// Copyright (c) 2026 Charles KWON OhJun (charleskwonohjun@gmail.com)
// All rights reserved.

package pgserver

import "github.com/jackc/pgx/v5/pgproto3"

// sqlStateFor maps a FiveSql2 error code (from FiveSqlDef.ch
// SQL_ERR_*) to a PostgreSQL SQLSTATE 5-char identifier so
// clients can dispatch error handlers in their native idiom.
//
// Codes that don't have a clean PG equivalent fall back to XX000
// (internal_error) — the universal "something went wrong" bucket.
func sqlStateFor(code int) string {
	// FiveSqlDef.ch numeric mapping (kept in sync with the .ch file):
	//   1   SQL_ERR_SYNTAX        → 42601 syntax_error
	//   2   SQL_ERR_TABLE         → 42P01 undefined_table
	//   3   SQL_ERR_COLUMN        → 42703 undefined_column
	//   4   SQL_ERR_TYPE          → 42804 datatype_mismatch
	//   5   SQL_ERR_UNIQUE        → 23505 unique_violation
	//   6   SQL_ERR_CHECK         → 23514 check_violation
	//   7   SQL_ERR_FK            → 23503 foreign_key_violation
	//   8   SQL_ERR_TXN           → 25P02 in_failed_sql_transaction
	//   9   SQL_ERR_PERM          → 42501 insufficient_privilege
	//   10  SQL_ERR_NOTFOUND      → 02000 no_data
	switch code {
	case 1:
		return "42601"
	case 2:
		return "42P01"
	case 3:
		return "42703"
	case 4:
		return "42804"
	case 5:
		return "23505"
	case 6:
		return "23514"
	case 7:
		return "23503"
	case 8:
		return "25P02"
	case 9:
		return "42501"
	case 10:
		return "02000"
	default:
		return "XX000"
	}
}

// buildErrorResponse assembles a pgproto3.ErrorResponse from the
// triplet FiveSql2 surfaces. Optional Query field carries the
// offending SQL so error-aware clients (pgAdmin, DataGrip) can
// highlight the source.
func buildErrorResponse(sqlState, message, query string) *pgproto3.ErrorResponse {
	resp := &pgproto3.ErrorResponse{
		Severity: "ERROR",
		Code:     sqlState,
		Message:  message,
	}
	if query != "" {
		// PG's "InternalQuery" field surfaces in psql with a
		// "QUERY:" line directly under the error message.
		resp.InternalQuery = query
	}
	return resp
}