/*
	PIP - Platform Independent Primitives
	Plugin helpers
	Ivan Pelipenko peri4ko@yandex.ru

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Lesser 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 Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef PIP_FREERTOS

#include "piplugin.h"
#include "pifile.h"
#include "piincludes_p.h"

/*! \class PIPluginLoader
 * \brief Plugin loader
 *
 * \section PIPluginLoader_sec0 Synopsis
 * This class provides several macro to define plugin and %PIPluginLoader - class
 * to load and check plugin.
 *
 * \section PIPluginLoader_sec1 Plugin side
 * Plugin is a shared library that can be loaded in run-time.
 * This is only PIP_PLUGIN macro necessary to define plugin.
 * If you want to set and check some version, use macro
 * \a PIP_PLUGIN_SET_USER_VERSION(version). Also you can
 * define a function to merge static sections between application
 * and plugin with macro \a PIP_PLUGIN_STATIC_SECTION_MERGE. Before
 * merge, you should set pointers to that sections with macro
 * \a PIP_PLUGIN_ADD_STATIC_SECTION(type, ptr).
 *
 * \section PIPluginLoader_sec2 Application side
 * Application should use class \a PIPluginLoader to load
 * plugin. Main function is \a load(PIString name).
 * "name" is base name of library, %PIPluginLoader
 * try to use sevaral names, <name>, lib<name> and
 * "dll", "so" and "dylib" extensions, depends on system.
 * For example:
 * \code
 * PIPluginLoader l;
 * l.load("foo");
 * \endcode
 * On Windows, try to open "foo", "libfoo", "foo.dll" and
 * "libfoo.dll".
 * If you using user version check, you should set it
 * with macro \a PIP_PLUGIN_SET_USER_VERSION(version).
 * When plugin is successfully loaded and checked,
 * you can load your custom cymbols with function
 * \a resolve(name), similar to PILibrary.
 * \note You should use PIP_PLUGIN_EXPORT and "export "C""
 * with functions you want to use with \a resolve(name)!
 *
 * \section PIPluginLoader_sec3 Static sections
 * Macro \a PIP_PLUGIN_STATIC_SECTION_MERGE defines function
 * with arguments (int type, void * from, void * to), so you
 * can leave this macro as declaration or define its body next:
 * \code
 * PIP_PLUGIN_STATIC_SECTION_MERGE() {
 *	switch (type) {
 * 	...
 *	}
 * }
 * \endcode
 * \note If you using singletones, remember that cpp-defined
 * singletones in shared libraries are single for whole application,
 * including plugins! But if you use h-defined singletones or
 * static linking, there are many objects in application and you
 * should merge their content with this macro.
 *
 * Anyway, if this is macro \a PIP_PLUGIN_STATIC_SECTION_MERGE, it
 * called once while loading plugin with "from" - plugin side
 * and "to" - application side, and second (optionally) on method
 * \a mergeStatic() with "from" - application side and "to" - plugin side.
 * First direction allow you to copy all defined static content from plugin
 * to application, and second - after loading all plugins (for example)
 * to copy static content from application (and all plugins) to plugin.
 *
 * \section PIPluginLoader_sec4 Examples
 * Simple plugin:
 * \code
 * #include <piplugin.h>
 *
 * PIP_PLUGIN
 *
 * extern "C" {
 * 	PIP_PLUGIN_EXPORT void myFunc() {
 * 		piCout << "Hello plugin!";
 * 	}
 * }
 * \endcode
 *
 * Application:
 * \code
 * #include <piplugin.h>
 * int main() {
 * 	PIPluginLoader pl;
 * 	pl.load("your_lib");
 * 	if (pl.isLoaded()) {
 * 		typedef void(*MyFunc)();
 * 		MyFunc f = (MyFunc)pl.resolve("myFunc");
 * 		if (f) f();
 * 	}
 * 	return 0;
 * }
 * \endcode
 *
 * Complex plugin:
 * \code
 * #include <piplugin.h>
 *
 * PIStringList global_list;
 *
 * PIP_PLUGIN
 * PIP_PLUGIN_SET_USER_VERSION("1.0.0")
 * PIP_PLUGIN_ADD_STATIC_SECTION(1, &global_list)
 *
 * STATIC_INITIALIZER_BEGIN
 * 	global_list << "plugin_init";
 * STATIC_INITIALIZER_END
 *
 * PIP_PLUGIN_STATIC_SECTION_MERGE {
 * 	PIStringList * sfrom = (PIStringList*)from, * sto = (PIStringList*)to;
 * 	*sto << *sfrom;
 * 	sto->removeDuplicates();
 * }
 * \endcode
 *
 * Application:
 * \code
 * #include <piplugin.h>
 *
 * PIStringList global_list;
 *
 * PIP_PLUGIN_SET_USER_VERSION("1.0.0");
 * PIP_PLUGIN_ADD_STATIC_SECTION(1, &global_list);
 *
 * int main() {
 * 	global_list << "app";
 * 	PIPluginLoader pl;
 * 	pl.load("your_lib");
 * 	pl.mergeStatic();
 * 	piCout << "list =" << global_list;
 * 	return 0;
 * }
 * \endcode
 *
 */

#define STR_WF(s) #s
#define STR(s) STR_WF(s)


PIPluginInfo::PIPluginInfo() {
	in_plugin = false;
}


void PIPluginInfo::setUserVersion(const PIString & v) {
	user_version[in_plugin ? 1 : 0] = v;
}


void PIPluginInfo::setStaticSection(int type, void * ptr) {
	static_sections[in_plugin ? 1 : 0][type] = ptr;
}


PIString PIPluginInfo::userVersion(bool plugin) const {
	return user_version[plugin ? 1 : 0];
}


PIMap<int, void *> PIPluginInfo::staticSections(bool plugin) const {
	return static_sections[plugin ? 1 : 0];
}


void PIPluginInfo::enterPlugin() {
	in_plugin = true;
}


PIPluginInfo * PIPluginInfo::instance() {
	static PIPluginInfo ret;
	return &ret;
}




PIPluginLoader::PIPluginLoader(const PIString & name) {
	func_loader_version = nullptr;
	func_plugin_info = nullptr;
	func_static_merge = nullptr;
	plugin_info = nullptr;
	loaded = false;
	if (!name.isEmpty())
		load(name);
}


PIPluginLoader::~PIPluginLoader() {
	lib.unload();
}


bool PIPluginLoader::load(const PIString & name) {
	unload();
	if (!lib.load(findLibrary(name))) return false;
	//piCout << "loading" << lib.path() << "...";
	func_loader_version = (FunctionLoaderVersion)lib.resolve(STR(__PIP_PLUGIN_LOADER_VERSION_FUNC__));
	if (!func_loader_version) {
		piCout << "Load plugin \"" << name << "\" error: can`t find" << STR(__PIP_PLUGIN_LOADER_VERSION_FUNC__);
		unload();
		return false;
	}
	if (__PIP_PLUGIN_LOADER_VERSION__ != func_loader_version()) {
		piCout << "Load plugin \"" << name << "\" error: invalid loader version: plugin" << __PIP_PLUGIN_LOADER_VERSION__ << "!=" << func_loader_version();
		unload();
		return false;
	}
	func_plugin_info = (FunctionPluginInfo)lib.resolve(STR(__PIP_PLUGIN_PLUGIN_INFO_FUNC__));
	if (!func_plugin_info) {
		piCout << "Load plugin \"" << name << "\" error: can`t find" << STR(__PIP_PLUGIN_PLUGIN_INFO_FUNC__);
		unload();
		return false;
	}
	plugin_info = func_plugin_info();
	if (!plugin_info) {
		piCout << "Load plugin \"" << name << "\" error: null PIPluginInfo";
		unload();
		return false;
	}
	if (PIPluginInfo::instance()->userVersion(false).size_s() > 1) {
		PIString pversion = plugin_info->userVersion(true), lversion = PIPluginInfo::instance()->userVersion(false);
		if (pversion != lversion) {
			piCout << "Load plugin \"" << name << "\" error: invalid user version: plugin" << pversion << "!=" << lversion;
			unload();
			return false;
		}
	}
	func_static_merge = (FunctionStaticMerge)lib.resolve(STR(__PIP_PLUGIN_STATIC_MERGE_FUNC__));
	if (func_static_merge) {
		auto pss = plugin_info->staticSections(true), lss = PIPluginInfo::instance()->staticSections(false);
		piCout << lss.keys() << pss.keys();

		auto it = lss.makeIterator();
		while (it.next()) {
			if (!pss.contains(it.key()))
				continue;
			void * from = pss.value(it.key()), * to = it.value();
			if (from != to)
				func_static_merge(it.key(), from, to);
		}
	}
	loaded = true;
	return true;
}


void PIPluginLoader::unload() {
	lib.unload();
	plugin_info = nullptr;
	loaded = false;
}


bool PIPluginLoader::isLoaded() const {
	return loaded;
}


PIString PIPluginLoader::libPath() {
	return lib.path();
}


void * PIPluginLoader::resolve(const char * name) {
	if (!loaded) return nullptr;
	return lib.resolve(name);
}


void PIPluginLoader::mergeStatic() {
	if (!loaded || !func_static_merge || !plugin_info) return;
	auto pss = plugin_info->staticSections(true), lss = PIPluginInfo::instance()->staticSections(false);
	auto it = lss.makeIterator();
	while (it.next()) {
		if (!pss.contains(it.key()))
			continue;
		void * from = it.value(), * to = pss.value(it.key());
		if (from != to)
			func_static_merge(it.key(), from, to);
	}
}


PIString PIPluginLoader::findLibrary(const PIString & path) {
	static const PIStringList prefixes({"", "lib"});
	static const PIStringList suffixes({"", libExtension()});
	PIFile::FileInfo fi(path);
	PIString dir = fi.dir(), name = fi.name();
	piForeachC (PIString & p, prefixes) {
		piForeachC (PIString & s, suffixes) {
			PIString fn = dir + p + name + s;
			if (PIFile::isExists(fn))
				return fn;
		}
	}
	return PIString();
}


PIString PIPluginLoader::libExtension() {
	return
#ifdef WINDOWS
			".dll"
#elif defined(MAC_OS)
			".dylib"
#else
			".so"
#endif
					;
}


#endif // PIP_FREERTOS