<?php

class CommuniApi {
    const BASE_URL = 'https://api.communiapp.de/rest/';
    const TIMEZONE = 'Europe/Berlin';

    private $authtoken = false;
    private $logininfo = null;
    private $userinfocache = array();
    private $groupinfocache = array();

    public function __construct($authtoken) {
        $this->authtoken = $authtoken;
    }

    private function get($sub, $params = null) {
        $url = self::BASE_URL . $sub;
        if (!empty($params)) {
            $url .= '?' . http_build_query($params);
        }

        $ch = curl_init();
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_TIMEOUT, 30);
        curl_setopt($ch, CURLOPT_HTTPHEADER, array(
            'User-Agent: WP Communi Events <jonas@kuemmerlin.eu>',
            'X-Authorization: Bearer ' . $this->authtoken
        ));

        curl_setopt($ch, CURLOPT_URL, $url);
        $result = curl_exec($ch);

        if ($result === false) {
            $cn = curl_errno($ch);
            $cm = curl_error($ch);
            trigger_error("curl error($cn): $cm", E_USER_NOTICE);
            curl_close($ch);
            return false;
        }

        curl_close($ch);
        return json_decode($result);
    }

    // retval: { id: User-ID, group: Main-Group-ID, ... }
    public function login() {
        if ($this->logininfo === null) {
            $info = $this->get('login');
            if (!empty($info) && !empty($info->id)) {
                $this->logininfo = $info;
            } else {
                $this->logininfo = false;
            }
        }
        return $this->logininfo;
    }

    public function userId() {
        $i = $this->login();
        if (!empty($i) && !empty($i->id)) {
            return $i->id;
        } else {
            return false;
        }
    }

    public function user($id = null) {
        if (empty($id))
            $id = $this->userId();

        if (empty($id))
            return false;

        if (!array_key_exists($id, $this->userinfocache)) {
            $info = $this->get('user/' . urlencode($id));
            if (!empty($info)) {
                $this->userinfocache[$id] = new CommuniUser($this, $id, $info);
            } else {
                $this->userinfocache[$id] = false;
            }
        }

        return $this->userinfocache[$id];

    }

    public function group($id = null) {
        if (empty($id))
            $id = $this->mainGroupId();

        if (empty($id))
            return false;

        if (!array_key_exists($id, $this->groupinfocache)) {
            $info = $this->get('group/' . urlencode($id));
            if (!empty($info)) {
                $this->groupinfocache[$id] = new CommuniGroup($this, $id, $info);
            } else {
                $this->groupinfocache[$id] = false;
            }
        }

        return $this->groupinfocache[$id];
    }

    public function userGroupIds($userid = null) {
        if (empty($userid))
            $userid = $this->userId();

        if (empty($userid))
            return array();

        if ($userid instanceof CommuniUser)
            $userid = $userid->id();

        $usergroups = $this->get('userGroup', array('user' => $userid));
        if (empty($usergroups))
            return array();

        $retval = array();
        foreach ($usergroups as $row) {
            if (!empty($row->status) && !empty($row->group) && $row->status == 2) {
                $retval[] = $row->group;
            }
        }

        return $retval;
    }

    public function userGroups($user = null) {
        $ids = $this->userGroupIds($user);
        $retval = array();

        foreach ($ids as $id) {
            $g = $this->group($id);
            if (!empty($g))
                $retval[] = $g;
        }

        return $retval;
    }

    public function events($groups = null) {
        $groupids = array();
        if ($groups !== null) {
            foreach ($groups as $g) {
                if ($g instanceof CommuniGroup) {
                    $groupids[] = $g->id();
                } else {
                    $groupids[] = $g;
                }
            }
        } else {
            $maingroup = $this->mainGroupId();
            if (!empty($maingroup))
                $groupids[] = $maingroup;
        }

        if (empty($groupids))
            return array();

        if (count($groupids) == 1)
            $groupids = $groupids[0];

        $infos = $this->get('event', array('group' => $groupids));
        if (empty($infos))
            return array();

        $retval = array();
        foreach ($infos as $i) {
            if (!empty($i) && !empty($i->id) && empty($i->baseType)) {
                $retval[] = new CommuniEvent($this, $i->id, $i);
            }
        }

        return $retval;
    }

    public function mainGroupId() {
        $i = $this->login();
        if (!empty($i) && !empty($i->group)) {
            return $i->group;
        } else {
            return false;
        }
    }

    public function webappUrl() {
        $g = $this->group();
        if (!empty($g) && !empty($g->name())) {
            return "https://{$g->name()}.communiapp.de/";
        } else {
            return false;
        }
    }

    public static function defaultInstance() {
        static $inst = null;
        if (empty($inst)) {
            $inst = new CommuniApi(get_option('communievents-auth-token'));
        }
        return $inst;
    }
}

class CommuniUser {
    private $api;
    private $id_;
    private $info;

    public function __construct($api, $id, $info) {
        $this->api = $api;
        $this->id_ = $id;
        $this->info = $info;
    }

    public function vorname() {
        if (!empty($this->info) && !empty($this->info->vorname)) {
            return $this->info->vorname;
        } else {
            return '';
        }
    }

    public function nachname() {
        if (!empty($this->info) && !empty($this->info->nachname)) {
            return $this->info->nachname;
        } else {
            return '';
        }
    }

    public function id() {
        return $this->id_;
    }

    public function name() {
        return "{$this->vorname()} {$this->nachname()}";
    }

    public function webappUrl() {
        $baseurl = $this->api->webappUrl();
        if (!empty($baseurl)) {
            return "{$baseurl}page/detail/tab/user-{$this->id()}";
        } else {
            return false;
        }
    }

    public function groupIds() {
        return $this->api->userGroupIds($this);
    }

    public function groups() {
        return $this->api->userGroups($this);
    }
}

class CommuniGroup {
    private $api;
    private $id_;
    private $info;

    public function __construct($api, $id, $info) {
        $this->api = $api;
        $this->id_ = $id;
        $this->info = $info;
    }

    public function id() {
        return $this->id_;
    }

    public function name() {
        if (!empty($this->info) && !empty($this->info->name)) {
            return $this->info->name;
        } else {
            return '';
        }
    }

    public function title() {
        if (!empty($this->info) && !empty($this->info->title)) {
            return $this->info->title;
        } else {
            return '';
        }
    }

    public function webappUrl() {
        if (!empty($this->info) && !empty($this->info->name)) {
            return "https://{$this->info->name}.communiapp.de/";
        } else {
            $baseurl = $this->api->webappUrl();
            if (!empty($baseurl)) {
                //return "{$baseurl}page/group/tab/content-{$this->id()}";
                return "{$baseurl}page/detail/tab/group-{$this->id()}";
            } else {
                return false;
            }
        }
    }

    public function members() {
        // TODO implement
        return array();
    }
}

class CommuniEvent {
    private $api;
    private $id_;
    private $info;
    private $start_dt;
    private $end_dt;
    private $allday;

    public function __construct($api, $id, $info) {
        $this->api = $api;
        $this->id_ = $id;
        $this->info = $info;

        // parse start and end date and figure out allday
        $tz = new DateTimeZone(CommuniApi::TIMEZONE);
        $this->start_dt = new DateTimeImmutable($info->dateTime, $tz);
        $this->end_dt = new DateTimeImmutable(!empty($info->endDateTime) ? $info->endDateTime : $info->dateTime, $tz);
        $this->allday = self::is_allday_time($this->start_dt) && self::is_allday_time($this->end_dt);
        if ($this->allday) {
            // set to datetime which contains date only
            $this->start_dt = self::make_allday_dt($this->start_dt);
            $this->end_dt = self::make_allday_dt($this->end_dt);
        }
    }

    // If the time is ambiguous (i.e. it is inside the "double hour" of
    // a DST transition, get the earliest UTC time that matches
    private static function get_earliest_timestamp($dt) {
        $ts_utc_php = $dt->getTimestamp();
        $ts_local = $ts_utc_php + $dt->getOffset();
        $tz = $dt->getTimezone();

        if (empty($tz))
            return $ts_utc_php;

        $t = $tz->getTransitions($ts_local - 259200, $ts_local + 259200);
        if (empty($t))
            return $ts_utc_php;

        for ($i = 0; $i < count($t)-1; ++$i) {
            $last_local_ts = $t[$i+1]['ts'] + $t[$i]['offset'];
            if ($ts_local < $last_local_ts) {
                return $ts_local - $t[$i]['offset'];
            }
        }

        return $ts_local - $t[count($t)-1]['offset'];
    }

    private static function is_allday_time($dt) {
        $ts = self::get_earliest_timestamp($dt);
        return ($ts % 86400) == 1;
    }

    private static function make_allday_dt($dt) {
        $ts = self::get_earliest_timestamp($dt);
        $ts -= $ts % 86400;
        return new DateTimeImmutable("@$ts");
    }

    public function id() {
        return $this->id_;
    }

    public function groupId() {
        if (!empty($this->info->group)) {
            return $this->info->group;
        } else {
            return false;
        }
    }

    public function group() {
        $i = $this->groupId();
        if (!empty($i)) {
            return $this->api->group($i);
        } else {
            return false;
        }
    }

    public function title() {
        if (!empty($this->info->titleFormatted)) {
            return $this->info->titleFormatted;
        } else {
            return '';
        }
    }

    public function location() {
        if (!empty($this->info->locationFormatted)) {
            return $this->info->locationFormatted;
        } else {
            return '';
        }
    }

    public function description() {
        if (!empty($this->info->descriptionFormatted)) {
            return $this->info->descriptionFormatted;
        } else {
            return '';
        }
    }

    public function official() {
        if (isset($this->info->isOfficial)) {
            return $this->info->isOfficial;
        } else {
            return false;
        }
    }

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

    public function start() {
        return $this->start_dt;
    }

    public function end() {
        return $this->end_dt;
    }

    public function webappUrl() {
        $baseurl = $this->api->webappUrl();
        if (!empty($baseurl)) {
            return "{$baseurl}page/detail/tab/event-{$this->id()}";
        } else {
            return false;
        }
    }
}