/*******************************************************************************
 *
 * Copyright (c) 2004-2010, Oracle Corporation.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *
 *
 *
 *
 *******************************************************************************/ 

package hudson.console;

import hudson.Extension;
import hudson.ExtensionList;
import hudson.ExtensionPoint;
import hudson.model.Hudson;
import hudson.model.Run;
import hudson.util.TimeUnit2;
import org.jvnet.tiger_types.Types;
import org.kohsuke.stapler.StaplerRequest;
import org.kohsuke.stapler.StaplerResponse;
import org.kohsuke.stapler.WebMethod;

import javax.servlet.ServletException;
import java.io.IOException;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.net.URL;

/**
 * Entry point to the {@link ConsoleAnnotator} extension point. This class
 * creates a new instance of {@link ConsoleAnnotator} that starts a new console
 * annotation session.
 *
 * <p> {@link ConsoleAnnotatorFactory}s are used whenever a browser requests
 * console output (as opposed to when the console output is being produced
 * — for that see {@link ConsoleNote}.)
 *
 * <p> {@link ConsoleAnnotator}s returned by {@link ConsoleAnnotatorFactory} are
 * asked to start from an arbitrary line of the output, because typically
 * browsers do not request the entire console output. Because of this,
 * {@link ConsoleAnnotatorFactory} is generally suitable for peep-hole local
 * annotation that only requires a small contextual information, such as keyword
 * coloring, URL hyperlinking, and so on.
 *
 * <p> To register, put
 *
 * @{@link Extension} on your {@link ConsoleAnnotatorFactory} subtype.
 *
 * <h2>Behaviour, JavaScript, and CSS</h2> <p> {@link ConsoleNote} can have
 * associated <tt>script.js</tt> and <tt>style.css</tt> (put them in the same
 * resource directory that you normally put Jelly scripts), which will be loaded
 * into the HTML page whenever the console notes are used. This allows you to
 * use minimal markup in code generation, and do the styling in CSS and perform
 * the rest of the interesting work as a CSS behaviour/JavaScript.
 *
 * @author Kohsuke Kawaguchi
 * @since 1.349
 */
public abstract class ConsoleAnnotatorFactory<T> implements ExtensionPoint {

    /**
     * Called when a console output page is requested to create a stateful
     * {@link ConsoleAnnotator}.
     *
     * <p> This method can be invoked concurrently by multiple threads.
     *
     * @param context The model object that owns the console output, such as
     * {@link Run}. This method is only called when the context object if
     * assignable to {@linkplain #type() the advertised type}.
     * @return null if this factory is not going to participate in the
     * annotation of this console.
     */
    public abstract ConsoleAnnotator newInstance(T context);

    /**
     * For which context type does this annotator work?
     */
    public Class type() {
        Type type = Types.getBaseClass(getClass(), ConsoleAnnotator.class);
        if (type instanceof ParameterizedType) {
            return Types.erasure(Types.getTypeArgument(type, 0));
        } else {
            return Object.class;
        }
    }

    /**
     * Returns true if this descriptor has a JavaScript to be inserted on
     * applicable console page.
     */
    public boolean hasScript() {
        return getResource("/script.js") != null;
    }

    public boolean hasStylesheet() {
        return getResource("/style.css") != null;
    }

    private URL getResource(String fileName) {
        Class c = getClass();
        return c.getClassLoader().getResource(c.getName().replace('.', '/').replace('$', '/') + fileName);
    }

    /**
     * Serves the JavaScript file associated with this console annotator
     * factory.
     */
    @WebMethod(name = "script.js")
    public void doScriptJs(StaplerRequest req, StaplerResponse rsp) throws IOException, ServletException {
        rsp.serveFile(req, getResource("/script.js"), TimeUnit2.DAYS.toMillis(1));
    }

    @WebMethod(name = "style.css")
    public void doStyleCss(StaplerRequest req, StaplerResponse rsp) throws IOException, ServletException {
        rsp.serveFile(req, getResource("/style.css"), TimeUnit2.DAYS.toMillis(1));
    }

    /**
     * All the registered instances.
     */
    public static ExtensionList<ConsoleAnnotatorFactory> all() {
        return Hudson.getInstance().getExtensionList(ConsoleAnnotatorFactory.class);
    }
}