<?php

namespace CrazyFactory\Slack;

/**
 * Class SlackClient
 */
class SlackClient
{
    protected $endpoint;
    protected $config;

    /**
     * Slack constructor.
     *
     * @param array|string $config
     *
     * @throws \Exception
     */
    public function __construct($config = [])
    {
        // string config will be used as endpoint
        if (is_string($config)) {
            $config = [
                'endpoint' => $config,
            ];
        }

        if (!$this->validateConfig($config)) {
            throw new \Exception('Slack configuration is invalid');
        }
        $this->config = $config;
    }

    /**
     * @param array $config
     * @param array $errors
     *
     * @return bool
     */
    protected function validateConfig(array $config = [], array &$errors = [])
    {
        if (empty($config['endpoint'])) {
            $errors[] = 'endpoint is not defined';
        }
        if (isset($config['context']) && !is_array($config['context'])) {
            $errors[] = 'context must be null or array';
        }
        if (isset($config['headers']) && !is_array($config['headers'])) {
            $errors[] = 'headers must be null or array';
        }

        return empty($errors);
    }

    /**
     * Logs the message to Slack channel.
     *
     * @param array|string $context
     *
     * @return bool
     * @throws \Exception
     */
    public function send($context = [])
    {
        if (is_string($context)) {
            $context = [
                'text' => $context,
            ];
        }

        // Merge with default context
		$config_context=isset($this->config['context']) ? $this->config['context']:[];
        $mergedContext = array_merge( $config_context, $context);


        return (isset($mergedContext['async'])? $mergedContext['async']: false)
            ? $this->sendAsync($mergedContext)
            : $this->sendSync($mergedContext);
    }

    /**
     * Send a message to a Slack webhook using PHP curl.
     *
     * @param array $context See https://api.slack.com/incoming-webhooks for more information
     *
     * @return bool
     */
    protected function sendSync(array $context)
    {
        $payload = json_encode($context, JSON_UNESCAPED_UNICODE);
        $curl = curl_init($this->config['endpoint']);
        $config_headers = isset($this->config['headers']) ? $this->config['headers'] : [];
        $headers = ['Content-Type' => 'application/json'] + $config_headers;

        curl_setopt_array($curl, [
            CURLOPT_POST => true,
            CURLOPT_VERBOSE => false,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_HTTPHEADER => $headers,
            CURLOPT_POSTFIELDS => $payload,
        ]);
        curl_exec($curl);
        $code = curl_getinfo($curl, CURLINFO_HTTP_CODE);
        curl_close($curl);

        return $code == 200;
    }

    /**
     * Send a message to a Slack webhook using system CURL.
     *
     * @param array $context See https://api.slack.com/incoming-webhooks for more information
     *
     * @return bool
     */
    protected function sendAsync(array $context)
    {
        $payload = json_encode($context, JSON_UNESCAPED_UNICODE);

        $command = 'curl -X POST ';
		$config_headers = isset($this->config['headers']) ? $this->config['headers'] : [];
        $headers = ['Content-Type' => 'application/json'] + $config_headers;
        foreach ($headers as $key => $value) {
            $command .= '-H ' . escapeshellarg("$key: $value") . ' ';
        }

        // Fire and forget.
        exec("$command --data '{$payload}' {$this->config['endpoint']} > /dev/null 2>&1 &");

        return true;
    }
}