<?php

declare(strict_types=1);

namespace OpenTelemetry\SDK\Common\Export\Http;

use function assert;
use BadMethodCallException;
use function explode;
use function in_array;
use OpenTelemetry\SDK\Common\Export\TransportInterface;
use OpenTelemetry\SDK\Common\Future\CancellationInterface;
use OpenTelemetry\SDK\Common\Future\CompletedFuture;
use OpenTelemetry\SDK\Common\Future\ErrorFuture;
use OpenTelemetry\SDK\Common\Future\FutureInterface;
use Psr\Http\Client\ClientInterface;
use Psr\Http\Client\NetworkExceptionInterface;
use Psr\Http\Message\RequestFactoryInterface;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\StreamFactoryInterface;
use RuntimeException;
use function strtolower;
use Throwable;
use function time_nanosleep;
use function trim;

/**
 * @psalm-template CONTENT_TYPE of string
 * @template-implements TransportInterface<CONTENT_TYPE>
 */
final class PsrTransport implements TransportInterface
{
    private ClientInterface $client;
    private RequestFactoryInterface $requestFactory;
    private StreamFactoryInterface $streamFactory;

    private string $endpoint;
    private string $contentType;
    private array $headers;
    private array $compression;
    private int $retryDelay;
    private int $maxRetries;

    private bool $closed = false;

    /**
     * @psalm-param CONTENT_TYPE $contentType
     */
    public function __construct(
        ClientInterface $client,
        RequestFactoryInterface $requestFactory,
        StreamFactoryInterface $streamFactory,
        string $endpoint,
        string $contentType,
        array $headers,
        array $compression,
        int $retryDelay,
        int $maxRetries
    ) {
        $this->client = $client;
        $this->requestFactory = $requestFactory;
        $this->streamFactory = $streamFactory;
        $this->endpoint = $endpoint;
        $this->contentType = $contentType;
        $this->headers = $headers;
        $this->compression = $compression;
        $this->retryDelay = $retryDelay;
        $this->maxRetries = $maxRetries;
    }

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

    public function send(string $payload, ?CancellationInterface $cancellation = null): FutureInterface
    {
        if ($this->closed) {
            return new ErrorFuture(new BadMethodCallException('Transport closed'));
        }

        $body = PsrUtils::encode($payload, $this->compression, $appliedEncodings);
        $request = $this->requestFactory
            ->createRequest('POST', $this->endpoint)
            ->withBody($this->streamFactory->createStream($body))
            ->withHeader('Content-Type', $this->contentType)
        ;
        if ($appliedEncodings) {
            $request = $request->withHeader('Content-Encoding', $appliedEncodings);
        }
        foreach ($this->headers as $header => $value) {
            $request = $request->withAddedHeader($header, $value);
        }

        for ($retries = 0;; $retries++) {
            $response = null;
            $e = null;

            try {
                $response = $this->client->sendRequest($request);
                if ($response->getStatusCode() >= 200 && $response->getStatusCode() < 300) {
                    break;
                }

                if ($response->getStatusCode() >= 400 && $response->getStatusCode() < 500 && !in_array($response->getStatusCode(), [408, 429], true)) {
                    throw new RuntimeException($response->getReasonPhrase(), $response->getStatusCode());
                }
            } catch (NetworkExceptionInterface $e) {
            } catch (Throwable $e) {
                return new ErrorFuture($e);
            }

            if ($retries >= $this->maxRetries) {
                return new ErrorFuture(new RuntimeException('Export retry limit exceeded', 0, $e));
            }

            $delay = PsrUtils::retryDelay($retries, $this->retryDelay, $response);
            $sec = (int) $delay;
            $nsec = (int) (($delay - $sec) * 1e9);

            /** @psalm-suppress ArgumentTypeCoercion */
            if (time_nanosleep($sec, $nsec) !== true) {
                return new ErrorFuture(new RuntimeException('Export cancelled', 0, $e));
            }
        }

        assert(isset($response));

        try {
            $body = PsrUtils::decode(
                $response->getBody()->__toString(),
                self::parseContentEncoding($response),
            );
        } catch (Throwable $e) {
            return new ErrorFuture($e);
        }

        return new CompletedFuture($body);
    }

    private static function parseContentEncoding(ResponseInterface $response): array
    {
        $encodings = [];
        foreach (explode(',', $response->getHeaderLine('Content-Encoding')) as $encoding) {
            if (($encoding = trim($encoding, " \t")) !== '') {
                $encodings[] = strtolower($encoding);
            }
        }

        return $encodings;
    }

    public function shutdown(?CancellationInterface $cancellation = null): bool
    {
        if ($this->closed) {
            return false;
        }

        $this->closed = true;

        return true;
    }

    public function forceFlush(?CancellationInterface $cancellation = null): bool
    {
        return !$this->closed;
    }
}