// Package repository holds every SQL statement in the service.
//
// Tenant isolation convention: any query touching a tenant-owned table
// (users, flights, bookings, passengers) takes tenantID as its FIRST argument
// and filters on it in the WHERE clause. Callers pass the id from the
// authenticated identity, never from client input.
package repository

import (
	"errors"

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

// ErrNotFound is returned when a lookup matches no row within the tenant.
// Handlers map it to 404, which also means a caller probing for another
// tenant's record sees a plain "not found" rather than a permission error.
var ErrNotFound = errors.New("not found")

// ErrNoSeats is returned when a booking asks for more seats than remain.
var ErrNoSeats = errors.New("not enough seats available")

// Repository is the data access layer over a pgx pool.
type Repository struct {
	pool *pgxpool.Pool
}

// New builds a Repository around an open pool.
func New(pool *pgxpool.Pool) *Repository {
	return &Repository{pool: pool}
}

// isUniqueViolation reports whether err is PostgreSQL's 23505, which lets
// callers retry a generated value instead of failing the request.
func isUniqueViolation(err error) bool {
	var pgErr *pgconn.PgError
	return errors.As(err, &pgErr) && pgErr.Code == "23505"
}