/*
** parser.c
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define MYPORT 3499    // the port users will be connecting to
#define BACKLOG 10     // how many pending connections queue will hold
#define MAXLEN 1024	//upper limit of the length of the string


int readline(int fd, char *buf, int maxlen);
void sendSomething(int fd, char * msg);

int main(void)
{
	char input[MAXLEN]; //the line that is read from the client
	char * token1; //GET request
	char * token2; //filepath
	char tmpstring[MAXLEN]; //filesize
    int sockfd, new_fd;  // listen on sock_fd, new connection on new_fd, file open on file_fd
    struct sockaddr_in my_addr;    // my address information
    struct sockaddr_in their_addr; // connector's address information
    int sin_size;
    int yes=1;
	int n; //the amount of read characters from the client

    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }

    if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {
        perror("setsockopt");
        exit(1);
    }
    
    my_addr.sin_family = AF_INET;         // host byte order
    my_addr.sin_port = htons(MYPORT);     // short, network byte order
    my_addr.sin_addr.s_addr = INADDR_ANY; // automatically fill with my IP
    memset(&(my_addr.sin_zero), '\0', 8); // zero the rest of the struct

    if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1) {
        perror("bind");
        exit(1);
    }

    if (listen(sockfd, BACKLOG) == -1) {
        perror("listen");
        exit(1);
    }

    while(1) {  // main accept() loop
        sin_size = sizeof(struct sockaddr_in);
        if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1) {
            perror("accept");
            continue;
        }

        printf("server: got connection from %s\n",inet_ntoa(their_addr.sin_addr));
	n = readline(new_fd, input, MAXLEN); //n is the amount of read characters
	if (n == -1) {
		perror("Unable to read line");
	}

	//Check if it is a GET message
	token1 = strtok(input," ");
	if(strcmp(token1, "GET") != 0)
	{
		sendSomething(new_fd, "Bad request\n");
	}
	else
	{
		//Retrieve the file path
		token2 = strtok(NULL, " ");
		if(token2 == NULL)
		{
			sendSomething(new_fd, "File path not specified\n"); //Check if filename is empty
			
		}
		sendSomething(new_fd, token2); //test
		printf("%s", token2);
		if(token2[0] == '/') //remove the initial slash	
			memmove(token2, token2 + 1, strlen(token2));
		sendSomething(new_fd, token2); //test
		sendSomething(new_fd, "test.html"); //test to compare		
		//Check if file is on the server
		if(open(token2, O_RDONLY) < 0) //Error opening file
		{
			if(errno == EACCES)			
				sendSomething(new_fd, "Access error\n");
			else
			{
				perror("Current problem: ");
				sendSomething(new_fd, "Not existed\n");
			}
				
		}
		else
		{

			FILE * requested_file = fopen(token2, "r");
			if(requested_file == NULL) //
			{
				sendSomething(new_fd, "Error in fopen\n");
			}
			else
			{
				sendSomething(new_fd, "File found\n"); //successful
			}
			fseek(requested_file, 0, SEEK_END); // move to the end of the file
			int end=  ftell(requested_file);	// get the position of the end of file
			int stringlen = sprintf(tmpstring, "file size: %d\n", end);
			send(new_fd, tmpstring, stringlen, 0);
		}
		
	}

        close(new_fd); //close connection
    }

    return 0;
}

//helper function for recieving text
int readline(int fd, char *buf, int maxlen)
{
    int n, rc;
    char c;

    for (n = 1; n < maxlen; n++) {
	if ((rc = read(fd, &c, 1)) == 1) {
		*buf++ = c;
		if (c == '\n')
	break;
	} else if (rc == 0) {
		if (n == 1)
		return 0; // EOF, no data read
	else
		break; // EOF, read some data
		} else
	return -1; // error
    }

    *buf = '\0'; // null-terminate
    return n;
}

void sendSomething(int fd, char * msg)
{
	int length = strlen(msg);
	send(fd, msg, length, 0);	
}