/* Copyright 2016 Luke Shumaker */

#include <error.h>
#include <errno.h>
#include <netdb.h> /* for {get,free}addrinfo() */
#include <stdlib.h> /* for EXIT_FAILURE */
#include <sys/socket.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/stat.h> /* for open */
#include <fcntl.h> /* for open */

#include "util.h"
#include "mpjpeg.h"

struct httpfile {
	char name[256];
	struct mpjpeg_stream *stream;
};

size_t filec = 0;
struct httpfile *filev = NULL;

struct reader_thread_args {
	struct mpjpeg_stream *stream;
	int fd;
	const char *boundary;
};

void *reader_thread(void *args_anon) {
	struct reader_thread_args *args = args_anon;
	mpjpeg_reader(args->stream, args->fd, args->boundary);
	error(EXIT_FAILURE, 0, "mpjpeg stream ended");
	return NULL;
}

void start_mpjpeg_reader(struct mpjpeg_stream *s, int fd, const char *boundary) {
	struct reader_thread_args *args = xrealloc(NULL, sizeof(struct reader_thread_args));
	args->stream = s;
	args->fd = fd;
	args->boundary = boundary;
	pthread_t thread;
	pthread_create(&thread, NULL, reader_thread, args);
}

void file_add(const char *filename) {
	struct mpjpeg_stream *stream = xrealloc(NULL, sizeof(struct mpjpeg_stream));
	init_mpjpeg_stream(stream);
	int fd = open(filename, O_RDONLY);
	if (fd < 0)
		error(EXIT_FAILURE, errno, "opening file: %s", filename);
	filev = xrealloc(filev, (++filec)*sizeof(*filev));
	const char *shortname = strrchr(filename, '/');
	if (shortname == NULL)
		shortname = filename;
	strncpy(filev[filec-1].name, shortname, sizeof(filev[filec-1].name));
	error(0, 0, "added file #%zd: %s", filec-1, filev[filec-1].name);
	filev[filec-1].stream = stream;
	start_mpjpeg_reader(stream, fd, "ffserver" /* FIXME */);
}

struct mpjpeg_stream *file_get(const char *filename) {
	for (size_t i = 0; i < filec; i++) {
		if (strncmp(filename, filev[i].name, sizeof(filev[i].name)) == 0) {
			return filev[i].stream;
		}
	}
	return NULL;
}

int tcp4_parse_listen(const char *port) {
	int r;
	struct addrinfo *addr = NULL;
	struct addrinfo hints = { 0 };
	hints.ai_family = AF_INET;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_flags = AI_PASSIVE;

	if ((r = getaddrinfo(NULL, port, &hints, &addr)) != 0)
		error(EXIT_FAILURE, r, _("Could not resolve TCP4 port %s"), port);

	int sock = socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
	if (sock < 0)
		error(EXIT_FAILURE, errno, _("Could not create a TCP4 socket"));

	int yes = 1;
	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));

	if (bind(sock, addr->ai_addr, addr->ai_addrlen) < 0)
		error(EXIT_FAILURE, errno, _("Could not bind to TCP4 port %s"), port);

	if (listen(sock, 5) < 0)
		error(EXIT_FAILURE, errno, _("Could not listen on TCP4 port %s"), port);

	freeaddrinfo(addr);
	return sock;
}

void connection_handler(int fd) {
	FILE *netstream = fdopen(fd, "r");
	char *line_buf = NULL;
	size_t line_cap = 0;
	ssize_t line_len = 0;

	line_len = getline(&line_buf, &line_cap, netstream);
	/* expect line to be "GET /path.mjpg HTTP/1.1" */
	if (strncmp(line_buf, "GET ", 4) != 0) {
		dprintf(fd,
		        "HTTP/1.1 405 Method Not Allowed\r\n"
		        "Allow: GET\r\n"
		        "\r\n");
		close(fd);
		return;
	}
	char *version = &line_buf[4];
	char *path = strsep(&version, " ");
	if (strcmp(version, "HTTP/1.1\r\n") != 0 && strcmp(version, "HTTP/1.0\r\n")) {
		close(fd);
		return;
	}
	path = strdupa(path);

	/* run through the rest of the headers */
	while (strcmp(line_buf, "\r\n") != 0 && line_len >= 0)
		line_len = getline(&line_buf, &line_cap, netstream);

	struct mpjpeg_stream *vidstream = file_get(path);
	if (vidstream == NULL) {
		error(0, 0, "404 %s", path);
		dprintf(fd,
		        "HTTP/1.1 404 Not Found\r\n"
		        "\r\n");
		return;
	}

	const char *boundary = "boundary" /* FIXME */;
	error(0, 0, "200 %s", path);
	dprintf(fd,
	        "HTTP/1.1 200 OK\r\n"
	        "Content-Type: multipart/x-mixed-replace;boundary=%s\r\n"
	        "\r\n",
	        boundary);
	mpjpeg_writer(vidstream, fd, boundary);
	close(fd);
}

void *connection_thread(void *arg_anon) {
	int fd = (int)(intptr_t)arg_anon;
	error(0, 0, "Connection %d opened", fd);
	connection_handler(fd);
	error(0, 0, "Connection %d closed", fd);
	return NULL;
}

void usage() {
	printf("Usage: %s [-h] PORT [FILENAME...]\n", program_invocation_name);
}

int main(int argc, char *argv[]) {
	if (argc < 2) {
		dup2(2, 1);
		usage();
		return EXIT_FAILURE;
	}
	if (strcmp(argv[1], "-h") == 0) {
		usage();
		return EXIT_SUCCESS;
	}
	int sock = tcp4_parse_listen(argv[1]);

	for (int i = 2; i < argc; i++)
		file_add(argv[i]);

	signal(SIGPIPE, SIG_IGN);
	while (1) {
		int conn = accept(sock, NULL, NULL);
		if (conn < 0)
			continue;
		pthread_t thread;
		pthread_create(&thread, NULL, connection_thread, (void*)(intptr_t)conn);
	}

	return 0;
}