package api

import (
	"errors"
	"log"

	"github.com/danielgtaylor/huma/v2"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgconn"
)

// Postgres error codes this package maps to specific HTTP statuses.
// See https://www.postgresql.org/docs/current/errcodes-appendix.html
const (
	pgCodeUniqueViolation     = "23505"
	pgCodeForeignKeyViolation = "23503"
)

// dbError turns a database error into the huma error a handler should
// return, so Postgres's own error text never reaches a client and callers
// get the right HTTP status instead of a generic 500.
func dbError(err error) error {
	if errors.Is(err, pgx.ErrNoRows) {
		return huma.Error404NotFound("not found")
	}

	var pgErr *pgconn.PgError
	if errors.As(err, &pgErr) {
		switch pgErr.Code {
		case pgCodeUniqueViolation:
			return huma.Error409Conflict("already exists")
		case pgCodeForeignKeyViolation:
			// A foreign key failure here is either a reference to a platform
			// that doesn't exist (create/update) or a delete blocked by
			// games that still reference this platform.
			return huma.Error409Conflict("referenced by another record, or refers to one that doesn't exist")
		}
	}

	log.Printf("unmapped database error: %v", err)
	return huma.Error500InternalServerError("internal error")
}

// notFoundIfZero turns the "0 rows affected" result of a soft-delete
// UPDATE into a 404, since the row either never existed or was already
// deleted.
func notFoundIfZero(rows int64) error {
	if rows == 0 {
		return huma.Error404NotFound("not found")
	}
	return nil
}