/* Copyright (c) 2013-2014 Boundless and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Distribution License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/org/documents/edl-v10.html
 *
 * Contributors:
 * Gabriel Roldan (Boundless) - initial implementation
 */
package org.locationtech.geogig.web.api.commands;

import java.util.Iterator;

import javax.annotation.Nullable;

import org.locationtech.geogig.api.Context;
import org.locationtech.geogig.api.ObjectId;
import org.locationtech.geogig.api.RevCommit;
import org.locationtech.geogig.api.plumbing.diff.DiffEntry;
import org.locationtech.geogig.api.porcelain.CommitOp;
import org.locationtech.geogig.api.porcelain.DiffOp;
import org.locationtech.geogig.api.porcelain.NothingToCommitException;
import org.locationtech.geogig.web.api.AbstractWebAPICommand;
import org.locationtech.geogig.web.api.CommandContext;
import org.locationtech.geogig.web.api.CommandResponse;
import org.locationtech.geogig.web.api.CommandSpecException;
import org.locationtech.geogig.web.api.ResponseWriter;

import com.google.common.base.Optional;

/**
 * Interface for the Commit operation in GeoGig.
 * 
 * Web interface for {@link CommitOp}
 */
public class Commit extends AbstractWebAPICommand {

    String message;

    boolean all;

    private Optional<String> authorName = Optional.absent();

    private Optional<String> authorEmail = Optional.absent();

    /**
     * Mutator for the message variable
     * 
     * @param message - the message for this commit
     */
    public void setMessage(String message) {
        this.message = message;
    }

    /**
     * Mutator for the all option
     * 
     * @param all - true to the commit everything in the working tree
     */
    public void setAll(boolean all) {
        this.all = all;
    }

    /**
     * @param authorName the author of the merge commit
     */
    public void setAuthorName(@Nullable String authorName) {
        this.authorName = Optional.fromNullable(authorName);
    }

    /**
     * @param authorEmail the email of the author of the merge commit
     */
    public void setAuthorEmail(@Nullable String authorEmail) {
        this.authorEmail = Optional.fromNullable(authorEmail);
    }

    /**
     * Runs the command and builds the appropriate response
     * 
     * @param context - the context to use for this command
     * @throws CommandSpecException
     */
    @Override
    public void run(CommandContext context) {
        if (this.getTransactionId() == null) {
            throw new CommandSpecException(
                    "No transaction was specified, commit requires a transaction to preserve the stability of the repository.");
        }
        final Context geogig = this.getCommandLocator(context);
        RevCommit commit;
        try {
            commit = geogig.command(CommitOp.class)
                    .setAuthor(authorName.orNull(), authorEmail.orNull()).setMessage(message)
                    .setAllowEmpty(true).setAll(all).call();
            assert commit != null;
        } catch (NothingToCommitException noChanges) {
            context.setResponseContent(CommandResponse.warning("Nothing to commit"));
            commit = null;
        } catch (IllegalStateException e) {
            context.setResponseContent(CommandResponse.warning(e.getMessage()));
            commit = null;
        }
        if (commit != null) {
            final RevCommit commitToWrite = commit;
            final ObjectId parentId = commit.parentN(0).or(ObjectId.NULL);
            final Iterator<DiffEntry> diff = geogig.command(DiffOp.class).setOldVersion(parentId)
                    .setNewVersion(commit.getId()).call();

            context.setResponseContent(new CommandResponse() {
                @Override
                public void write(ResponseWriter out) throws Exception {
                    out.start();
                    out.writeCommitResponse(commitToWrite, diff);
                    out.finish();
                }
            });
        }
    }
}