/*******************************************************************************
 *
 * Copyright (c) 2004-2009, 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.diagnosis;

import hudson.model.AdministrativeMonitor;
import hudson.model.Hudson;
import hudson.model.AbstractModelObject;
import hudson.Extension;
import hudson.ExtensionPoint;
import hudson.ExtensionList;
import org.kohsuke.stapler.HttpResponse;
import org.kohsuke.stapler.HttpResponses;
import org.kohsuke.stapler.QueryParameter;

import java.io.IOException;
import java.util.List;

/**
 * Monitors the disk usage of <tt>HUDSON_HOME</tt>, and if it's almost filled
 * up, warn the user.
 *
 * @author Kohsuke Kawaguchi
 */
@Extension
public final class HudsonHomeDiskUsageMonitor extends AdministrativeMonitor {

    /**
     * Value updated by {@link HudsonHomeDiskUsageChecker}.
     */
    /*package*/ boolean activated;

    public HudsonHomeDiskUsageMonitor() {
        super("hudsonHomeIsFull");
    }

    public boolean isActivated() {
        return activated;
    }

    /**
     * Depending on whether the user said "yes" or "no", send him to the right
     * place.
     */
    public HttpResponse doAct(@QueryParameter String no) throws IOException {
        if (no != null) {
            disable(true);
            return HttpResponses.redirectViaContextPath("/manage");
        } else {
            return HttpResponses.redirectToDot();
        }
    }

    public List<Solution> getSolutions() {
        return Solution.all();
    }

    /**
     * Binds a solution to the URL.
     */
    public Solution getSolution(String id) {
        for (Solution s : Solution.all()) {
            if (s.id.equals(id)) {
                return s;
            }
        }
        return null;
    }

    /**
     * Short cut for getting the singleton instance.
     */
    public static HudsonHomeDiskUsageMonitor get() {
        return all().get(HudsonHomeDiskUsageMonitor.class);
    }

    /**
     * Extension point for suggesting solutions for full HUDSON_HOME.
     *
     * <h3>Views</h3> <dl> <dt>message.jelly</dt> <dd> This view is rendered
     * inside an LI tag as a possible solution to the full HUDSON_HOME problem.
     * </dd> </dl>
     */
    public static abstract class Solution extends AbstractModelObject implements ExtensionPoint {

        /**
         * Human-readable ID of this monitor, which needs to be unique within
         * the system.
         *
         * <p> This ID is used to remember persisted setting for this monitor,
         * so the ID should remain consistent beyond the Hudson JVM lifespan.
         */
        public final String id;

        protected Solution(String id) {
            this.id = id;
        }

        protected Solution() {
            this.id = this.getClass().getName();
        }

        /**
         * Returns the URL of this monitor, relative to the context path.
         */
        public String getUrl() {
            return HudsonHomeDiskUsageMonitor.get().getUrl() + "/solution/" + id;
        }

        /**
         * All registered {@link Solution}s.
         */
        public static ExtensionList<Solution> all() {
            return Hudson.getInstance().getExtensionList(Solution.class);
        }
    }
}