#include <thread>
#include <map>
#include <stdexcept>
#include <tuple>

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/param.h> // for MAXPATHLEN
#include <fcntl.h>
#if defined ARCH_WIN
	#include <windows.h>
	#include <direct.h>
#else
	#include <dlfcn.h> // for dlopen
#endif
#include <dirent.h>

#include <osdialog.h>
#include <jansson.h>

#include <plugin.hpp>
#include <system.hpp>
#include <asset.hpp>
#include <string.hpp>
#include <context.hpp>
#include <plugin/callbacks.hpp>
#include <settings.hpp>


namespace rack {

namespace core {
void init(rack::plugin::Plugin* plugin);
} // namespace core

namespace plugin {


////////////////////
// private API
////////////////////

static void* loadLibrary(std::string libraryPath) {
#if defined ARCH_WIN
	SetErrorMode(SEM_NOOPENFILEERRORBOX | SEM_FAILCRITICALERRORS);
	std::wstring libraryFilenameW = string::UTF8toUTF16(libraryPath);
	HINSTANCE handle = LoadLibraryW(libraryFilenameW.c_str());
	SetErrorMode(0);
	if (!handle) {
		int error = GetLastError();
		throw Exception("Failed to load library %s: code %d", libraryPath.c_str(), error);
	}
#else
	// As of Rack v2.0, plugins are linked with `-rpath=.` so change current directory so it can find libRack.
	std::string cwd = system::getWorkingDirectory();
	system::setWorkingDirectory(asset::systemDir);
	// Change it back when we're finished
	DEFER({system::setWorkingDirectory(cwd);});
	// Load library with dlopen
	void* handle = NULL;
	#if defined ARCH_LIN
	handle = dlopen(libraryPath.c_str(), RTLD_NOW | RTLD_DEEPBIND);
	#elif defined ARCH_MAC
	handle = dlopen(libraryPath.c_str(), RTLD_NOW | RTLD_LOCAL);
	#endif
	if (!handle)
		throw Exception("Failed to load library %s: %s", libraryPath.c_str(), dlerror());
#endif
	return handle;
}

typedef void (*InitCallback)(Plugin*);

static InitCallback loadPluginCallback(Plugin* plugin) {
	// Load plugin library
	std::string libraryExt;
#if defined ARCH_LIN
	libraryExt = "so";
#elif defined ARCH_WIN
	libraryExt = "dll";
#elif ARCH_MAC
	libraryExt = "dylib";
#endif
	std::string libraryPath = system::join(plugin->path, "plugin." + libraryExt);

	// Check file existence
	if (!system::isFile(libraryPath))
		throw Exception("Plugin binary not found at %s", libraryPath.c_str());

	// Load dynamic/shared library
	plugin->handle = loadLibrary(libraryPath);

	// Get plugin's init() function
	InitCallback initCallback;
#if defined ARCH_WIN
	initCallback = (InitCallback) GetProcAddress((HMODULE) plugin->handle, "init");
#else
	initCallback = (InitCallback) dlsym(plugin->handle, "init");
#endif
	if (!initCallback)
		throw Exception("Failed to read init() symbol in %s", libraryPath.c_str());

	return initCallback;
}


/** If path is blank, loads Core */
static Plugin* loadPlugin(std::string path) {
	if (path == "")
		INFO("Loading Core plugin");
	else
		INFO("Loading plugin from %s", path.c_str());

	Plugin* plugin = new Plugin;
	try {
		// Set plugin path
		plugin->path = (path == "") ? asset::systemDir : path;

		// Get modified timestamp
		if (path != "") {
			struct stat statbuf;
			if (!stat(path.c_str(), &statbuf)) {
#if defined ARCH_MAC
				plugin->modifiedTimestamp = (double) statbuf.st_mtimespec.tv_sec + statbuf.st_mtimespec.tv_nsec * 1e-9;
#elif defined ARCH_WIN
				plugin->modifiedTimestamp = (double) statbuf.st_mtime;
#elif defined ARCH_LIN
				plugin->modifiedTimestamp = (double) statbuf.st_mtim.tv_sec + statbuf.st_mtim.tv_nsec * 1e-9;
#endif
			}
		}

		// Load plugin.json
		std::string manifestFilename = (path == "") ? asset::system("Core.json") : system::join(path, "plugin.json");
		FILE* file = std::fopen(manifestFilename.c_str(), "r");
		if (!file)
			throw Exception("Manifest file %s does not exist", manifestFilename.c_str());
		DEFER({std::fclose(file);});

		json_error_t error;
		json_t* rootJ = json_loadf(file, 0, &error);
		if (!rootJ)
			throw Exception("JSON parsing error at %s %d:%d %s", manifestFilename.c_str(), error.line, error.column, error.text);
		DEFER({json_decref(rootJ);});

		// Call init callback
		InitCallback initCallback;
		if (path == "") {
			initCallback = core::init;
		}
		else {
			initCallback = loadPluginCallback(plugin);
		}
		initCallback(plugin);

		// Load manifest
		plugin->fromJson(rootJ);

		// Reject plugin if slug already exists
		Plugin* existingPlugin = getPlugin(plugin->slug);
		if (existingPlugin)
			throw Exception("Plugin %s is already loaded, not attempting to load it again", plugin->slug.c_str());
	}
	catch (Exception& e) {
		WARN("Could not load plugin %s: %s", path.c_str(), e.what());
		delete plugin;
		return NULL;
	}

	INFO("Loaded %s v%s", plugin->slug.c_str(), plugin->version.c_str());
	plugins.push_back(plugin);
	return plugin;
}


static void loadPlugins(std::string path) {
	for (std::string pluginPath : system::getEntries(path)) {
		if (!system::isDirectory(pluginPath))
			continue;
		if (!loadPlugin(pluginPath)) {
			// Ignore bad plugins. They are reported in the log.
		}
	}
}


static void extractPackages(std::string path) {
	std::string message;

	for (std::string packagePath : system::getEntries(path)) {
		if (!system::isFile(packagePath))
			continue;
		if (system::getExtension(packagePath) != ".vcvplugin")
			continue;

		// Extract package
		INFO("Extracting package %s", packagePath.c_str());
		try {
			system::unarchiveToDirectory(packagePath, path);
		}
		catch (Exception& e) {
			WARN("Plugin package %s failed to extract: %s", packagePath.c_str(), e.what());
			message += string::f("Could not extract plugin package %s\n", packagePath.c_str());
			continue;
		}
		// Remove package
		system::remove(packagePath.c_str());
	}
	if (!message.empty()) {
		osdialog_message(OSDIALOG_WARNING, OSDIALOG_OK, message.c_str());
	}
}

////////////////////
// public API
////////////////////

void init() {
	// Don't re-initialize
	assert(plugins.empty());

	// Load Core
	loadPlugin("");

	pluginsPath = asset::user("plugins");

	// Get user plugins directory
	system::createDirectory(pluginsPath);

	// Extract packages and load plugins
	extractPackages(pluginsPath);
	loadPlugins(pluginsPath);

	// If Fundamental wasn't loaded, copy the bundled Fundamental package and load it
	if (!settings::devMode && !getPlugin("Fundamental")) {
		std::string fundamentalSrc = asset::system("Fundamental.vcvplugin");
		std::string fundamentalDir = system::join(pluginsPath, "Fundamental");
		if (system::isFile(fundamentalSrc)) {
			INFO("Extracting bundled Fundamental package");
			system::unarchiveToDirectory(fundamentalSrc.c_str(), pluginsPath.c_str());
			loadPlugin(fundamentalDir);
		}
	}
}


void destroy() {
	for (Plugin* plugin : plugins) {
		void* handle = plugin->handle;

		// Call destroy() if defined in the plugin library
		typedef void (*DestroyCallback)();
		DestroyCallback destroyCallback = NULL;
		if (handle) {
#if defined ARCH_WIN
			destroyCallback = (DestroyCallback) GetProcAddress((HMODULE) handle, "destroy");
#else
			destroyCallback = (DestroyCallback) dlsym(handle, "destroy");
#endif
		}
		if (destroyCallback)
			destroyCallback();

		// We must delete the Plugin instance *before* freeing the library, because the vtables of Model subclasses are defined in the library, which are needed in the Plugin destructor.
		delete plugin;

		// Free library handle
		if (handle) {
#if defined ARCH_WIN
			FreeLibrary((HINSTANCE) handle);
#else
			dlclose(handle);
#endif
		}
	}
	plugins.clear();
}


// To request fallback slugs to be added to this list, open a GitHub issue.
static const std::map<std::string, std::string> pluginSlugFallbacks = {
	// {"", ""},
};


Plugin* getPlugin(const std::string& pluginSlug) {
	if (pluginSlug.empty())
		return NULL;
	for (Plugin* plugin : plugins) {
		if (plugin->slug == pluginSlug) {
			return plugin;
		}
	}
	// Use fallback plugin slug
	auto it = pluginSlugFallbacks.find(pluginSlug);
	if (it != pluginSlugFallbacks.end()) {
		return getPlugin(it->second);
	}
	return NULL;
}


// To request fallback slugs to be added to this list, open a GitHub issue.
using PluginModuleSlug = std::tuple<std::string, std::string>;
static const std::map<PluginModuleSlug, PluginModuleSlug> moduleSlugFallbacks = {
	{{"AudibleInstrumentsPreview", "Plaits"}, {"AudibleInstruments", "Plaits"}},
	{{"AudibleInstrumentsPreview", "Marbles"}, {"AudibleInstruments", "Marbles"}},
	// {{"", ""}, {"", ""}},
};


Model* getModel(const std::string& pluginSlug, const std::string& modelSlug) {
	if (pluginSlug.empty() || modelSlug.empty())
		return NULL;
	Plugin* plugin = getPlugin(pluginSlug);
	if (plugin) {
		Model* model = plugin->getModel(modelSlug);
		if (model)
			return model;
	}
	// Use fallback (module slug, plugin slug)
	auto it = moduleSlugFallbacks.find(std::make_tuple(pluginSlug, modelSlug));
	if (it != moduleSlugFallbacks.end()) {
		return getModel(std::get<0>(it->second), std::get<1>(it->second));
	}
	return NULL;
}


Model* modelFromJson(json_t* moduleJ) {
	// Get slugs
	json_t* pluginSlugJ = json_object_get(moduleJ, "plugin");
	if (!pluginSlugJ)
		throw Exception("\"plugin\" property not found in module JSON");
	std::string pluginSlug = json_string_value(pluginSlugJ);
	pluginSlug = normalizeSlug(pluginSlug);

	json_t* modelSlugJ = json_object_get(moduleJ, "model");
	if (!modelSlugJ)
		throw Exception("\"model\" property not found in module JSON");
	std::string modelSlug = json_string_value(modelSlugJ);
	modelSlug = normalizeSlug(modelSlug);

	// Get Model
	Model* model = getModel(pluginSlug, modelSlug);
	if (!model)
		throw Exception("Could not find module \"%s\" \"%s\"", pluginSlug.c_str(), modelSlug.c_str());
	return model;
}


bool isSlugValid(const std::string& slug) {
	for (char c : slug) {
		if (!(std::isalnum(c) || c == '-' || c == '_'))
			return false;
	}
	return true;
}


std::string normalizeSlug(const std::string& slug) {
	std::string s;
	for (char c : slug) {
		if (!(std::isalnum(c) || c == '-' || c == '_'))
			continue;
		s += c;
	}
	return s;
}


std::string pluginsPath;
std::vector<Plugin*> plugins;


} // namespace plugin
} // namespace rack