/*

Partner Names:
	Jonathan Beebe - <jjbeebe>
	Mark Loh - <mloh>

Description:
	
	This is our proxy that uses concurrent processes. It does not
implement a cache (although we have spent many many hours trying to get
it to work).

*/

#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "csapp.h"

#define MAX_CACHE_SIZE (1<<20)
#define MAX_OBJECT_SIZE (100*(1<<10))

/* function prototypes */
void *doit(void *fdp);
void read_requesthdrs(rio_t *rp, int fd);
void parseUrl(char **url, char **hostname, char **port, char **filename);

/* main function */
int main(int argc, char **argv) 
{
	int listenfd, port, clientlen = sizeof(struct sockaddr_in);
    	int *connfdp;
	struct sockaddr_in clientaddr;
	pthread_t tid;

    	/* Check command line args */
    	if (argc != 2) {
		fprintf(stderr, "usage: %s <port>\n", argv[0]);
		exit(1);
    	}
    	port = atoi(argv[1]);

	/* handle the SIGPIPE signal */
	signal(SIGPIPE, SIG_IGN);		

	/* open the neccessary ports */
    	listenfd = Open_listenfd(port);
    	while (1) {
		connfdp = Malloc(sizeof(int));
		*connfdp = Accept(listenfd, (SA *)&clientaddr, (unsigned int *) &clientlen); 
		/* spawn the new threads */
		pthread_create(&tid, NULL, doit, connfdp);
		pthread_detach(tid);
	}
}

/*
 * doit - handle one HTTP request/response transaction
 */
void *doit(void *fdp) 
{
    	char buf[MAXLINE], method[MAXLINE], uri[MAXLINE], version[MAXLINE];
	char *filename, *hostname, *port, *url;
    	char requestLine[MAXLINE];
	int serverfd, bytesRead; 
	int fd = *((int *) fdp);
	rio_t rio, rio2;
	
	/* stored it in the file descriptor - fd, thus free the pointer */ 
	Free(fdp);
	 
	url = uri;

    	/* Read request line and headers */
    	Rio_readinitb(&rio, fd);
    	Rio_readlineb(&rio, buf, MAXLINE);                   
    	sscanf(buf, "%s %s %s", method, url, version);       

	/* calls our parse Url function */	
	parseUrl(&url, &hostname, &port, &filename);

	/* open connection to correct host and port */	
	serverfd = Open_clientfd(hostname, atoi(port));
	
	/* parse the request line, and create string */	
	strcpy(requestLine, method);
	strcat(requestLine, " ");
	strcat(requestLine, filename);
	strcat(requestLine, " HTTP/1.0\r\n");
		
	/* writes the request line */
	Rio_writen(serverfd, requestLine, strlen(requestLine));

	/* then read the rest of the request headers */
	read_requesthdrs(&rio, serverfd);
	
	
	/* writes information back to the server */
	Rio_readinitb(&rio2, serverfd);
	while ( ((bytesRead = Rio_readnb(&rio2, buf, MAXBUF)) > 0) ){
		Rio_writen(fd, buf, bytesRead);
	}
	Close(serverfd);
	Close(fd);
	return NULL;
}


/*
 * read_requesthdrs - read and parse HTTP request headers
 */
void read_requesthdrs(rio_t *rp, int fd) 
{
    	char buf[MAXBUF];
	char *connection;
	int lineLength;
	
	/* read in the Host: <hostname> line */
    	lineLength = Rio_readlineb(rp, buf, MAXBUF);
	Rio_writen(fd, buf, lineLength);
	/* reads in request headers until last line */
	while(strcmp(buf, "\r\n")) {
		lineLength = Rio_readlineb(rp, buf, MAXBUF);
		/* handle header cases described in write-up */
    		if (strstr(buf, "Proxy-Connection")){
			connection = "Proxy-Connection: close\r\n";
			Rio_writen(fd, connection, strlen(connection));
		}
		else if(strstr(buf, "Connection")){
			connection = "Connection: close\r\n";
			Rio_writen(fd, connection, strlen(connection));
		}
		else if (!(strstr(buf, "Keep-Alive"))){
			Rio_writen(fd, buf, lineLength);
		}
	}
	
}

/* parses the given URL */
void parseUrl(char **url, char **hostname, char **port, char **filename){

	char * portVal;
	/* move past the http:// */
	char *temp = *url + 7;	
	
	int totLen = 0;
	int uriLen = 0;
	int portLen = 0;
	int hostLen = 0;

	*filename = strstr(temp, "/");
	*port = strstr(temp, ":");
	totLen = strlen(temp);
	
	/* check to see if there is a filename at the end */
	if(*filename)
		uriLen = strlen(*filename);
	else
		*filename = "/";
	/* return the port */
	if(*port){
		portLen = strlen(*port) - uriLen; 
		portVal = strndup(*port, portLen); 
		portVal++;
		*port = portVal;
	}	
	else
		*port = "80";
	
	/* default is to return the hostname */
	hostLen = totLen - (portLen + uriLen);	
	*hostname = strndup(temp, hostLen);

}