package httpserver;

import java.io.IOException;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.text.SimpleDateFormat;

import java.util.HashMap;

import java.util.Date;

import java.util.Map;

import java.util.TimeZone;

public abstract class HttpResponse {

protected static SimpleDateFormat rfc1123Format;

static {

rfc1123Format = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss 'GMT'");

rfc1123Format.setTimeZone(TimeZone.getTimeZone("UTC"));

}

protected HttpStatus status;

protected HashMap<String, String> headers;

protected HttpRequest request;

protected boolean persistent;

private void setPersistentFlag() {

String connectionRequest = request.getHeader("Connection");

persistent = connectionRequest == null ||

connectionRequest.toLowerCase().equals("keep-alive");

}

public HttpResponse() {

this(new HttpRequest());

}

public HttpResponse(HttpRequest httpRequest) {

this(HttpStatus.OK(), httpRequest);

}

public HttpResponse(HttpStatus responseStatus, HttpRequest httpRequest) {

status = responseStatus;

headers = new HashMap<String, String>();

request = httpRequest;

setPersistentFlag();

}

public String toString() {

return status.toResponseBody();

}

public void setHeader(String headerName, String headerValue) {

headers.put(headerName.toLowerCase(), headerValue.trim());

}

public boolean hasBody() {

return !(

status.equals(HttpStatus.NoContent()) ||

status.equals(HttpStatus.NotModified()) ||

request.getMethod() == HttpRequest.Method.HEAD);

}

protected void addRequiredHeaders() {

Date now = new Date(System.currentTimeMillis());

setHeader("Date", rfc1123Format.format(now));

if (!persistent) {

setHeader("Connection", "close");

} else {

setHeader("Keep-Alive", String.format("timeout=%1d", HttpServer.DEFAULT_TIMEOUT));

}

}

public boolean isPersistent() {

return persistent;

}

public void write(OutputStream out) throws IOException {

// Finalize Reponse

addRequiredHeaders();

PrintWriter writer = new PrintWriter(out, true);

writer.println(status.toResponseLine());

for (Map.Entry<String, String> header: headers.entrySet()) {

writer.println(String.format("%1s: %2s", header.getKey(), header.getValue()));

}

writer.println("");

writer.flush();

if (hasBody()) {

writeBody(out);

}

}

public abstract void writeBody(OutputStream out) throws IOException;

}