/*
	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 MICRO_PIP

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

//! \addtogroup System
//! \{
//! \class PIPluginLoader piplugin.h
//!
//! \brief
//! \~english Plugin loader
//! \~russian Загрузчик плагина
//!
//! \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 symbols 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() {
}


void PIPluginInfo::setUserVersion(const PIString & v) {
	user_version = v;
}


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


PIString PIPluginInfo::userVersion() const {
	return user_version;
}


PIMap<int, void *> PIPluginInfo::staticSections() const {
	return static_sections;
}





PIPluginInfoStorage::PIPluginInfoStorage() {
	enterPlugin(0);
}


PIPluginInfo * PIPluginInfoStorage::currentInfo() {
	return info[current];
}


PIPluginInfo * PIPluginInfoStorage::pluginInfo(void * p) {
	return info.value(p, nullptr);
}


PIPluginInfo * PIPluginInfoStorage::applicationInfo() {
	return info[0];
}


PIPluginInfo * PIPluginInfoStorage::enterPlugin(void * p) {
	current = p;
	PIPluginInfo *& i(info[p]);
	if (!i) i = new PIPluginInfo();
	return i;
}


void PIPluginInfoStorage::unloadPlugin(void * p) {
	if (current == p) current = 0;
	PIPluginInfo *& i(info[p]);
	if (i) delete i;
	info.remove(p);
}


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




PIPluginLoader::PIPluginLoader(const PIString & name) {
	func_loader_version = nullptr;
	func_static_merge = nullptr;
	error = Unknown;
	loaded = false;
	messages = true;
	if (!name.isEmpty())
		load(name);
}


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


bool PIPluginLoader::load(const PIString & name) {
	unload();
	PIPluginInfo * ai = PIPluginInfoStorage::instance()->applicationInfo();
	PIPluginInfo * pi = PIPluginInfoStorage::instance()->enterPlugin(this);
	if (!lib.load(findLibrary(name))) {
		unload();
		error = LibraryLoadError;
		error_str = "Load plugin \"" + lib.path() + "\" error: can`t load lib: " + lib.lastError();
		if (messages) piCout << error_str;
		return false;
	}
	//piCout << "loading" << lib.path() << "...";
	func_loader_version = (FunctionLoaderVersion)lib.resolve(STR(__PIP_PLUGIN_LOADER_VERSION_FUNC__));
	if (!func_loader_version) {
		unload();
		error = MissingSymbols;
		error_str = "Load plugin \"" + lib.path() + "\" error: can`t find " + STR(__PIP_PLUGIN_LOADER_VERSION_FUNC__);
		if (messages) piCout << error_str;
		return false;
	}
	if (__PIP_PLUGIN_LOADER_VERSION__ != func_loader_version()) {
		unload();
		error = InvalidLoaderVersion;
		error_str = "Load plugin \"" + lib.path() + "\" error: invalid loader version: application = " + PIString::fromNumber(func_loader_version())
				  + ", plugin = " + PIString::fromNumber(__PIP_PLUGIN_LOADER_VERSION__);
		if (messages) piCout << error_str;
		return false;
	}
	if (ai->userVersion().size_s() > 1) {
		PIString pversion = pi->userVersion(), lversion = ai->userVersion();
		if (pversion != lversion) {
			unload();
			error = InvalidUserVersion;
			error_str = "Load plugin \"" + lib.path() + "\" error: invalid user version: application = " + lversion + ", plugin = " + pversion;
			if (messages) piCout << error_str;
			return false;
		}
	}
	func_static_merge = (FunctionStaticMerge)lib.resolve(STR(__PIP_PLUGIN_STATIC_MERGE_FUNC__));
	if (func_static_merge) {
		auto pss = pi->staticSections(), lss = ai->staticSections();
		//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;
	error = NoError;
	return true;
}


void PIPluginLoader::unload() {
	lib.unload();
	loaded = false;
	error_str.clear();
	error = Unknown;
	PIPluginInfoStorage::instance()->unloadPlugin(this);
}


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


PIPluginLoader::Error PIPluginLoader::lastError() const {
	return error;
}


PIString PIPluginLoader::lastErrorText() const {
	return error_str;
}


void PIPluginLoader::setMessages(bool yes) {
	messages = yes;
}


bool PIPluginLoader::isMessages() const {
	return messages;
}


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) return;
	PIPluginInfo * ai = PIPluginInfoStorage::instance()->applicationInfo();
	PIPluginInfo * pi = PIPluginInfoStorage::instance()->pluginInfo(this);
	auto pss = pi->staticSections(), lss = ai->staticSections();
	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);
	}
}


PIStringList PIPluginLoader::pluginsDirectories(const PIString & name) {
	static PIStringList dl({".", "./plugins", "../PlugIns"});
	PIString ret;
	piForeachC (PIString d, dl) {
		PIString dp = d + "/" + name;
		if (PIDir::isExists(dp))
			ret << dp;
	}
	return ret;
}


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 // MICRO_PIP