#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <poll.h>

#include "logger.h"
#include "fader.h"

#include "udpproto.h"

#define SET_COLOUR   0
#define FADE_COLOUR  1
#define ADD_COLOUR   2
#define SET_FADESTEP 3

int sock;

int udpproto_init(uint16_t port)
{
	struct sockaddr_in listen_addr;

	// initialize UDP server socket
	sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if(sock == -1) {
		LOG(LVL_ERR, "udpproto: Could not initialize UDP socket: %s.", strerror(errno));
		return -1;
	}

	memset(&listen_addr, 0, sizeof(listen_addr));
	listen_addr.sin_family = AF_INET;
	listen_addr.sin_port = htons(port);
	listen_addr.sin_addr.s_addr = htonl(INADDR_ANY);

	if(bind(sock, (struct sockaddr*)&listen_addr, sizeof(listen_addr)) == -1) {
		LOG(LVL_ERR, "udpproto: Could not bind socket to port %i: %s.", port, strerror(errno));
		return -1;
	}

	return 0;
}

int udpproto_process(void)
{
	socklen_t remote_addr_len;
	struct sockaddr remote_addr;
	uint8_t pkgbuf[65536];
	ssize_t rcvbytes, offset = 0;

	uint8_t r, g, b, w, action, module;
	int fds_ready;

	// check if there is data to be read (to prevent blocking)
	struct pollfd pfd = {
		.fd = sock,
		.events = POLLIN,
		.revents = 0
	};

	fds_ready = poll(&pfd, 1, 0);
	if(fds_ready == -1) {
		LOG(LVL_ERR, "udpproto: poll() failed: %s.", strerror(errno));
		return -1;
	} else if(fds_ready == 0) {
		// there's nothing to be read
		return 0;
	}

	// receive the data
	remote_addr_len = sizeof(remote_addr);
	rcvbytes = recvfrom(sock, pkgbuf, 65536, 0, (struct sockaddr*)&remote_addr, &remote_addr_len);
	if(rcvbytes == -1) {
		LOG(LVL_ERR, "udpproto: recvfrom() failed: %s.", strerror(errno));
		return -1;
	}

	pkgbuf[rcvbytes] = 0;

	// parse commands from packet
	offset = 0;
	while(offset <= rcvbytes - 5) {
		action = pkgbuf[offset + 0];
		module = pkgbuf[offset + 1];
		r      = pkgbuf[offset + 2];
		g      = pkgbuf[offset + 3];
		b      = pkgbuf[offset + 4];
		w      = pkgbuf[offset + 5];
		offset += 5;

		switch(action) {
			case SET_COLOUR:
				fader_set_colour(module, r, g, b, w);
				break;

			case FADE_COLOUR:
				fader_fade_colour(module, r, g, b, w);
				break;

			case ADD_COLOUR:
				fader_add_colour(module, r, g, b, w);
				break;

			case SET_FADESTEP:
				fader_set_fadestep(r); // red channel contains the fadestep in this case
				break;

			default:
				LOG(LVL_DEBUG, "udpproto: Action %u not implemented yet.", action);
		}
	}

	return rcvbytes / 6; // number of commands in packet
}

void udpproto_shutdown(void)
{
	close(sock);
}