<?php

declare(strict_types=1);

namespace KTXF\Preview;

use Closure;
use InvalidArgumentException;
use KTXF\Resource\BinaryResource;

final readonly class PreviewSource
{
    public string $mimeType;

    /**
     * @param Closure(): BinaryResource $resourceFactory
     */
    public function __construct(
        public string $sourceType,
        public string $identity,
        public string $signature,
        string $mimeType,
        public ?int $size,
        public Closure $resourceFactory,
    ) {
        if (preg_match('/^[a-z][a-z0-9-]*$/', $this->sourceType) !== 1) {
            throw new InvalidArgumentException('Preview source type must use lowercase letters, numbers, and hyphens');
        }
        if ($this->identity === '' || $this->signature === '') {
            throw new InvalidArgumentException('Preview sources require an identity and content signature');
        }
        if ($this->size !== null && $this->size < 0) {
            throw new InvalidArgumentException('Preview source size cannot be negative');
        }
        $this->mimeType = MimeType::normalize($mimeType);
    }

    public function open(): BinaryResource
    {
        $resource = ($this->resourceFactory)();
        if (!$resource instanceof BinaryResource) {
            throw new PreviewGenerationException('Preview source factory did not return a BinaryResource');
        }
        return $resource;
    }
}