package repository

import (
	"context"
	"errors"
	"time"

	"bugulma/backend/internal/domain"

	"gorm.io/gorm"
)

// SubscriptionRepository implements domain.SubscriptionRepository with GORM
type SubscriptionRepository struct {
	*BaseRepository[domain.Subscription]
	db *gorm.DB
}

// NewSubscriptionRepository creates a new GORM-based subscription repository
func NewSubscriptionRepository(db *gorm.DB) domain.SubscriptionRepository {
	return &SubscriptionRepository{
		BaseRepository: NewBaseRepository[domain.Subscription](db),
		db:             db,
	}
}

// GetByUserID retrieves a subscription by user ID
func (r *SubscriptionRepository) GetByUserID(ctx context.Context, userID string) (*domain.Subscription, error) {
	var subscription domain.Subscription
	result := r.db.WithContext(ctx).Where("user_id = ?", userID).First(&subscription)
	if result.Error != nil {
		if errors.Is(result.Error, gorm.ErrRecordNotFound) {
			return nil, ErrNotFound
		}
		return nil, result.Error
	}
	return &subscription, nil
}

// GetActiveByUserID retrieves an active subscription by user ID
func (r *SubscriptionRepository) GetActiveByUserID(ctx context.Context, userID string) (*domain.Subscription, error) {
	var subscription domain.Subscription
	result := r.db.WithContext(ctx).
		Where("user_id = ? AND status IN ?", userID, []domain.SubscriptionStatus{
			domain.SubscriptionStatusActive,
			domain.SubscriptionStatusTrialing,
		}).
		First(&subscription)
	if result.Error != nil {
		if errors.Is(result.Error, gorm.ErrRecordNotFound) {
			return nil, ErrNotFound
		}
		return nil, result.Error
	}
	return &subscription, nil
}

// UpdateStatus updates the status of a subscription
func (r *SubscriptionRepository) UpdateStatus(ctx context.Context, id string, status domain.SubscriptionStatus) error {
	result := r.db.WithContext(ctx).
		Model(&domain.Subscription{}).
		Where("id = ?", id).
		Update("status", status)
	if result.Error != nil {
		return result.Error
	}
	if result.RowsAffected == 0 {
		return ErrNotFound
	}
	return nil
}

// PaymentMethodRepository implements domain.PaymentMethodRepository with GORM
type PaymentMethodRepository struct {
	*BaseRepository[domain.PaymentMethod]
	db *gorm.DB
}

// NewPaymentMethodRepository creates a new GORM-based payment method repository
func NewPaymentMethodRepository(db *gorm.DB) domain.PaymentMethodRepository {
	return &PaymentMethodRepository{
		BaseRepository: NewBaseRepository[domain.PaymentMethod](db),
		db:             db,
	}
}

// GetByUserID retrieves all payment methods for a user
func (r *PaymentMethodRepository) GetByUserID(ctx context.Context, userID string) ([]*domain.PaymentMethod, error) {
	var paymentMethods []*domain.PaymentMethod
	result := r.db.WithContext(ctx).
		Where("user_id = ?", userID).
		Order("is_default DESC, created_at DESC").
		Find(&paymentMethods)
	if result.Error != nil {
		return nil, result.Error
	}
	return paymentMethods, nil
}

// GetDefaultByUserID retrieves the default payment method for a user
func (r *PaymentMethodRepository) GetDefaultByUserID(ctx context.Context, userID string) (*domain.PaymentMethod, error) {
	var paymentMethod domain.PaymentMethod
	result := r.db.WithContext(ctx).
		Where("user_id = ? AND is_default = ?", userID, true).
		First(&paymentMethod)
	if result.Error != nil {
		if errors.Is(result.Error, gorm.ErrRecordNotFound) {
			return nil, ErrNotFound
		}
		return nil, result.Error
	}
	return &paymentMethod, nil
}

// SetDefault sets a payment method as default for a user
func (r *PaymentMethodRepository) SetDefault(ctx context.Context, userID string, paymentMethodID string) error {
	// Start transaction
	tx := r.db.WithContext(ctx).Begin()
	defer func() {
		if r := recover(); r != nil {
			tx.Rollback()
		}
	}()

	// Unset all defaults for user
	if err := tx.Model(&domain.PaymentMethod{}).
		Where("user_id = ?", userID).
		Update("is_default", false).Error; err != nil {
		tx.Rollback()
		return err
	}

	// Set new default
	if err := tx.Model(&domain.PaymentMethod{}).
		Where("id = ? AND user_id = ?", paymentMethodID, userID).
		Update("is_default", true).Error; err != nil {
		tx.Rollback()
		return err
	}

	return tx.Commit().Error
}

// InvoiceRepository implements domain.InvoiceRepository with GORM
type InvoiceRepository struct {
	*BaseRepository[domain.Invoice]
	db *gorm.DB
}

// NewInvoiceRepository creates a new GORM-based invoice repository
func NewInvoiceRepository(db *gorm.DB) domain.InvoiceRepository {
	return &InvoiceRepository{
		BaseRepository: NewBaseRepository[domain.Invoice](db),
		db:             db,
	}
}

// GetByUserID retrieves invoices for a user with pagination
func (r *InvoiceRepository) GetByUserID(ctx context.Context, userID string, limit, offset int) ([]*domain.Invoice, int64, error) {
	var invoices []*domain.Invoice
	var total int64

	// Get total count
	if err := r.db.WithContext(ctx).
		Model(&domain.Invoice{}).
		Where("user_id = ?", userID).
		Count(&total).Error; err != nil {
		return nil, 0, err
	}

	// Get paginated results
	result := r.db.WithContext(ctx).
		Where("user_id = ?", userID).
		Order("created_at DESC").
		Limit(limit).
		Offset(offset).
		Find(&invoices)
	if result.Error != nil {
		return nil, 0, result.Error
	}

	return invoices, total, nil
}

// GetBySubscriptionID retrieves all invoices for a subscription
func (r *InvoiceRepository) GetBySubscriptionID(ctx context.Context, subscriptionID string) ([]*domain.Invoice, error) {
	var invoices []*domain.Invoice
	result := r.db.WithContext(ctx).
		Where("subscription_id = ?", subscriptionID).
		Order("created_at DESC").
		Find(&invoices)
	if result.Error != nil {
		return nil, result.Error
	}
	return invoices, nil
}

// UsageTrackingRepository implements domain.UsageTrackingRepository with GORM
type UsageTrackingRepository struct {
	*BaseRepository[domain.UsageTracking]
	db *gorm.DB
}

// NewUsageTrackingRepository creates a new GORM-based usage tracking repository
func NewUsageTrackingRepository(db *gorm.DB) domain.UsageTrackingRepository {
	return &UsageTrackingRepository{
		BaseRepository: NewBaseRepository[domain.UsageTracking](db),
		db:             db,
	}
}

// GetByUserIDAndType retrieves usage tracking for a user and limit type in a specific period
func (r *UsageTrackingRepository) GetByUserIDAndType(ctx context.Context, userID string, limitType domain.UsageLimitType, periodStart time.Time) (*domain.UsageTracking, error) {
	var usage domain.UsageTracking
	result := r.db.WithContext(ctx).
		Where("user_id = ? AND limit_type = ? AND period_start = ?", userID, limitType, periodStart).
		First(&usage)
	if result.Error != nil {
		if errors.Is(result.Error, gorm.ErrRecordNotFound) {
			return nil, ErrNotFound
		}
		return nil, result.Error
	}
	return &usage, nil
}

// UpdateUsage updates or creates usage tracking
func (r *UsageTrackingRepository) UpdateUsage(ctx context.Context, userID string, limitType domain.UsageLimitType, periodStart time.Time, amount int64) error {
	// Try to get existing record
	usage, err := r.GetByUserIDAndType(ctx, userID, limitType, periodStart)
	if err != nil && !errors.Is(err, ErrNotFound) {
		return err
	}

	if usage != nil {
		// Update existing
		usage.CurrentUsage = amount
		return r.db.WithContext(ctx).Save(usage).Error
	}

	// Create new
	periodEnd := periodStart.AddDate(0, 1, 0) // Default to monthly period
	if limitType == domain.UsageLimitTypeAPICalls {
		// API calls reset monthly
		periodEnd = periodStart.AddDate(0, 1, 0)
	}

	newUsage := &domain.UsageTracking{
		UserID:       userID,
		LimitType:    limitType,
		CurrentUsage: amount,
		PeriodStart:  periodStart,
		PeriodEnd:    periodEnd,
	}
	return r.db.WithContext(ctx).Create(newUsage).Error
}

// GetCurrentPeriodUsage retrieves current period usage
func (r *UsageTrackingRepository) GetCurrentPeriodUsage(ctx context.Context, userID string, limitType domain.UsageLimitType) (*domain.UsageTracking, error) {
	// Get current month start
	now := time.Now()
	periodStart := time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, now.Location())

	return r.GetByUserIDAndType(ctx, userID, limitType, periodStart)
}