<?php

class OutlookCalendar {
    private $clientId;
    private $clientSecret;
    private $redirectUri;
    private $accessToken;
    private $refreshToken;

    public function __construct($clientId, $clientSecret, $redirectUri, $accessToken, $refreshToken) {
        $this->clientId     = $clientId;
        $this->clientSecret = $clientSecret;
        $this->redirectUri  = $redirectUri;
        $this->accessToken  = $accessToken;
        $this->refreshToken = $refreshToken;
    }

    // ------------------------------------------
    // 🔁 Refresh Token verwenden
    public function refreshAccessToken() {
        $url = "https://login.microsoftonline.com/common/oauth2/v2.0/token";

        $data = [
            'grant_type'    => 'refresh_token',
            'refresh_token' => $this->refreshToken,
            'client_id'     => $this->clientId,
            'client_secret' => $this->clientSecret,
            'redirect_uri'  => $this->redirectUri,
            'scope'         => 'https://graph.microsoft.com/.default'
        ];

        $response = $this->sendRequest($url, $data, true);
        if (isset($response['access_token'])) {
            $this->accessToken = $response['access_token'];
            $this->refreshToken = $response['refresh_token'] ?? $this->refreshToken;
        }

        return $response;
    }

    // ------------------------------------------
    // Termin erstellen
    public function createEvent($eventData) {
        $url = "https://graph.microsoft.com/v1.0/me/events";
        return $this->sendRequest($url, $eventData, false, 'POST');
    }

    // Termin bearbeiten
    public function updateEvent($eventId, $eventData) {
        $url = "https://graph.microsoft.com/v1.0/me/events/{$eventId}";
        return $this->sendRequest($url, $eventData, false, 'PATCH');
    }

    // Termin löschen
    public function deleteEvent($eventId) {
        $url = "https://graph.microsoft.com/v1.0/me/events/{$eventId}";
        return $this->sendRequest($url, [], false, 'DELETE');
    }

    // Termin laden
    public function getEvents($top = 10) {
        $url = "https://graph.microsoft.com/v1.0/me/events?\$top=" . intval($top);
        $headers = [
            "Authorization: Bearer " . $this->accessToken,
            "Accept: application/json"
        ];

        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        if ($httpCode === 200) {
            return json_decode($response, true);
        } else {
            return [
                "error" => true,
                "status" => $httpCode,
                "message" => $response
            ];
        }
    }


    // ------------------------------------------
    // 🔧 API Request senden (intern)
    private function sendRequest($url, $data = [], $isForm = false, $method = 'POST') {
        $ch = curl_init($url);
        $headers = [
            'Authorization: Bearer ' . $this->accessToken,
        ];

        if ($isForm) {
            $body = http_build_query($data);
            $headers[] = 'Content-Type: application/x-www-form-urlencoded';
        } else {
            $body = json_encode($data);
            $headers[] = 'Content-Type: application/json';
        }

        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $method);
        if ($method !== 'GET' && !empty($data)) {
            curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
        }
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

        $response = curl_exec($ch);
        $err = curl_error($ch);
        curl_close($ch);

        if ($err) {
            return ['error' => $err];
        }

        return json_decode($response, true);
    }

    // 🔓 Getter für AccessToken
    public function getAccessToken() {
        return $this->accessToken;
    }

    public function getRefreshToken() {
        return $this->refreshToken;
    }
}