<?php declare(strict_types=1);

/*
    This file is a part of myTinyTodo.
    (C) Copyright 2022 Max Pozdeev <maxpozdeev@gmail.com>
    Licensed under the GNU GPL version 2 or any later. See file COPYRIGHT for details.
*/

require_once(MTTINC. 'markup.php');

class TasksController extends ApiController {

    /**
     * Get tasks.
     * Filters are set with query parameters.
     * @return array
     * @throws Exception
     */
    function get()
    {
        $listId = (int)_get('list');
        checkReadAccess($listId);
        $db = DBConnection::instance();

        $sqlWhere = $inner = $sqlWhereListId = $sqlInnerWhereListId = '';
        if ($listId == -1) {
            $userLists = $this->getUserListsSimple();
            $sqlWhereListId = "{$db->prefix}todolist.list_id IN (". implode(',', array_keys($userLists)). ") ";
            $sqlInnerWhereListId = "list_id IN (". implode(',', array_keys($userLists)). ") ";
        }
        else {
            $sqlWhereListId = "{$db->prefix}todolist.list_id=". $listId;
            $sqlInnerWhereListId = "list_id=$listId ";
        }
        if (_get('compl') == 0) {
            $sqlWhere .= ' AND compl=0';
        }

        $tag = trim(_get('t'));
        if ($tag != '')
        {
            $at = explode(',', $tag);
            $tagIds = array();
            $tagExIds = array();
            foreach ($at as $i=>$atv) {
                $atv = trim($atv);
                if ($atv == '' || $atv == '^') continue;
                if (substr($atv,0,1) == '^') {
                    $tagExIds[] = $this->getTagId(substr($atv,1));
                } else {
                    $tagIds[] = $this->getTagId($atv);
                }
            }

            // Include tags: All
            if (sizeof($tagIds) > 1) {
                $inner .= "INNER JOIN (SELECT task_id, COUNT(tag_id) AS c FROM {$db->prefix}tag2task WHERE $sqlInnerWhereListId AND tag_id IN (".
                            implode(',',$tagIds). ") GROUP BY task_id) AS t2t ON id=t2t.task_id";
                $sqlWhere .= " AND c=". sizeof($tagIds);
            }
            elseif ($tagIds) {
                $inner .= "INNER JOIN {$db->prefix}tag2task ON id=task_id";
                $sqlWhere .= " AND tag_id = {$tagIds[0]}";
            }

            // Exclude tags
            if (sizeof($tagExIds) > 0) {
                $sqlWhere .= " AND {$db->prefix}todolist.id NOT IN (SELECT DISTINCT task_id FROM {$db->prefix}tag2task WHERE $sqlInnerWhereListId AND tag_id IN (".
                            implode(',',$tagExIds). "))";
            }
            //no optimization for single exTag
        }

        $s = trim(_get('s'));
        if ($s != '') {
            if (preg_match("|^#(\d+)$|", $s, $m)) $sqlWhere .= " AND {$db->prefix}todolist.id = ". (int)$m[1];
            else $sqlWhere .= " AND (title LIKE ". $db->quoteForLike("%%%s%%",$s). " OR note LIKE ". $db->quoteForLike("%%%s%%",$s). ")";
        }

        $sort = (int)_get('sort');
        $sqlSort = "ORDER BY compl ASC, ";
        if ($sort == 1) $sqlSort .= "prio DESC, ddn ASC, duedate ASC, ow ASC";          // byPrio
        elseif ($sort == 101) $sqlSort .= "prio ASC, ddn DESC, duedate DESC, ow DESC";  // byPrio (reverse)
        elseif ($sort == 2) $sqlSort .= "ddn ASC, duedate ASC, prio DESC, ow ASC";      // byDueDate
        elseif ($sort == 102) $sqlSort .= "ddn DESC, duedate DESC, prio ASC, ow DESC";  // byDueDate (reverse)
        elseif ($sort == 3) $sqlSort .= "d_created ASC, prio DESC, ow ASC";             // byDateCreated
        elseif ($sort == 103) $sqlSort .= "d_created DESC, prio ASC, ow DESC";          // byDateCreated (reverse)
        elseif ($sort == 4) $sqlSort .= "d_edited ASC, prio DESC, ow ASC";              // byDateModified
        elseif ($sort == 104) $sqlSort .= "d_edited DESC, prio ASC, ow DESC";           // byDateModified (reverse)
        else $sqlSort .= "ow ASC";

        $t = array();
        $t['total'] = 0;
        $t['list'] = array();
        $q = $db->dq("SELECT *, duedate IS NULL AS ddn FROM {$db->prefix}todolist $inner WHERE $sqlWhereListId $sqlWhere $sqlSort");
        while ($r = $q->fetchAssoc())
        {
            $t['total']++;
            $t['list'][] = $this->prepareTaskRow($r);
        }
        if (_get('setCompl') && haveWriteAccess($listId)) {
            ListsController::setListShowCompletedById($listId, !(_get('compl') == 0) );
        }
        if (_get('saveSort') == 1 && haveWriteAccess($listId)) {
            ListsController::setListSortingById($listId, $sort);
        }
        return $t;
    }

    /**
     * Create new task
     * action: simple or full
     * @return mixed
     * @throws Exception
     */
    function post()
    {
        $listId = (int)($this->req->jsonBody['list'] ?? 0);
        checkWriteAccess($listId);
        $action = $this->req->jsonBody['action'] ?? '';
        if ($action == 'full') {
            return $this->fullNewTaskInList($listId);
        }
        return $this->newTaskInList($listId);
    }

    /**
     * Actions with multiple tasks
     * @return array
     * @throws Exception
     */
    function put()
    {
        checkWriteAccess();
        $action = $this->req->jsonBody['action'] ?? '';
        switch ($action) {
            case 'order': return $this->changeTaskOrder(); break;
            default:      return ['total' => 0]; // error 400 ?
        }
    }


    /**
     * Delete task by Id
     * @param mixed $id
     * @return array
     * @throws Exception
     */
    function deleteId($id)
    {
        checkWriteAccess();
        $id = (int)$id;
        $db = DBConnection::instance();
        $db->ex("BEGIN");
        $db->ex("DELETE FROM {$db->prefix}tag2task WHERE task_id=$id");
        //TODO: delete unused tags?
        $db->dq("DELETE FROM {$db->prefix}todolist WHERE id=$id");
        $deleted = $db->affected();
        $db->ex("COMMIT");
        $t = array();
        $t['total'] = $deleted;
        $t['list'][] = array('id' => $id);
        return $t;
    }

    /**
     * Edit some properties of Task
     * @param mixed $id
     * @return array
     * @throws Exception
     */
    function putId($id)
    {
        checkWriteAccess();
        $id = (int)$id;

        $action = $this->req->jsonBody['action'] ?? '';
        switch ($action) {
            case 'edit':     return $this->editTask($id);     break;
            case 'complete': return $this->completeTask($id); break;
            case 'note':     return $this->editNote($id);     break;
            case 'move':     return $this->moveTask($id);     break;
            case 'priority': return $this->priorityTask($id); break;
            default:         return ['total' => 0];
        }
    }


    /**
     * Parse task input string to components for representing in edit/add form
     * @return array
     * @throws Exception
     */
    function postTitleParse()
    {
        checkWriteAccess();
        $t = array(
            'title' => trim( $this->req->jsonBody['title'] ?? '' ),
            'prio' => 0,
            'tags' => ''
        );
        if (Config::get('smartsyntax') != 0 && (false !== $a = $this->parseSmartSyntax($t['title'])))
        {
            $t['title'] = $a['title'];
            $t['prio'] = $a['prio'];
            $t['tags'] = $a['tags'];
        }
        return $t;
    }

    /* Private Functions */

    private function newTaskInList(int $listId)
    {
        $db = DBConnection::instance();
        $t = array();
        $t['total'] = 0;
        $title = trim($this->req->jsonBody['title'] ?? '');
        $prio = 0;
        $tags = '';
        if (Config::get('smartsyntax') != 0)
        {
            $a = $this->parseSmartSyntax($title);
            if ($a === false) {
                return $t;
            }
            $title = $a['title'];
            $prio = $a['prio'];
            $tags = $a['tags'];
        }
        if ($title == '') {
            return $t;
        }
        if (Config::get('autotag')) {
            $tags .= ',' . ($this->req->jsonBody['tag'] ?? '');
        }
        $ow = 1 + (int)$db->sq("SELECT MAX(ow) FROM {$db->prefix}todolist WHERE list_id=$listId AND compl=0");
        $date = time();
        $db->ex("BEGIN");
        $db->dq("INSERT INTO {$db->prefix}todolist (uuid,list_id,title,d_created,d_edited,ow,prio) VALUES (?,?,?,?,?,?,?)",
                    array(generateUUID(), $listId, $title, $date, $date, $ow, $prio) );
        $id = (int) $db->lastInsertId();
        if ($tags != '')
        {
            $aTags = $this->prepareTags($tags);
            if ($aTags) {
                $this->addTaskTags($id, $aTags['ids'], $listId);
                $db->ex("UPDATE {$db->prefix}todolist SET tags=?,tags_ids=? WHERE id=$id", array(implode(',',$aTags['tags']), implode(',',$aTags['ids'])));
            }
        }
        $db->ex("COMMIT");
        $r = $db->sqa("SELECT * FROM {$db->prefix}todolist WHERE id=$id");
        $oo = $this->prepareTaskRow($r);
        MTTNotificationCenter::postNotification(MTTNotification::didCreateTask, $oo);
        $t['list'][] = $oo;
        $t['total'] = 1;
        return $t;
    }

    private function fullNewTaskInList(int $listId)
    {
        $db = DBConnection::instance();
        $title = trim($this->req->jsonBody['title'] ?? '');
        $note = str_replace("\r\n", "\n", $this->req->jsonBody['note'] ?? '');
        $prio = (int)($this->req->jsonBody['prio'] ?? 0);
        if ($prio < -1) $prio = -1;
        elseif ($prio > 2) $prio = 2;
        $duedate = $this->parseDuedate(trim( $this->req->jsonBody['duedate'] ?? '' ));
        $t = array();
        $t['total'] = 0;
        if ($title == '') {
            return $t;
        }
        $tags = $this->req->jsonBody['tags'] ?? '';
        if (Config::get('autotag'))
            $tags .= ',' . ($this->req->jsonBody['tag'] ?? '');
        $ow = 1 + (int)$db->sq("SELECT MAX(ow) FROM {$db->prefix}todolist WHERE list_id=$listId AND compl=0");
        $date = time();
        $db->ex("BEGIN");
        $db->dq("INSERT INTO {$db->prefix}todolist (uuid,list_id,title,d_created,d_edited,ow,prio,note,duedate) VALUES (?,?,?,?,?,?,?,?,?)",
                    array(generateUUID(), $listId, $title, $date, $date, $ow, $prio, $note, $duedate) );
        $id = (int) $db->lastInsertId();
        if ($tags != '')
        {
            $aTags = $this->prepareTags($tags);
            if ($aTags) {
                $this->addTaskTags($id, $aTags['ids'], $listId);
                $db->ex("UPDATE {$db->prefix}todolist SET tags=?,tags_ids=? WHERE id=$id", array(implode(',',$aTags['tags']), implode(',',$aTags['ids'])));
            }
        }
        $db->ex("COMMIT");
        $r = $db->sqa("SELECT * FROM {$db->prefix}todolist WHERE id=$id");
        $oo = $this->prepareTaskRow($r);
        MTTNotificationCenter::postNotification(MTTNotification::didCreateTask, $oo);
        $t['list'][] = $oo;
        $t['total'] = 1;
        return $t;
    }

    private function editTask(int $id)
    {
        $db = DBConnection::instance();
        $title = trim($this->req->jsonBody['title'] ?? '');
        $note = str_replace("\r\n", "\n", $this->req->jsonBody['note'] ?? '');
        $prio = (int)($this->req->jsonBody['prio'] ?? 0);
        if ($prio < -1) $prio = -1;
        elseif ($prio > 2) $prio = 2;
        $duedate = $this->parseDuedate(trim( $this->req->jsonBody['duedate'] ?? '' ));
        $t = array();
        $t['total'] = 0;
        if ($title == '') {
            return $t;
        }
        $listId = (int) $db->sq("SELECT list_id FROM {$db->prefix}todolist WHERE id=$id");
        $tags = trim( $this->req->jsonBody['tags'] ?? '' );
        $db->ex("BEGIN");
        $db->ex("DELETE FROM {$db->prefix}tag2task WHERE task_id=$id");
        $aTags = $this->prepareTags($tags);
        if($aTags) {
            $tags = implode(',', $aTags['tags']);
            $tags_ids = implode(',',$aTags['ids']);
            $this->addTaskTags($id, $aTags['ids'], $listId);
        }
        $db->dq("UPDATE {$db->prefix}todolist SET title=?,note=?,prio=?,tags=?,tags_ids=?,duedate=?,d_edited=? WHERE id=$id",
                array($title, $note, $prio, $tags, $tags_ids, $duedate, time()) );
        $db->ex("COMMIT");
        $r = $db->sqa("SELECT * FROM {$db->prefix}todolist WHERE id=$id");
        if ($r) {
            $t['list'][] = $this->prepareTaskRow($r);
            $t['total'] = 1;
        }
        return $t;
    }

    private function moveTask(int $id)
    {
        $db = DBConnection::instance();
        $fromId = (int)($this->req->jsonBody['from'] ?? 0);
        $toId = (int)($this->req->jsonBody['to'] ?? 0);
        $result = $this->doMoveTask($id, $toId);
        $t = array('total' => $result ? 1 : 0);
        if ($fromId == -1 && $result && $r = $db->sqa("SELECT * FROM {$db->prefix}todolist WHERE id=$id")) {
            $t['list'][] = $this->prepareTaskRow($r);
        }
        return $t;
    }

    private function doMoveTask(int $id, int $listId)
    {
        $db = DBConnection::instance();

        // Check task exists and not in target list
        $r = $db->sqa("SELECT * FROM {$db->prefix}todolist WHERE id=?", array($id));
        if (!$r || $listId == $r['list_id']) return false;

        // Check target list exists
        if (!$db->sq("SELECT COUNT(*) FROM {$db->prefix}lists WHERE id=?", [$listId]))
            return false;

        $ow = 1 + (int)$db->sq("SELECT MAX(ow) FROM {$db->prefix}todolist WHERE list_id=? AND compl=?", array($listId, $r['compl']?1:0));

        $db->ex("BEGIN");
        $db->ex("UPDATE {$db->prefix}tag2task SET list_id=? WHERE task_id=?", array($listId, $id));
        $db->dq("UPDATE {$db->prefix}todolist SET list_id=?, ow=?, d_edited=? WHERE id=?", array($listId, $ow, time(), $id));
        $db->ex("COMMIT");
        return true;
    }

    private function completeTask(int $id)
    {
        $db = DBConnection::instance();
        $compl = (int)($this->req->jsonBody['compl'] ?? 0);
        $listId = (int)$db->sq("SELECT list_id FROM {$db->prefix}todolist WHERE id=$id");
        if ($compl) $ow = 1 + (int)$db->sq("SELECT MAX(ow) FROM {$db->prefix}todolist WHERE list_id=$listId AND compl=1");
        else $ow = 1 + (int)$db->sq("SELECT MAX(ow) FROM {$db->prefix}todolist WHERE list_id=$listId AND compl=0");
        $date = time();
        $dateCompleted = $compl ? $date : 0;
        $db->dq("UPDATE {$db->prefix}todolist SET compl=$compl,ow=$ow,d_completed=?,d_edited=? WHERE id=$id",
                    array($dateCompleted, $date) );
        $t = array();
        $t['total'] = 1;
        $r = $db->sqa("SELECT * FROM {$db->prefix}todolist WHERE id=$id");
        $t['list'][] = $this->prepareTaskRow($r);
        return $t;
    }

    private function editNote(int $id)
    {
        $db = DBConnection::instance();
        $note = $this->req->jsonBody['note'] ?? '';
        $note = str_replace("\r\n", "\n", $note);
        $db->dq("UPDATE {$db->prefix}todolist SET note=?,d_edited=? WHERE id=$id", array($note, time()) );
        $t = array();
        $t['total'] = 1;
        $t['list'][] = array('id'=>$id, 'note'=> noteMarkup($note), 'noteText'=>(string)$note);
        return $t;
    }

    private function priorityTask(int $id)
    {
        $db = DBConnection::instance();
        $prio = (int)($this->req->jsonBody['prio'] ?? 0);
        if ($prio < -1) $prio = -1;
        elseif ($prio > 2) $prio = 2;
        $db->ex("UPDATE {$db->prefix}todolist SET prio=$prio,d_edited=? WHERE id=$id", array(time()) );
        $t = array();
        $t['total'] = 1;
        $t['list'][] = array('id'=>$id, 'prio'=>$prio);
        return $t;
    }


    private function changeTaskOrder()
    {
        $db = DBConnection::instance();
        $order = $this->req->jsonBody['order'] ?? null;
        $t = array();
        $t['total'] = 0;
        if (is_array($order))
        {
            $ad = array();
            foreach ($order as $obj) {
                $id = $obj['id'] ?? 0;
                $diff = $obj['diff'] ?? 0;
                $ad[(int)$diff][] = (int)$id;
            }
            $db->ex("BEGIN");
            foreach ($ad as $diff=>$ids) {
                if ($diff >=0) $set = "ow=ow+".$diff;
                else $set = "ow=ow-".abs($diff);
                $db->dq("UPDATE {$db->prefix}todolist SET $set,d_edited=? WHERE id IN (".implode(',',$ids).")", array(time()) );
            }
            $db->ex("COMMIT");
            $t['total'] = 1;
        }
        return $t;
    }

    private function getUserListsSimple()
    {
        $db = DBConnection::instance();
        $a = array();
        $q = $db->dq("SELECT id,name FROM {$db->prefix}lists ORDER BY id ASC");
        while($r = $q->fetchRow()) {
            $a[$r[0]] = $r[1];
        }
        return $a;
    }

    private function prepareTaskRow(array $r)
    {
        $lang = Lang::instance();
        $dueA = $this->prepareDuedate($r['duedate']);
        $dCreated = timestampToDatetime($r['d_created']);
        $isEdited = $r['d_edited'] != $r['d_created'];
        $dEdited = $isEdited ? timestampToDatetime($r['d_edited']) : '';
        $dCompleted = $r['d_completed'] ? timestampToDatetime($r['d_completed']) : '';

        return array(
            'id' => $r['id'],
            'title' => titleMarkup( $r['title'] ),
            'titleText' => (string)$r['title'],
            'listId' => $r['list_id'],
            'date' => htmlarray($dCreated),
            'dateInt' => (int)$r['d_created'],
            'dateInlineTitle' => htmlarray(sprintf($lang->get('taskdate_inline_created'), $dCreated)),
            'dateEdited' => htmlarray($dEdited),
            'dateEditedInt' => (int)$r['d_edited'],
            'dateEditedInlineTitle' => htmlarray(sprintf($lang->get('taskdate_inline_edited'), $dEdited)),
            'isEdited' => (bool)$isEdited,
            'dateCompleted' => htmlarray($dCompleted),
            'dateCompletedInlineTitle' => htmlarray(sprintf($lang->get('taskdate_inline_completed'), $dCompleted)),
            'compl' => (int)$r['compl'],
            'prio' => $r['prio'],
            'note' => noteMarkup($r['note']),
            'noteText' => (string)$r['note'],
            'ow' => (int)$r['ow'],
            'tags' => htmlarray($r['tags']),
            'tags_ids' => htmlarray($r['tags_ids']),
            'duedate' => $dueA['formatted'],
            'dueClass' => $dueA['class'],
            'dueStr' => htmlarray($dueA['str']),
            'dueInt' => $this->date2int($r['duedate']),
            'dueTitle' => htmlarray(sprintf($lang->get('taskdate_inline_duedate'), $dueA['formattedlong'])),
        );
    }


    private function parseDuedate($s)
    {
        $df2 = Config::get('dateformat2');
        if (max((int)strpos($df2,'n'), (int)strpos($df2,'m')) > max((int)strpos($df2,'d'), (int)strpos($df2,'j'))) $formatDayFirst = true;
        else $formatDayFirst = false;

        $y = $m = $d = 0;
        if (preg_match("|^(\d+)-(\d+)-(\d+)\b|", $s, $ma)) {
            $y = (int)$ma[1]; $m = (int)$ma[2]; $d = (int)$ma[3];
        }
        elseif (preg_match("|^(\d+)\/(\d+)\/(\d+)\b|", $s, $ma))
        {
            if($formatDayFirst) {
                $d = (int)$ma[1]; $m = (int)$ma[2]; $y = (int)$ma[3];
            } else {
                $m = (int)$ma[1]; $d = (int)$ma[2]; $y = (int)$ma[3];
            }
        }
        elseif (preg_match("|^(\d+)\.(\d+)\.(\d+)\b|", $s, $ma)) {
            $d = (int)$ma[1]; $m = (int)$ma[2]; $y = (int)$ma[3];
        }
        elseif (preg_match("|^(\d+)\.(\d+)\b|", $s, $ma)) {
            $d = (int)$ma[1]; $m = (int)$ma[2];
            $a = explode(',', date('Y,m,d'));
            if( $m<(int)$a[1] || ($m==(int)$a[1] && $d<(int)$a[2]) ) $y = (int)$a[0]+1;
            else $y = (int)$a[0];
        }
        elseif (preg_match("|^(\d+)\/(\d+)\b|", $s, $ma))
        {
            if($formatDayFirst) {
                $d = (int)$ma[1]; $m = (int)$ma[2];
            } else {
                $m = (int)$ma[1]; $d = (int)$ma[2];
            }
            $a = explode(',', date('Y,m,d'));
            if( $m<(int)$a[1] || ($m==(int)$a[1] && $d<(int)$a[2]) ) $y = (int)$a[0]+1;
            else $y = (int)$a[0];
        }
        else return null;
        if ($y < 100) $y = 2000 + $y;
        elseif ($y < 1000 || $y > 2099) $y = 2000 + (int)substr((string)$y, -2);
        if ($m > 12) $m = 12;
        $maxdays = $this->daysInMonth($m,$y);
        if ($m < 10) $m = '0'.$m;
        if ($d > $maxdays) $d = $maxdays;
        elseif ($d < 10) $d = '0'.$d;
        return "$y-$m-$d";
    }

    private function prepareDuedate($duedate)
    {
        $lang = Lang::instance();

        $a = array( 'class'=>'', 'str'=>'', 'formatted'=>'', 'formattedlong'=>'', 'timestamp'=>0 );
        if ($duedate == '') {
            return $a;
        }
        $ad = explode('-', $duedate);
        $at = explode('-', date('Y-m-d'));
        $a['timestamp'] = mktime(0,0,0, (int)$ad[1], (int)$ad[2], (int)$ad[0]);
        $diff = mktime(0,0,0, (int)$ad[1], (int)$ad[2], (int)$ad[0]) - mktime(0,0,0, (int)$at[1], (int)$at[2], (int)$at[0]);

        if ($diff < -604800 && $ad[0] == $at[0]) { $a['class'] = 'past'; $a['str'] = formatDate3(Config::get('dateformatshort'), (int)$ad[0], (int)$ad[1], (int)$ad[2], $lang); }
        elseif ($diff < -604800)    { $a['class'] = 'past'; $a['str'] = formatDate3(Config::get('dateformat2'), (int)$ad[0], (int)$ad[1], (int)$ad[2], $lang); }
        elseif ($diff < -86400)     { $a['class'] = 'past'; $a['str'] = sprintf($lang->get('daysago'),ceil(abs($diff)/86400)); }
        elseif ($diff < 0)          { $a['class'] = 'past'; $a['str'] = $lang->get('yesterday'); }
        elseif ($diff < 86400)      { $a['class'] = 'today'; $a['str'] = $lang->get('today'); }
        elseif ($diff < 172800)     { $a['class'] = 'today'; $a['str'] = $lang->get('tomorrow'); }
        elseif ($diff < 691200)     { $a['class'] = 'soon'; $a['str'] = sprintf($lang->get('indays'),ceil($diff/86400)); }
        elseif ($ad[0] == $at[0])   { $a['class'] = 'future'; $a['str'] = formatDate3(Config::get('dateformatshort'), (int)$ad[0], (int)$ad[1], (int)$ad[2], $lang); }
        else                        { $a['class'] = 'future'; $a['str'] = formatDate3(Config::get('dateformat2'), (int)$ad[0], (int)$ad[1], (int)$ad[2], $lang); }

        #avoid short year
        $fmt = str_replace('y', 'Y', Config::get('dateformat2'));
        $a['formatted'] = formatTime($fmt, $a['timestamp']);
        $a['formattedlong'] = formatTime(Config::get('dateformat'), $a['timestamp']);

        return $a;
    }

    private function date2int($d) : int
    {
        if (!$d) return 33330000;
        $ad = explode('-', $d);
        $s = $ad[0];
        if (strlen($ad[1]) < 2) $s .= "0$ad[1]"; else $s .= $ad[1];
        if (strlen($ad[2]) < 2) $s .= "0$ad[2]"; else $s .= $ad[2];
        return (int)$s;
    }

    private function daysInMonth(int $m, int $y = 0)
    {
        if ($y == 0)  $y = (int)date('Y');
        $a = array(1=>31,(($y-2000)%4?28:29),31,30,31,30,31,31,30,31,30,31);
        if (isset($a[$m])) return $a[$m];
        else return 0;
    }

    private function getTagId($tag)
    {
        $db = DBConnection::instance();
        $id = $db->sq("SELECT id FROM {$db->prefix}tags WHERE name=?", array($tag));
        return $id ? $id : 0;
    }

    private function getOrCreateTag($name)
    {
        $db = DBConnection::instance();
        $tagId = $db->sq("SELECT id FROM {$db->prefix}tags WHERE name=?", array($name));
        if ($tagId)
            return array('id'=>$tagId, 'name'=>$name);

        $db->ex("INSERT INTO {$db->prefix}tags (name) VALUES (?)", array($name));
        return array(
            'id' => $db->lastInsertId(),
            'name' => $name
        );
    }

    private function prepareTags(string $tagsStr)
    {
        $tags = explode(',', $tagsStr);
        if (!$tags) return 0;

        $aTags = array('tags'=>array(), 'ids'=>array());
        foreach ($tags as $tag)
        {
            $tag = str_replace(array('^','#'),'',trim($tag));
            if ($tag == '') continue;

            $aTag = $this->getOrCreateTag($tag);
            if ($aTag && !in_array($aTag['id'], $aTags['ids'])) {
                $aTags['tags'][] = $aTag['name'];
                $aTags['ids'][] = $aTag['id'];
            }
        }
        return $aTags;
    }

    private function addTaskTags(int $taskId, array $tagIds, int $listId)
    {
        $db = DBConnection::instance();
        if (!$tagIds) return;
        foreach ($tagIds as $tagId) {
            $db->ex(
                "INSERT INTO {$db->prefix}tag2task (task_id,tag_id,list_id) VALUES (?,?,?)",
                array($taskId, $tagId, $listId)
            );
        }
    }

    private function parseSmartSyntax($title)
    {
        $a = [
            'prio' => 0,
            'title' => $title,
            'tags' => ''
        ];
        if ( preg_match("|^([-+]{1}\d+)(.+)|", $a['title'], $m) ) {
            $a['prio'] = (int) $m[1];
            if ( $a['prio'] < -1 ) $a['prio'] = -1;
            elseif ( $a['prio'] > 2 ) $a['prio'] = 2;
            $a['title'] = trim($m[2]);
        }
        $tags = [];
        $a['title'] = trim( preg_replace_callback(
            "/(?:^|\s+)#([^#\s]+)/",
            function ($matches) use (&$tags) {
                $tags[] = $matches[1];
                return '';
            },
            $a['title']
        ) );
        if (count($tags) > 0) {
            $a['tags'] = implode( ',' , $tags );
        }
        return $a;
    }

}