<?php
/**
 * Copyright 2020 Google LLC.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

namespace Google\Cloud\TestUtils;

use Google\Cloud\TestUtils\GcloudWrapper\CloudFunction;
use Google\CloudFunctions\CloudEvent;
use GuzzleHttp\Client;

/**
 * Trait CloudFunctionLocalTestTrait.
 *
 * Uses the function framework to run the function as a local service for system tests.
 */
trait CloudFunctionLocalTestTrait
{
    use TestTrait;

    /** @var \GuzzleHttp\Client */
    private $client;

    /** @var \Google\Cloud\TestUtils\GcloudWrapper\CloudFunction */
    private static $fn;

    /** @var \Symfony\Component\Process\Process; */
    private static $localhost;

    /**
     * Prepare and start the function in a local development server.
     *
     * @beforeClass
     */
    public static function startFunction()
    {
        $props = [
            'projectId' => self::requireEnv('GOOGLE_PROJECT_ID')
        ];
        if (isset(self::$entryPoint)) {
            $props['entryPoint'] = self::$entryPoint;
        }
        if (isset(self::$functionSignatureType)) {
            $props['functionSignatureType'] = self::$functionSignatureType;
        }
        self::$fn = CloudFunction::fromArray(
            self::initFunctionProperties($props)
        );
        self::$localhost = self::doRun();
    }

    /**
     * Start the development server based on the prepared function.
     *
     * Allows configuring server properties, for example:
     *
     *     return self::$fn->run(['FOO' => 'bar'], '9090', '/usr/local/bin/php');
     */
    private static function doRun()
    {
        return self::$fn->run();
    }

    /**
     * Customize startFunction properties.
     *
     * Example:
     *
     *     $props['dir'] = 'path/to/function-dir';
     *     $props['region'] = 'us-west1';
     *     return $props;
     */
    private static function initFunctionProperties(array $props = [])
    {
        return $props;
    }

    /**
     * Set up the client.
     *
     * @before
     */
    public function setUpClient()
    {
        $baseUrl = self::$fn->getLocalBaseUrl();
        $this->client = new Client([
            'base_uri' => $baseUrl,
            'http_errors' => false
        ]);
    }

    /**
     * Stop the function.
     *
     * @afterClass
     */
    public static function stopFunction()
    {
        self::$fn->stop();
    }

    /**
     * Make a request using a cloud event
     *
     * Example:
     *
     *     $this->request(CloudEvent::fromArray($params));
     */
    private function request(CloudEvent $cloudevent, array $params = [])
    {
        $cloudEventHeaders = array_filter([
            'ce-id' => $cloudevent->getId(),
            'ce-source' => $cloudevent->getSource(),
            'ce-specversion' => $cloudevent->getSpecVersion(),
            'ce-type' => $cloudevent->getType(),
            'ce-datacontenttype' => $cloudevent->getDataContentType(),
            'ce-dataschema' => $cloudevent->getDataSchema(),
            'ce-subject' => $cloudevent->getSubject(),
            'ce-time' => $cloudevent->getTime(),
        ]);

        return $this->client->request('POST', '/', array_merge_recursive(
            $params,
            [
                'json' => $cloudevent->getData(),
                'headers' => $cloudEventHeaders,
            ]
        ));
    }
}