/*
 * 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_UNAUTHORIZED;
import static javax.servlet.http.HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE;
import static org.eclipse.jgit.http.server.GitSmartHttpTools.UPLOAD_PACK;
import static org.eclipse.jgit.http.server.GitSmartHttpTools.UPLOAD_PACK_REQUEST_TYPE;
import static org.eclipse.jgit.http.server.GitSmartHttpTools.UPLOAD_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.http.server.UploadPackErrorHandler.statusCodeForThrowable;
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.PackProtocolException;
import org.eclipse.jgit.http.server.UploadPackErrorHandler.UploadPackRunnable;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.transport.InternalHttpServerGlue;
import org.eclipse.jgit.transport.PacketLineOut;
import org.eclipse.jgit.transport.RefAdvertiser.PacketLineOutRefAdvertiser;
import org.eclipse.jgit.transport.ServiceMayNotContinueException;
import org.eclipse.jgit.transport.UploadPack;
import org.eclipse.jgit.transport.UploadPackInternalServerErrorException;
import org.eclipse.jgit.transport.resolver.ServiceNotAuthorizedException;
import org.eclipse.jgit.transport.resolver.ServiceNotEnabledException;
import org.eclipse.jgit.transport.resolver.UploadPackFactory;

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

	static class InfoRefs extends SmartServiceInfoRefs {
		private final UploadPackFactory<HttpServletRequest> uploadPackFactory;

		InfoRefs(UploadPackFactory<HttpServletRequest> uploadPackFactory,
				List<Filter> filters) {
			super(UPLOAD_PACK, filters);
			this.uploadPackFactory = uploadPackFactory;
		}

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

		@Override
		protected void advertise(HttpServletRequest req,
				PacketLineOutRefAdvertiser pck) throws IOException,
				ServiceNotEnabledException, ServiceNotAuthorizedException {
			UploadPack up = (UploadPack) req.getAttribute(ATTRIBUTE_HANDLER);
			try {
				up.setBiDirectionalPipe(false);
				up.sendAdvertisedRefs(pck);
			} finally {
				// TODO(jonathantanmy): Move responsibility for closing the
				// RevWalk to UploadPack, either by making it AutoCloseable
				// or by making sendAdvertisedRefs clean up after itself.
				up.getRevWalk().close();
			}
		}

		@Override
		protected void respond(HttpServletRequest req,
				PacketLineOut pckOut, String serviceName) throws IOException,
				ServiceNotEnabledException, ServiceNotAuthorizedException {
			UploadPack up = (UploadPack) req.getAttribute(ATTRIBUTE_HANDLER);
			try {
				up.setBiDirectionalPipe(false);
				up.sendAdvertisedRefs(new PacketLineOutRefAdvertiser(pckOut), serviceName);
			} finally {
				// TODO(jonathantanmy): Move responsibility for closing the
				// RevWalk to UploadPack, either by making it AutoCloseable
				// or by making sendAdvertisedRefs clean up after itself.
				up.getRevWalk().close();
			}
		}
	}

	static class Factory implements Filter {
		private final UploadPackFactory<HttpServletRequest> uploadPackFactory;

		Factory(UploadPackFactory<HttpServletRequest> uploadPackFactory) {
			this.uploadPackFactory = uploadPackFactory;
		}

		@Override
		public void doFilter(ServletRequest request, ServletResponse response,
				FilterChain chain) throws IOException, ServletException {
			HttpServletRequest req = (HttpServletRequest) request;
			HttpServletResponse rsp = (HttpServletResponse) response;
			UploadPack rp;
			try {
				rp = uploadPackFactory.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.
		}
	}

	private final UploadPackErrorHandler handler;

	UploadPackServlet(@Nullable UploadPackErrorHandler handler) {
		this.handler = handler != null ? handler
				: this::defaultUploadPackHandler;
	}

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

		UploadPackRunnable r = () -> {
			upload(req, rsp);
		};

		handler.upload(req, rsp, r);
	}

	private void upload(HttpServletRequest req, HttpServletResponse rsp)
			throws IOException, ServiceMayNotContinueException {
		// to be explicitly closed by caller
		@SuppressWarnings("resource")
		SmartOutputStream out = new SmartOutputStream(req, rsp, false) {
			@Override
			public void flush() throws IOException {
				doFlush();
			}
		};
		Repository repo = null;
		try (UploadPack up = (UploadPack) req.getAttribute(ATTRIBUTE_HANDLER)) {
			up.setBiDirectionalPipe(false);
			rsp.setContentType(UPLOAD_PACK_RESULT_TYPE);
			repo = up.getRepository();
			up.uploadWithExceptionPropagation(getInputStream(req), out, null);
			out.close();
		} catch (ServiceMayNotContinueException e) {
			if (e.isOutput()) {
				consumeRequestBody(req);
				out.close();
			}
			throw e;
		} catch (UploadPackInternalServerErrorException e) {
			// Special case exception, error message was sent to client.
			log(repo, e.getCause());
			consumeRequestBody(req);
			out.close();
		}
	}

	private void defaultUploadPackHandler(HttpServletRequest req,
			HttpServletResponse rsp, UploadPackRunnable r) throws IOException {
		try {
			r.upload();
		} catch (ServiceMayNotContinueException e) {
			if (!e.isOutput() && !rsp.isCommitted()) {
				rsp.reset();
				sendError(req, rsp, e.getStatusCode(), e.getMessage());
			}
		} catch (Throwable e) {
			UploadPack up = (UploadPack) req.getAttribute(ATTRIBUTE_HANDLER);
			log(up.getRepository(), e);
			if (!rsp.isCommitted()) {
				rsp.reset();
				String msg = null;
				if (e instanceof PackProtocolException
						|| e instanceof ServiceNotEnabledException) {
					msg = e.getMessage();
				}
				sendError(req, rsp, statusCodeForThrowable(e), msg);
			}
		}
	}

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