package repository

import (
	"context"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"

	"shop/internal/models"
)

type OrderRepository struct {
	pool *pgxpool.Pool
}

func NewOrderRepository(pool *pgxpool.Pool) *OrderRepository {
	return &OrderRepository{pool: pool}
}

func (r *OrderRepository) Create(ctx context.Context, order *models.Order, items []models.CartItem) error {
	tx, err := r.pool.Begin(ctx)
	if err != nil {
		return err
	}
	defer tx.Rollback(ctx)

	err = tx.QueryRow(ctx, `
		INSERT INTO orders (user_id, guest_name, guest_email, guest_phone, address, total, status)
		VALUES ($1, $2, $3, $4, $5, $6, 'pending')
		RETURNING id, created_at
	`, order.UserID, order.GuestName, order.GuestEmail, order.GuestPhone, order.Address, order.Total,
	).Scan(&order.ID, &order.CreatedAt)
	if err != nil {
		return err
	}

	for _, item := range items {
		_, err = tx.Exec(ctx, `
			INSERT INTO order_items (order_id, product_id, product_name, price, quantity)
			VALUES ($1, $2, $3, $4, $5)
		`, order.ID, item.ProductID, item.Product.Name, item.Product.EffectivePrice(), item.Quantity)
		if err != nil {
			return err
		}
	}

	return tx.Commit(ctx)
}

func (r *OrderRepository) ByUser(ctx context.Context, userID int) ([]models.Order, error) {
	rows, err := r.pool.Query(ctx, `
		SELECT id, user_id, guest_name, guest_email, guest_phone, address, total, status, created_at
		FROM orders WHERE user_id = $1 ORDER BY created_at DESC
	`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var orders []models.Order
	for rows.Next() {
		var o models.Order
		if err := rows.Scan(&o.ID, &o.UserID, &o.GuestName, &o.GuestEmail, &o.GuestPhone, &o.Address, &o.Total, &o.Status, &o.CreatedAt); err != nil {
			return nil, err
		}
		o.Items, err = r.items(ctx, o.ID)
		if err != nil {
			return nil, err
		}
		orders = append(orders, o)
	}
	return orders, rows.Err()
}

func (r *OrderRepository) items(ctx context.Context, orderID int) ([]models.OrderItem, error) {
	rows, err := r.pool.Query(ctx, `
		SELECT id, order_id, product_id, product_name, price, quantity
		FROM order_items WHERE order_id = $1
	`, orderID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var items []models.OrderItem
	for rows.Next() {
		var i models.OrderItem
		if err := rows.Scan(&i.ID, &i.OrderID, &i.ProductID, &i.ProductName, &i.Price, &i.Quantity); err != nil {
			return nil, err
		}
		items = append(items, i)
	}
	return items, rows.Err()
}

func (r *OrderRepository) All(ctx context.Context, limit int) ([]models.Order, error) {
	rows, err := r.pool.Query(ctx, `
		SELECT id, user_id, guest_name, guest_email, guest_phone, address, total, status, created_at
		FROM orders ORDER BY created_at DESC LIMIT $1
	`, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	return r.collectOrders(ctx, rows)
}

func (r *OrderRepository) GetByID(ctx context.Context, id int) (models.Order, error) {
	var o models.Order
	err := r.pool.QueryRow(ctx, `
		SELECT id, user_id, guest_name, guest_email, guest_phone, address, total, status, created_at
		FROM orders WHERE id = $1
	`, id).Scan(&o.ID, &o.UserID, &o.GuestName, &o.GuestEmail, &o.GuestPhone, &o.Address, &o.Total, &o.Status, &o.CreatedAt)
	if err != nil {
		return models.Order{}, err
	}
	o.Items, err = r.items(ctx, o.ID)
	return o, err
}

func (r *OrderRepository) UpdateStatus(ctx context.Context, id int, status string) error {
	tag, err := r.pool.Exec(ctx, `UPDATE orders SET status = $1 WHERE id = $2`, status, id)
	if err != nil {
		return err
	}
	if tag.RowsAffected() == 0 {
		return pgx.ErrNoRows
	}
	return nil
}

func (r *OrderRepository) Count(ctx context.Context) (int, error) {
	var n int
	err := r.pool.QueryRow(ctx, `SELECT COUNT(*) FROM orders`).Scan(&n)
	return n, err
}

func (r *OrderRepository) collectOrders(ctx context.Context, rows pgx.Rows) ([]models.Order, error) {
	var orders []models.Order
	for rows.Next() {
		var o models.Order
		if err := rows.Scan(&o.ID, &o.UserID, &o.GuestName, &o.GuestEmail, &o.GuestPhone, &o.Address, &o.Total, &o.Status, &o.CreatedAt); err != nil {
			return nil, err
		}
		var err error
		o.Items, err = r.items(ctx, o.ID)
		if err != nil {
			return nil, err
		}
		orders = append(orders, o)
	}
	return orders, rows.Err()
}