package game

import (
	"bindbox-game/configs"
	"bindbox-game/internal/pkg/logger"
	"bindbox-game/internal/repository/mysql"
	"bindbox-game/internal/repository/mysql/model"
	"context"
	"fmt"
	"time"

	"github.com/golang-jwt/jwt/v5"
	"github.com/redis/go-redis/v9"
	"go.uber.org/zap"
)

// GameTokenClaims contains the claims for a game token
type GameTokenClaims struct {
	UserID   int64  `json:"user_id"`
	Username string `json:"username"`
	Avatar   string `json:"avatar"`
	GameType string `json:"game_type"`
	Ticket   string `json:"ticket"`
	jwt.RegisteredClaims
}

// GameTokenService handles game token generation and validation
type GameTokenService interface {
	GenerateToken(ctx context.Context, userID int64, username, avatar, gameType string) (token string, ticket string, expiresAt time.Time, err error)
	ValidateToken(ctx context.Context, tokenString string) (*GameTokenClaims, error)
	InvalidateTicket(ctx context.Context, ticket string) error
}

type gameTokenService struct {
	logger logger.CustomLogger
	db     mysql.Repo
	redis  *redis.Client
	secret string
}

// NewGameTokenService creates a new game token service
func NewGameTokenService(l logger.CustomLogger, db mysql.Repo, rdb *redis.Client) GameTokenService {
	// Use a dedicated secret for game tokens
	secret := configs.Get().Random.CommitMasterKey + "_game_token"
	return &gameTokenService{
		logger: l,
		db:     db,
		redis:  rdb,
		secret: secret,
	}
}

// GenerateToken creates a new game token for a user (does NOT consume ticket, only validates)
func (s *gameTokenService) GenerateToken(ctx context.Context, userID int64, username, avatar, gameType string) (token string, ticket string, expiresAt time.Time, err error) {
	// 1. Check if user has game tickets (do NOT deduct - will be done on match success)
	var userTicket model.UserGameTickets
	if err = s.db.GetDbR().Where("user_id = ? AND game_code = ? AND available > 0", userID, gameType).First(&userTicket).Error; err != nil {
		return "", "", time.Time{}, fmt.Errorf("no available game tickets")
	}

	// 2. Generate unique ticket ID
	ticket = fmt.Sprintf("GT%d%d", userID, time.Now().UnixNano())

	// 3. Store ticket in Redis (for single-use validation)
	ticketKey := fmt.Sprintf("game:token:ticket:%s", ticket)
	// Check for error when setting Redis key - CRITICAL FIX
	if err := s.redis.Set(ctx, ticketKey, fmt.Sprintf("%d", userID), 15*time.Minute).Err(); err != nil {
		s.logger.Error("Failed to store ticket in Redis", zap.Error(err), zap.String("ticket", ticket), zap.Int64("user_id", userID))
		return "", "", time.Time{}, fmt.Errorf("failed to generate ticket: %w", err)
	}

	s.logger.Info("DEBUG: Generated ticket and stored in Redis", zap.String("ticket", ticket), zap.String("key", ticketKey), zap.Int64("user_id", userID))

	// 4. Generate JWT token
	expiresAt = time.Now().Add(10 * time.Minute)
	claims := GameTokenClaims{
		UserID:   userID,
		Username: username,
		Avatar:   avatar,
		GameType: gameType,
		Ticket:   ticket,
		RegisteredClaims: jwt.RegisteredClaims{
			Subject:   fmt.Sprintf("%d", userID),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			ExpiresAt: jwt.NewNumericDate(expiresAt),
			NotBefore: jwt.NewNumericDate(time.Now()),
		},
	}

	jwtToken := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	token, err = jwtToken.SignedString([]byte(s.secret))
	if err != nil {
		return "", "", time.Time{}, fmt.Errorf("failed to sign token: %w", err)
	}

	s.logger.Info("Generated game token", zap.Int64("user_id", userID), zap.String("game_type", gameType), zap.String("ticket", ticket))
	return token, ticket, expiresAt, nil
}

// ValidateToken validates a game token and returns the claims
func (s *gameTokenService) ValidateToken(ctx context.Context, tokenString string) (*GameTokenClaims, error) {
	// 1. Parse and validate JWT
	token, err := jwt.ParseWithClaims(tokenString, &GameTokenClaims{}, func(token *jwt.Token) (interface{}, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}
		return []byte(s.secret), nil
	})

	if err != nil {
		s.logger.Warn("Token JWT validation failed", zap.Error(err))
		return nil, fmt.Errorf("invalid token: %w", err)
	}

	claims, ok := token.Claims.(*GameTokenClaims)
	if !ok || !token.Valid {
		return nil, fmt.Errorf("invalid token claims")
	}

	// 2. Check if ticket is still valid (not used)
	ticketKey := fmt.Sprintf("game:token:ticket:%s", claims.Ticket)
	storedUserID, err := s.redis.Get(ctx, ticketKey).Result()
	if err != nil {
		s.logger.Warn("DEBUG: Ticket not found in Redis", zap.String("ticket", claims.Ticket), zap.String("key", ticketKey), zap.Error(err))
		return nil, fmt.Errorf("ticket not found or expired")
	}

	if storedUserID != fmt.Sprintf("%d", claims.UserID) {
		s.logger.Warn("DEBUG: Ticket user mismatch", zap.String("stored", storedUserID), zap.Int64("claim_user", claims.UserID))
		return nil, fmt.Errorf("ticket user mismatch")
	}

	s.logger.Info("DEBUG: Token validated successfully", zap.String("ticket", claims.Ticket))
	return claims, nil
}

// InvalidateTicket marks a ticket as used
func (s *gameTokenService) InvalidateTicket(ctx context.Context, ticket string) error {
	ticketKey := fmt.Sprintf("game:token:ticket:%s", ticket)
	s.logger.Info("DEBUG: Invalidating ticket", zap.String("ticket", ticket), zap.String("key", ticketKey))
	return s.redis.Del(ctx, ticketKey).Err()
}