#include "extenwindow.h"
#include "ui_extenwindow.h"
#include "defs.h"
#include "text.h"
#include "types.h"
#include "misc.h"
#include <QDragEnterEvent>
#include <QDropEvent>
#include <QMimeData>
#include <QUrl>
#include <QLabel>

namespace
{

	struct Extension
	{
		std::wstring name;
		wchar_t*(*callback)(wchar_t*, const InfoForExtension*);
	};

	class : std::shared_mutex
	{
	public:
		void lock() { ++queuedWrites; shared_mutex::lock(); }
		void unlock() { --queuedWrites; shared_mutex::unlock(); }
		void lock_shared() { while (queuedWrites) Sleep(100); shared_mutex::lock_shared(); }
		void unlock_shared() { shared_mutex::unlock_shared(); }

	private:
		std::atomic<int> queuedWrites = 0;
	} extenMutex;
	std::vector<Extension> extensions;

	void Load(QString extenName)
	{
		if (extenName == ITH_DLL) return;
		// Extension is dll and exports "OnNewSentence"
		if (auto callback = (decltype(Extension::callback))GetProcAddress(LoadLibraryOnce(S(extenName)), "OnNewSentence"))
		{
			std::scoped_lock writeLock(extenMutex);
			extensions.push_back({ S(extenName), callback });
		}
	}

	void Unload(int index)
	{
		std::scoped_lock writeLock(extenMutex);
		FreeLibrary(GetModuleHandleW(extensions.at(index).name.c_str()));
		extensions.erase(extensions.begin() + index);
	}

	void Reorder(QStringList extenNames)
	{
		std::scoped_lock writeLock(extenMutex);
		std::vector<Extension> extensions;
		for (auto extenName : extenNames)
			extensions.push_back(*std::find_if(::extensions.begin(), ::extensions.end(), [&](auto extension) { return extension.name == S(extenName); }));
		::extensions = extensions;
	}
}

bool DispatchSentenceToExtensions(std::wstring& sentence, const InfoForExtension* miscInfo)
{
	wchar_t* sentenceBuffer = (wchar_t*)HeapAlloc(GetProcessHeap(), 0, (sentence.size() + 1) * sizeof(wchar_t));
	wcscpy_s(sentenceBuffer, sentence.size() + 1, sentence.c_str());

	std::shared_lock readLock(extenMutex);
	for (const auto& extension : extensions)
	{
		wchar_t* nextBuffer = extension.callback(sentenceBuffer, miscInfo);
		if (nextBuffer != sentenceBuffer) HeapFree(GetProcessHeap(), 0, sentenceBuffer);
		if (nextBuffer == nullptr) return false;
		sentenceBuffer = nextBuffer;
	}
	sentence = sentenceBuffer;

	HeapFree(GetProcessHeap(), 0, sentenceBuffer);
	return true;
}

ExtenWindow::ExtenWindow(QWidget* parent) :
	QMainWindow(parent, Qt::WindowCloseButtonHint),
	ui(new Ui::ExtenWindow)
{
	ui->setupUi(this);

	ui->vboxLayout->addWidget(new QLabel(EXTEN_WINDOW_INSTRUCTIONS, this));
	setWindowTitle(EXTENSIONS);

	ui->extenList->installEventFilter(this);

	if (!QFile::exists(EXTEN_SAVE_FILE)) QTextFile(EXTEN_SAVE_FILE, QIODevice::WriteOnly).write(DEFAULT_EXTENSIONS);
	for (auto extenName : QString(QTextFile(EXTEN_SAVE_FILE, QIODevice::ReadOnly).readAll()).split(">")) Load(extenName);
	Sync();
}

ExtenWindow::~ExtenWindow()
{
	delete ui;
}

void ExtenWindow::Sync()
{
	ui->extenList->clear();
	QTextFile extenSaveFile(EXTEN_SAVE_FILE, QIODevice::WriteOnly | QIODevice::Truncate);
	std::shared_lock readLock(extenMutex);
	for (auto extension : extensions)
	{
		ui->extenList->addItem(S(extension.name));
		extenSaveFile.write((S(extension.name) + ">").toUtf8());
	}
}

void ExtenWindow::Add(QFileInfo extenFile)
{
	if (extenFile.suffix() != "dll") return;
	QFile::copy(extenFile.absoluteFilePath(), extenFile.fileName());
	Load(extenFile.completeBaseName());
	Sync();
}

bool ExtenWindow::eventFilter(QObject* target, QEvent* event)
{
	// See https://stackoverflow.com/questions/1224432/how-do-i-respond-to-an-internal-drag-and-drop-operation-using-a-qlistwidget/1528215
	if (event->type() == QEvent::ChildRemoved)
	{
		QStringList extenNames;
		for (int i = 0; i < ui->extenList->count(); ++i) extenNames.push_back(ui->extenList->item(i)->text());
		Reorder(extenNames);
		Sync();
	}
	return false;
}

void ExtenWindow::keyPressEvent(QKeyEvent* event)
{
	if (event->key() == Qt::Key_Delete && ui->extenList->currentItem() != nullptr)
	{
		Unload(ui->extenList->currentIndex().row());
		Sync();
	}
}

void ExtenWindow::dragEnterEvent(QDragEnterEvent* event)
{
	event->acceptProposedAction();
}

void ExtenWindow::dropEvent(QDropEvent* event)
{
	for (auto file : event->mimeData()->urls()) Add(file.toLocalFile());
}