http.ServeFile(w, r, "./secure/admin.html")
}

func handleAdminList(w http.ResponseWriter, r *http.Request) {
	listType := r.URL.Query().Get("type")
	redisKey := "leaderboard:unverified"
	if listType == "public" {
		redisKey = "leaderboard:public"
	}

	vals, _ := rdb.ZRevRangeWithScores(ctx, redisKey, 0, -1).Result()
	var adminList []AdminEntry

	for _, z := range vals {
		sid := z.Member.(string)
		info, _ := rdb.HGetAll(ctx, "session:"+sid).Result()

		name := info["name"]
		if name == "" {
			name = "Unbekannt"
		}

		adminList = append(adminList, AdminEntry{
			SessionID: sid,
			Name:      name,
			Score:     int(z.Score),
			Code:      info["claim_code"],
			Time:      info["created_at"],
		})
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(adminList)
}

func handleAdminAction(w http.ResponseWriter, r *http.Request) {
	var req AdminActionRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Bad Request", 400)
		return
	}

	log.Printf("👮 ADMIN ACTION: %s on %s", req.Action, req.SessionID)

	if req.Action == "approve" {
		score, err := rdb.ZScore(ctx, "leaderboard:unverified", req.SessionID).Result()
		if err != nil {
			http.Error(w, "Entry not found", 404)
			return
		}
		rdb.ZAdd(ctx, "leaderboard:public", redis.Z{Score: score, Member: req.SessionID})
		rdb.ZRem(ctx, "leaderboard:unverified", req.SessionID)

	} else if req.Action == "delete" {
		rdb.ZRem(ctx, "leaderboard:unverified", req.SessionID)
		rdb.ZRem(ctx, "leaderboard:public", req.SessionID)
	}

	w.WriteHeader(http.StatusOK)
}

func handleClaimDelete(w http.ResponseWriter, r *http.Request) {
	var req ClaimDeleteRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Bad Request", 400)
		return
	}

	sessionKey := "session:" + req.SessionID
	realCode, err := rdb.HGet(ctx, sessionKey, "claim_code").Result()

	if err != nil || realCode == "" {
		log.Printf("⚠️ Claim Delete Failed: Session/Code missing %s", req.SessionID)
		http.Error(w, "Not found", 404)
		return
	}

	if realCode != req.ClaimCode {
		log.Printf("⛔ Claim Delete Denied: Wrong Code %s vs %s", req.ClaimCode, realCode)
		http.Error(w, "Wrong Code", 403)
		return
	}

	log.Printf("🗑️ USER DELETE: Session %s deleted via code", req.SessionID)
	rdb.ZRem(ctx, "leaderboard:unverified", req.SessionID)
	rdb.ZRem(ctx, "leaderboard:public", req.SessionID)
	rdb.HDel(ctx, sessionKey, "name")

	w.WriteHeader(http.StatusOK)
}