package com.sf.vertx.handle;

import java.io.File;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicInteger;

import com.sf.vertx.constans.SacErrorCode;

/*
 * Copyright 2014 Red Hat, Inc.
 *
 *  All rights reserved. This program and the accompanying materials
 *  are made available under the terms of the Eclipse Public License v1.0
 *  and Apache License v2.0 which accompanies this distribution.
 *
 *  The Eclipse Public License is available at
 *  http://www.eclipse.org/legal/epl-v10.html
 *
 *  The Apache License v2.0 is available at
 *  http://www.opensource.org/licenses/apache2.0.php
 *
 *  You may elect to redistribute this code under either of these licenses.
 */

import io.netty.handler.codec.DecoderException;
import io.netty.handler.codec.http.HttpHeaderValues;
import io.vertx.core.Future;
import io.vertx.core.Handler;
import io.vertx.core.buffer.Buffer;
import io.vertx.core.file.FileSystem;
import io.vertx.core.http.HttpHeaders;
import io.vertx.core.http.HttpServerRequest;
import io.vertx.core.http.HttpServerResponse;
import io.vertx.core.http.HttpVersion;
import io.vertx.core.impl.logging.Logger;
import io.vertx.core.impl.logging.LoggerFactory;
import io.vertx.ext.web.FileUpload;
import io.vertx.ext.web.RoutingContext;
import io.vertx.ext.web.handler.HttpException;
import io.vertx.ext.web.impl.FileUploadImpl;
import io.vertx.ext.web.impl.RoutingContextInternal;

/**
 * @author <a href="http://tfox.org">Tim Fox</a>
 */
public class BodyHandlerImpl implements BodyHandler {

	private static final Logger LOG = LoggerFactory.getLogger(BodyHandlerImpl.class);

	private long bodyLimit = DEFAULT_BODY_LIMIT;
	private boolean handleFileUploads;
	private String uploadsDir;
	private boolean mergeFormAttributes = DEFAULT_MERGE_FORM_ATTRIBUTES;
	private boolean deleteUploadedFilesOnEnd = DEFAULT_DELETE_UPLOADED_FILES_ON_END;
	private boolean isPreallocateBodyBuffer = DEFAULT_PREALLOCATE_BODY_BUFFER;
	private static final int DEFAULT_INITIAL_BODY_BUFFER_SIZE = 1024; // bytes

	public BodyHandlerImpl() {
		this(true, DEFAULT_UPLOADS_DIRECTORY);
	}

	public BodyHandlerImpl(boolean handleFileUploads) {
		this(handleFileUploads, DEFAULT_UPLOADS_DIRECTORY);
	}

	public BodyHandlerImpl(String uploadDirectory) {
		this(true, uploadDirectory);
	}

	private BodyHandlerImpl(boolean handleFileUploads, String uploadDirectory) {
		this.handleFileUploads = handleFileUploads;
		setUploadsDirectory(uploadDirectory);
	}

	@Override
	public void handle(RoutingContext context) {
		// TODO 改造了这个地方
		final HttpServerRequest request = context.request();
		final HttpServerResponse response = context.response();
		String appCode = context.request().headers().get(AppConfigHandler.getAppCodeHeaderKey());
		String apiCode = context.request().headers().get(AppConfigHandler.getApiCodeHeaderKey());
		String contentType = context.request().headers().get(HttpHeaders.CONTENT_TYPE);
		boolean isLoadBody = false;
		try {
			// TODO 测试异常
			isLoadBody = AppConfigHandler.isAnalysisBody(appCode, apiCode, contentType);
		} catch (Exception e) {
			e.printStackTrace();
			context.fail(new HttpException(SacErrorCode.DEFAULT_ERROR_CODE));
			return;
		}
		if (isLoadBody) {
			// =======源码流程
//		    final HttpServerRequest request = context.request();
//		    final HttpServerResponse response = context.response();
			//
			// we need to keep state since we can be called again on reroute
			if (!((RoutingContextInternal) context).seenHandler(RoutingContextInternal.BODY_HANDLER)) {
				((RoutingContextInternal) context).visitHandler(RoutingContextInternal.BODY_HANDLER);

				// Check if a request has a request body.
				// A request with a body __must__ either have `transfer-encoding`
				// or `content-length` headers set.
				// http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.3
				final long parsedContentLength = parseContentLengthHeader(request);
				// http2 never transmits a `transfer-encoding` as frames are chunks.
				final boolean hasTransferEncoding = request.version() == HttpVersion.HTTP_2
						|| request.headers().contains(HttpHeaders.TRANSFER_ENCODING);

				if (!hasTransferEncoding && parsedContentLength == -1) {
					// there is no "body", so we can skip this handler
					context.next();
					return;
				}

				// before parsing the body we can already discard a bad request just by
				// inspecting the content-length against
				// the body limit, this will reduce load, on the server by totally skipping
				// parsing the request body
				if (bodyLimit != -1 && parsedContentLength != -1) {
					if (parsedContentLength > bodyLimit) {
						context.fail(413);
						return;
					}
				}

				// handle expectations
				// https://httpwg.org/specs/rfc7231.html#header.expect
				final String expect = request.getHeader(HttpHeaders.EXPECT);
				if (expect != null) {
					// requirements validation
					if (expect.equalsIgnoreCase("100-continue")) {
						// A server that receives a 100-continue expectation in an HTTP/1.0 request MUST
						// ignore that expectation.
						if (request.version() != HttpVersion.HTTP_1_0) {
							// signal the client to continue
							response.writeContinue();
						}
					} else {
						// the server cannot meet the expectation, we only know about 100-continue
						context.fail(417);
						return;
					}
				}

				final BHandler handler = new BHandler(context, isPreallocateBodyBuffer ? parsedContentLength : -1);
				boolean ended = request.isEnded();
				if (!ended) {
					request
							// resume the request (if paused)
							.handler(handler).endHandler(handler::end).resume();
				}
			} else {
				// on reroute we need to re-merge the form params if that was desired
				if (mergeFormAttributes && request.isExpectMultipart()) {
					request.params().addAll(request.formAttributes());
				}

				context.next();
			}
		} else {
			// 非加解密不处理
			context.next();
			return;
		}
	}

	@Override
	public BodyHandler setHandleFileUploads(boolean handleFileUploads) {
		this.handleFileUploads = handleFileUploads;
		return this;
	}

	@Override
	public BodyHandler setBodyLimit(long bodyLimit) {
		this.bodyLimit = bodyLimit;
		return this;
	}

	@Override
	public BodyHandler setUploadsDirectory(String uploadsDirectory) {
		this.uploadsDir = uploadsDirectory;
		return this;
	}

	@Override
	public BodyHandler setMergeFormAttributes(boolean mergeFormAttributes) {
		this.mergeFormAttributes = mergeFormAttributes;
		return this;
	}

	@Override
	public BodyHandler setDeleteUploadedFilesOnEnd(boolean deleteUploadedFilesOnEnd) {
		this.deleteUploadedFilesOnEnd = deleteUploadedFilesOnEnd;
		return this;
	}

	@Override
	public BodyHandler setPreallocateBodyBuffer(boolean isPreallocateBodyBuffer) {
		this.isPreallocateBodyBuffer = isPreallocateBodyBuffer;
		return this;
	}

	private long parseContentLengthHeader(HttpServerRequest request) {
		String contentLength = request.getHeader(HttpHeaders.CONTENT_LENGTH);
		if (contentLength == null || contentLength.isEmpty()) {
			return -1;
		}
		try {
			long parsedContentLength = Long.parseLong(contentLength);
			return parsedContentLength < 0 ? -1 : parsedContentLength;
		} catch (NumberFormatException ex) {
			return -1;
		}
	}

	private class BHandler implements Handler<Buffer> {
		private static final int MAX_PREALLOCATED_BODY_BUFFER_BYTES = 65535;

		final RoutingContext context;
		final long contentLength;
		Buffer body;
		boolean failed;
		final AtomicInteger uploadCount = new AtomicInteger();
		boolean ended;
		long uploadSize = 0L;
		final boolean isMultipart;
		final boolean isUrlEncoded;

		public BHandler(RoutingContext context, long contentLength) {
			this.context = context;
			this.contentLength = contentLength;
			// the request clearly states that there should
			// be a body, so we respect the client and ensure
			// that the body will not be null
			if (contentLength != -1) {
				initBodyBuffer();
			}

			List<FileUpload> fileUploads = context.fileUploads();

			final String contentType = context.request().getHeader(HttpHeaders.CONTENT_TYPE);
			if (contentType == null) {
				isMultipart = false;
				isUrlEncoded = false;
			} else {
				final String lowerCaseContentType = contentType.toLowerCase();
				isMultipart = lowerCaseContentType.startsWith(HttpHeaderValues.MULTIPART_FORM_DATA.toString());
				isUrlEncoded = lowerCaseContentType
						.startsWith(HttpHeaderValues.APPLICATION_X_WWW_FORM_URLENCODED.toString());
			}

			if (isMultipart || isUrlEncoded) {
				context.request().setExpectMultipart(true);
				if (handleFileUploads) {
					makeUploadDir(context.vertx().fileSystem());
				}
				context.request().uploadHandler(upload -> {
					if (bodyLimit != -1 && upload.isSizeAvailable()) {
						// we can try to abort even before the upload starts
						long size = uploadSize + upload.size();
						if (size > bodyLimit) {
							failed = true;
							context.cancelAndCleanupFileUploads();
							context.fail(413);
							return;
						}
					}
					if (handleFileUploads) {
						// we actually upload to a file with a generated filename
						uploadCount.incrementAndGet();
						String uploadedFileName = new File(uploadsDir, UUID.randomUUID().toString()).getPath();
						FileUploadImpl fileUpload = new FileUploadImpl(context.vertx().fileSystem(), uploadedFileName,
								upload);
						fileUploads.add(fileUpload);
						Future<Void> fut = upload.streamToFileSystem(uploadedFileName);
						fut.onComplete(ar -> {
							if (fut.succeeded()) {
								uploadEnded();
							} else {
								context.cancelAndCleanupFileUploads();
								context.fail(ar.cause());
							}
						});
					}
				});
			}

			context.request().exceptionHandler(t -> {
				context.cancelAndCleanupFileUploads();
				int sc = 200;
				if (t instanceof DecoderException) {
					// bad request
					sc = 400;
					if (t.getCause() != null) {
						t = t.getCause();
					}
				}
				context.fail(sc, t);
			});
		}

		private void initBodyBuffer() {
			int initialBodyBufferSize;
			if (contentLength < 0) {
				initialBodyBufferSize = DEFAULT_INITIAL_BODY_BUFFER_SIZE;
			} else if (contentLength > MAX_PREALLOCATED_BODY_BUFFER_BYTES) {
				initialBodyBufferSize = MAX_PREALLOCATED_BODY_BUFFER_BYTES;
			} else {
				initialBodyBufferSize = (int) contentLength;
			}

			if (bodyLimit != -1) {
				initialBodyBufferSize = (int) Math.min(initialBodyBufferSize, bodyLimit);
			}

			this.body = Buffer.buffer(initialBodyBufferSize);
		}

		private void makeUploadDir(FileSystem fileSystem) {
			if (!fileSystem.existsBlocking(uploadsDir)) {
				fileSystem.mkdirsBlocking(uploadsDir);
			}
		}

		@Override
		public void handle(Buffer buff) {
			if (failed) {
				return;
			}
			uploadSize += buff.length();
			if (bodyLimit != -1 && uploadSize > bodyLimit) {
				failed = true;
				context.cancelAndCleanupFileUploads();
				context.fail(413);
			} else {
				// multipart requests will not end up in the request body
				// url encoded should also not, however jQuery by default
				// post in urlencoded even if the payload is something else
				if (!isMultipart /* && !isUrlEncoded */) {
					if (body == null) {
						initBodyBuffer();
					}
					body.appendBuffer(buff);
				}
			}
		}

		void uploadEnded() {
			int count = uploadCount.decrementAndGet();
			// only if parsing is done and count is 0 then all files have been processed
			if (ended && count == 0) {
				doEnd();
			}
		}

		void end(Void v) {
			// this marks the end of body parsing, calling doEnd should
			// only be possible from this moment onwards
			ended = true;

			// only if parsing is done and count is 0 then all files have been processed
			if (uploadCount.get() == 0) {
				doEnd();
			}
		}

		void doEnd() {

			if (failed || context.failed()) {
				context.cancelAndCleanupFileUploads();
				return;
			}

			if (deleteUploadedFilesOnEnd) {
				context.addBodyEndHandler(x -> context.cancelAndCleanupFileUploads());
			}

			HttpServerRequest req = context.request();
			if (mergeFormAttributes && req.isExpectMultipart()) {
				req.params().addAll(req.formAttributes());
			}
			((RoutingContextInternal) context).setBody(body);
			// release body as it may take lots of memory
			body = null;

			context.next();
		}
	}
}