<?php

namespace Artmark\Assets;

/**
 * Description of AssetManager
 *
 * @author Andrey Pokidov <pokidov@e-traffic.ru>
 */
class AssetManager
{
    /**
     * @var AssetManager
     */
    private static $manager = null;
    
    /**
     *
     * @var Asset[]
     */
    private $assets = [];

    private function __construct()
    {
    }
    
    /**
     * 
     * @return AssetManager
     */
    public static function instance()
    {
        if (is_null(self::$manager)) {
            self::$manager = new AssetManager();
        }
        
        return self::$manager;
    }
    
    /**
     * 
     * @return $this
     */
    public function resetAssets()
    {
        $this->assets = [];
        
        return $this;
    }
    
    /**
     * 
     * @param string $name
     * @return $this
     */
    public function loadCollection($name)
    {
        $assets = config('assets.' . $name);

        if (!is_array($assets) || count($assets) == 0) {
            return $this;
        }
        
        foreach ($assets as $name => $assetInfo) {
            $this->loadAsset($name, $assetInfo);
        }
        
        return $this;
    }
    
    private function loadAsset($name, $assetInfo)
    {
        if (!is_array($assetInfo) || !array_key_exists('type', $assetInfo) || !array_key_exists('path', $assetInfo)) {
            return;
        }
        
        $version = array_key_exists('version', $assetInfo) ? $assetInfo['version'] : '';
        $position = array_key_exists('position', $assetInfo) ? $assetInfo['position'] : Asset::POSITION_HEAD;
        
        $this->pushAsset(new Asset($name, $assetInfo['path'], $version, $assetInfo['type'], $position));
    }
    
    /**
     * 
     * @param string $name
     * @return boolean
     */
    public function has($name)
    {
        return array_key_exists(Asset::correctName($name), $this->assets);
    }

    /**
     * 
     * @param string $name
     * @return Asset
     */
    public function get($name)
    {
        $correctedName = Asset::correctName($name);
        return array_key_exists($correctedName, $this->assets) ? $this->assets[$correctedName] : null;
    }
    
    /**
     * 
     * @param Asset $asset
     * @return $this
     */
    public function pushAsset(Asset $asset)
    {
        $this->assets[$asset->name()] = $asset;
        return $this;
    }
    
    /**
     * 
     * @param string $name
     * @param string $url
     * @param string|int $version
     * @param string $position
     * @return $this
     */
    public function setStyleSheet($name, $url, $version = '', $position = Asset::POSITION_HEAD)
    {
        $asset = new Asset($name, $url, $version, Asset::TYPE_CSS, $position);
        $this->pushAsset($asset);
        return $this;
    }
    
    /**
     * 
     * @param string $name
     * @param string $url
     * @param string|int $version
     * @param string $position
     * @return $this
     */
    public function setJavaScript($name, $url, $version = '', $position = Asset::POSITION_HEAD)
    {
        $asset = new Asset($name, $url, $version, Asset::TYPE_JAVASCRIPT, $position);
        $this->pushAsset($asset);
        return $this;
    }
    
    /**
     * 
     * @param string $position
     * @param string $type
     * @return Asset[]
     */
    public function getAssetsFor($position, $type)
    {
        if (!is_string($position) || !is_string($type)) {
            return [];
        }
        
        $assets = [];
        
        foreach ($this->assets as $asset) {
            if ($asset->type() == $type && $asset->position() == $position) {
                $assets[] = $asset;
            }
        }
        
        return $assets;
    }
}