<?php
/**
 * @author Daniel J. Summers <daniel@bitbadger.solutions>
 * @license MIT
 */

declare(strict_types=1);

namespace BitBadger\PDODocument;

/**
 * The types of comparison operators allowed for JSON fields
 */
enum Op
{
    /** Equals (=) */
    case Equal;
    /** Greater Than (>) */
    case Greater;
    /** Greater Than or Equal To (>=) */
    case GreaterOrEqual;
    /** Less Than (<) */
    case Less;
    /** Less Than or Equal To (<=) */
    case LessOrEqual;
    /** Not Equal to (<>) */
    case NotEqual;
    /** Between (BETWEEN) */
    case Between;
    /** In (IN) */
    case In;
    /** In Array (PostgreSQL - ?|, SQLite - EXISTS / json_each / IN) */
    case InArray;
    /** Exists (IS NOT NULL) */
    case Exists;
    /** Does Not Exist (IS NULL) */
    case NotExists;

    /**
     * Get the SQL representation of this operator
     *
     * @return string The operator to use in SQL statements
     */
    public function toSQL(): string
    {
        return match ($this) {
            Op::Equal           => "=",
            Op::Greater         => ">",
            Op::GreaterOrEqual  => ">=",
            Op::Less            => "<",
            Op::LessOrEqual     => "<=",
            Op::NotEqual        => "<>",
            Op::Between         => "BETWEEN",
            Op::In              => "IN",
            Op::InArray         => "??|", // The actual operator is ?|, but needs to be escaped by doubling
            Op::Exists          => "IS NOT NULL",
            Op::NotExists       => "IS NULL",
        };
    }
}