import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Date;
import java.util.StringTokenizer;

public class HTTPServer {

	public static final int MIMETYPE_HTML = 0;
	public static final int MIMETYPE_JPEG = 2;
	public static final int MIMETYPE_ZIP = 3;
	public static final int MIMETYPE_GIF = 4;
	public static final int MIMETYPE_PNG = 5;
	public static final int MIMETYPE_MP3 = 6;
	public static final int MIMETYPE_ASF = 7;
	public static final String serverVersion = "Custom Web server v.0.1";
	public static  String wwwRoot;

	HTTPServerConsole console = null;
	ServerSocket serverSocket = null;
	public HTTPServer(int port, HTTPServerConsole console, String wwwRoot) {
		this.wwwRoot = wwwRoot;
		this.console = console;
		try {
			console.logInfo("Trying to bind server to port " + port);
			serverSocket = new ServerSocket(port);
			console.logInfo("Server bound to port: " + port);
			console.logInfo("Server started normally");

		} catch(Exception e) {
			console.logError(e.toString());
		}

	}


	public void run() {

		while(true) {
			try {
				console.logInfo("Waiting for connections");
				Socket clientConnection = serverSocket.accept();

				console.logInfo("Incoming connection from " + clientConnection.getInetAddress().getHostName());
				BufferedReader bis = new BufferedReader(new InputStreamReader(clientConnection.getInputStream()));
				DataOutputStream dos = new DataOutputStream(clientConnection.getOutputStream());
				protocolHandler(bis, dos);

			} catch(Exception e) {
				console.logError(e.toString());
			}
		}
	}



	private void protocolHandler(BufferedReader input, DataOutputStream output) {
		try {
			String request = input.readLine();
			System.out.println(request);
			//processing the request

			if (request == null) {
				//null request is not valid
				output.writeBytes(constructHTTPHeader(403, MIMETYPE_HTML));
				output.close();
				console.logError("Request is null");
				return;
			}

			//process the request
			StringTokenizer strTok = new StringTokenizer(request, " ");
			String reqMethod = strTok.nextToken();
           		String resourceName = strTok.nextToken().substring(1); //remove slash

			if (reqMethod.equals("HEAD") || reqMethod.equals("GET") || reqMethod.equals("OPTIONS")) {
				try {
					console.logInfo("Client requested resource:" + new File(wwwRoot + resourceName).getAbsolutePath());
					FileInputStream fis = new FileInputStream(wwwRoot + resourceName);
					//check the type of resource
					if (supportedResource(resourceName)) {
						output.writeBytes(constructHTTPHeader(200, getMimeType(wwwRoot + resourceName)));
						if (reqMethod.equals("GET")){
						while (true) { //write the resource to the stream
							int b = fis.read();
							if (b == -1) {
								break; // end of file
							}
							output.write(b);}
						}
						output.close();
						fis.close();
						return;
					} else { //media type not supported
						output.writeBytes(constructHTTPHeader(403, MIMETYPE_HTML)); //access to this resource is forbidden
						output.close();
						console.logError("Resource type not supported:" + resourceName);
						return;
					}


				} catch(FileNotFoundException fnf) {
					output.writeBytes(constructHTTPHeader(404, MIMETYPE_HTML));
					output.close();
					console.logError("Resource not found");
					return;
				} catch(SecurityException se) {
					output.writeBytes(constructHTTPHeader(403, MIMETYPE_HTML));
					console.logError("Access is denied");
					output.close();
					return;
				}catch(Exception e) {
					output.writeBytes(constructHTTPHeader(500, MIMETYPE_HTML));
					output.close();
					return;
				}
			} else {
				output.writeBytes(constructHTTPHeader(501, 0)); //not implemented
				output.close();
				return;
			}



		} catch(Exception e) {
			console.logError("ERROR" + e.toString());
		}
	}


	private boolean supportedResource(String resource) {
		String cResource = resource.toUpperCase();

		if(cResource.endsWith(".JPEG") ||
				cResource.endsWith(".JPG") ||
				cResource.endsWith(".PNG") ||
				cResource.endsWith(".GIF") ||
				cResource.endsWith(".ZIP") ||
				cResource.endsWith("MP3")  ||
				cResource.endsWith("WMV")  ||
				cResource.endsWith(".HTML")) {
			return true;
		} else {
			return false;
		}
	}

	private int getMimeType(String resource) {
		String cResource = resource.toUpperCase();

		if (cResource.endsWith(".JPG") || cResource.endsWith(".JPEG"))
			return this.MIMETYPE_JPEG;
		else if (cResource.endsWith(".GIF") )
			return this.MIMETYPE_GIF;
		else if (cResource.endsWith(".PNG"))
			return this.MIMETYPE_PNG;
		else if (cResource.endsWith(".ZIP"))
			return this.MIMETYPE_ZIP;
		else if (cResource.endsWith(".MP3"))
			return this.MIMETYPE_MP3;
		else if (cResource.endsWith(".WMV"))
			return this.MIMETYPE_ASF;
		else //html
			return this.MIMETYPE_HTML;
	}

	private String constructHTTPHeader(int replyCode, int mimeType) {
		File file = new File(wwwRoot);
		String replyHeader = "HTTP/1.1 ";

		switch(replyCode) {
		case 200:
			replyHeader += "200 OK";
			break;
		case 400:
			replyHeader += "400 Bad Request";
			break;
		case 404:
			replyHeader += "404 Not Found";
			break;
		case 403:
			replyHeader += "403 Forbidden";
			break;
		case 501:
			replyHeader += "501 NOT Implemented";
			break;
		case 500:
			replyHeader += "500 Internal Server error";
			break;
		}
		replyHeader += "\r\n";
		Date d = new Date();
		replyHeader += "Date:" + d.toString() + "\r\n";
		//replyHeader += "Server:" + serverVersion + "\r\n";

		replyHeader += "Allow: GET, HEAD, OPTIONS\r\n";//It usually appears on a 405 error message, but as this message isn't handled above, the Allow option appears every time
		replyHeader += "Connection: close\r\n";
		replyHeader += "Content-Length: " + file.length() + "\r\n";
		replyHeader += "Last-Modified: " + file.lastModified() + "\r\n";

		switch(mimeType) {
		case MIMETYPE_JPEG:
			replyHeader  += "Content-Type: image/jpeg\r\n";
			break;
		case MIMETYPE_PNG:
			replyHeader  += "Content-Type: image/png\r\n";
			break;
		case MIMETYPE_GIF:
			replyHeader  += "Content-Type: image/GIF\r\n";
			break;
		case MIMETYPE_ZIP:
			replyHeader += "Content-Type: application/zip\r\n";
			break;
		case MIMETYPE_MP3:
			replyHeader  += "Content-Type: audio/mp3\r\n";
			break;
		case MIMETYPE_ASF:
			replyHeader += "Content-Type: video/x-ms-asf\r\n";
			break;
		default:
			replyHeader  += "Content-Type: text/html\r\n";
			break;
		}

		replyHeader += "\r\n";
		//System.out.println(replyHeader);
		return replyHeader;
	}

}