/*
 * Copyright (C) 2009-2010, 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.http.server;

import static javax.servlet.http.HttpServletResponse.SC_FORBIDDEN;
import static javax.servlet.http.HttpServletResponse.SC_INTERNAL_SERVER_ERROR;
import static javax.servlet.http.HttpServletResponse.SC_UNAUTHORIZED;
import static javax.servlet.http.HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE;
import static org.eclipse.jgit.http.server.GitSmartHttpTools.RECEIVE_PACK;
import static org.eclipse.jgit.http.server.GitSmartHttpTools.RECEIVE_PACK_REQUEST_TYPE;
import static org.eclipse.jgit.http.server.GitSmartHttpTools.RECEIVE_PACK_RESULT_TYPE;
import static org.eclipse.jgit.http.server.GitSmartHttpTools.sendError;
import static org.eclipse.jgit.http.server.ServletUtils.ATTRIBUTE_HANDLER;
import static org.eclipse.jgit.http.server.ServletUtils.consumeRequestBody;
import static org.eclipse.jgit.http.server.ServletUtils.getInputStream;
import static org.eclipse.jgit.http.server.ServletUtils.getRepository;
import static org.eclipse.jgit.util.HttpSupport.HDR_USER_AGENT;

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

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.eclipse.jgit.annotations.Nullable;
import org.eclipse.jgit.errors.CorruptObjectException;
import org.eclipse.jgit.errors.PackProtocolException;
import org.eclipse.jgit.errors.UnpackException;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.transport.InternalHttpServerGlue;
import org.eclipse.jgit.transport.ReceivePack;
import org.eclipse.jgit.transport.RefAdvertiser.PacketLineOutRefAdvertiser;
import org.eclipse.jgit.transport.resolver.ReceivePackFactory;
import org.eclipse.jgit.transport.resolver.ServiceNotAuthorizedException;
import org.eclipse.jgit.transport.resolver.ServiceNotEnabledException;

/** Server side implementation of smart push over HTTP. */
class ReceivePackServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	static class InfoRefs extends SmartServiceInfoRefs {
		private final ReceivePackFactory<HttpServletRequest> receivePackFactory;

		InfoRefs(ReceivePackFactory<HttpServletRequest> receivePackFactory,
				List<Filter> filters) {
			super(RECEIVE_PACK, filters);
			this.receivePackFactory = receivePackFactory;
		}

		@Override
		protected void begin(HttpServletRequest req, Repository db)
				throws IOException, ServiceNotEnabledException,
				ServiceNotAuthorizedException {
			ReceivePack rp = receivePackFactory.create(req, db);
			InternalHttpServerGlue.setPeerUserAgent(
					rp,
					req.getHeader(HDR_USER_AGENT));
			req.setAttribute(ATTRIBUTE_HANDLER, rp);
		}

		@Override
		protected void advertise(HttpServletRequest req,
				PacketLineOutRefAdvertiser pck) throws IOException,
				ServiceNotEnabledException, ServiceNotAuthorizedException {
			ReceivePack rp = (ReceivePack) req.getAttribute(ATTRIBUTE_HANDLER);
			try {
				rp.sendAdvertisedRefs(pck);
			} finally {
				rp.getRevWalk().close();
			}
		}
	}

	static class Factory implements Filter {
		private final ReceivePackFactory<HttpServletRequest> receivePackFactory;

		Factory(ReceivePackFactory<HttpServletRequest> receivePackFactory) {
			this.receivePackFactory = receivePackFactory;
		}

		@Override
		public void doFilter(ServletRequest request, ServletResponse response,
				FilterChain chain) throws IOException, ServletException {
			HttpServletRequest req = (HttpServletRequest) request;
			HttpServletResponse rsp = (HttpServletResponse) response;
			ReceivePack rp;
			try {
				rp = receivePackFactory.create(req, getRepository(req));
			} catch (ServiceNotAuthorizedException e) {
				rsp.sendError(SC_UNAUTHORIZED, e.getMessage());
				return;
			} catch (ServiceNotEnabledException e) {
				sendError(req, rsp, SC_FORBIDDEN, e.getMessage());
				return;
			}

			try {
				req.setAttribute(ATTRIBUTE_HANDLER, rp);
				chain.doFilter(req, rsp);
			} finally {
				req.removeAttribute(ATTRIBUTE_HANDLER);
			}
		}

		@Override
		public void init(FilterConfig filterConfig) throws ServletException {
			// Nothing.
		}

		@Override
		public void destroy() {
			// Nothing.
		}
	}

	@Nullable
	private final ReceivePackErrorHandler handler;

	ReceivePackServlet(@Nullable ReceivePackErrorHandler handler) {
		this.handler = handler;
	}

	/** {@inheritDoc} */
	@Override
	public void doPost(final HttpServletRequest req,
			final HttpServletResponse rsp) throws IOException {
		if (!RECEIVE_PACK_REQUEST_TYPE.equals(req.getContentType())) {
			rsp.sendError(SC_UNSUPPORTED_MEDIA_TYPE);
			return;
		}

		SmartOutputStream out = new SmartOutputStream(req, rsp, false) {
			@Override
			public void flush() throws IOException {
				doFlush();
			}
		};

		ReceivePack rp = (ReceivePack) req.getAttribute(ATTRIBUTE_HANDLER);
		rp.setBiDirectionalPipe(false);
		rsp.setContentType(RECEIVE_PACK_RESULT_TYPE);

		if (handler != null) {
			handler.receive(req, rsp, () -> {
				rp.receiveWithExceptionPropagation(getInputStream(req), out,
						null);
				out.close();
			});
		} else {
			try {
				rp.receive(getInputStream(req), out, null);
				out.close();
			} catch (CorruptObjectException e ) {
				// This should be already reported to the client.
				getServletContext().log(MessageFormat.format(
						HttpServerText.get().receivedCorruptObject,
						e.getMessage(),
						ServletUtils.identify(rp.getRepository())));
				consumeRequestBody(req);
				out.close();

			} catch (UnpackException | PackProtocolException e) {
				// This should be already reported to the client.
				log(rp.getRepository(), e.getCause());
				consumeRequestBody(req);
				out.close();

			} catch (Throwable e) {
				log(rp.getRepository(), e);
				if (!rsp.isCommitted()) {
					rsp.reset();
					sendError(req, rsp, SC_INTERNAL_SERVER_ERROR);
				}
				return;
			}
		}
	}

	private void log(Repository git, Throwable e) {
		getServletContext().log(MessageFormat.format(
				HttpServerText.get().internalErrorDuringReceivePack,
				ServletUtils.identify(git)), e);
	}
}