<?php

class YandexMapImage
{
    const ATTEMPTS_COUNT = 4;
    const ATTEMPTS_TIMEOUT = 10;
    const DOMAIN = 'http://static-maps.yandex.ru/1.x/';

    private $x;

    private $y;

    private $points = [];

    private $width;

    private $height;

    private $zoom = 10;

    private $imageFile = null;

    public function __construct($x, $y, $width, $height, $zoom = 10)
    {
        $this->x = $x;
        $this->y = $y;
        $this->width = (int)$width;
        $this->height = (int)$height;
        $this->zoom  = (int)$zoom;
    }

    public function addPoint($x, $y)
    {
        $this->points[] = [$x, $y];

        return $this;
    }

    private function getPointsString()
    {
        $points = empty($this->points) ? [[$this->x, $this->y]] : $this->points;
        $p = [];
        foreach ($points as $point) {
            $p[] = implode(',', $point);
        }
        return implode('~', $p);
    }

    private function buildUrl()
    {
        $params = [
            'll' => $this->x . ',' . $this->y,
            'size' => $this->width . ',' . $this->height,
            'z' => (int)$this->zoom,
            'l' => 'map',
            'pt' => $this->getPointsString(),
        ];

        return self::DOMAIN . '?' . http_build_query($params);
    }

    private function loadData($url)
    {
        $data = false;
        $attempt = self::ATTEMPTS_COUNT;
        do {
            if ($attempt != self::ATTEMPTS_COUNT) {
                sleep(self::ATTEMPTS_TIMEOUT);
            }
            try {
                $data = file_get_contents($url);
            } catch (\Exception $e) {
                $data = false;
            }
        } while (--$attempt > 0 && $data === false);

        return $data;
    }

    private function getTmpFile()
    {
        if (!empty($this->imageFile) && is_file($this->imageFile)) {
            return $this->imageFile;
        }

        $tmpDir = sys_get_temp_dir();
        do {
            $filename = $tmpDir.'/'.uniqid();
        } while (file_exists($filename));

        $data = $this->loadData($this->buildUrl());
        file_put_contents($filename, $data);

        return $this->imageFile = $filename;
    }

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