//g++ -std=c++11 threads.cpp picohttpparser.c -march=native -pthread -O3 -o threads
//requires picohttpparser.{c,h} from https://github.com/h2o/picohttpparser
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <thread>

#include "picohttpparser.h"

void error(const char *msg) {
  perror(msg);
  exit(1);
}

void thread_main(int childfd) {
    while(1) {
            char buf[4096], *method, *path;
            int pret, minor_version;
            struct phr_header headers[100];
            size_t buflen = 0, prevbuflen = 0, method_len, path_len, num_headers;
            ssize_t rret;
	    while (1) {
		    /* read the request */
		    while ((rret = read(childfd, buf + buflen, sizeof(buf) - buflen)) == -1 && errno == EINTR)
			    ;
		    if (rret < 0)
			    error("ERROR reading from socket");
		    else if(rret == 0) {
			    //EOF
			    goto got_eof;
		    }
		    prevbuflen = buflen;
		    buflen += rret;
		    /* parse the request */
		    num_headers = sizeof(headers) / sizeof(headers[0]);
		    pret = phr_parse_request(buf, buflen, (const char**) &method, &method_len, (const char**) &path, &path_len,
				    &minor_version, headers, &num_headers, prevbuflen);
		    if (pret > 0)
			    goto got_http;
		    else if (pret == -1)
                            error("ERROR http parse error");
		    /* request is incomplete, continue the loop */
		    if (buflen == sizeof(buf))
                            error("ERROR http request too long");
	    }
            got_http:
	    //printf("request is %d bytes long\n", pret);
	    //printf("method is %.*s\n", (int)method_len, method);
	    //printf("path is %.*s\n", (int)path_len, path);
	    //printf("HTTP version is 1.%d\n", minor_version);
	    //printf("headers:\n");
	    //for (int i = 0; i != num_headers; ++i) {
	    //        printf("%.*s: %.*s\n", (int)headers[i].name_len, headers[i].name,
	    //    		    (int)headers[i].value_len, headers[i].value);
	    //}
            const char out[]  = "HTTP/1.1 200\r\nServer: Performance Test\r\n\r\n";
            int out_written = 0;
            while(out_written != sizeof(out) -1) {
              int n = write(childfd, out + out_written, sizeof(out) - 1 - out_written);
              if(n == -1) {
                if(errno == EINTR) continue;
                error("ERROR writing to socket");
              }
              out_written += n;
            }
    }
    got_eof:
    close(childfd);
}

int main(int argc, char **argv) {
  int parentfd; /* parent socket */
  int childfd; /* child socket */
  int portno; /* port to listen on */
  socklen_t clientlen; /* byte size of client's address */
  struct sockaddr_in serveraddr; /* server's addr */
  struct sockaddr_in clientaddr; /* client addr */
  int optval; /* flag value for setsockopt */

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

  parentfd = socket(AF_INET, SOCK_STREAM, 0);
  if (parentfd < 0) 
    error("ERROR opening socket");

  optval = 1;
  setsockopt(parentfd, SOL_SOCKET, SO_REUSEADDR, 
	     (const void *)&optval , sizeof(int));

  bzero((char *) &serveraddr, sizeof(serveraddr));

  serveraddr.sin_family = AF_INET;

  serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
  serveraddr.sin_port = htons((unsigned short)portno);
  if (bind(parentfd, (struct sockaddr *) &serveraddr, 
	   sizeof(serveraddr)) < 0) 
    error("ERROR on binding");
  if (listen(parentfd, 128) < 0) /* allow 5 requests to queue up */ 
    error("ERROR on listen");
  clientlen = sizeof(clientaddr);
  while (1) {
    childfd = accept(parentfd, (struct sockaddr *) &clientaddr, &clientlen);
    if (childfd < 0) 
      error("ERROR on accept");
    std::thread t(thread_main, childfd);
    t.detach();
  }
}