<?php

namespace App\Services;

use Google\Client as GoogleClient;
use Google\Service\Gmail as GoogleServiceGmail;
use Google\Service\Gmail\Message as GoogleGmailMessage;
use Illuminate\Support\Facades\View;

class GmailService
{
    protected $client;
    protected $service;

    public function __construct()
    {
        $this->client = new GoogleClient();
        $this->client->setAuthConfig(storage_path('app/credentials.json'));
        $this->client->addScope("https://www.googleapis.com/auth/gmail.send");

        $tokenPath = storage_path('app/token.json');
        if (!file_exists($tokenPath)) {
            throw new \Exception("OAuth token not found. Authenticate first.");
        }

        $token = json_decode(file_get_contents($tokenPath), true);
        $this->client->setAccessToken($token);

        if ($this->client->isAccessTokenExpired()) {
            $this->client->fetchAccessTokenWithRefreshToken($this->client->getRefreshToken());
            file_put_contents($tokenPath, json_encode($this->client->getAccessToken()));
        }

        $this->service = new GoogleServiceGmail($this->client);
    }

    /**
     * Send email using Gmail OAuth
     * 
     * @param string $to
     * @param string $subject
     * @param string $view
     * @param array $data
     */
    public function send(string $to, string $subject, string $view, array $data = [])
    {
        $html = View::make($view, $data)->render();

        $raw = "From: you@gmail.com\r\n";
        $raw .= "To: $to\r\n";
        $raw .= "Subject: $subject\r\n";
        $raw .= "Content-Type: text/html; charset=UTF-8\r\n\r\n";
        $raw .= $html;

        $message = new GoogleGmailMessage();
        $message->setRaw(base64_encode($raw));

        $this->service->users_messages->send("me", $message);
    }
}