package main

import (
	"encoding/json"
	"html"
	"math/rand"
	"net/http"
	"strconv"
	"time"

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

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()
	rawSeed := time.Now().UnixNano()
	seed32 := uint32(rawSeed)

	emptyObs, _ := json.Marshal([]ActiveObstacle{})

	err := rdb.HSet(ctx, "session:"+sessionID, map[string]interface{}{
		"seed":      seed32,
		"rng_state": seed32,
		"score":     0,
		"is_dead":   0,
		"pos_y":     PlayerYBase,
		"vel_y":     0.0,
		"obstacles": string(emptyObs),
	}).Err()

	if err != nil {
		http.Error(w, "DB Error", 500)
		return
	}
	rdb.Expire(ctx, "session:"+sessionID, 4000*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 {
		http.Error(w, "Bad Request", 400)
		return
	}

	key := "session:" + req.SessionID
	vals, err := rdb.HGetAll(ctx, key).Result()
	if err != nil || len(vals) == 0 {
		http.Error(w, "Session invalid", 401)
		return
	}

	if vals["is_dead"] == "1" {
		json.NewEncoder(w).Encode(ValidateResponse{Status: "dead", VerifiedScore: 0})
		return
	}

	// ---> HIER RUFEN WIR JETZT DIE SIMULATION AUF <---
	isDead, score, obstacles := simulateChunk(req.SessionID, req.Inputs, req.TotalTicks, vals)

	status := "alive"
	if isDead {
		status = "dead"
		rdb.HSet(ctx, key, "is_dead", 1)
	}
	rdb.Expire(ctx, key, 4000*time.Hour)

	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
	}

	safeName := html.EscapeString(req.Name)
	sessionKey := "session:" + req.SessionID
	scoreVal, err := rdb.HGet(ctx, sessionKey, "score").Result()
	if err != nil {
		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 && 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
	}
	if req.Action == "approve" {
		score, err := rdb.ZScore(ctx, "leaderboard:unverified", req.SessionID).Result()
		if err == nil {
			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 != req.ClaimCode {
		http.Error(w, "Error", 403)
		return
	}
	rdb.ZRem(ctx, "leaderboard:unverified", req.SessionID)
	rdb.ZRem(ctx, "leaderboard:public", req.SessionID)
	rdb.HDel(ctx, sessionKey, "name")
	w.WriteHeader(http.StatusOK)
}

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