/*
    * bmpServer.c
    * 1917 serve that 3x3 bmp from lab3 Image activity
    *
    * Created by Tim Lambert on 02/04/12.
    * Containing code created by Richard Buckland on 28/01/11.
    * Copyright 2012 Licensed under Creative Commons SA-BY-NC 3.0.
    *
    */

    #include <stdlib.h>
    #include <stdio.h>
    #include <netinet/in.h>
    #include <string.h>
    #include <assert.h>
    #include <unistd.h>

    int waitForConnection (int serverSocket);
    int makeServerSocket (int portno);
    void serveBMP (int socket);

    #define SIMPLE_SERVER_VERSION 1.0
    #define REQUEST_BUFFER_SIZE 1000
    #define DEFAULT_PORT 1917
    #define NUMBER_OF_PAGES_TO_SERVE 10
    // after serving this many pages the server will halt

    int main (int argc, char *argv[]) {
    printf ("************************************\n");
    printf ("Starting simple server %f\n", SIMPLE_SERVER_VERSION);
    printf ("Serving bmps since 2012\n");
    int serverSocket = makeServerSocket (DEFAULT_PORT);
    printf ("Access this server at http://localhost:%d/\n", DEFAULT_PORT);
    printf ("************************************\n");
    char request[REQUEST_BUFFER_SIZE];
    int numberServed = 0;
    while (numberServed < NUMBER_OF_PAGES_TO_SERVE) {
    printf ("*** So far served %d pages ***\n", numberServed);
    int connectionSocket = waitForConnection (serverSocket);
    // wait for a request to be sent from a web browser, open a new
    // connection for this conversation
    // read the first line of the request sent by the browser
    int bytesRead;
    bytesRead = read (connectionSocket, request, (sizeof request)-1);
    assert (bytesRead >= 0);
    // were we able to read any data from the connection?
    // print entire request to the console
    printf (" *** Received http request ***\n %s\n", request);
    //send the browser a simple html page using http
    printf (" *** Sending http response ***\n");
    serveBMP(connectionSocket);
    // close the connection after sending the page- keep aust beautiful
    close(connectionSocket);
    numberServed++;
    }
    // close the server connection after we are done- keep aust beautiful
    printf ("** shutting down the server **\n");
    close (serverSocket);
    return EXIT_SUCCESS;
    }

    void serveBMP (int socket) {
    char* message;
    // first send the http response header
    // (if you write stings one after another like this on separate
    // lines the c compiler kindly joins them togther for you into
    // one long string)
    message = "HTTP/1.0 200 OK\r\n"
    "Content-Type: image/bmp\r\n"
    "\r\n";
    printf ("about to send=> %s\n", message);
    write (socket, message, strlen (message));
    // now send the BMP
    unsigned char bmp[] = {
    0x42,0x4d,0x5a,0x00,0x00,0x00,0x00,0x00,
    0x00,0x00,0x36,0x00,0x00,0x00,0x28,0x00,
    0x00,0x00,0x03,0x00,0x00,0x00,0x03,0x00,
    0x00,0x00,0x01,0x00,0x18,0x00,0x00,0x00,
    0x00,0x00,0x24,0x00,0x00,0x00,0x13,0x0b,
    0x00,0x00,0x13,0x0b,0x00,0x00,0x00,0x00,
    0x00,0x00,0x00,0x00,0x00,0x00,0x07,0x07,
    0xff,0x07,0x07,0x07,0x07,0x07,0xff,0x00,
    0x00,0x0e,0x07,0x07,0x07,0x66,0x07,0x07,
    0x07,0x07,0x07,0x00,0x00,0x0d,0x07,0x07,
    0x07,0x07,0x07,0x07,0xff,0xff,0xff,0x00,
    0x00,0x0d};


    write (socket, bmp, sizeof(bmp));
    }


    // start the server listening on the specified port number
    int makeServerSocket (int portNumber) {
    // create socket
    int serverSocket = socket (AF_INET, SOCK_STREAM, 0);
    assert (serverSocket >= 0);
    // error opening socket
    // bind socket to listening port
    struct sockaddr_in serverAddress;
    bzero ((char *) &serverAddress, sizeof (serverAddress));
    serverAddress.sin_family = AF_INET;
    serverAddress.sin_addr.s_addr = INADDR_ANY;
    serverAddress.sin_port = htons (portNumber);
    // let the server start immediately after a previous shutdown
    int optionValue = 1;
    setsockopt (
    serverSocket,
    SOL_SOCKET,
    SO_REUSEADDR,
    &optionValue,
    sizeof(int)
    );

    int bindSuccess =
    bind (
    serverSocket,
    (struct sockaddr *) &serverAddress,
    sizeof (serverAddress)
    );
    assert (bindSuccess >= 0);
    // if this assert fails wait a short while to let the operating
    // system clear the port before trying again
    return serverSocket;
    }

    // wait for a browser to request a connection,
    // returns the socket on which the conversation will take place
    int waitForConnection (int serverSocket) {
    // listen for a connection
    const int serverMaxBacklog = 10;
    listen (serverSocket, serverMaxBacklog);
    // accept the connection
    struct sockaddr_in clientAddress;
    socklen_t clientLen = sizeof (clientAddress);
    int connectionSocket =
    accept (
    serverSocket,
    (struct sockaddr *) &clientAddress,
    &clientLen
    );
    assert (connectionSocket >= 0);
    // error on accept
    return (connectionSocket);
    }