package repository

import (
	"context"

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

	"shop/internal/models"
)

const orderSelect = `
	SELECT id, user_id, guest_name, guest_email, guest_phone, address, total, status,
	       COALESCE(payment_method, 'cod'), COALESCE(heleket_uuid, ''), COALESCE(heleket_order_id, ''),
	       COALESCE(heleket_payment_url, ''), COALESCE(heleket_payment_status, ''), created_at
	FROM orders
`

type OrderRepository struct {
	pool *pgxpool.Pool
}

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

func scanOrder(row pgx.Row) (models.Order, error) {
	var o models.Order
	err := row.Scan(
		&o.ID, &o.UserID, &o.GuestName, &o.GuestEmail, &o.GuestPhone, &o.Address, &o.Total, &o.Status,
		&o.PaymentMethod, &o.HeleketUUID, &o.HeleketOrderID, &o.HeleketPaymentURL, &o.HeleketPaymentStatus, &o.CreatedAt,
	)
	return o, err
}

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)

	status := order.Status
	if status == "" {
		status = "pending"
	}
	paymentMethod := order.PaymentMethod
	if paymentMethod == "" {
		paymentMethod = "cod"
	}

	err = tx.QueryRow(ctx, `
		INSERT INTO orders (user_id, guest_name, guest_email, guest_phone, address, total, status, payment_method)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
		RETURNING id, created_at
	`, order.UserID, order.GuestName, order.GuestEmail, order.GuestPhone, order.Address, order.Total, status, paymentMethod,
	).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) UpdateHeleketPayment(ctx context.Context, orderID int, uuid, externalID, paymentURL, paymentStatus string) error {
	_, err := r.pool.Exec(ctx, `
		UPDATE orders SET
			heleket_uuid = $1,
			heleket_order_id = $2,
			heleket_payment_url = $3,
			heleket_payment_status = $4
		WHERE id = $5
	`, uuid, externalID, paymentURL, paymentStatus, orderID)
	return err
}

func (r *OrderRepository) UpdateHeleketStatus(ctx context.Context, orderID int, paymentStatus, orderStatus string) error {
	_, err := r.pool.Exec(ctx, `
		UPDATE orders SET heleket_payment_status = $1, status = $2 WHERE id = $3
	`, paymentStatus, orderStatus, orderID)
	return err
}

func (r *OrderRepository) GetByHeleketOrderID(ctx context.Context, externalID string) (models.Order, error) {
	row := r.pool.QueryRow(ctx, orderSelect+` WHERE heleket_order_id = $1`, externalID)
	o, err := scanOrder(row)
	if err != nil {
		return models.Order{}, err
	}
	o.Items, err = r.items(ctx, o.ID)
	return o, err
}

func (r *OrderRepository) ByUser(ctx context.Context, userID int) ([]models.Order, error) {
	rows, err := r.pool.Query(ctx, orderSelect+` 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() {
		o, err := scanOrder(rows)
		if 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, orderSelect+` 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) {
	row := r.pool.QueryRow(ctx, orderSelect+` WHERE id = $1`, id)
	o, err := scanOrder(row)
	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() {
		o, err := scanOrder(rows)
		if 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()
}