<?php

/**
 * Method not implemented.
 */
class NotImplementedException extends BadMethodCallException {}

/**
 * Resource was not found on the filesystem.
 */
class ResourceNotFoundException extends Exception {}

/**
 * Resource interface. Vsi resoursi (JS, CSS) ga morajo implementirati.
 * (in ga, posredno preko BaseResource razreda).
 */
interface Resource {
    static function printResources();
}

/**
 * BaseResource class. Opravlja delo, skupno vsem resource classom.
 * Recimo, dodajanje resoursa preko URL, dodajanje resoursa preko aliasa,
 * kompresija, etc.
 * BaseResource sam po sebi ni uporaben, torej je nesmiselno klicati
 * recimo BaseResource::add() itd., ker se bo BaseResource::print() sesu.
 */
class BaseResource implements Resource {

    /**
     * @var $RESOURCE_DIR Root direktorij z resoursi.
     */
    protected static $RESOURCE_DIR = "/keje/keje";

    /**
     * @var $resources Seznam resoursov.
     */
    protected static $resources = array();

    /**
     * Dodajanje resoursa.
     *
     * @param string $url  URL resoursa ali njegov veljavni alias.
     * @return void
     */
    public static function add($url) {
        if (isset(static::$aliases[$url])) {
            $url = static::$aliases[$url];
        }

        static::$resources[] = $url;
    }

    /**
     * Racunanje poti datoteke, ki vsebuje trenutne resurse.
     *
     * @return string
     */
    protected static function computeHashFileName() {
        $sortedResources = sort(static::$resources, SORT_STRING);
        $hash = md5(join(",", $sortedResources));
        $fileName = sprintf("%s/%s/%s.%s", static::$RESOURCE_DIR, static::$extension, $hash, static::$extension);
        return $fileName;
    }

    /**
     * Zdruzevanje vseh resursov (ki niso http) v eno datoteko.
     *
     * @throws ResourceNotFoundException Ce resurs ne obstaja.
     * @return string
     */
    public static function compress() {
        $fileName = static::computeHashFileName();
        $contents = "";
        foreach (static::$resources as $res) {
            if (substr($res, 0, 8) != "http://") {
                $resourceFileName = sprintf("%s/%s/%s", static::$RESOURCE_DIR, static::$extension, $res);
                if (!file_exists($resourceFileName))
                    throw new ResourceNotFoundException(sprintf("Resource file for <%s> not found (looking for <%s>).",  $res, $resourceFileName));
                $content .= sprintf("%s\n", file_get_contents($resourceFileName));
            }
        }

        file_put_contents($fileName, $content);
    }

    /**
     * Generiranje HTML includov za kompresirane resurse (ena datoteka).
     * Ce datoteka ne obstaja, jo zgeneriramo (lahko casovno potratno).
     *
     * @throws ResourceNotFoundException Ce kateri izmed resursov med kompresiranjem ne obstaja.
     * @return string
     */
    public static function printCompressed() {
        $hashFileName = static::computeHashFileName();
        if (!file_exists($hashFileName)) {
            static::compress();
        }

        $tmp = static::$resources;
        static::$resources = array($hashFileName);
        $out = static::printResources();
        static::$resources = $tmp;
        return $out;
    }

    /**
     * Izpise vse HTML include za resurse.
     *
     * @return string
     */
    public static function print() {
        static::printResources();
    }

    /**
     * Metoda, ki jo podrazred mora povoziti. Izpise include tage za vse resurse.
     * @throws NotImplementedException
     */
    static function printResources() {
        throw new NotImplementedException("Calling: you're doing it wrong.");
    }
}

/**
 * Resource class za vse JavaScript datoteke.
 */
class JS extends BaseResource {

    /**
     * @var $extension
     */
    protected static $extension = "js";

    /**
     * @var $aliases Aliasi JavaScriptov.
     */
    protected static $aliases = [
        "jquery" => "http://jquerasldsDSADASDAS.COM",
        "jquery-ui-custom" => "/scripts/jquery.dscadsa"
    ];

    /**
     * Izpise <script> tage za vse JavaScripte.
     *
     * @return string
     */
    public static function printResources() {
        $out = "";
        foreach (static::$resources as $script) {
            $out .= sprintf("<script type=\"text/javascript\" src=\"%s\"></script>\n", $script);
        }
        return $out;
    }
}

/**
 * Resource class za vse CSS datoteke.
 */
class CSS extends BaseResource {

    /**
     * @var $extension
     */
    protected static $extension = "css";

    /**
     * @var $aliases Aliasi CSS-jev.
     */
    protected static $aliases = [
        "dashboard-main" => "http://jquerasldsDSADASDAS.COM",
        "jquery-ui-custom" => "/scripts/jquery.dscadsa"
    ];

    /**
     * Izpise <link> tage za vse CSS-je.
     *
     * @return string
     */
    public static function printResources() {
        $out = "";
        foreach (static::$resources as $script) {
            $out .= sprintf("<link rel=\"stylesheet\" href=\"%s\"></script>\n", $script);
        }
        return $out;
    }
}



// Primer uporabe.

JS::add('jquery');
JS::add('jquery-ui');

echo JS::print();

try {
    echo JS::printCompressed();
} catch (ResourceNotFoundException $e) {
    // $logger->report(.......); ... pac, logaj.
    echo JS::print();
}