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

declare(strict_types=1);

namespace BitBadger\PDODocument\Mapper;

use BitBadger\PDODocument\DocumentException;
use Exception;
use JsonMapper;

/**
 * Map domain class instances from JSON documents
 *
 * @template TDoc The type of document returned by this mapper
 * @implements Mapper<TDoc> Provide a mapping from JSON
 */
class DocumentMapper implements Mapper
{
    /**
     * Constructor
     *
     * @param class-string<TDoc> $className The type of class to be returned by this mapping
     * @param string $fieldName The name of the field (optional; defaults to `data`)
     */
    public function __construct(public string $className, public string $fieldName = 'data') {}

    /**
     * Map a result to a domain class instance
     *
     * @param array<string|int, mixed> $result An associative array representing a single database result
     * @return TDoc The document, deserialized from its JSON representation
     * @throws DocumentException If the JSON cannot be deserialized
     */
    public function map(array $result): mixed
    {
        try {
            if (method_exists($this->className, 'fromJsonString')) {
                return $this->className::fromJsonString($result[$this->fieldName]);
            }
            $json = json_decode($result[$this->fieldName]);
            if (is_null($json)) {
                throw new DocumentException("Could not map document for $this->className: " . json_last_error_msg());
            }
            return (new JsonMapper())->map($json, $this->className);
        } catch (Exception $ex) {
            throw new DocumentException("Could not map document for $this->className", previous: $ex);
        }
    }
}