/*
    Copyright (C) 2012 Carl Hetherington <cth@carlh.net>
    Copyright (C) 2000-2007 Paul Davis

    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 2 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, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

/** @file src/lib/util.cc
 *  @brief Some utility functions and classes.
 */

#include <sstream>
#include <iomanip>
#include <iostream>
#include <execinfo.h>
#include <cxxabi.h>
#include <signal.h>
#include <sys/types.h> 
#include <sys/socket.h>
#include <boost/algorithm/string.hpp>
#include <openjpeg.h>
#include <magick/MagickCore.h>
#include <magick/version.h>
#include <libssh/libssh.h>
#include <libdcp/version.h>
extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavfilter/avfiltergraph.h>
#include <libpostproc/postprocess.h>
#include <libavutil/pixfmt.h>
}
#include "util.h"
#include "exceptions.h"
#include "scaler.h"
#include "format.h"
#include "dcp_content_type.h"
#include "filter.h"
#include "screen.h"
#include "film_state.h"
#include "player_manager.h"

#ifdef DEBUG_HASH
#include <mhash.h>
#endif

using namespace std;
using namespace boost;

/** Convert some number of seconds to a string representation
 *  in hours, minutes and seconds.
 *
 *  @param s Seconds.
 *  @return String of the form H:M:S (where H is hours, M
 *  is minutes and S is seconds).
 */
string
seconds_to_hms (int s)
{
	int m = s / 60;
	s -= (m * 60);
	int h = m / 60;
	m -= (h * 60);

	stringstream hms;
	hms << h << ":";
	hms.width (2);
	hms << setfill ('0') << m << ":";
	hms.width (2);
	hms << setfill ('0') << s;

	return hms.str ();
}

/** @param s Number of seconds.
 *  @return String containing an approximate description of s (e.g. "about 2 hours")
 */
string
seconds_to_approximate_hms (int s)
{
	int m = s / 60;
	s -= (m * 60);
	int h = m / 60;
	m -= (h * 60);

	stringstream ap;
	
	if (h > 0) {
		if (m > 30) {
			ap << (h + 1) << " hours";
		} else {
			if (h == 1) {
				ap << "1 hour";
			} else {
				ap << h << " hours";
			}
		}
	} else if (m > 0) {
		if (m == 1) {
			ap << "1 minute";
		} else {
			ap << m << " minutes";
		}
	} else {
		ap << s << " seconds";
	}

	return ap.str ();
}

/** @param l Mangled C++ identifier.
 *  @return Demangled version.
 */
static string
demangle (string l)
{
	string::size_type const b = l.find_first_of ("(");
	if (b == string::npos) {
		return l;
	}

	string::size_type const p = l.find_last_of ("+");
	if (p == string::npos) {
		return l;
	}

	if ((p - b) <= 1) {
		return l;
	}
	
	string const fn = l.substr (b + 1, p - b - 1);

	int status;
	try {
		
		char* realname = abi::__cxa_demangle (fn.c_str(), 0, 0, &status);
		string d (realname);
		free (realname);
		return d;
		
	} catch (std::exception) {
		
	}
	
	return l;
}

/** Write a stacktrace to an ostream.
 *  @param out Stream to write to.
 *  @param levels Number of levels to go up the call stack.
 */
void
stacktrace (ostream& out, int levels)
{
	void *array[200];
	size_t size;
	char **strings;
	size_t i;
     
	size = backtrace (array, 200);
	strings = backtrace_symbols (array, size);
     
	if (strings) {
		for (i = 0; i < size && (levels == 0 || i < size_t(levels)); i++) {
			out << "  " << demangle (strings[i]) << endl;
		}
		
		free (strings);
	}
}

/** @param s Sample format.
 *  @return String representation.
 */
string
audio_sample_format_to_string (AVSampleFormat s)
{
	/* Our sample format handling is not exactly complete */
	
	switch (s) {
	case AV_SAMPLE_FMT_S16:
		return "S16";
	default:
		break;
	}

	return "Unknown";
}

/** @param s String representation of a sample format, as returned from audio_sample_format_to_string().
 *  @return Sample format.
 */
AVSampleFormat
audio_sample_format_from_string (string s)
{
	if (s == "S16") {
		return AV_SAMPLE_FMT_S16;
	}

	return AV_SAMPLE_FMT_NONE;
}

/** @return Version of vobcopy that is on the path (and hence that we will use) */
static string
vobcopy_version ()
{
	FILE* f = popen ("vobcopy -V 2>&1", "r");
	if (f == 0) {
		throw EncodeError ("could not run vobcopy to check version");
	}

	string version = "unknown";
	
	while (!feof (f)) {
		char* buf = 0;
		size_t n = 0;
		ssize_t const r = getline (&buf, &n, f);
		if (r > 0) {
			string s (buf);
			vector<string> b;
			split (b, s, is_any_of (" "));
			if (b.size() >= 2 && b[0] == "Vobcopy") {
				version = b[1];
			}
			free (buf);
		}
	}

	pclose (f);

	return version;
}

/** @param v Version as used by FFmpeg.
 *  @return A string representation of v.
 */
static string
ffmpeg_version_to_string (int v)
{
	stringstream s;
	s << ((v & 0xff0000) >> 16) << "." << ((v & 0xff00) >> 8) << "." << (v & 0xff);
	return s.str ();
}

/** Return a user-readable string summarising the versions of our dependencies */
string
dependency_version_summary ()
{
	stringstream s;
	s << "libopenjpeg " << opj_version () << ", "
	  << "vobcopy " << vobcopy_version() << ", "
	  << "libavcodec " << ffmpeg_version_to_string (avcodec_version()) << ", "
	  << "libavfilter " << ffmpeg_version_to_string (avfilter_version()) << ", "
	  << "libavformat " << ffmpeg_version_to_string (avformat_version()) << ", "
	  << "libavutil " << ffmpeg_version_to_string (avutil_version()) << ", "
	  << "libpostproc " << ffmpeg_version_to_string (postproc_version()) << ", "
	  << "libswscale " << ffmpeg_version_to_string (swscale_version()) << ", "
	  << MagickVersion << ", "
	  << "libssh " << ssh_version (0) << ", "
	  << "libdcp " << libdcp::version << " git " << libdcp::git_commit;

	return s.str ();
}

/** Write some data to a socket.
 *  @param fd Socket file descriptor.
 *  @param data Data.
 *  @param size Amount to write, in bytes.
 */
void
socket_write (int fd, uint8_t const * data, int size)
{
	uint8_t const * p = data;
	while (size) {
		int const n = send (fd, p, size, MSG_NOSIGNAL);
		if (n < 0) {
			stringstream s;
			s << "could not write (" << strerror (errno) << ")";
			throw NetworkError (s.str ());
		}

		size -= n;
		p += n;
	}
}

double
seconds (struct timeval t)
{
	return t.tv_sec + (double (t.tv_usec) / 1e6);
}

/** @param fd File descriptor to read from */
SocketReader::SocketReader (int fd)
	: _fd (fd)
	, _buffer_data (0)
{

}

/** Mark some data as being `consumed', so that it will not be returned
 *  as data again.
 *  @param size Amount of data to consume, in bytes.
 */
void
SocketReader::consume (int size)
{
	assert (_buffer_data >= size);
	
	_buffer_data -= size;
	if (_buffer_data > 0) {
		/* Shift still-valid data to the start of the buffer */
		memmove (_buffer, _buffer + size, _buffer_data);
	}
}

/** Read a definite amount of data from our socket, and mark
 *  it as consumed.
 *  @param data Where to put the data.
 *  @param size Number of bytes to read.
 */
void
SocketReader::read_definite_and_consume (uint8_t* data, int size)
{
	int const from_buffer = min (_buffer_data, size);
	if (from_buffer > 0) {
		/* Get data from our buffer */
		memcpy (data, _buffer, from_buffer);
		consume (from_buffer);
		/* Update our output state */
		data += from_buffer;
		size -= from_buffer;
	}

	/* read() the rest */
	while (size > 0) {
		int const n = ::read (_fd, data, size);
		if (n <= 0) {
			throw NetworkError ("could not read");
		}

		data += n;
		size -= n;
	}
}

/** Read as much data as is available, up to some limit.
 *  @param data Where to put the data.
 *  @param size Maximum amount of data to read.
 */
void
SocketReader::read_indefinite (uint8_t* data, int size)
{
	assert (size < int (sizeof (_buffer)));

	/* Amount of extra data we need to read () */
	int to_read = size - _buffer_data;
	while (to_read > 0) {
		/* read as much of it as we can (into our buffer) */
		int const n = ::read (_fd, _buffer + _buffer_data, to_read);
		if (n <= 0) {
			throw NetworkError ("could not read");
		}

		to_read -= n;
		_buffer_data += n;
	}

	assert (_buffer_data >= size);

	/* copy data into the output buffer */
	assert (size >= _buffer_data);
	memcpy (data, _buffer, size);
}

void
sigchld_handler (int, siginfo_t* info, void *)
{
	PlayerManager::instance()->child_exited (info->si_pid);
}

/** Call the required functions to set up DVD-o-matic's static arrays, etc. */
void
dvdomatic_setup ()
{
	Format::setup_formats ();
	DCPContentType::setup_dcp_content_types ();
	Scaler::setup_scalers ();
	Filter::setup_filters ();

	struct sigaction sa;
	sa.sa_flags = SA_SIGINFO;
	sigemptyset (&sa.sa_mask);
	sa.sa_sigaction = sigchld_handler;
	sigaction (SIGCHLD, &sa, 0);
}

string
crop_string (Position start, Size size)
{
	stringstream s;
	s << "crop=" << size.width << ":" << size.height << ":" << start.x << ":" << start.y;
	return s.str ();
}

vector<string>
split_at_spaces_considering_quotes (string s)
{
	vector<string> out;
	bool in_quotes = false;
	string c;
	for (string::size_type i = 0; i < s.length(); ++i) {
		if (s[i] == ' ' && !in_quotes) {
			out.push_back (c);
			c = "";
		} else if (s[i] == '"') {
			in_quotes = !in_quotes;
		} else {
			c += s[i];
		}
	}

	out.push_back (c);
	return out;
}

#ifdef DEBUG_HASH
void
md5_data (string title, void const * data, int size)
{
	MHASH ht = mhash_init (MHASH_MD5);
	if (ht == MHASH_FAILED) {
		throw EncodeError ("could not create hash thread");
	}

	mhash (ht, data, size);
	
	uint8_t hash[16];
	mhash_deinit (ht, hash);
	
	printf ("%s [%d]: ", title.c_str (), size);
	for (int i = 0; i < int (mhash_get_block_size (MHASH_MD5)); ++i) {
		printf ("%.2x", hash[i]);
	}
	printf ("\n");
}
#endif