/* 
 *  Squeezelite - lightweight headless squeezebox emulator
 *
 *  (c) Adrian Smith 2012-2015, triode1@btinternet.com
 *      Ralph Irving 2015-2017, ralph_irving@hotmail.com
 *  
 * 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, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * 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, see <http://www.gnu.org/licenses/>.
 *
 */

// stream thread

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#include "squeezelite.h"

#include <fcntl.h>

#if USE_SSL
#include "openssl/ssl.h"
#include "openssl/err.h"
#endif

#if SUN
#include <signal.h>
#endif
static log_level loglevel;

static struct buffer buf;
struct buffer *streambuf = &buf;

#define LOCK     mutex_lock(streambuf->mutex)
#define UNLOCK   mutex_unlock(streambuf->mutex)

/* 
After a lot of hesitation, I've added that "poll mutex" to prevent
socket from being allocated while we are still in poll(). The issue 
happens is we have a close quickly followed by an open, we might still
be in the poll() and simple OS fail as they re-allocate the same socket
on which a thread is still waiting. 
Ideally, you want to set the lock in the disconnect() but that would mean
very often we'd have to always wait for the end of the poll(), i.e. up to
100ms for nothing most of the time where if it is in the open(), it is 
less elegant as closing a socket on which there is a poll() is not good 
but it's more efficient as it is very rare that you'd have an open() less 
then 100ms after a close()
*/
#if EMBEDDED
static mutex_type poll_mutex;
#define LOCK_L   mutex_lock(poll_mutex)
#define UNLOCK_L mutex_unlock(poll_mutex)
#else
#define LOCK_L   
#define UNLOCK_L 
#endif

static sockfd fd;

struct streamstate stream;

#if USE_SSL
static SSL_CTX *SSLctx;
SSL *ssl;
#endif

#if !USE_SSL
#define _recv(ssl, fc, buf, n, opt) recv(fd, buf, n, opt)
#define _send(ssl, fd, buf, n, opt) send(fd, buf, n, opt)
#define _poll(ssl, pollinfo, timeout) poll(pollinfo, 1, timeout)
#define _last_error() last_error()
#else
#define _last_error() ERROR_WOULDBLOCK

static int _recv(SSL *ssl, int fd, void *buffer, size_t bytes, int options) {
	int n;
	if (!ssl) return recv(fd, buffer, bytes, options);
	n = SSL_read(ssl, (u8_t*) buffer, bytes);
	if (n <= 0 && SSL_get_error(ssl, n) == SSL_ERROR_ZERO_RETURN) return 0;
	return n;
}

static int _send(SSL *ssl, int fd, void *buffer, size_t bytes, int options) {
	int n;
	if (!ssl) return send(fd, buffer, bytes, options);
	while (1) {
		int err;
		ERR_clear_error();
		if ((n = SSL_write(ssl, (u8_t*) buffer, bytes)) >= 0) return n;
		err = SSL_get_error(ssl, n);
		if (err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_WRITE) continue;
		LOG_INFO("SSL write error %d", err );
		return n;
	}
}

/*
can't mimic exactly poll as SSL is a real pain. Even if SSL_pending returns
0, there might be bytes to read but when select (poll) return > 0, there might
be no frame available. As well select (poll) < 0 does not mean that there is
no data pending
*/
static int _poll(SSL *ssl, struct pollfd *pollinfo, int timeout) {
	if (!ssl) return poll(pollinfo, 1, timeout);
	if (pollinfo->events & POLLIN && SSL_pending(ssl)) {
		if (pollinfo->events & POLLOUT) poll(pollinfo, 1, 0);
		pollinfo->revents = POLLIN;
		return 1;
	}
	return poll(pollinfo, 1, timeout);
}
#endif


static bool send_header(void) {
	char *ptr = stream.header;
	int len = stream.header_len;

	unsigned try = 0;
	ssize_t n;
	
	while (len) {
		n = _send(ssl, fd, ptr, len, MSG_NOSIGNAL);
		if (n <= 0) {
			if (n < 0 && _last_error() == ERROR_WOULDBLOCK && try < 10) {
				LOG_SDEBUG("retrying (%d) writing to socket", ++try);
				usleep(1000);
				continue;
			}
			LOG_INFO("failed writing to socket: %s", strerror(last_error()));
			stream.disconnect = LOCAL_DISCONNECT;
			stream.state = DISCONNECT;
			wake_controller();
			return false;
		}
		LOG_SDEBUG("wrote %d bytes to socket", n);
		ptr += n;
		len -= n;
	}
	LOG_SDEBUG("wrote header");
	return true;
}

static bool running = true;

static void _disconnect(stream_state state, disconnect_code disconnect) {
	stream.state = state;
	stream.disconnect = disconnect;
#if USE_SSL
	if (ssl) {
		SSL_shutdown(ssl);
		SSL_free(ssl);
		ssl = NULL;
	}
#endif
	closesocket(fd);
	fd = -1;
	wake_controller();
}

static void *stream_thread() {

	while (running) {

		struct pollfd pollinfo;
		size_t space;

		LOCK;

		space = min(_buf_space(streambuf), _buf_cont_write(streambuf));

		if (fd < 0 || !space || stream.state <= STREAMING_WAIT) {
			UNLOCK;
			usleep(space ? 100000 : 25000);
			continue;
		}

		if (stream.state == STREAMING_FILE) {

			int n = read(fd, streambuf->writep, space);
			if (n == 0) {
				LOG_INFO("end of stream");
				_disconnect(DISCONNECT, DISCONNECT_OK);
			}
			if (n > 0) {
				_buf_inc_writep(streambuf, n);
				stream.bytes += n;
				LOG_SDEBUG("streambuf read %d bytes", n);
			}
			if (n < 0) {
				LOG_WARN("error reading: %s", strerror(last_error()));
				_disconnect(DISCONNECT, REMOTE_DISCONNECT);
			}

			UNLOCK;
			continue;

		} else {

			LOCK_L;
			pollinfo.fd = fd;
			pollinfo.events = POLLIN;
			if (stream.state == SEND_HEADERS) {
				pollinfo.events |= POLLOUT;
			}
		}

		UNLOCK;
		
		if (_poll(ssl, &pollinfo, 100)) {

			UNLOCK_L;	
			LOCK;

			// check socket has not been closed while in poll
			if (fd < 0) {
				UNLOCK;
				continue;
			}

			if ((pollinfo.revents & POLLOUT) && stream.state == SEND_HEADERS) {
				if (send_header()) stream.state = RECV_HEADERS;
				stream.header_len = 0;
				UNLOCK;
				continue;
			}
					
			if (pollinfo.revents & (POLLIN | POLLHUP)) {

				// get response headers
				if (stream.state == RECV_HEADERS) {

					// read one byte at a time to catch end of header
					char c;
					static int endtok;

					int n = _recv(ssl, fd, &c, 1, 0);
					if (n <= 0) {
						if (n < 0 && _last_error() == ERROR_WOULDBLOCK) {
							UNLOCK;
							continue;
						}
						LOG_INFO("error reading headers: %s", n ? strerror(last_error()) : "closed");
						_disconnect(STOPPED, LOCAL_DISCONNECT);
						UNLOCK;
						continue;
					}

					*(stream.header + stream.header_len) = c;
					stream.header_len++;

					if (stream.header_len > MAX_HEADER - 1) {
						LOG_ERROR("received headers too long: %u", stream.header_len);
						_disconnect(DISCONNECT, LOCAL_DISCONNECT);
					}

					if (stream.header_len > 1 && (c == '\r' || c == '\n')) {
						endtok++;
						if (endtok == 4) {
							*(stream.header + stream.header_len) = '\0';
							LOG_INFO("headers: len: %d\n%s", stream.header_len, stream.header);
							stream.state = stream.cont_wait ? STREAMING_WAIT : STREAMING_BUFFERING;
							wake_controller();
						}
					} else {
						endtok = 0;
					}
				
					UNLOCK;
					continue;
				}
				
				// receive icy meta data
				if (stream.meta_interval && stream.meta_next == 0) {

					if (stream.meta_left == 0) {
						// read meta length
						u8_t c;
						int n = _recv(ssl, fd, &c, 1, 0);
						if (n <= 0) {
							if (n < 0 && _last_error() == ERROR_WOULDBLOCK) {
								UNLOCK;
								continue;
							}
							LOG_INFO("error reading icy meta: %s", n ? strerror(last_error()) : "closed");
							_disconnect(STOPPED, LOCAL_DISCONNECT);
							UNLOCK;
							continue;
						}
						stream.meta_left = 16 * c;
						stream.header_len = 0; // amount of received meta data
						// MAX_HEADER must be more than meta max of 16 * 255
					}

					if (stream.meta_left) {
						int n = _recv(ssl, fd, stream.header + stream.header_len, stream.meta_left, 0);
						if (n <= 0) {
							if (n < 0 && _last_error() == ERROR_WOULDBLOCK) {
								UNLOCK;
								continue;
							}
							LOG_INFO("error reading icy meta: %s", n ? strerror(last_error()) : "closed");
							_disconnect(STOPPED, LOCAL_DISCONNECT);
							UNLOCK;
							continue;
						}
						stream.meta_left -= n;
						stream.header_len += n;
					}
					
					if (stream.meta_left == 0) {
						if (stream.header_len) {
							*(stream.header + stream.header_len) = '\0';
							LOG_INFO("icy meta: len: %u\n%s", stream.header_len, stream.header);
							stream.meta_send = true;
							wake_controller();
						}
						stream.meta_next = stream.meta_interval;
						UNLOCK;
						continue;
					}

				// stream body into streambuf
				} else {
					int n;

					space = min(_buf_space(streambuf), _buf_cont_write(streambuf));
					if (stream.meta_interval) {
						space = min(space, stream.meta_next);
					}
					
					n = _recv(ssl, fd, streambuf->writep, space, 0);
					if (n == 0) {
						LOG_INFO("end of stream");
						_disconnect(DISCONNECT, DISCONNECT_OK);
					}
					if (n < 0 && _last_error() != ERROR_WOULDBLOCK) {
						LOG_INFO("error reading: %s", strerror(last_error()));
						_disconnect(DISCONNECT, REMOTE_DISCONNECT);
					}
					
					if (n > 0) {
						_buf_inc_writep(streambuf, n);
						stream.bytes += n;
						if (stream.meta_interval) {
							stream.meta_next -= n;
						}
					} else {
						UNLOCK;
						continue;
					}

					if (stream.state == STREAMING_BUFFERING && stream.bytes > stream.threshold) {
						stream.state = STREAMING_HTTP;
						wake_controller();
					}
				
					LOG_SDEBUG("streambuf read %d bytes", n);
				}
			}

			UNLOCK;
			
		} else {
			UNLOCK_L;
			LOG_SDEBUG("poll timeout");
		}
	}
	
#if USE_SSL	
	if (SSLctx) {
		SSL_CTX_free(SSLctx);
	}	
#endif	

	return 0;
}

static thread_type thread;

void stream_init(log_level level, unsigned stream_buf_size) {
	loglevel = level;

	LOG_INFO("init stream");
	LOG_DEBUG("streambuf size: %u", stream_buf_size);

	buf_init(streambuf, stream_buf_size);
	if (streambuf->buf == NULL) {
		LOG_ERROR("unable to malloc buffer");
		exit(0);
	}
	
#if USE_SSL
#if !LINKALL && !NO_SSLSYM
	if (ssl_loaded) {
#endif
	SSL_library_init();
	SSLctx = SSL_CTX_new(SSLv23_client_method());
	if (SSLctx == NULL) {
		LOG_ERROR("unable to allocate SSL context");
		exit(0);
	}	
	SSL_CTX_set_options(SSLctx, SSL_OP_NO_SSLv2);
#if !LINKALL && !NO_SSLSYM
	}
#endif	
	ssl = NULL;
#endif
	
#if SUN
	signal(SIGPIPE, SIG_IGN);	/* Force sockets to return -1 with EPIPE on pipe signal */
#endif
	stream.state = STOPPED;
	stream.header = malloc(MAX_HEADER);
	*stream.header = '\0';

	fd = -1;
#if EMBEDDED	
	mutex_create_p(poll_mutex);
#endif	

#if LINUX || FREEBSD
	touch_memory(streambuf->buf, streambuf->size);
#endif

#if LINUX || OSX || FREEBSD || EMBEDDED
	pthread_attr_t attr;
	pthread_attr_init(&attr);
#ifdef PTHREAD_STACK_MIN	
	pthread_attr_setstacksize(&attr, PTHREAD_STACK_MIN + STREAM_THREAD_STACK_SIZE);
#endif
	pthread_create_name(&thread, &attr, stream_thread, NULL, "stream");
	pthread_attr_destroy(&attr);
#endif
#if WIN
	thread = CreateThread(NULL, STREAM_THREAD_STACK_SIZE, (LPTHREAD_START_ROUTINE)&stream_thread, NULL, 0, NULL);
#endif
}

void stream_close(void) {
	LOG_INFO("close stream");
	LOCK;
	running = false;
	UNLOCK;
#if LINUX || OSX || FREEBSD || EMBEDDED
	pthread_join(thread, NULL);
#endif
	free(stream.header);
	buf_destroy(streambuf);
#if EMBEDDED	
	mutex_destroy(poll_mutex);
#endif	
}

void stream_file(const char *header, size_t header_len, unsigned threshold) {
	buf_flush(streambuf);

	LOCK;
	
	stream.header_len = header_len;
	memcpy(stream.header, header, header_len);
	*(stream.header+header_len) = '\0';

	LOG_INFO("opening local file: %s", stream.header);

#if WIN
	fd = open(stream.header, O_RDONLY | O_BINARY);
#else
	fd = open(stream.header, O_RDONLY);
#endif

	stream.state = STREAMING_FILE;
	if (fd < 0) {
		LOG_INFO("can't open file: %s", stream.header);
		stream.state = DISCONNECT;
	}
	wake_controller();
	
	stream.cont_wait = false;
	stream.meta_interval = 0;
	stream.meta_next = 0;
	stream.meta_left = 0;
	stream.meta_send = false;
	stream.sent_headers = false;
	stream.bytes = 0;
	stream.threshold = threshold;

	UNLOCK;
}

void stream_sock(u32_t ip, u16_t port, const char *header, size_t header_len, unsigned threshold, bool cont_wait) {
	struct sockaddr_in addr;

	LOCK_L;
	int sock = socket(AF_INET, SOCK_STREAM, 0);
	UNLOCK_L;

	if (sock < 0) {
		LOG_ERROR("failed to create socket");
		return;
	}

	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = ip;
	addr.sin_port = port;

	LOG_INFO("connecting to %s:%d", inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));

	set_nonblock(sock);
	set_nosigpipe(sock);

	if (connect_timeout(sock, (struct sockaddr *) &addr, sizeof(addr), 10) < 0) {
		LOG_INFO("unable to connect to server");
		LOCK;
		stream.state = DISCONNECT;
		stream.disconnect = UNREACHABLE;
		UNLOCK;
		return;
	}
	
#if USE_SSL
	if (ntohs(port) == 443) {
		char *server = strcasestr(header, "Host:");

		ssl = SSL_new(SSLctx);
		SSL_set_fd(ssl, sock);

		// add SNI
		if (server) {
			char *p, *servername = malloc(1024);

			sscanf(server, "Host:%255[^:]s", servername);
			for (p = servername; *p == ' '; p++);
			SSL_set_tlsext_host_name(ssl, p);
			free(servername);
		}
		
		while (1) {
			int status, err = 0;

			ERR_clear_error();
			status = SSL_connect(ssl);

			// successful negotiation
			if (status == 1) break;

			// error or non-blocking requires more time
			if (status < 0) {
				err = SSL_get_error(ssl, status);
				if (err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_WRITE) continue;
			}

			LOG_WARN("unable to open SSL socket %d (%d)", status, err);
			closesocket(sock);
			SSL_free(ssl);
			ssl = NULL;
			LOCK;
			stream.state = DISCONNECT;
			stream.disconnect = UNREACHABLE;
			UNLOCK;

			return;
		}
	} else {
		ssl = NULL;	
	}
#endif

	buf_flush(streambuf);

	LOCK;

	fd = sock;
	stream.state = SEND_HEADERS;
	stream.cont_wait = cont_wait;
	stream.meta_interval = 0;
	stream.meta_next = 0;
	stream.meta_left = 0;
	stream.meta_send = false;
	stream.header_len = header_len;
	memcpy(stream.header, header, header_len);
	*(stream.header+header_len) = '\0';

	LOG_INFO("header: %s", stream.header);

	stream.sent_headers = false;
	stream.bytes = 0;
	stream.threshold = threshold;

	UNLOCK;
}

bool stream_disconnect(void) {
	bool disc = false;
	LOCK;
#if USE_SSL
	if (ssl) {
		SSL_shutdown(ssl);
		SSL_free(ssl);
		ssl = NULL;
	}
#endif
	if (fd != -1) {
		closesocket(fd);
		fd = -1;
		disc = true;
	}
	stream.state = STOPPED;
	UNLOCK;
	return disc;
}