<?php

define('X', 0);
define('Y', 1);

class PvsGenerator
{

    public static function generate()
    {

        if (!Module::isAvailable('locations')) {
           die('sorry, but the locations module is required');
        }


        /* get all rooms */
        $rooms = array();
        $ret = Database::simpleQuery(
                'SELECT l.locationid, l.locationname, lr.managerip, lr.tutoruuid, m.clientip as tutorip '
                .'FROM location l '
		          .'INNER JOIN location_roomplan lr ON (l.locationid = lr.locationid)'
		          .'LEFT JOIN machine m ON (lr.tutoruuid = m.machineuuid)');
        while ($row = $ret->fetch(PDO::FETCH_ASSOC)) {
            if (Location::isLeaf($row['locationid'])) { // TODO: This creates extra queries, optimize?
					$row['locationname'] = str_replace(',', ';', $row['locationname']); // comma probably not the best sep here
                $rooms[] = $row;
            }
        }
        /* collect names */
        $roomNames = array();

        foreach($rooms as $room) {
            $roomNames[] = $room['locationname'];
        }

        /* add [General]-block */
        $config  = "[General]\n";
        $config .= 'rooms=' . implode(', ', $roomNames) . "\n";
        $config .= "allowClientQuit=True\n"; // TODO: remove this
        $config .= "showLockDesktopButton=True\n"; // TODO: Make this configurable (or not)
        $config .= "\n\n";

        /* foreach room generate room-block */
        foreach($rooms as $room) {
            $config .= PvsGenerator::generateRoomBlock($room);
            $config .= "\n";
        }

        return $config;
    }

    private static function generateRoomBlock($room)
    {
        $out = '[' . $room['locationname'] . "]\n";


        /* find all clients in that room */
        $machines = PvsGenerator::getMachines($room['locationid']);
        /* manager */
        $mgr = $room['managerip'];
        $tutor = $room['tutorip'];
        if ($mgr) {
            $out .= 'mgrIP=' . $mgr . "\n";
        }
        /* tutor */
        if ($tutor) {
            $out .= 'tutorIP=' . $tutor . "\n";
        }

        /* grid */
        $out .= PvsGenerator::generateGrid($machines);

        return $out;
    }

    private static function generateGrid($machines)
    {
        $out = "";

        /* this is a virtual grid, we first need this to do some optimizations */
        $grid = array();
        /* add each contained client with position and ip */
        foreach ($machines as $machine) {
            $grid[$machine['clientip']] = [$machine['gridCol'], $machine['gridRow']];
        }
        /* find bounding box */
        PvsGenerator::boundingBox($grid, $minX, $minY, $maxX, $maxY);
        $clientSizeX = 4; /* TODO: optimize */
        $clientSizeY = 4; /* TODO: optimize */
        $sizeX = max($maxX - $minX + $clientSizeX, 1); /* never negative */
        $sizeY = max($maxY - $minY + $clientSizeY, 1); /* and != 0 to avoid divide-by-zero in pvsmgr */

        /* zoom all clients into bounding box */
        foreach ($grid as $ip => $pos) {
            $newX = $grid[$ip][X] - $minX;
            $newY = $grid[$ip][Y] - $minY;
            $grid[$ip] =  [$newX, $newY];
        }

        $out .= "gridSize=@Size($sizeX $sizeY)\n";
        $out .= "clientSize=@Size($clientSizeX $clientSizeY)\n";
        $out .= "client\\size=" . count($grid) . "\n";

        $i = 1;
        foreach ($grid as $ip => $pos) {
            $out .= "client\\" . $i   . "\\ip=$ip\n";
            $out .= "client\\" . $i++ . "\\pos=@Point(" . $pos[X] . ' ' . $pos[Y] . ")\n";
        }

        return $out;

    }


    private static function getMachines($roomid) {
        $ret = Database::simpleQuery(
            'SELECT clientip, position FROM machine WHERE locationid = :locationid',
            ['locationid' => $roomid]);

        $machines = array();

		while ($row = $ret->fetch(PDO::FETCH_ASSOC)) {
            $position = json_decode($row['position'], true);

            $machine = array();
            $machine['clientip'] = $row['clientip'];
            $machine['gridRow'] = $position['gridRow'];
            $machine['gridCol'] = $position['gridCol'];
            $machine['tutor'] = false; /* TODO: find out if machine is default tutor */
            $machine['manager'] = false; /* TODO: find out if machine is manager */

            $machines[] = $machine;
        }

        return $machines;

    }

    private static function boundingBox($grid, &$minX, &$minY, &$maxX, &$maxY ) {
        $minX =  PHP_INT_MAX; /* PHP_INT_MIN is only avaiable since PHP 7 */
        $maxX = ~PHP_INT_MAX;
        $minY =  PHP_INT_MAX;
        $maxY = ~PHP_INT_MAX;

        foreach ($grid as $pos) {
            $minX = min($minX, $pos[X]);
            $maxX = max($maxX, $pos[X]);
            $minY = min($minY, $pos[Y]);
            $maxY = max($maxY, $pos[Y]);
        }
    }

}