<?php
error_reporting(-1);

define('SUBWAY', 'sub');
define('FOOT', 'foot');
define('BUS', 'bus');

$transportName = array(
    SUBWAY  =>  'едешь на метро',
    FOOT    =>  'идешь пешком',
    BUS     =>  'едешь на автобусе'
);

$startPoint = 'pet'; // Петроградская
$endPoint = 'nov'; // Новая Голландия

$pointNames = array(
    'pet'   =>  'ст. м. Петроградская',
    'chk'   =>  'ст. м. Чкаловская',
    'gor'   =>  'ст. м. Горьковская',
    'spo'   =>  'ст. м. Спортивная',
    'vas'   =>  'ст. м. Василеостровская',
    'kre'   =>  'Петропавловская крепость',
    'let'   =>  'Летний сад',
    'dvo'   =>  'Дворцовая площадь',
    'isa'   =>  'Исакиевский собор',
    'nov'   =>  'Новая Голландия',
    'ras'   =>  'Дом Раскольникова',
    'gos'   =>  'Гостиный Двор',
    'sen'   =>  'Сенная Площадь',
    'vla'   =>  'ст. м. Владимирская',
    'vit'   =>  'Витебский вокзал',
    'teh'   =>  'Технологический Институт'
);

$paths = array(
    'pet'   =>  array(
        'chk'   =>  canGet(10, BUS),
        'gor'   =>  canGet(3, SUBWAY)
    ),

    'chk'   =>  array(
        'pet'   =>  canGet(10, BUS),
        'spo'   =>  canGet(3, SUBWAY)
    ),

    'gor'   =>  array(
        'pet'   =>  canGet(3, BUS),
        'kre'   =>  canGet(5, FOOT),
        'gos'   =>  canGet(6, SUBWAY)
    ),

    'spo'   =>  array(
        'chk'   =>  canGet(3, SUBWAY),
        'vas'   =>  canGet(10, BUS),
        'sen'   =>  canGet(7, SUBWAY)
    ),

    'vas'   =>  array(
        'spo'   =>  canGet(10, BUS),
        'gos'   =>  canGet(7, SUBWAY),
        'nov'   =>  canGet(11, FOOT)
    ),

    'kre'   =>  array(
        'gor'   =>  canGet(5, FOOT)
    ),

    'let'   =>  array(
        'dvo'   =>  canGet(6, FOOT),
        'gos'   =>  canGet(7, FOOT)
    ),

    'dvo'   =>  array(
        'isa'   =>  canGet(6, FOOT),
        'gos'   =>  canGet(6, FOOT),
        'let'   =>  canGet(6, FOOT)
    ),

    'isa'   =>  array(
        'dvo'   =>  canGet(6, FOOT),
        'nov'   =>  canGet(5, FOOT)
    ),

    'nov'   =>  array(
        'vas'   =>  canGet(11, FOOT),
        'isa'   =>  canGet(5, FOOT),
        'ras'   =>  canGet(7, BUS)
    ),

    'ras'   =>  array(
        'nov'   =>  canGet(7, BUS),
        'sen'   =>  canGet(3, FOOT)
    ),

    'gos'   =>  array(
        'vas'   =>  canGet(7, SUBWAY),
        'sen'   =>  canGet(3, SUBWAY),
        'dvo'   =>  canGet(6, FOOT),
        'gor'   =>  canGet(6, SUBWAY),
        'let'   =>  canGet(7, FOOT),
        'vla'   =>  canGet(7, FOOT)        
    ),

    'sen'   =>  array(
        'ras'   =>  canGet(3, FOOT),
        'spo'   =>  canGet(7, SUBWAY),
        'gos'   =>  canGet(3, SUBWAY),
        'vla'   =>  canGet(4, SUBWAY),
        'vit'   =>  canGet(2, SUBWAY),
        'teh'   =>  canGet(3, SUBWAY)
    ),

    'vla'   =>  array(
        'sen'   =>  canGet(4, SUBWAY),
        'gos'   =>  canGet(7, FOOT),
        'vit'   =>  canGet(3, SUBWAY)
    ),

    'vit'   =>  array(
        'sen'   =>  canGet(2, SUBWAY),
        'teh'   =>  canGet(2, SUBWAY),
        'vla'   =>  canGet(3, SUBWAY)
    ),

    'teh'   =>  array(
        'sen'   =>  canGet(3, SUBWAY),
        'vit'   =>  canGet(2, SUBWAY)        
    )
);

function canGet($time, $byWhat) {
    return array('time'     =>  $time, 'by' =>  $byWhat);
}

function make1step($paths, $pathDone, $time, $point, $target){	
	$result=array();
	$result['time'] = 0;
	$result['path'] = $pathDone;
	$result['time'] = $time;
	if(isset($paths[$point][$target])){
		$result['time'] += $paths[$point][$target]['time'];
		$result['path'][] = $target;
		return $result;
	}
	else
		foreach($paths[$point] as $station => $values){
				$step = make1step($paths, $result['path'], $result['time'], $station, $target);
				//var_dump($step);
				if(in_array($step['path'][count($step['path'])-1], $result['path'])) continue;
				$result['path'][] = $step['path'][count($step['path'])-1];
				$result['time'] += $step['time'];
				//if ($step['path'][count($step['path'])-1] == $target) break;
		}
	
	}
$output="Начальная точка: ". $pointNames[$startPoint] . "\n";
$pathDone = array(); 
$pathDone[]=$startPoint;
$time = 0;
$onestep = make1step($paths, $pathDone, $time, 'pet', 'spo');
for ($i=1; $i<count($onestep['path']); $i++){
	$output .="Из нее ". 
	$transportName[$paths[$onestep['path'][$i-1]][$onestep['path'][$i]]['by']] 
	. " до точки " . $pointNames[$onestep['path'][$i]]  . " " 
	. $paths[$onestep['path'][$i-1]][$onestep['path'][$i]]['time']  
	. " мин \n";	
}
echo $output;
echo "Всего:" . $onestep['time'] . " мин.";