/**
 * libpsyc test server for packet parsing & rendering
 * based on selectserver.c from http://beej.us/guide/bgnet/
 */

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

#include <psyc/lib.h>
#include <psyc/parser.h>
#include <psyc/render.h>

const size_t RECV_BUF_SIZE = 256;
const size_t SEND_BUF_SIZE = 1024;
const size_t NUM_PARSERS = 100;

// get sockaddr, IPv4 or IPv6:
void *get_in_addr(struct sockaddr *sa)
{
	if (sa->sa_family == AF_INET) {
		return &(((struct sockaddr_in*)sa)->sin_addr);
	}

	return &(((struct sockaddr_in6*)sa)->sin6_addr);
}

int main(int argc, char **argv)
{
	char *port = argc > 1 ? argv[1] : "4440";
	uint8_t verbose = argc > 2;

	fd_set master;    // master file descriptor list
	fd_set read_fds;  // temp file descriptor list for select()
	int fdmax;        // maximum file descriptor number

	int listener;     // listening socket descriptor
	int newfd;        // newly accept()ed socket descriptor
	struct sockaddr_storage remoteaddr; // client address
	socklen_t addrlen;

	char buf[2*RECV_BUF_SIZE];            // cont buf + recv buf: [  ccrrrr]
	char *recvbuf = buf + RECV_BUF_SIZE;  // recv buf:                 ^^^^
	char *parsebuf;                       // parse buf:              ^^^^^^
	char sendbuf[SEND_BUF_SIZE];
	size_t nbytes, contbytes = 0;

	char remoteIP[INET6_ADDRSTRLEN];

	int yes = 1;        // for setsockopt() SO_REUSEADDR, below
	int i, rv;

	struct addrinfo hints, *ai, *p;

	psycParseState parsers[NUM_PARSERS];
	psycPacket packets[NUM_PARSERS];

	int ret, retl;
	char oper;
	psycString name, value, elem;
	psycParseListState listState;

	FD_ZERO(&master);    // clear the master and temp sets
	FD_ZERO(&read_fds);

	// get us a socket and bind it
	memset(&hints, 0, sizeof hints);
	hints.ai_family = AF_UNSPEC;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_flags = AI_PASSIVE;
	if ((rv = getaddrinfo(NULL, port, &hints, &ai)) != 0) {
		fprintf(stderr, "error: %s\n", gai_strerror(rv));
		exit(1);
	}
	
	for (p = ai; p != NULL; p = p->ai_next) {
		listener = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
		if (listener < 0) { 
			continue;
		}
		
		// lose the pesky "address already in use" error message
		setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));

		if (bind(listener, p->ai_addr, p->ai_addrlen) < 0) {
			close(listener);
			continue;
		}

		break;
	}

	// if we got here, it means we didn't get bound
	if (p == NULL) {
		fprintf(stderr, "failed to bind\n");
		exit(2);
	}

	freeaddrinfo(ai); // all done with this

	// listen
	if (listen(listener, 10) == -1) {
		perror("listen");
		exit(3);
	}

	// add the listener to the master set
	FD_SET(listener, &master);

	// keep track of the biggest file descriptor
	fdmax = listener; // so far, it's this one

	// main loop
	for (;;) {
		read_fds = master; // copy it
		if (select(fdmax+1, &read_fds, NULL, NULL, NULL) == -1) {
			perror("select");
			exit(4);
		}

		// run through the existing connections looking for data to read
		for (i = 0; i <= fdmax; i++) {
			if (FD_ISSET(i, &read_fds)) { // we got one!!
				if (i == listener) {
					// handle new connections
					if (fdmax == NUM_PARSERS - 1)
						continue; // ignore if there's too many

					addrlen = sizeof remoteaddr;
					newfd = accept(listener, (struct sockaddr *)&remoteaddr, &addrlen);

					if (newfd == -1) {
						perror("accept");
					} else {
						FD_SET(newfd, &master); // add to master set
						if (newfd > fdmax) {    // keep track of the max
							fdmax = newfd;
						}

						// reset parser state & packet
						psyc_initParseState(&parsers[newfd]);
						memset(&packets[newfd], 0, sizeof(psycPacket));

						printf("# New connection from %s on socket %d\n",
						       inet_ntop(remoteaddr.ss_family,
						                 get_in_addr((struct sockaddr*)&remoteaddr),
						                 remoteIP, INET6_ADDRSTRLEN),
						       newfd);
					}
				} else {
					// handle data from a client
					if ((nbytes = recv(i, recvbuf, RECV_BUF_SIZE, 0)) <= 0) {
						// got error or connection closed by client
						if (nbytes == 0) {
							// connection closed
							printf("socket %d hung up\n", i);
						} else {
							perror("recv");
						}
						close(i); // bye!
						FD_CLR(i, &master); // remove from master set
					} else {
						// we got some data from a client
						parsebuf = recvbuf - contbytes;
						psyc_nextParseBuffer(&parsers[i], psyc_newString(parsebuf, contbytes + nbytes));
						contbytes = 0;

						do {
							ret = psyc_parse(&parsers[i], &oper, &name, &value);
							switch (ret) {
								case PSYC_PARSE_ROUTING:
								case PSYC_PARSE_ENTITY:
								case PSYC_PARSE_ENTITY_INCOMPLETE:
									if (verbose)
										write(1, &oper, 1);
								case PSYC_PARSE_BODY:
								case PSYC_PARSE_BODY_INCOMPLETE:
									if (ret == PSYC_PARSE_BODY_INCOMPLETE ||
									    ret == PSYC_PARSE_ENTITY_INCOMPLETE)
										ret = 0;

									// printf("the string is '%.*s'\n", name);
									if (verbose) {
										write(1, name.ptr, name.length);
										write(1, " = ", 3);
										write(1, value.ptr, value.length);
										write(1, "\n", 1);
									}
									if (memcmp(name.ptr, "_list", 5) == 0) {
										if (verbose)
											write(1, ">>> LIST START\n", 15);
										psyc_initParseListState(&listState);
										psyc_nextParseListBuffer(&listState, value);
										do {
											retl = psyc_parseList(&listState, &name, &value, &elem);
											switch (retl) {
												case PSYC_PARSE_LIST_END:
													retl = 0;
												case PSYC_PARSE_LIST_ELEM:
													if (verbose) {
														write(1, "|", 1);
														write(1, elem.ptr, elem.length);
														write(1, "\n", 1);
														if (ret == PSYC_PARSE_LIST_END)
															write(1, ">>> LIST END\n", 13);
													}
													break;
												default:
													printf("# Error while parsing list: %i\n", ret);
													ret = retl = -1;
											}
										} while (retl > 0);
									}
									break;
								case PSYC_PARSE_COMPLETE:
									printf("# Done parsing.\n");
#ifdef RENDER_WORKS
									psyc_render(&packets[i], sendbuf, SEND_BUF_SIZE);
									if (send(i, sendbuf, packets[i].length, 0) == -1) {
										perror("send");
									}
#endif
									ret = -1;
									break;
								case PSYC_PARSE_INSUFFICIENT:
									printf("# Insufficient data.\n");
									contbytes = parsers[i].buffer.length - parsers[i].cursor;
									if (contbytes > 0) { // copy end of parsebuf before start of recvbuf
										assert(recvbuf - contbytes >= buf); // make sure it's still in the buffer
										memcpy(recvbuf - contbytes, parsebuf + parsers[i].cursor, contbytes);
									}
									ret = 0;
									break;
								default:
									printf("# Error while parsing: %i\n", ret);
									ret = -1;
							}
						} while (ret > 0);
						if (ret < 0) {
							printf("# Closing connection: %i\n", i);
							close(i); // bye!
							FD_CLR(i, &master); // remove from master set
						}
					}
				} // END handle data from client
			} // END got new incoming connection
		} // END looping through file descriptors
	} // END for(;;)--and you thought it would never end!

	return 0;
}