package orders

import (
	"context"
	"errors"

	"github.com/google/uuid"
	"gorm.io/gorm"
)

var ErrNotFound = errors.New("order not found")

type Repository interface {
	Create(ctx context.Context, order *Order, items []*OrderItem) error
	FindByID(ctx context.Context, id uuid.UUID) (*Order, []*OrderItem, error)
	List(ctx context.Context, status string) ([]*Order, error)
	UpdateStatus(ctx context.Context, id uuid.UUID, status string) (*Order, error)
}

type gormRepository struct {
	db *gorm.DB
}

func NewRepository(db *gorm.DB) Repository {
	return &gormRepository{db: db}
}

func (r *gormRepository) Create(ctx context.Context, order *Order, items []*OrderItem) error {
	return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		if err := tx.Create(order).Error; err != nil {
			return err
		}
		for _, item := range items {
			item.OrderID = order.ID
		}
		if len(items) > 0 {
			if err := tx.Create(&items).Error; err != nil {
				return err
			}
		}
		return nil
	})
}

func (r *gormRepository) FindByID(ctx context.Context, id uuid.UUID) (*Order, []*OrderItem, error) {
	var order Order
	if err := r.db.WithContext(ctx).Where("id = ?", id).First(&order).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, nil, ErrNotFound
		}
		return nil, nil, err
	}
	var items []*OrderItem
	if err := r.db.WithContext(ctx).Where("order_id = ?", id).Order("created_at asc").Find(&items).Error; err != nil {
		return nil, nil, err
	}
	return &order, items, nil
}

func (r *gormRepository) List(ctx context.Context, status string) ([]*Order, error) {
	q := r.db.WithContext(ctx).Order("created_at desc")
	if status != "" {
		q = q.Where("status = ?", status)
	}
	var list []*Order
	if err := q.Find(&list).Error; err != nil {
		return nil, err
	}
	return list, nil
}

func (r *gormRepository) UpdateStatus(ctx context.Context, id uuid.UUID, status string) (*Order, error) {
	res := r.db.WithContext(ctx).Model(&Order{}).Where("id = ?", id).Update("status", status)
	if res.Error != nil {
		return nil, res.Error
	}
	if res.RowsAffected == 0 {
		return nil, ErrNotFound
	}
	var order Order
	if err := r.db.WithContext(ctx).Where("id = ?", id).First(&order).Error; err != nil {
		return nil, err
	}
	return &order, nil
}