/*******************************************************************************
 *
 * 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:
 * 
 *    Kohsuke Kawaguchi
 *
 *
 *******************************************************************************/ 

package hudson.fsp;

import hudson.scm.PollingResult;
import hudson.scm.SCM;
import hudson.scm.ChangeLogParser;
import hudson.scm.SCMDescriptor;
import hudson.scm.SCMRevisionState;
import hudson.model.AbstractProject;
import hudson.model.TaskListener;
import hudson.model.AbstractBuild;
import hudson.model.BuildListener;
import hudson.model.Hudson;
import hudson.model.Result;
import hudson.model.PermalinkProjectAction.Permalink;
import hudson.Launcher;
import hudson.FilePath;
import hudson.WorkspaceSnapshot;
import hudson.PermalinkList;

import java.io.IOException;
import java.io.File;

import org.kohsuke.stapler.DataBoundConstructor;

/**
 * {@link SCM} that inherits the workspace from another build through
 * {@link WorkspaceSnapshot}
 *
 * @author Kohsuke Kawaguchi
 */
public class WorkspaceSnapshotSCM extends SCM {

    /**
     * The job name from which we inherit the workspace.
     */
    //TODO: review and check whether we can do it private
    public String jobName;
    /**
     * The permalink name indicating the build from which to inherit the
     * workspace.
     */
    public String permalink;

    @DataBoundConstructor
    public WorkspaceSnapshotSCM(String jobName, String permalink) {
        this.jobName = jobName;
        this.permalink = permalink;
    }

    public String getJobName() {
        return jobName;
    }

    public String getPermalink() {
        return permalink;
    }

    /**
     * {@link Exception} indicating that the resolution of the job/permalink
     * failed.
     */
    private final class ResolvedFailedException extends Exception {

        private ResolvedFailedException(String message) {
            super(message);
        }
    }

    private static class Snapshot {

        final WorkspaceSnapshot snapshot;
        final AbstractBuild<?, ?> owner;

        private Snapshot(WorkspaceSnapshot snapshot, AbstractBuild<?, ?> owner) {
            this.snapshot = snapshot;
            this.owner = owner;
        }

        void restoreTo(FilePath dst, TaskListener listener) throws IOException, InterruptedException {
            snapshot.restoreTo(owner, dst, listener);
        }
    }

    /**
     * Obtains the {@link WorkspaceSnapshot} object that this {@link SCM} points
     * to, or throws {@link ResolvedFailedException} upon failing.
     *
     * @return never null.
     */
    public Snapshot resolve() throws ResolvedFailedException {
        Hudson h = Hudson.getInstance();
        AbstractProject<?, ?> job = h.getItemByFullName(jobName, AbstractProject.class);
        if (job == null) {
            if (h.getItemByFullName(jobName) == null) {
                AbstractProject nearest = AbstractProject.findNearest(jobName);
                throw new ResolvedFailedException(Messages.WorkspaceSnapshotSCM_NoSuchJob(jobName, nearest.getFullName()));
            } else {
                throw new ResolvedFailedException(Messages.WorkspaceSnapshotSCM_IncorrectJobType(jobName));
            }
        }

        PermalinkList permalinks = job.getPermalinks();
        Permalink p = permalinks.get(permalink);
        if (p == null) {
            throw new ResolvedFailedException(Messages.WorkspaceSnapshotSCM_NoSuchPermalink(permalink, jobName));
        }

        AbstractBuild<?, ?> b = (AbstractBuild<?, ?>) p.resolve(job);
        if (b == null) {
            throw new ResolvedFailedException(Messages.WorkspaceSnapshotSCM_NoBuild(permalink, jobName));
        }

        WorkspaceSnapshot snapshot = b.getAction(WorkspaceSnapshot.class);
        if (snapshot == null) {
            throw new ResolvedFailedException(Messages.WorkspaceSnapshotSCM_NoWorkspace(jobName, permalink));
        }

        return new Snapshot(snapshot, b);
    }

    public SCMRevisionState calcRevisionsFromBuild(AbstractBuild<?, ?> build, Launcher launcher, TaskListener listener) throws IOException, InterruptedException {
        return null;
    }

    protected PollingResult compareRemoteRevisionWith(AbstractProject project, Launcher launcher, FilePath workspace, TaskListener listener, SCMRevisionState baseline) throws IOException, InterruptedException {
        return PollingResult.NO_CHANGES;
    }

    public boolean checkout(AbstractBuild build, Launcher launcher, FilePath workspace, BuildListener listener, File changelogFile) throws IOException, InterruptedException {
        try {
            resolve().restoreTo(workspace, listener);
            return true;
        } catch (ResolvedFailedException e) {
            listener.error(e.getMessage()); // stack trace is meaningless
            build.setResult(Result.FAILURE);
            return false;
        }
    }

    public ChangeLogParser createChangeLogParser() {
        return null;
    }

    public SCMDescriptor<?> getDescriptor() {
        return null;
    }
}