<?php declare(strict_types=1);

namespace Amp\Http\Client;

use Amp\ByteStream\ReadableBuffer;
use Amp\ByteStream\ReadableStream;
use Amp\File\Filesystem;
use Amp\File\FilesystemException;
use function Amp\File\read;

final class BufferedContent implements HttpContent
{
    public static function fromString(string $content, ?string $contentType = null): self
    {
        return new self($content, $contentType);
    }

    /**
     * Creates an instance using the given JSON serializable data with the content-type application/json.
     *
     * @param mixed $json Data which may be JSON serialized with {@see json_encode()}.
     */
    public static function fromJson(mixed $json): self
    {
        try {
            return self::fromString(\json_encode($json, flags: \JSON_THROW_ON_ERROR), 'application/json');
        } catch (\JsonException $exception) {
            throw new HttpException(
                'Exception thrown encoding JSON content: ' . $exception->getMessage(),
                previous: $exception,
            );
        }
    }

    public static function fromFile(
        string $path,
        ?string $contentType = null,
    ): self {
        if (!\class_exists(Filesystem::class)) {
            throw new \Error("File request bodies require amphp/file to be installed");
        }

        try {
            return self::fromString(read($path), $contentType);
        } catch (FilesystemException $filesystemException) {
            throw new HttpException('Failed to open file: ' . $path, 0, $filesystemException);
        }
    }

    private function __construct(
        private readonly string $content,
        private readonly ?string $contentType,
    ) {
    }

    public function getContent(): ReadableStream
    {
        return new ReadableBuffer($this->content);
    }

    public function getContentLength(): int
    {
        return \strlen($this->content);
    }

    public function getContentType(): ?string
    {
        return $this->contentType;
    }
}