/*
 * Copyright (C) 2016, Google Inc. and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.eclipse.jgit.internal.ketch;

import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.eclipse.jgit.internal.ketch.Proposal.State.EXECUTED;
import static org.eclipse.jgit.internal.ketch.Proposal.State.QUEUED;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.NOT_ATTEMPTED;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.REJECTED_OTHER_REASON;

import java.io.IOException;
import java.util.Collection;

import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.transport.PreReceiveHook;
import org.eclipse.jgit.transport.ProgressSpinner;
import org.eclipse.jgit.transport.ReceiveCommand;
import org.eclipse.jgit.transport.ReceivePack;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

PreReceiveHook for handling push traffic in a Ketch system.
 Install an instance on ReceivePack to capture the commands and other connection state and relay them through the KetchLeader, allowing the leader to gain consensus about the new reference state. /**
 * PreReceiveHook for handling push traffic in a Ketch system.
 * <p>
 * Install an instance on {@link org.eclipse.jgit.transport.ReceivePack} to
 * capture the commands and other connection state and relay them through the
 * {@link org.eclipse.jgit.internal.ketch.KetchLeader}, allowing the leader to
 * gain consensus about the new reference state.
 */
public class KetchPreReceive implements PreReceiveHook {
	private static final Logger log = LoggerFactory.getLogger(KetchPreReceive.class);

	private final KetchLeader leader;

	
Construct a hook executing updates through a KetchLeader. 
Params:
leader – 
           leader for this repository./**
	 * Construct a hook executing updates through a
	 * {@link org.eclipse.jgit.internal.ketch.KetchLeader}.
	 *
	 * @param leader
	 *            leader for this repository.
	 */
	public KetchPreReceive(KetchLeader leader) {
		this.leader = leader;
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public void onPreReceive(ReceivePack rp, Collection<ReceiveCommand> cmds) {
		cmds = ReceiveCommand.filter(cmds, NOT_ATTEMPTED);
		if (cmds.isEmpty()) {
			return;
		}

		try {
			Proposal proposal = new Proposal(rp.getRevWalk(), cmds)
				.setPushCertificate(rp.getPushCertificate())
				.setAuthor(rp.getRefLogIdent())
				.setMessage("push"); //$NON-NLS-1$
			leader.queueProposal(proposal);
			if (proposal.isDone()) {
				// This failed fast, e.g. conflict or bad precondition.
				return;
			}

			ProgressSpinner spinner = new ProgressSpinner(
					rp.getMessageOutputStream());
			if (proposal.getState() == QUEUED) {
				waitForQueue(proposal, spinner);
			}
			if (!proposal.isDone()) {
				waitForPropose(proposal, spinner);
			}
		} catch (IOException | InterruptedException e) {
			String msg = JGitText.get().transactionAborted;
			for (ReceiveCommand cmd : cmds) {
				if (cmd.getResult() == NOT_ATTEMPTED) {
					cmd.setResult(REJECTED_OTHER_REASON, msg);
				}
			}
			log.error(msg, e);
		}
	}

	private void waitForQueue(Proposal proposal, ProgressSpinner spinner)
			throws InterruptedException {
		spinner.beginTask(KetchText.get().waitingForQueue, 1, SECONDS);
		while (!proposal.awaitStateChange(QUEUED, 250, MILLISECONDS)) {
			spinner.update();
		}
		switch (proposal.getState()) {
		case RUNNING:
		default:
			spinner.endTask(KetchText.get().starting);
			break;

		case EXECUTED:
			spinner.endTask(KetchText.get().accepted);
			break;

		case ABORTED:
			spinner.endTask(KetchText.get().failed);
			break;
		}
	}

	private void waitForPropose(Proposal proposal, ProgressSpinner spinner)
			throws InterruptedException {
		spinner.beginTask(KetchText.get().proposingUpdates, 2, SECONDS);
		while (!proposal.await(250, MILLISECONDS)) {
			spinner.update();
		}
		spinner.endTask(proposal.getState() == EXECUTED
				? KetchText.get().accepted
				: KetchText.get().failed);
	}
}