import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.*;


/**
 * Clasa ce implementeaza parsarea header-elor HTTP.
 * Se interpreteaza cererea utilizatorului.
 *Se livreaza pagina ceruta, in cazul in care aceasta exista.
 * @author Apostol Ioana
 */

public class HTTP_parser{
    /**
     *  Declararea si instantierea membrilor clasei Parser
     *  Realizarea administrarii conexiunii clientului
     */
    static final File WEB_ROOT = new File(".");
    static final String DEFAULT_FILE = "index.html";
    static final String MOVED_PERMANENTLY = "301.html";
    static final String BAD_REQUEST = "400.html";
    static final String UNAUTHORIZED= "401.html";
    static final String FILE_NOT_FOUND = "404.html";
    static final String INTERNAL_SERVER_ERR = "500.html";
    static final String NOT_IMPLEMENTED = "501.html";
    static final String HTTPversion_NOTsupported = "505.html";
    static final boolean verbose = true;
    static  String fileRequested=null;
    static Logger a = Logger.getInstance();
    static String mod = ReadFile.getLoglevel();
    private static int PortClient;
    public static void Parser(Socket connect) {

        PortClient=JavaHTTPServer.getPortClient();
        BufferedReader in = null;
        PrintWriter out = null;
        BufferedOutputStream dataOut = null;
       // String fileRequested = null;

        try {
            // Se citesc caracterele de la client prin intermediul stream-ului de input din socket
            in = new BufferedReader(new InputStreamReader(connect.getInputStream()));
            // Se obtine stream-ul de output de caractere catre client (pentru headere)
            out = new PrintWriter(connect.getOutputStream());
            // Se obtine stream-ul binar de output catre client (pentru datele cerute)
            dataOut = new BufferedOutputStream(connect.getOutputStream());

            // Se citeste prima linie din cererea clientului
            String input = in.readLine();
            // se interpreteaza cererea cu un string tokenizer
                StringTokenizer parse = new StringTokenizer(input);
                String method = parse.nextToken().toUpperCase(); //Se obtine metoda HTTP a clientului
                // Se obtine pagina ceruta
                fileRequested = parse.nextToken().toLowerCase();

            if (!method.equals("GET") && !method.equals("POST")) {
                    NotImplemented(out, dataOut, fileRequested);
            } else {
               if (fileRequested.endsWith("/")) {
                    fileRequested += DEFAULT_FILE;
                }

                File file = new File(WEB_ROOT, fileRequested);
                int fileLength = (int) file.length();
                //Se returneaza tipul MIME(Multipurpose Internet Mail Extensions)
                String content = GetMimeType.getType(fileRequested);
                String[] phpCode;
                    if (method.equals("GET")) {
                         /*if(content.equals("text/html")){
                            if(SenderPHP.PHP_identifier(fileRequested))
                                    phpCode = SenderPHP.SendFileRequested(fileRequested);
                        } */
                    byte[] fileData = readFileData(file, fileLength);
                    // Se trimit header-ele HTTP
                    out.println("HTTP/1.1 200 OK");
                    out.println("Server: Java HTTP Server: 1.0");
                    out.println("Date: " + new Date());
                    out.println("Content-type: " + content);
                    out.println("Content-length: " + fileLength);
                    out.println();
                    out.flush();
                        Logger.notice= " ";
                        Logger.notice += PortClient;
                        Logger.notice += " GET ";
                        Logger.notice += fileRequested ;
                        Logger.notice += " 200 Ok ";
                        Logger.notice += new Date();
                        Logger.notice += "\n";
                        if(Objects.equals(mod,"verbose"))
                           a.WriteFile();

                        dataOut.write(fileData, 0, fileLength);
                    dataOut.flush();
                }
                    if(method.equals("POST")){
                        File fileToRead = new File(WEB_ROOT, fileRequested);

                        int fileLen = (int) file.length();
                        if(fileToRead.isDirectory()){

                            try {
                                BadRequest(out,dataOut,fileRequested);
                            } catch (IOException ioe1) {
                                System.err.println("Bad Request : ");
                            }
                        }

                        String contentType = GetMimeType.getType(fileRequested);
                        if(contentType == null || !contentType.equals("application/x-www-form-urlencoded")){
                                try {
                                    InternalServerError(out, dataOut, fileRequested);
                                } catch (IOException ioe1) {
                                    Logger.error = "Server error";
                                    if(Objects.equals(mod,"error"))
                                    a.WriteFile1();
                                }
                        }

                        String extension = fileRequested.substring(fileRequested.lastIndexOf('.') + 1);
                        if(!extension.equalsIgnoreCase("cgi")){
                            try {
                                Unauthorized(out, dataOut, fileRequested);
                            } catch (IOException ioe1) {
                                System.err.println("Unauthorized : ");
                                Logger.error = "Unauthorized ";
                                if(Objects.equals(mod,"error"))
                                a.WriteFile1();                            }
                        }

                        ProcessBuilder pb = new ProcessBuilder(fileToRead.getAbsoluteFile().toString());

                        Map<String, String> env = pb.environment();
                        env.put("SCRIPT_NAME", fileRequested);
                        ((Map) env).put("CONTENT_LENGTH", "" + fileLen);
                        env.put("SERVER_NAME", connect.getInetAddress().toString());
                        env.put("SERVER_PORT", "" + connect.getPort());

                        String responsePayload = readInputStream(connect.getInputStream());
                        String status;
                        if(responsePayload.equals("")){
                            status = "HTTP/1.0 204 No Content";
                        }
                        else status = "HTTP/1.0 200 OK";

                        //set headers again
                        String headerLines = addHeaders(fileToRead, responsePayload.length(),contentType);
                    }
            }

        } catch (FileNotFoundException fnfe) {
                try {
                    fileNotFound(out, dataOut, fileRequested);
                } catch (IOException ioe) {
                    System.err.println("Error with file not found exception : " + ioe.getMessage());
                }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                in.close();
                out.close();
                dataOut.close();
                connect.close(); // Se inchide conexiunea
            } catch (Exception e) {
                System.err.println("Error closing stream : " + e.getMessage());
            }

            }
        }

    /**
     * Se citeste si se returneaza marimea paginii cerute, in cazul in care aceasta exista.
     * In caz contrar, se arunca o exceptie si se inchide fisierul.
     */

    static byte[] readFileData(File file, int fileLength) throws IOException {
        FileInputStream fileIn = null;
        byte[] fileData = new byte[fileLength];

        try {
            fileIn = new FileInputStream(file);
            fileIn.read(fileData);
        } finally {
            if (fileIn != null)
                fileIn.close();
        }

        return fileData;
    }


    /**
     * Se trateaza cazul in care utilizatorul cere o pagina care nu exista.
     * Pentru aceasta situatie, codul de return este "404 File Not Found".
     */

    private static void fileNotFound(PrintWriter out, OutputStream dataOut, String fileRequested) throws IOException {
        Logger a = Logger.getInstance();
        File file = new File(WEB_ROOT, FILE_NOT_FOUND);
        int fileLength = (int) file.length();
        String content = "text/html";
        byte[] fileData = readFileData(file, fileLength);

        out.println("HTTP/1.1 404 File Not Found");
        out.println("Server: Java HTTP Server: 1.0");
        out.println("Date: " + new Date());
        out.println("Content-type: " + content);
        out.println("Content-length: " + fileLength);
        out.println();
        out.flush();
        dataOut.write(fileData, 0, fileLength);
        dataOut.flush();
        Logger.notice = " ";
        Logger.notice += PortClient;
        Logger.notice += " GET ";
        Logger.notice += "404  ";
        Logger.notice += fileRequested ;
        Logger.notice += " File Not Found ";
        Logger.notice += new Date();
        Logger.notice += "\n";
        if(Objects.equals(mod,"error"))
        a.WriteFile();
    }

    /**
     * Codul de raspuns al statusului de redirect indica faptul ca resursa ceruta a fost mutata definitiv catre alt URL.
     * Browser-ul redirecteaza utilizatorul la aceasta pagina si cauta sa updateze link-urile catre resura ceruta.
     */
    private static void movedPermanently(PrintWriter out, OutputStream dataOut, String fileRequested) throws IOException {
        File file = new File(WEB_ROOT, MOVED_PERMANENTLY);
        int fileLength = (int) file.length();
        String content = "text/html";
        byte[] fileData = readFileData(file, fileLength);

        out.println("HTTP/1.1 301 Moved Permanently");
        out.println("Server: Java HTTP Server: 1.0");
        out.println("Date: " + new Date());
        out.println("Content-type: " + content);
        out.println("Content-length: " + fileLength);
        out.println();
        out.flush();
        Logger.notice = " ";
        Logger.notice += PortClient;
        Logger.notice += " GET ";
        Logger.notice += "301  ";
        Logger.notice += fileRequested ;
        Logger.notice += " Moved Permanently ";
        Logger.notice += new Date();
        Logger.notice += "\n";
        if(Objects.equals(mod,"error"))
        a.WriteFile();

        dataOut.write(fileData, 0, fileLength);
        dataOut.flush();
    }

    /**
     * Cererea nu poate fi aplicata, deoarece lipsesc credentialele valide pentru autentificare, necesare resursei cerute.
     */
    private static void Unauthorized(PrintWriter out, OutputStream dataOut, String fileRequested) throws IOException {
        File file = new File(WEB_ROOT, UNAUTHORIZED);
        int fileLength = (int) file.length();
        String content = "text/html";
        byte[] fileData = readFileData(file, fileLength);

        out.println("HTTP/1.1 401 Unauthorized");
        out.println("Server: Java HTTP Server: 1.0");
        out.println("Date: " + new Date());
        out.println("Content-type: " + content);
        out.println("Content-length: " + fileLength);
        out.println();
        out.flush();
        Logger.notice = " ";
        Logger.notice += PortClient;
        Logger.notice += " GET ";
        Logger.notice += "401  ";
        Logger.notice += fileRequested ;
        Logger.notice += " Unauthorized ";
        Logger.notice += new Date();
        Logger.notice += "\n";
        if(Objects.equals(mod,"error"))
        a.WriteFile();

        dataOut.write(fileData, 0, fileLength);
        dataOut.flush();
    }

    /**
     * Se indica faptul ca serverul nu a putut procesa cererea trimisa de catre client din cauza sintaxei invalide
     */
    private static void BadRequest(PrintWriter out, OutputStream dataOut, String fileRequested) throws IOException {
        File file = new File(WEB_ROOT, BAD_REQUEST);
        int fileLength = (int) file.length();
        String content = "text/html";
        byte[] fileData = readFileData(file, fileLength);

        out.println("HTTP/1.1 400 Bad Request");
        out.println("Server: Java HTTP Server: 1.0");
        out.println("Date: " + new Date());
        out.println("Content-type: " + content);
        out.println("Content-length: " + fileLength);
        out.println();
        out.flush();
        Logger.notice = " ";
        Logger.notice += PortClient;
        Logger.notice += " GET ";
        Logger.notice += "400  ";
        Logger.notice += fileRequested ;
        Logger.notice += " Bad Request ";
        Logger.notice += new Date();
        Logger.notice += "\n";
        if(Objects.equals(mod,"error"))
        a.WriteFile();



        dataOut.write(fileData, 0, fileLength);
        dataOut.flush();
    }
    /**
     * Apare in momentul in care ceva nu functioneaza pe serverul site-ului, dar serverul nu poate specifica exact ce anume.
     */
    private static void InternalServerError(PrintWriter out, OutputStream dataOut, String fileRequested) throws IOException {
        File file = new File(WEB_ROOT, INTERNAL_SERVER_ERR);
        int fileLength = (int) file.length();
        String content = "text/html";
        byte[] fileData = readFileData(file, fileLength);

        out.println("HTTP/1.1 500 Internal Server Error");
        out.println("Server: Java HTTP Server: 1.0");
        out.println("Date: " + new Date());
        out.println("Content-type: " + content);
        out.println("Content-length: " + fileLength);
        out.println();
        out.flush();
        Logger.notice = " ";
        Logger.notice += PortClient;
        Logger.notice += " GET ";
        Logger.notice += "500  ";
        Logger.notice += fileRequested ;
        Logger.notice += " Internal Server Error ";
        Logger.notice += new Date();
        Logger.notice += "\n";
        if(Objects.equals(mod,"error"))
        a.WriteFile();


        dataOut.write(fileData, 0, fileLength);
        dataOut.flush();
    }

    /**
     * Este tratat cazul in care serverul nu poate realiza functionalitatea ceruta pentru a indeplini cererea facuta de catre utilizator
     */
    private static void NotImplemented(PrintWriter out, OutputStream dataOut, String fileRequested) throws IOException {
        File file = new File(WEB_ROOT, NOT_IMPLEMENTED);
        int fileLength = (int) file.length();
        String content = "text/html";
        byte[] fileData = readFileData(file, fileLength);

        out.println("HTTP/1.1 501 Not Implemented");
        out.println("Server: Java HTTP Server: 1.0");
        out.println("Date: " + new Date());
        out.println("Content-type: " + content);
        out.println("Content-length: " + fileLength);
        out.println();
        out.flush();
        Logger.notice = " ";
        Logger.notice += PortClient;
        Logger.notice = " GET ";
        Logger.notice += "501  ";
        Logger.notice += fileRequested ;
        Logger.notice += " Not Implemented ";
        Logger.notice += new Date();
        Logger.notice += "\n";
        if(Objects.equals(mod,"error"))
        a.WriteFile();


        dataOut.write(fileData, 0, fileLength);
        dataOut.flush();
    }

     /**
       * Se indica faptul ca serverul nu lucreaza cu versiunea de HTTP folosita in request
       */

    private static void NotSupported(PrintWriter out, OutputStream dataOut, String fileRequested) throws IOException {
        File file = new File(WEB_ROOT, HTTPversion_NOTsupported);
        int fileLength = (int) file.length();
        String contentMimeType = "text/html";
        //read content to return to client
        byte[] fileData = readFileData(file, fileLength);


        out.println("HTTP/1.1 505 Not Supported");
        out.println("Server: Java HTTP Server: 1.0");
        out.println("Date: " + new Date());
        out.println("Content-type: " + contentMimeType);
        out.println("Content-length: " + fileLength);
        out.println();
        out.flush();

        Logger.notice = " ";
        Logger.notice += PortClient;
        Logger.notice = " 505 ";
        Logger.notice += "400  ";
        Logger.notice += fileRequested ;
        Logger.notice += " Not Supported ";
        Logger.notice += new Date();
        Logger.notice += "\n";
        if(Objects.equals(mod,"error"))
        a.WriteFile();


        dataOut.write(fileData, 0, fileLength);
        dataOut.flush();
    }

    public String getFrom(String request) throws IOException{
            String [] lines = request.split("\r\n");
            for(String i: lines){
            String field = i.split(" ")[0];
            if(field.equals("From:")){
                 return i.substring(6);
            }
        }
            return null;
            }

    public static String readInputStream(InputStream is) throws IOException{
        String retval = "";
        BufferedReader buff = new BufferedReader(new InputStreamReader(is));
        while(buff.ready()){
            retval += (char)buff.read();
        }
        return retval;
    }
    public static String addHeaders(File fileToRead, int CL, String type){

        String typeLine = "Content-Type: ";

        typeLine += type  + '\r' + '\n';

        String lengthLine = "Content-Length: "+ CL + '\r' + '\n';

        long time = fileToRead.lastModified();
        String modifiedLine = "Last-Modified: " + getFormattedTime(time)  + '\r' + '\n';

        String encodingLine = "Content-Encoding: identity"  + '\r' + '\n';

        String allowLine = "Allow: GET, POST"  + '\r' + '\n';

        String expireLine = "Expires: " + getFormattedTime(System.currentTimeMillis() + 525600) + '\r' + '\n';

        return typeLine + lengthLine + modifiedLine + encodingLine + allowLine + expireLine;


    }

    public static String getFormattedTime(long millis){

        DateFormat formatter = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz");
        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(millis);

        String s = formatter.format(calendar.getTime());

        return s;

    }
    public static String getFileRequested(){
        return fileRequested;
}
}