/*
    Copyright (C) 2011 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.

*/

#include <unistd.h>

#include <glibmm/pattern.h>
#include <glibmm/fileutils.h>

#include "pbd/error.h"
#include "pbd/compose.h"
#include "pbd/file_utils.h"

#include "ardour/debug.h"
#include "ardour/panner_manager.h"
#include "ardour/panner_search_path.h"

#include "i18n.h"

using namespace std;
using namespace ARDOUR;
using namespace PBD;

PannerManager* PannerManager::_instance = 0;

PannerManager::PannerManager ()
{
}

PannerManager::~PannerManager ()
{
	for (list<PannerInfo*>::iterator p = panner_info.begin(); p != panner_info.end(); ++p) {
		delete *p;
	}
}

PannerManager&
PannerManager::instance ()
{
	if (_instance == 0) {
		_instance = new PannerManager ();
	}

	return *_instance;
}

void
PannerManager::discover_panners ()
{
	vector<std::string> panner_modules;

	Glib::PatternSpec so_extension_pattern("*.so");
	Glib::PatternSpec dylib_extension_pattern("*.dylib");

	find_matching_files_in_search_path (panner_search_path (),
	                                    so_extension_pattern, panner_modules);

	find_matching_files_in_search_path (panner_search_path (),
	                                    dylib_extension_pattern, panner_modules);

	DEBUG_TRACE (DEBUG::Panning, string_compose (_("looking for panners in %1"), panner_search_path().to_string()));

	for (vector<std::string>::iterator i = panner_modules.begin(); i != panner_modules.end(); ++i) {
		panner_discover (*i);
	}
}
int
PannerManager::panner_discover (string path)
{
	PannerInfo* pinfo;

	if ((pinfo = get_descriptor (path)) != 0) {

		list<PannerInfo*>::iterator i;

		for (i = panner_info.begin(); i != panner_info.end(); ++i) {
			if (pinfo->descriptor.name == (*i)->descriptor.name) {
				break;
			}
		}

		if (i == panner_info.end()) {
			panner_info.push_back (pinfo);
			DEBUG_TRACE (DEBUG::Panning, string_compose(_("Panner discovered: \"%1\" in %2"), pinfo->descriptor.name, path));
		}
	}

	return 0;
}

PannerInfo*
PannerManager::get_descriptor (string path)
{
	void *module;
	PannerInfo* info = 0;
	PanPluginDescriptor *descriptor = 0;
	PanPluginDescriptor* (*dfunc)(void);
	const char *errstr;

	if ((module = dlopen (path.c_str(), RTLD_NOW)) == 0) {
		error << string_compose(_("PannerManager: cannot load module \"%1\" (%2)"), path, dlerror()) << endmsg;
		return 0;
	}

	dfunc = (PanPluginDescriptor* (*)(void)) dlsym (module, "panner_descriptor");

	if ((errstr = dlerror()) != 0) {
		error << string_compose(_("PannerManager: module \"%1\" has no descriptor function."), path) << endmsg;
		error << errstr << endmsg;
		dlclose (module);
		return 0;
	}

	descriptor = dfunc();
	if (descriptor) {
		info = new PannerInfo (*descriptor, module);
	} else {
		dlclose (module);
	}

	return info;
}

PannerInfo*
PannerManager::select_panner (ChanCount in, ChanCount out)
{
	PanPluginDescriptor* d;
	int32_t nin = in.n_audio();
	int32_t nout = out.n_audio();

	/* look for exact match first */

	for (list<PannerInfo*>::iterator p = panner_info.begin(); p != panner_info.end(); ++p) {
		d = &(*p)->descriptor;

		if (d->in == nin && d->out == nout) {
			return *p;
		}
	}

	/* no exact match, look for good fit on inputs and variable on outputs */

	for (list<PannerInfo*>::iterator p = panner_info.begin(); p != panner_info.end(); ++p) {
		d = &(*p)->descriptor;

		if (d->in == nin && d->out == -1) {
			return *p;
		}
	}

	/* no exact match, look for good fit on outputs and variable on inputs */

	for (list<PannerInfo*>::iterator p = panner_info.begin(); p != panner_info.end(); ++p) {
		d = &(*p)->descriptor;

		if (d->in == -1 && d->out == nout) {
			return *p;
		}
	}

	/* no exact match, look for variable fit on inputs and outputs */

	for (list<PannerInfo*>::iterator p = panner_info.begin(); p != panner_info.end(); ++p) {
		d = &(*p)->descriptor;

		if (d->in == -1 && d->out == -1) {
			return *p;
		}
	}

	warning << string_compose (_("no panner discovered for in/out = %1/%2"), nin, nout) << endmsg;

	return 0;
}