/* TinyHttpdImpl.java
 Copyright (C) 2011,2012 Red Hat, Inc.

 This file is part of IcedTea.

IcedTea is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, version 2.

IcedTea is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
IcedTea; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is making a
combined work based on this library. Thus, the terms and conditions of the GNU
General Public License cover the whole combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent modules, and
to copy and distribute the resulting executable under terms of your choice,
provided that you also meet, for each linked independent module, the terms and
conditions of the license of that module. An independent module is a module
which is not derived from or based on this library. If you modify this library,
you may extend this exception to your version of the library, but you are not
obligated to do so. If you do not wish to do so, delete this exception
statement from your version.
*/
package net.adoptopenjdk.icedteaweb.testing;

import net.adoptopenjdk.icedteaweb.http.HttpMethod;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.Socket;
import java.net.SocketException;
import java.net.URLDecoder;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.StringTokenizer;

import static java.nio.charset.StandardCharsets.UTF_8;

/**
 * based on http://www.mcwalter.org/technology/java/httpd/tiny/index.html Very
 * small implementation of http return headers for our served resources
 * Originally Licenced under GPLv2.0
 * <p>
 * When resource starts with XslowX prefix, then resource (without XslowX) is
 * returned, but its delivery is delayed
 */
public class TinyHttpdImpl extends Thread {

    private static final String CRLF = "\r\n";
    private static final String HTTP_NOT_IMPLEMENTED = "HTTP/1.0 " + HttpURLConnection.HTTP_NOT_IMPLEMENTED + " Not Implemented" + CRLF;
    private static final String HTTP_NOT_FOUND = "HTTP/1.0 " + HttpURLConnection.HTTP_NOT_FOUND + " Not Found" + CRLF;
    private static final String HTTP_OK = "HTTP/1.0 " + HttpURLConnection.HTTP_OK + " OK" + CRLF;
    private static final String XSX = "/XslowX";

    private final Socket socket;
    private final File testDir;
    private boolean supportingHeadRequest = true;
    private boolean supportLastModified = false;

    public TinyHttpdImpl(final Socket socket, final File dir) {
        this(socket, dir, true);
    }

    public TinyHttpdImpl(final Socket socket, final File dir, final boolean start) {
        this.socket = socket;
        this.testDir = dir;
        if (start) {
            start();
        }
    }

    public void setSupportingHeadRequest(final boolean supportsHead) {
        this.supportingHeadRequest = supportsHead;
    }

    public boolean isSupportingHeadRequest() {
        return this.supportingHeadRequest;
    }

    public void setSupportLastModified(final boolean supportLastModified) {
        this.supportLastModified = supportLastModified;
    }

    @Override
    public void run() {
        try {
            final BufferedReader reader = new BufferedReader(new InputStreamReader(this.socket.getInputStream()));
            final DataOutputStream writer = new DataOutputStream(this.socket.getOutputStream());
            try {
                while (true) {
                    final String line = reader.readLine();
                    if (line.length() < 1) {
                        break;
                    }

                    final StringTokenizer t = new StringTokenizer(line, " ");
                    final String request = t.nextToken();
                    String filePath = t.nextToken();

                    final boolean isHeadRequest = Objects.equals(request, HttpMethod.HEAD.name());
                    final boolean isGetRequest = Objects.equals(request, HttpMethod.GET.name());

                    if (isHeadRequest && !isSupportingHeadRequest()) {
                        ServerAccess.logOutputReprint("Received HEAD request but not supported");
                        writer.writeBytes(HTTP_NOT_IMPLEMENTED);
                        continue;
                    }

                    if (!isHeadRequest && !isGetRequest) {
                        ServerAccess.logOutputReprint("Received unknown request type " + request);
                        continue;
                    }
                    final boolean slowSend = filePath.startsWith(XSX);

                    if (requestsCounter != null) {
                        String resource = filePath.replace(XSX, "/");
                        resource = urlToFilePath(resource);
                        Map<String, Integer> resourceRecord = requestsCounter.get(resource);
                        if (resourceRecord == null) {
                            resourceRecord = new HashMap<>();
                            requestsCounter.put(resource, resourceRecord);
                        }
                        Integer i = resourceRecord.get(request);
                        if (i == null) {
                            i = 0;
                        }
                        i++;
                        resourceRecord.put(request, i);
                    }


                    if (slowSend) {
                        filePath = filePath.replace(XSX, "/");
                    }

                    ServerAccess.logOutputReprint("Getting- " + request + ": " + filePath);
                    filePath = urlToFilePath(filePath);

                    final File resource = new File(this.testDir, filePath);

                    if (!(resource.isFile() && resource.canRead())) {
                        ServerAccess.logOutputReprint("Could not open file " + filePath);
                        writer.writeBytes(HTTP_NOT_FOUND);
                        continue;
                    }
                    ServerAccess.logOutputReprint("Serving- " + request + ": " + filePath);

                    final int resourceLength = (int) resource.length();
                    final byte[] buff = new byte[resourceLength];
                    final FileInputStream fis = new FileInputStream(resource);
                    fis.read(buff);
                    fis.close();

                    String contentType = "Content-Type: ";
                    if (filePath.toLowerCase().endsWith(".jnlp")) {
                        contentType += "application/x-java-jnlp-file";
                    } else if (filePath.toLowerCase().endsWith(".jar")) {
                        contentType += "application/x-jar";
                    } else {
                        contentType += "text/html";
                    }
                    String lastModified = "";
                    if (supportLastModified) {
                        lastModified = "Last-Modified: " + new Date(resource.lastModified()) + CRLF;
                    }
                    writer.writeBytes(HTTP_OK + "Content-Length:" + resourceLength + CRLF + lastModified + contentType + CRLF + CRLF);

                    if (isGetRequest) {
                        if (slowSend) {
                            final byte[][] bb = splitArray(buff, 10);
                            for (final byte[] aBb : bb) {
                                Thread.sleep(2000);
                                writer.write(aBb, 0, aBb.length);
                            }
                        } else {
                            writer.write(buff, 0, resourceLength);
                        }
                    }
                }

            } catch (final SocketException e) {
                ServerAccess.logException(e, false);
            } catch (final Exception e) {
                writer.writeBytes(HTTP_NOT_FOUND);
                ServerAccess.logException(e, false);
            } finally {
                reader.close();
                writer.close();
            }
        } catch (final Exception e) {
            ServerAccess.logException(e, false);
        }
    }

    /**
     * This function splits input array to several pieces from byte[length]
     * split to n pieces s is returned byte[n][length/n], except last piece
     * which contains length%n
     *
     * @param input  - array to be split
     * @param pieces - to how many pieces it should be broken
     * @return individual pieces of original array, which concatet again givs
     * original array
     */
    public static byte[][] splitArray(final byte[] input, int pieces) {
        int rest = input.length;
        int rowLength = rest / pieces;
        if (rest % pieces > 0) {
            rowLength++;
        }
        if (pieces * rowLength >= rest + rowLength) {
            pieces--;
        }
        int i = 0, j = 0;
        final byte[][] array = new byte[pieces][];
        array[0] = new byte[rowLength];
        for (byte b : input) {
            if (i >= rowLength) {
                i = 0;
                array[++j] = new byte[Math.min(rowLength, rest)];
            }
            array[j][i++] = b;
            rest--;
        }
        return array;
    }

    /**
     * This function transforms a request URL into a path to a file which the
     * server will return to the requester.
     *
     * @param url - the request URL
     * @return a String representation of the local path to the file
     * @throws UnsupportedEncodingException
     */
    public static String urlToFilePath(String url) throws UnsupportedEncodingException {
        url = URLDecoder.decode(url, UTF_8.name()); // Decode URL encoded characters, eg "%3B" becomes ';'
        if (url.startsWith(XSX)) {
            url = url.replace(XSX, "/");
        }
        url = url.replaceAll("\\?.*", ""); // Remove query string from URL
        url = ".".concat(url); // Change path into relative path
        if (url.endsWith("/")) {
            url += "index.html";
        }
        url = url.replace('/', File.separatorChar); // If running on Windows, replace '/' in path with "\\"
        url = stripHttpPathParams(url);
        return url;
    }

    /**
     * This function removes the HTTP Path Parameter from a given JAR URL,
     * assuming that the path param delimiter is a semicolon
     *
     * @param url - the URL from which to remove the path parameter
     * @return the URL with the path parameter removed
     */
    public static String stripHttpPathParams(String url) {
        if (url == null) {
            return null;
        }

        // If JNLP specifies JAR URL with .JAR extension (as it should), then look for any semicolons
        // after this position. If one is found, remove it and any following characters.
        final int fileExtension = url.toUpperCase().lastIndexOf(".JAR");
        if (fileExtension != -1) {
            final int firstSemiColon = url.indexOf(';', fileExtension);
            if (firstSemiColon != -1) {
                url = url.substring(0, firstSemiColon);
            }
        }
        return url;
    }


    //resource -> request -> number of requests on of this resource on this server
    // eg   simpletest1.jnlp -> GET -> 3
    private Map<String, Map<String, Integer>> requestsCounter;

    public void setRequestsCounter(final Map<String, Map<String, Integer>> requestsCounter) {
        this.requestsCounter = requestsCounter;
    }


}
