package services

import (
	"fmt"
	"time"

	"github.com/google/uuid"
	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"
	"github.com/golang-jwt/jwt/v5"
	"github.com/ydn/yourdreamnamehere/internal/config"
	"github.com/ydn/yourdreamnamehere/internal/models"
)

type UserService struct {
	db     *gorm.DB
	config *config.Config
}

func NewUserService(db *gorm.DB, config *config.Config) *UserService {
	return &UserService{
		db:     db,
		config: config,
	}
}

func (s *UserService) CreateUser(email, firstName, lastName, password string) (*models.User, error) {
	// Check if user already exists
	var existingUser models.User
	if err := s.db.Where("email = ?", email).First(&existingUser).Error; err == nil {
		return nil, fmt.Errorf("user with email %s already exists", email)
	}

	// Hash password
	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	if err != nil {
		return nil, fmt.Errorf("failed to hash password: %w", err)
	}

	// Create user and customer in a transaction
	err = s.db.Transaction(func(tx *gorm.DB) error {
		user := &models.User{
			ID:           uuid.New(),
			Email:        email,
			FirstName:    firstName,
			LastName:     lastName,
			PasswordHash: string(hashedPassword),
			CreatedAt:    time.Now(),
			UpdatedAt:    time.Now(),
		}

		if err := tx.Create(user).Error; err != nil {
			return fmt.Errorf("failed to create user: %w", err)
		}

		// Create associated customer record for future Stripe integration
		customer := &models.Customer{
			UserID: user.ID,
			Email:  email,
			Status: "pending", // Will be updated when Stripe customer is created
		}

		if err := tx.Create(customer).Error; err != nil {
			return fmt.Errorf("failed to create customer: %w", err)
		}

		return nil
	})

	if err != nil {
		return nil, err
	}

	// Return the created user
	var user models.User
	if err := s.db.Where("email = ?", email).First(&user).Error; err != nil {
		return nil, fmt.Errorf("failed to retrieve created user: %w", err)
	}

	return &user, nil
}

func (s *UserService) AuthenticateUser(email, password string) (string, error) {
	var user models.User
	if err := s.db.Where("email = ?", email).First(&user).Error; err != nil {
		if err == gorm.ErrRecordNotFound {
			return "", fmt.Errorf("invalid credentials")
		}
		return "", fmt.Errorf("failed to authenticate user: %w", err)
	}

	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(password)); err != nil {
		return "", fmt.Errorf("invalid credentials")
	}

	// Generate JWT token
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"user_id": user.ID.String(),
		"email":   user.Email,
		"role":    user.Role,
		"exp":     time.Now().Add(s.config.JWT.Expiry).Unix(),
	})

	tokenString, err := token.SignedString([]byte(s.config.JWT.Secret))
	if err != nil {
		return "", fmt.Errorf("failed to generate token: %w", err)
	}

	return tokenString, nil
}

func (s *UserService) GetUserByID(userID string) (*models.User, error) {
	var user models.User
	if err := s.db.Where("id = ?", userID).First(&user).Error; err != nil {
		return nil, err
	}
	return &user, nil
}

func (s *UserService) UpdateUser(userID, firstName, lastName string) (*models.User, error) {
	var user models.User
	if err := s.db.Where("id = ?", userID).First(&user).Error; err != nil {
		return nil, err
	}

	if firstName != "" {
		user.FirstName = firstName
	}
	if lastName != "" {
		user.LastName = lastName
	}
	user.UpdatedAt = time.Now()

	if err := s.db.Save(&user).Error; err != nil {
		return nil, fmt.Errorf("failed to update user: %w", err)
	}

	return &user, nil
}

func (s *UserService) GetUserDomains(userID string) ([]models.Domain, error) {
	var domains []models.Domain
	if err := s.db.Joins("JOIN customers ON domains.customer_id = customers.id").
		Where("customers.user_id = ?", userID).
		Find(&domains).Error; err != nil {
		return nil, err
	}
	return domains, nil
}

func (s *UserService) GetDomainByID(userID string, domainID uuid.UUID) (*models.Domain, error) {
	var domain models.Domain
	if err := s.db.Joins("JOIN customers ON domains.customer_id = customers.id").
		Where("customers.user_id = ? AND domains.id = ?", userID, domainID).
		First(&domain).Error; err != nil {
		return nil, err
	}
	return &domain, nil
}

func (s *UserService) GetUserVPS(userID string) ([]models.VPS, error) {
	var vpsList []models.VPS
	if err := s.db.Joins("JOIN domains ON vps.domain_id = domains.id").
		Joins("JOIN customers ON domains.customer_id = customers.id").
		Where("customers.user_id = ?", userID).
		Find(&vpsList).Error; err != nil {
		return nil, err
	}
	return vpsList, nil
}

func (s *UserService) GetVPSByID(userID string, vpsID uuid.UUID) (*models.VPS, error) {
	var vps models.VPS
	if err := s.db.Joins("JOIN domains ON vps.domain_id = domains.id").
		Joins("JOIN customers ON domains.customer_id = customers.id").
		Where("customers.user_id = ? AND vps.id = ?", userID, vpsID).
		First(&vps).Error; err != nil {
		return nil, err
	}
	return &vps, nil
}

func (s *UserService) GetUserSubscriptions(userID string) ([]models.Subscription, error) {
	var subscriptions []models.Subscription
	if err := s.db.Joins("JOIN customers ON subscriptions.customer_id = customers.id").
		Where("customers.user_id = ?", userID).
		Find(&subscriptions).Error; err != nil {
		return nil, err
	}
	return subscriptions, nil
}

func (s *UserService) GetDeploymentLogs(userID string, vpsID *uuid.UUID) ([]models.DeploymentLog, error) {
	var logs []models.DeploymentLog
	query := s.db.Joins("JOIN vps ON deployment_logs.vps_id = vps.id").
		Joins("JOIN domains ON vps.domain_id = domains.id").
		Joins("JOIN customers ON domains.customer_id = customers.id").
		Where("customers.user_id = ?", userID)

	if vpsID != nil {
		query = query.Where("vps.id = ?", *vpsID)
	}

	if err := query.Order("deployment_logs.created_at DESC").Find(&logs).Error; err != nil {
		return nil, err
	}
	return logs, nil
}

func (s *UserService) GetInvitationByToken(token string) (*models.Invitation, error) {
	var invitation models.Invitation
	if err := s.db.Where("token = ? AND status = 'pending' AND expires_at > ?", token, time.Now()).
		First(&invitation).Error; err != nil {
		return nil, err
	}
	return &invitation, nil
}

func (s *UserService) AcceptInvitation(token, password, firstName, lastName string) error {
	return s.db.Transaction(func(tx *gorm.DB) error {
		// Get invitation
		var invitation models.Invitation
		if err := tx.Where("token = ? AND status = 'pending' AND expires_at > ?", token, time.Now()).
			First(&invitation).Error; err != nil {
			return fmt.Errorf("invitation not found or expired")
		}

		// Get VPS to extract email
		var vps models.VPS
		if err := tx.Preload("Domain.Customer").Where("id = ?", invitation.VPSID).First(&vps).Error; err != nil {
			return fmt.Errorf("failed to get VPS: %w", err)
		}

		// Create user
		hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
		if err != nil {
			return fmt.Errorf("failed to hash password: %w", err)
		}

		user := &models.User{
			ID:           uuid.New(),
			Email:        invitation.Email,
			FirstName:    firstName,
			LastName:     lastName,
			PasswordHash: string(hashedPassword),
			CreatedAt:    time.Now(),
			UpdatedAt:    time.Now(),
		}

		if err := tx.Create(user).Error; err != nil {
			return fmt.Errorf("failed to create user: %w", err)
		}

		// Update customer user_id
		if err := tx.Model(&vps.Domain.Customer).Update("user_id", user.ID).Error; err != nil {
			return fmt.Errorf("failed to update customer: %w", err)
		}

		// Update invitation
		now := time.Now()
		invitation.Status = "accepted"
		invitation.AcceptedAt = &now
		if err := tx.Save(&invitation).Error; err != nil {
			return fmt.Errorf("failed to update invitation: %w", err)
		}

		return nil
	})
}