<?php declare(strict_types=1);

namespace BitBadger\PDODocument\Query;

use BitBadger\PDODocument\{Configuration, DocumentException, Field, Mode, Query};

/**
 * Queries to perform partial updates on documents
 */
class Patch
{
    /**
     * Create an UPDATE statement to patch documents
     *
     * @param string $tableName The name of the table in which documents should be patched
     * @param string $whereClause The body of the WHERE clause to use in the UPDATE statement
     * @return string The UPDATE statement to perform the patch
     * @throws DocumentException If the database mode has not been set
     */
    public static function update(string $tableName, string $whereClause): string
    {
        $setValue = match (Configuration::$mode) {
            Mode::PgSQL  => 'data || :data',
            Mode::SQLite => 'json_patch(data, json(:data))',
            default      => throw new DocumentException('Database mode not set; cannot make patch statement')
        };
        return "UPDATE $tableName SET data = $setValue WHERE $whereClause";
    }

    /**
     * Query to patch (partially update) a document by its ID
     *
     * @param string $tableName The name of the table in which a document should be patched
     * @return string The query to patch a document by its ID
     * @throws DocumentException If the database mode has not been set
     */
    public static function byId(string $tableName): string
    {
        return self::update($tableName, Query::whereById());
    }

    /**
     * Query to patch (partially update) a document via a comparison on a JSON field
     *
     * @param string $tableName The name of the table in which documents should be patched
     * @param array|Field[] $field The field comparison to match
     * @param string $conjunction How to handle multiple conditions (optional; defaults to `AND`)
     * @return string The query to patch documents via field comparison
     * @throws DocumentException If the database mode has not been set
     */
    public static function byFields(string $tableName, array $field, string $conjunction = 'AND'): string
    {
        return self::update($tableName, Query::whereByFields($field, $conjunction));
    }
}