package services

import (
	"context"
	"fmt"
	"time"

	"github.com/google/uuid"
	"go.uber.org/zap"

	"github.com/kms/api-key-service/internal/domain"
	"github.com/kms/api-key-service/internal/repository"
)

// tokenService implements the TokenService interface
type tokenService struct {
	tokenRepo repository.StaticTokenRepository
	appRepo   repository.ApplicationRepository
	permRepo  repository.PermissionRepository
	grantRepo repository.GrantedPermissionRepository
	logger    *zap.Logger
}

// NewTokenService creates a new token service
func NewTokenService(
	tokenRepo repository.StaticTokenRepository,
	appRepo repository.ApplicationRepository,
	permRepo repository.PermissionRepository,
	grantRepo repository.GrantedPermissionRepository,
	logger *zap.Logger,
) TokenService {
	return &tokenService{
		tokenRepo: tokenRepo,
		appRepo:   appRepo,
		permRepo:  permRepo,
		grantRepo: grantRepo,
		logger:    logger,
	}
}

// CreateStaticToken creates a new static token
func (s *tokenService) CreateStaticToken(ctx context.Context, req *domain.CreateStaticTokenRequest, userID string) (*domain.CreateStaticTokenResponse, error) {
	s.logger.Info("Creating static token", zap.String("app_id", req.AppID), zap.String("user_id", userID))

	// TODO: Validate permissions
	// TODO: Validate application exists
	// TODO: Generate secure token
	// TODO: Grant permissions

	tokenID := uuid.New()
	now := time.Now()

	// Create the token entity
	token := &domain.StaticToken{
		ID:    tokenID,
		AppID: req.AppID,
		Owner: domain.Owner{
			Type:  domain.OwnerTypeIndividual,
			Name:  userID,
			Owner: userID,
		},
		KeyHash:   "placeholder-hash-" + tokenID.String(),
		Type:      "hmac",
		CreatedAt: now,
		UpdatedAt: now,
	}

	// Save the token to the database
	err := s.tokenRepo.Create(ctx, token)
	if err != nil {
		s.logger.Error("Failed to create token in database", zap.Error(err), zap.String("token_id", tokenID.String()))
		return nil, fmt.Errorf("failed to create token: %w", err)
	}

	response := &domain.CreateStaticTokenResponse{
		ID:          tokenID,
		Token:       "static-token-placeholder-" + tokenID.String(),
		Permissions: req.Permissions,
		CreatedAt:   now,
	}

	s.logger.Info("Static token created successfully", zap.String("token_id", tokenID.String()))
	return response, nil
}

// ListByApp lists all tokens for an application
func (s *tokenService) ListByApp(ctx context.Context, appID string, limit, offset int) ([]*domain.StaticToken, error) {
	s.logger.Debug("Listing tokens for application", zap.String("app_id", appID))

	// TODO: Implement actual token listing
	return []*domain.StaticToken{}, nil
}

// Delete deletes a token
func (s *tokenService) Delete(ctx context.Context, tokenID uuid.UUID, userID string) error {
	s.logger.Info("Deleting token", zap.String("token_id", tokenID.String()), zap.String("user_id", userID))

	// Check if token exists
	exists, err := s.tokenRepo.Exists(ctx, tokenID)
	if err != nil {
		s.logger.Error("Failed to check token existence", zap.Error(err), zap.String("token_id", tokenID.String()))
		return err
	}

	if !exists {
		s.logger.Error("Token not found", zap.String("token_id", tokenID.String()))
		return fmt.Errorf("token with ID '%s' not found", tokenID.String())
	}

	// Delete the token
	err = s.tokenRepo.Delete(ctx, tokenID)
	if err != nil {
		s.logger.Error("Failed to delete token", zap.Error(err), zap.String("token_id", tokenID.String()))
		return err
	}

	// TODO: Revoke associated permissions

	return nil
}

// GenerateUserToken generates a user token
func (s *tokenService) GenerateUserToken(ctx context.Context, appID, userID string, permissions []string) (string, error) {
	s.logger.Info("Generating user token", zap.String("app_id", appID), zap.String("user_id", userID))

	// TODO: Validate application
	// TODO: Validate permissions
	// TODO: Generate JWT token

	return "user-token-placeholder-" + userID, nil
}

// VerifyToken verifies a token and returns verification response
func (s *tokenService) VerifyToken(ctx context.Context, req *domain.VerifyRequest) (*domain.VerifyResponse, error) {
	s.logger.Debug("Verifying token", zap.String("app_id", req.AppID), zap.String("type", string(req.Type)))

	// TODO: Implement actual token verification logic
	response := &domain.VerifyResponse{
		Valid:       true,
		UserID:      req.UserID,
		Permissions: []string{"basic"},
		TokenType:   req.Type,
	}

	return response, nil
}

// RenewUserToken renews a user token
func (s *tokenService) RenewUserToken(ctx context.Context, req *domain.RenewRequest) (*domain.RenewResponse, error) {
	s.logger.Info("Renewing user token", zap.String("app_id", req.AppID), zap.String("user_id", req.UserID))

	// TODO: Validate current token
	// TODO: Generate new token with extended expiry but same max valid date

	response := &domain.RenewResponse{
		Token:      "renewed-token-placeholder",
		ExpiresAt:  time.Now().Add(7 * 24 * time.Hour),
		MaxValidAt: time.Now().Add(30 * 24 * time.Hour),
	}

	return response, nil
}