<?php

namespace DeliciousBrains\WP_Offload_Media\Aws3\Aws;

use DeliciousBrains\WP_Offload_Media\Aws3\Aws\EndpointDiscovery\Configuration;
use Closure;
use DeliciousBrains\WP_Offload_Media\Aws3\Psr\Http\Message\RequestInterface;
/**
 * Builds and injects the user agent header values.
 * This middleware must be appended into step where all the
 * metrics to be gathered are already resolved. As of now it should be
 * after the signing step.
 */
class UserAgentMiddleware
{
    const AGENT_VERSION = 2.1;
    static $userAgentFnList = ['getSdkVersion', 'getUserAgentVersion', 'getHhvmVersion', 'getOsName', 'getLangVersion', 'getExecEnv', 'getEndpointDiscovery', 'getAppId', 'getMetrics'];
    /** @var callable  */
    private $nextHandler;
    /** @var array */
    private $args;
    /** @var MetricsBuilder */
    private $metricsBuilder;
    /**
     * Returns a middleware wrapper function.
     *
     * @param array $args
     *
     * @return Closure
     */
    public static function wrap(array $args) : Closure
    {
        return function (callable $handler) use($args) {
            return new self($handler, $args);
        };
    }
    /**
     * @param callable $nextHandler
     * @param array $args
     */
    public function __construct(callable $nextHandler, array $args = [])
    {
        $this->nextHandler = $nextHandler;
        $this->args = $args;
    }
    /**
     * When invoked, its injects the user agent header into the
     * request headers.
     *
     * @param CommandInterface $command
     * @param RequestInterface $request
     *
     * @return mixed
     */
    public function __invoke(CommandInterface $command, RequestInterface $request)
    {
        $handler = $this->nextHandler;
        $this->metricsBuilder = MetricsBuilder::fromCommand($command);
        $request = $this->requestWithUserAgentHeader($request);
        return $handler($command, $request);
    }
    /**
     * Builds the user agent header value, and injects it into the request
     * headers. Then, it returns the mutated request.
     *
     * @param RequestInterface $request
     *
     * @return RequestInterface
     */
    private function requestWithUserAgentHeader(RequestInterface $request) : RequestInterface
    {
        $uaAppend = $this->args['ua_append'] ?? [];
        $userAgentValue = \array_merge($this->buildUserAgentValue(), $uaAppend);
        // It includes the user agent values just for the User-Agent header.
        // The reason is that the SEP does not mention appending the
        // metrics into the X-Amz-User-Agent header.
        return $request->withHeader('User-Agent', \implode(' ', \array_merge($userAgentValue, $request->getHeader('User-Agent'))));
    }
    /**
     * Builds the different user agent values.
     *
     * @return array
     */
    private function buildUserAgentValue() : array
    {
        $userAgentValue = [];
        foreach (self::$userAgentFnList as $fn) {
            $val = $this->{$fn}();
            if (!empty($val)) {
                $userAgentValue[] = $val;
            }
        }
        return $userAgentValue;
    }
    /**
     * Returns the user agent value for SDK version.
     *
     * @return string
     */
    private function getSdkVersion() : string
    {
        return 'aws-sdk-php/' . Sdk::VERSION;
    }
    /**
     * Returns the user agent value for the agent version.
     *
     * @return string
     */
    private function getUserAgentVersion() : string
    {
        return 'ua/' . self::AGENT_VERSION;
    }
    /**
     * Returns the user agent value for the hhvm version, but just
     * when it is defined.
     *
     * @return string
     */
    private function getHhvmVersion() : string
    {
        if (\defined('DeliciousBrains\\WP_Offload_Media\\Aws3\\HHVM_VERSION')) {
            return 'HHVM/' . HHVM_VERSION;
        }
        return "";
    }
    /**
     * Returns the user agent value for the os version.
     *
     * @return string
     */
    private function getOsName() : string
    {
        $disabledFunctions = \explode(',', \ini_get('disable_functions'));
        if (\function_exists('php_uname') && !\in_array('php_uname', $disabledFunctions, \true)) {
            $osName = "OS/" . \php_uname('s') . '#' . \php_uname('r');
            if (!empty($osName)) {
                return $osName;
            }
        }
        return "";
    }
    /**
     * Returns the user agent value for the php language used.
     *
     * @return string
     */
    private function getLangVersion() : string
    {
        return 'lang/php#' . \phpversion();
    }
    /**
     * Returns the user agent value for the execution env.
     *
     * @return string
     */
    private function getExecEnv() : string
    {
        if ($executionEnvironment = \getenv('AWS_EXECUTION_ENV')) {
            return $executionEnvironment;
        }
        return "";
    }
    /**
     * Returns the user agent value for endpoint discovery as cfg.
     * This feature is deprecated.
     *
     * @return string
     */
    private function getEndpointDiscovery() : string
    {
        $args = $this->args;
        if (isset($args['endpoint_discovery'])) {
            if ($args['endpoint_discovery'] instanceof Configuration && $args['endpoint_discovery']->isEnabled()) {
                return 'cfg/endpoint-discovery';
            } elseif (\is_array($args['endpoint_discovery']) && isset($args['endpoint_discovery']['enabled']) && $args['endpoint_discovery']['enabled']) {
                return 'cfg/endpoint-discovery';
            }
        }
        return "";
    }
    /**
     * Returns the user agent value for app id, but just when an
     * app id was provided as a client argument.
     *
     * @return string
     */
    private function getAppId() : string
    {
        if (empty($this->args['app_id'])) {
            return "";
        }
        return 'app/' . $this->args['app_id'];
    }
    /**
     * Returns the user agent value for metrics.
     *
     * @return string
     */
    private function getMetrics() : string
    {
        // Resolve first metrics related to client arguments.
        $this->metricsBuilder->resolveAndAppendFromArgs($this->args);
        // Build the metrics.
        $metricsEncoded = $this->metricsBuilder->build();
        if (empty($metricsEncoded)) {
            return "";
        }
        return "m/" . $metricsEncoded;
    }
}
