<?php

namespace Artmark\Assets;

/**
 * Description of Asset
 *
 * @author Andrey Pokidov <pokidov@e-traffic.ru>
 */
class Asset
{
    const TYPE_JAVASCRIPT = 'js';
    const TYPE_CSS = 'css';
    
    const POSITION_HEAD = 'head';
    const POSITION_TOP = 'top';
    const POSITION_BOTTOM = 'bottom';
    
    private $name = '';
    private $type = self::TYPE_JAVASCRIPT;
    private $position = self::POSITION_HEAD;
    private $url = '';
    private $version = '';
    

    /**
     * Создаёт новый объекс Script, описывающий данные о скрипте
     * @param string $url URL скрипта
     * @param string|int $version Версия скрипта
     * @param string $type Тип скрипта, может принимать одно из значений Script::TYPE_JAVASCRIPT или Script::TYPE_CSS
     * @param string $position Место скрипта в коде страницы, может принимать одно из значений:
     * <ul>
     *  <li>Script::POSITION_HEAD в секции &lt;head&gt;...&lt;/head&gt;</li>
     *  <li>Script::POSITION_TOP сразу после открывающего тега &lt;body&gt;</li>
     *  <li>Script::POSITION_BOTTOM непосредственно перед закрывающим тегом &lt;/body&gt;</li>
     * </ul>
     */
    public function __construct($name, $url, $version, $type = self::TYPE_JAVASCRIPT, $position = self::POSITION_HEAD)
    {
        self::checkName($name);
        self::checkUrl($url);
        self::checkVersion($url);
        self::checkAssetType($type);
        self::checkAssetPosition($position);
        
        $this->name = self::correctName($name);
        $this->url = trim($url);
        $this->version = is_string($version) ? trim($version) : $version;
        $this->type = $type;
        $this->position = $position;
    }
    
    public function name()
    {
        return $this->name;
    }
    
    public function type()
    {
        return $this->type;
    }
    
    public function isJavaScript()
    {
        return $this->type == self::TYPE_JAVASCRIPT;
    }
    
    public function isCss()
    {
        return $this->type == self::TYPE_CSS;
    }
    
    public function position()
    {
        return $this->position;
    }
    
    public function isAtHead()
    {
        return $this->position == self::POSITION_HEAD;
    }
    
    public function isAtTop()
    {
        return $this->position == self::POSITION_TOP;
    }
    
    public function isAtBottom()
    {
        return $this->position == self::POSITION_BOTTOM;
    }
    
    public function url()
    {
        return $this->url;
    }
    
    public function urlWithVersion()
    {
        if (!$this->hasVersion())
        {
            return $this->url;
        }
        
        return $this->url . (strpos($this->url, '?') === false ? '?' : '&') . 'v=' . urlencode($this->version);
    }
    
    public function hasVersion()
    {
        return !empty($this->version);
    }
    
    public function version()
    {
        return $this->version;
    }

    
    public static function correctName($name)
    {
        return strtolower(trim(strval($name)));
    }
    
    public static function checkName($name)
    {
        if (!is_string($name)) {
            throw new AssetException('Incorrect name type: `' . gettype($name) . '`, the name of an asset must be a string');
        }
        
        if (trim($name) == '') {
            throw new AssetException('The name of an asset cannot be an empty string');
        }
    }
    
    public static function checkUrl($url)
    {
        if (!is_string($url)) {
            throw new AssetException('Incorrect URL type: `' . gettype($url) . '`, the URL of an asset must be a string');
        }
        
        if (trim($url) == '') {
            throw new AssetException('The URL of an asset cannot be an empty string');
        }
    }
    
    public static function checkVersion($verison)
    {
        if (!is_string($verison) && !is_int($verison)) {
            throw new AssetException('Incorrect version type: `' . gettype($verison) . '`, the version of an asset must be a string or an integer number');
        }
    }
    
    public static function checkAssetType($type)
    {
        if ($type != self::TYPE_JAVASCRIPT && $type != self::TYPE_CSS) {
            throw new AssetException('Incorrect asset type: `' . $type . '`');
        }
    }
    
    public static function checkAssetPosition($position)
    {
        if ($position != self::POSITION_HEAD && $position != self::POSITION_TOP && $position != self::POSITION_BOTTOM) {
            throw new AssetException('Incorrect asset position: `' . $position . '`');
        }
    }
}