/***************************************************************************
 *   Copyright (C) 07/2007 by Olaf Rempel                                  *
 *   razzor@kopf-tisch.de                                                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; version 2 of the License                *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "configfile.h"
#include "event.h"
#include "httpd.h"
#include "linebuffer.h"
#include "list.h"
#include "logging.h"
#include "sockaddr.h"
#include "tcpsocket.h"
#include "torrentfile.h"

struct client_stats {
	/* current bandwidth up/down */
	int bw_up;
	int bw_dn;

	/* total bytes up/down */
	unsigned long long total_up;
	unsigned long long total_dn;

	/* clients cloud view */
	int chunk_total;
	int chunk_avail;
	int chunk_have;
};

struct client_con {
	struct list_head list;
	struct torrent_file *torrent;

	struct sockaddr_in addr;
	struct event_fd *event;
	struct linebuffer *lbuf;

	/* download stats */
	struct client_stats stats;

	/* timestamp when this client completed */
	long completed;
};

static struct event_fd *listen_event;
static struct event_fd *httpd_event;
static struct event_timeout *timeout_event;

static void free_client(struct client_con *con)
{
	list_del(&con->list);

	/* remove torrents without clients */
	if (list_empty(&con->torrent->client_list))
		destroy_torrent(con->torrent);

	close(event_get_fd(con->event));
	event_remove_fd(con->event);
	free(con->lbuf);
	free(con);
}

static int ctcs_data_handler(int fd, void *privdata)
{
	struct client_con *con = (struct client_con *)privdata;
	struct client_stats *stats = &con->stats;

	/* get data from socket */
	if (linebuffer_readfd(con->lbuf, fd) < 0) {
		free_client(con);
		return -1;
	}

	char *line;
	while ((line = linebuffer_getline(con->lbuf, NULL)) != NULL) {
		/* bandwidth update */
		if (strncmp(line, "CTBW ", 5) == 0) {
			int bwup, bwdn, liup, lidn;
			if (sscanf(line +5, "%d,%d %d,%d", &bwdn, &bwup, &lidn, &liup) == 4) {
				stats->bw_up = bwup;
				stats->bw_dn = bwdn;
			}

		/* status update (assume protocol v2) */
		} else if (strncmp(line, "CTSTATUS ", 9) == 0) {
			int seeds1 = 0, seeds2 = 0, leech1 = 0, leech2 = 0, count = 0;
			int chunk1 = 0, chunk2 = 0, chunk3 = 0, bwdn = 0, bwup = 0;
			int lidn = 0, liup = 0, cache = 0;
			unsigned long long totdn = 0, totup = 0;

			if (sscanf(line +9, "%d:%d/%d:%d/%d %d/%d/%d %d,%d %llu,%llu %d,%d %d",
						&seeds1, &seeds2, &leech1, &leech2, &count,
						&chunk1, &chunk2, &chunk3,
						&bwdn, &bwup, &totdn, &totup,
						&lidn, &liup, &cache) == 15) {

				stats->bw_up = bwup;
				stats->bw_dn = bwdn;
				stats->total_up = totup;
				stats->total_dn = totdn;
				stats->chunk_have = chunk1;
				stats->chunk_total = chunk2;
				stats->chunk_avail = chunk3;
			}

		/* update torrent-file */
		} else if (strncmp(line, "CTORRENT ", 9) == 0) {
			char *filename = strrchr(line +9, ' ');
			if (filename != NULL && strcmp(filename, con->torrent->name) != 0) {
				struct torrent_file *torrent = find_create_torrent(filename +1);
				if (torrent != NULL) {
					list_del(&con->list);
					list_add_tail(&con->list, &torrent->client_list);
					con->torrent = torrent;
				}
			}
		}
		linebuffer_freeline(con->lbuf);
	}

	/* client completed? */
	if (stats->chunk_have == stats->chunk_total && stats->chunk_total != 0 && con->completed == 0) {
		con->completed = time(NULL);

		list_del(&con->list);

		/* sorted insert, completed on top of list, ordered by complete-timestamp */
		struct client_con *search;
		list_for_each_entry(search, &con->torrent->client_list, list) {
			if (search->completed == 0)
				break;

			if (search->completed > con->completed)
				break;
		}
		list_add_tail(&con->list, &search->list);
		return 0;
	}
	return 0;
}

static int ctcs_trigger_status(void *privdata)
{
	long timeout = time(NULL) - (int)privdata;

	struct torrent_file *torrent;
	list_for_each_entry(torrent, &torrent_list, list) {
		int seeder = 0;
		int leecher = 0;

		struct client_con *con;
		list_for_each_entry(con, &torrent->client_list, list) {
			write(event_get_fd(con->event), "SENDSTATUS\n", 11);

			if (con->completed)
				seeder++;
			else
				leecher++;
		}

		/* no seeders available and no local seeder running => spawn one */
		if (leecher > 0 && seeder == 0 && torrent->child == NULL)
			seed_torrent(torrent);

		/* delete holds the number of clients to quit */
		int delete = seeder - leecher;
		list_for_each_entry(con, &torrent->client_list, list) {
			if (delete <= 0)
				break;

			if (con->completed == 0 || con->completed > timeout)
				continue;

			write(event_get_fd(con->event), "CTQUIT\n", 7);
			delete--;
		}
	}
	return 0;
}

static int ctcs_accept_handler(int fd, void *privdata)
{
	struct client_con *con = malloc(sizeof(struct client_con));
	if (con == NULL) {
		log_print(LOG_WARN, "accept_cb(): out of memory");
		return 0;
	}

	memset(con, 0, sizeof(struct client_con));

	con->lbuf = create_linebuffer(1024);
	if (con->lbuf == NULL) {
		log_print(LOG_WARN, "accept_cb(): out of memory");
		free(con);
		return 0;
	}

	int sockfd = tcp_accept(fd, &con->addr);
	if (sockfd < 0) {
		log_print(LOG_WARN, "accept_cb(): tcp_accept()");
		free(con->lbuf);
		free(con);
		return 0;
	}

	con->event = event_add_readfd(NULL, sockfd, ctcs_data_handler, con);

	/* assign default torrent */
	con->torrent = find_create_torrent("[unknown]");
	list_add_tail(&con->list, &con->torrent->client_list);
	return 0;
}

static int ctcs_httpd_show(struct httpd_con *con, void *privdata)
{
	struct linebuffer *lbuf = create_linebuffer(16384);
	if (lbuf == NULL) {
		httpd_send_error(con, "500 ERROR", "Out of Memory");
		return -1;
	}

	linebuffer_printf(lbuf, "HTTP/1.0 200 OK\r\nContent-Type: text/html\r\nConnection: close\r\n\r\n");
	linebuffer_printf(lbuf, "<html><head><meta http-equiv=\"refresh\" content=\"30;\"></head><body><h1>ctorrent stats</h1>\n");

	struct torrent_file *torrent;
	list_for_each_entry(torrent, &torrent_list, list) {
		if (list_empty(&torrent->client_list))
			continue;

		linebuffer_printf(lbuf, "<table border=\"1\">\n<tr><td colspan=\"6\" align=\"center\">%s</td></tr>\n", torrent->name);
		linebuffer_printf(lbuf, "<tr></td><td><b>Client IP:Port</b></td><td><b>Chunks (have/total/avail)</b></td><td><b>Download total(current)</b></td>");
		linebuffer_printf(lbuf, "<td><b>Upload total(current)</b></td><td><b>Completed since</b></td><td><b>Quit</b></td></tr>\n");

		struct client_con *tmp;
		list_for_each_entry(tmp, &torrent->client_list, list) {
			struct client_stats *stats = &tmp->stats;
			linebuffer_printf(lbuf, "<tr><td align=\"right\">%s</td><td align=\"right\">%3.2lf%% (%d/%d/%d)</td>",
				get_sockaddr_buf(&tmp->addr),
				(double)stats->chunk_have / (double)stats->chunk_total * 100.0,
				stats->chunk_have,
				stats->chunk_total,
				stats->chunk_avail);

			linebuffer_printf(lbuf, "<td align=\"right\">%llu (%d)</td><td align=\"right\">%llu (%d)</td><td align=\"right\">%s</td>",
				stats->total_dn,
				stats->bw_dn,
				stats->total_up,
				stats->bw_up,
				(tmp->completed != 0) ? ctime(&tmp->completed) : "-");

			linebuffer_printf(lbuf, "<td><a href=\"/quit?client=%s\">Quit</td></tr>\n", get_sockaddr_buf(&tmp->addr));
		}
		linebuffer_printf(lbuf, "</table>\n<br><br>\n");
	}
	linebuffer_printf(lbuf, "</body></html>\n");

	linebuffer_writefd(lbuf, con->fd);
	linebuffer_free(lbuf);
	return 0;
}

static int ctcs_httpd_quit(struct httpd_con *con, void *privdata)
{
	if (con->req_arg_cnt == 2 && strncmp(con->req_args[1], "client=", 7) == 0) {
		struct sockaddr_in addr;
		if (parse_sockaddr(con->req_args[1] +7, &addr) == 0) {
			struct torrent_file *torrent;
			list_for_each_entry(torrent, &torrent_list, list) {
				struct client_con *search;
				list_for_each_entry(search, &torrent->client_list, list) {
					if (!same_sockaddr(&search->addr, &addr))
						continue;

					write(event_get_fd(search->event), "CTQUIT\n", 7);
				}
			}
		}
	}

	char *text = "HTTP/1.0 302 OK\r\nContent-Type: text/html\r\nConnection: close\r\nLocation: /\r\n\r\n";
	write(con->fd, text, strlen(text));
	return 0;
}

int ctcs_init(void)
{
	const char *listen_addr = config_get_string("global", "listen", "0.0.0.0:2780");
	listen_event = tcp_listen_event(listen_addr, ctcs_accept_handler, NULL);
	if (listen_event == NULL)
		return -1;

	const char *httpd_addr = config_get_string("global", "listen-http", "0.0.0.0:8080");
	httpd_event = tcp_listen_event(httpd_addr, httpd_accept_handler, NULL);
	if (httpd_event == NULL) {
		event_remove_fd(listen_event);
		close(event_get_fd(listen_event));
		return -1;
	}

	httpd_add_cb("/quit", 0, ctcs_httpd_quit, NULL);
	httpd_add_cb("/", 1, ctcs_httpd_show, NULL);

	int interval = config_get_int("global", "status-interval", 10);
	int timeout = config_get_int("global", "seed-timeout", 60);

	struct timeval tv = { .tv_sec = interval, .tv_usec = 0 };
	timeout_event = event_add_timeout(&tv, ctcs_trigger_status, (void *)timeout);
	if (timeout_event == NULL) {
		event_remove_fd(httpd_event);
		close(event_get_fd(httpd_event));
		event_remove_fd(listen_event);
		close(event_get_fd(listen_event));
		return -1;
	}

	return 0;
}

int ctcs_free(void)
{
	struct torrent_file *torrent, *torrent2;
	list_for_each_entry_safe(torrent, torrent2, &torrent_list, list) {

		struct client_con *con, *con2;
		list_for_each_entry_safe(con, con2, &torrent->client_list, list) {
			free_client(con);
		}
	}

	event_remove_timeout(timeout_event);

	event_remove_fd(httpd_event);
	close(event_get_fd(httpd_event));

	httpd_free();

	event_remove_fd(listen_event);
	close(event_get_fd(listen_event));

	return 0;
}