/*
	Copyright 2006-2026 The QElectroTech Team
	This file is part of QElectroTech.

	QElectroTech 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.

	QElectroTech 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 QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
*/
#include "liveserver.h"

#include "assistantinfo.h"
#include "macrorecorder.h"
#include "qetscripting.h"
#include "scriptlibrary.h"
#include "../diagram.h"
#include "../diagramview.h"
#include "../qetapp.h"
#include "../qetdiagrameditor.h"
#include "../qetproject.h"
#include "../utils/qetsettings.h"

#include <QApplication>
#include <QFontDatabase>
#include <QCoreApplication>
#include <QFile>
#include <QJsonArray>
#include <QJsonDocument>
#include <QLocalServer>
#include <QLocalSocket>
#include <QMessageBox>
#include <QPushButton>
#include <QRandomGenerator>
#include <QSaveFile>
#include <QTimer>
#include <QUndoStack>
#include <QAction>
#include <QBuffer>
#include <QPixmap>
#include <QPlainTextEdit>
#include <QVBoxLayout>
#include <QDialog>
#include <QDialogButtonBox>
#include <QLabel>
#include "../projectview.h"
#include "../shortcutmanager.h"

namespace {
	QString randomHex(int bytes)
	{
		QByteArray raw(bytes, Qt::Uninitialized);
		for (char &c : raw) c = char(QRandomGenerator::system()->bounded(256));
		return QString::fromLatin1(raw.toHex());
	}

	QJsonObject failure(const QString &error)
	{
		return {{QStringLiteral("ok"), false}, {QStringLiteral("error"), error}};
	}
}

LiveServer &LiveServer::instance()
{
	static LiveServer server;
	return server;
}

LiveServer::LiveServer()
{
	connect(qApp, &QCoreApplication::aboutToQuit, this, &LiveServer::stop);
}

LiveServer::~LiveServer()
{
}

/**
	@brief LiveServer::askAndStart
	Called by every editor window as it opens; acts once per run. With the
	setting on, warn and let the user decide for this session before the
	channel exists.
*/
void LiveServer::askAndStart(QWidget *parent)
{
	if (m_asked) return;
	if (!QetSettings::liveAssistantEnabled()) {
		m_asked = true;
		return;
	}
		//Not on top of another start-up question (the backup copy, the
		//recovery files): two stacked boxes, and an answer meant for one
		//lands on the other. Ask once nothing else is waiting.
	if (QApplication::activeModalWidget()) {
		QPointer<QWidget> anchor(parent);
		QTimer::singleShot(300, this, [this, anchor]() { askAndStart(anchor); });
		return;
	}
	m_asked = true;

	QMessageBox box(QMessageBox::Warning, tr("Mode direct"),
			tr("Le mode direct est activé : un assistant IA connecté "
			   "pourra exécuter des scripts sur le projet ouvert.\n\n"
			   "Chaque action s'annule d'un Ctrl+Z, et le bouton "
			   "« Arrêter » de la barre d'état coupe la connexion.\n\n"
			   "Ce réglage se trouve dans Configurer QElectroTech > Général > "
			   "Projets."),
			QMessageBox::NoButton, parent);
	QPushButton *go = box.addButton(tr("&Continuer"), QMessageBox::AcceptRole);
	box.addButton(tr("&Pas pour cette session"), QMessageBox::RejectRole);
	QPushButton *off = box.addButton(tr("&Désactiver"), QMessageBox::DestructiveRole);
	box.setDefaultButton(go);
	box.exec();

	if (box.clickedButton() == off) {
		QetSettings::setLiveAssistantEnabled(false);
	} else if (box.clickedButton() == go) {
		start();
	}
}

bool LiveServer::start()
{
	if (m_server) return true;
	m_server = new QLocalServer(this);
	m_server->setSocketOptions(QLocalServer::UserAccessOption);
	if (!m_server->listen(QStringLiteral("qet-live-") + randomHex(8))) {
		delete m_server;
		m_server = nullptr;
		return false;
	}
	m_token = randomHex(16);

		//Where the MCP server finds the channel: the "live" part of
		//qet-assistant.json, the one file it reads about this QElectroTech
	AssistantInfo::setLive(QJsonObject{
		{QStringLiteral("socket"), m_server->fullServerName()},
		{QStringLiteral("token"), m_token},
		{QStringLiteral("pid"), QCoreApplication::applicationPid()}});

	connect(m_server, &QLocalServer::newConnection, this, &LiveServer::newConnection);
	setState(Waiting);
	return true;
}

/**
	@brief LiveServer::stop
	Drop the assistant and close the channel for the rest of the session.
*/
void LiveServer::stop()
{
	if (m_client) {
		m_client->disconnectFromServer();
		m_client->deleteLater();
	}
	if (m_server) {
		m_server->close();
		m_server->deleteLater();
		m_server = nullptr;
	}
	if (!m_token.isEmpty()) AssistantInfo::setLive(QJsonObject());
	m_token.clear();
	m_buffer.clear();
	setState(Off);
}

void LiveServer::setState(State state)
{
	if (state == m_state) return;
	m_state = state;
	emit stateChanged(state);
}

void LiveServer::newConnection()
{
	while (QLocalSocket *socket = m_server ? m_server->nextPendingConnection() : nullptr) {
		if (m_client) {
			socket->write(QJsonDocument(failure(QStringLiteral(
				"another assistant is already connected"))).toJson(QJsonDocument::Compact) + '\n');
			socket->disconnectFromServer();
			socket->deleteLater();
			continue;
		}
		m_client = socket;
		m_buffer.clear();
		connect(socket, &QLocalSocket::readyRead, this, &LiveServer::readClient);
			//Connected stays on once an assistant has used the channel:
			//the MCP server connects per request, so following the socket
			//would flicker the indicator off between two actions.
		connect(socket, &QLocalSocket::disconnected, socket, &QObject::deleteLater);
	}
}

void LiveServer::readClient()
{
	if (!m_client) return;
	m_buffer += m_client->readAll();
	int newline;
	while ((newline = m_buffer.indexOf('\n')) >= 0) {
		const QByteArray line = m_buffer.left(newline).trimmed();
		m_buffer.remove(0, newline + 1);
		if (line.isEmpty()) continue;
		const QJsonObject request = QJsonDocument::fromJson(line).object();
		if (request.value(QStringLiteral("token")).toString() != m_token || m_token.isEmpty()) {
			send(failure(QStringLiteral("bad token")));
			m_client->disconnectFromServer();
			return;
		}
		setState(Connected);
			//Out of the socket handler before anything runs (see class doc)
		QTimer::singleShot(0, this, [this, request]() { handle(request); });
	}
}

void LiveServer::send(const QJsonObject &answer)
{
	if (m_client) {
		m_client->write(QJsonDocument(answer).toJson(QJsonDocument::Compact) + '\n');
		m_client->flush();
	}
}

void LiveServer::handle(const QJsonObject &request)
{
	const QString cmd = request.value(QStringLiteral("cmd")).toString();
	QJsonObject answer;
	if (m_busy) {
		answer = failure(QStringLiteral("busy: the previous request is still running"));
	} else {
		m_busy = true;
		if (cmd == QLatin1String("status")) {
			answer = status();
		} else if (cmd == QLatin1String("run_script")) {
			const QString name = request.value(QStringLiteral("name")).toString();
			const QString source = request.value(QStringLiteral("source")).toString();
				//A script the assistant just wrote: the user sees it first,
				//unless they said "always" this session. A stored script
				//is one the user already has, so it runs as a click would.
			if (m_ask_first && !confirm(name, source))
				answer = failure(QStringLiteral("refused by the user"));
			else
				answer = runScript(name, source);
		} else if (cmd == QLatin1String("run_stored")) {
			answer = runStored(request.value(QStringLiteral("script")).toString());
		} else if (cmd == QLatin1String("command")) {
			answer = command(request.value(QStringLiteral("action")).toString());
		} else if (cmd == QLatin1String("show_folio")) {
			answer = showFolio(request.value(QStringLiteral("folio")).toInt(-1));
		} else if (cmd == QLatin1String("undo_last")) {
			answer = undoLast();
		} else if (cmd == QLatin1String("screenshot")) {
			answer = screenshot();
		} else {
			answer = failure(QStringLiteral("unknown command: %1").arg(cmd));
		}
		m_busy = false;
	}
	if (request.contains(QStringLiteral("id")))
		answer.insert(QStringLiteral("id"), request.value(QStringLiteral("id")));
	send(answer);
		//One request per connection: close it from this side once it is
		//answered. Waiting for the client to hang up raced the next
		//request on Windows, where a named pipe's disconnection reaches
		//QLocalSocket late -- the second call of a quick pair was turned
		//away as "another assistant" (found under Wine, 2026-10-02).
	if (m_client) {
		m_client->disconnectFromServer();
		m_client = nullptr;
	}
	emit handled(request, answer);
}

/**
	@brief LiveServer::editor
	The editor window the user is working in: the active one, or the first
	shown.
*/
QETDiagramEditor *LiveServer::editor() const
{
	QETDiagramEditor *chosen = nullptr;
	for (QETDiagramEditor *e : QETApp::diagramEditors()) {
		if (e->isActiveWindow()) {
			chosen = e;
			break;
		}
		if (!chosen && e->isVisible()) chosen = e;
	}
		//While the user is typing to the assistant, QElectroTech is not
		//the active application, and QMdiArea then has no active
		//sub-window: every "current project" in the editor reads as none.
		//The one it remembers is the project the user was looking at.
	if (chosen && !chosen->m_workspace.activeSubWindow()
	    && chosen->m_workspace.currentSubWindow()) {
		chosen->m_workspace.setActiveSubWindow(chosen->m_workspace.currentSubWindow());
	}
	return chosen;
}

QJsonObject LiveServer::status()
{
	QJsonObject answer{{QStringLiteral("ok"), true},
			   {QStringLiteral("scripting"), QetSettings::scriptingEnabled()}};
	QJsonArray scripts;
	for (const ScriptLibrary::Script &s : ScriptLibrary::instance().scripts())
		scripts.append(QJsonObject{{QStringLiteral("id"), s.header.id},
					   {QStringLiteral("name"), s.header.name}});
	answer.insert(QStringLiteral("stored_scripts"), scripts);
		//So an assistant can notice a recording the user just made
	answer.insert(QStringLiteral("macro_recorder"), QJsonObject{
		{QStringLiteral("recording"), MacroRecorder::instance().isRecording()},
		{QStringLiteral("steps"), MacroRecorder::instance().stepCount()},
		{QStringLiteral("last_recording"), MacroRecorder::instance().lastId()}});

	QETDiagramEditor *e = editor();
	QETProject *project = e ? e->currentProject() : nullptr;
	if (!project) {
		answer.insert(QStringLiteral("project"), QJsonValue());
		return answer;
	}
	DiagramView *view = e->currentDiagramView();
	Diagram *diagram = view ? view->diagram() : nullptr;
	QJsonArray selected;
	if (diagram) {
		for (QGraphicsItem *item : diagram->selectedItems())
			if (item->type() == Element::Type)
				selected.append(static_cast<Element *>(item)->uuid().toString());
	}
	answer.insert(QStringLiteral("project"), QJsonObject{
		{QStringLiteral("title"), project->title()},
		{QStringLiteral("path"), project->filePath()},
		{QStringLiteral("folios"), int(project->diagrams().count())},
		{QStringLiteral("folio"), diagram ? int(project->diagrams().indexOf(diagram)) : -1},
		{QStringLiteral("folio_title"), diagram ? diagram->title() : QString()},
		{QStringLiteral("selected_elements"), selected},
		{QStringLiteral("read_only"), project->isReadOnly()},
		{QStringLiteral("last_undo"), project->undoStack()->text(project->undoStack()->index() - 1)}});
	return answer;
}

QJsonObject LiveServer::runScript(const QString &name, const QString &source)
{
	if (source.trimmed().isEmpty()) return failure(QStringLiteral("no script given"));
	QETDiagramEditor *e = editor();
	QETProject *project = e ? e->currentProject() : nullptr;
	if (!project) return failure(QStringLiteral("no project is open in QElectroTech"));

	const QString title = name.trimmed().isEmpty() ? tr("script") : name.trimmed();
	QetScripting::LiveRun run;
	const bool ok = QetScripting::runSource(source, QStringLiteral("assistant:") + title, title,
						project, e->currentDiagramView(), &run);
	QJsonObject answer{{QStringLiteral("ok"), ok},
			   {QStringLiteral("log"), QJsonArray::fromStringList(run.log)},
			   {QStringLiteral("undo"), run.undoText}};
	if (!run.error.isEmpty()) answer.insert(QStringLiteral("error"), run.error);
	return answer;
}

QJsonObject LiveServer::runStored(const QString &id)
{
	for (const ScriptLibrary::Script &s : ScriptLibrary::instance().scripts()) {
		if (s.header.id != id) continue;
		QFile file(s.path);
		if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
			return failure(QStringLiteral("cannot read %1").arg(s.path));
		QJsonObject answer = runScript(s.header.name, QString::fromUtf8(file.readAll()));
		answer.insert(QStringLiteral("name"), s.header.name);
		return answer;
	}
	return failure(QStringLiteral("no stored script with id %1").arg(id));
}

void LiveServer::setAskFirst(bool ask)
{
	if (ask == m_ask_first) return;
	m_ask_first = ask;
	emit askFirstChanged(ask);
}

/**
	@brief LiveServer::allowedCommands
	The editor commands an assistant may trigger: ones that open no dialog
	(a dialog would wait for an answer nobody is there to give the
	assistant) and change nothing that undo cannot take back. Saving,
	printing, exporting, deleting, opening and closing are not in it: a
	script can delete, as one undo step, and the rest stay the user's.
*/
QStringList LiveServer::allowedCommands()
{
	static const QStringList ids{
		QStringLiteral("diagrameditor.select_all"),
		QStringLiteral("diagrameditor.select_nothing"),
		QStringLiteral("diagrameditor.select_invert"),
		QStringLiteral("diagrameditor.select_all_conductors"),
		QStringLiteral("diagrameditor.select_all_text_fields"),
		QStringLiteral("diagrameditor.zoom_in"),
		QStringLiteral("diagrameditor.zoom_out"),
		QStringLiteral("diagrameditor.zoom_content"),
		QStringLiteral("diagrameditor.zoom_fit"),
		QStringLiteral("diagrameditor.zoom_reset"),
		QStringLiteral("diagrameditor.rotate_selection"),
		QStringLiteral("diagrameditor.rotate_texts"),
		QStringLiteral("diagrameditor.snap_selection_to_grid"),
		QStringLiteral("diagrameditor.group_selection"),
		QStringLiteral("diagrameditor.ungroup_selection"),
		QStringLiteral("diagrameditor.conductor_reset")};
	return ids;
}

QJsonObject LiveServer::command(const QString &id)
{
	if (!allowedCommands().contains(id))
		return failure(QStringLiteral("%1 is not a command an assistant may use; allowed: %2")
			       .arg(id, allowedCommands().join(QStringLiteral(", "))));
	QETDiagramEditor *e = editor();
	QAction *action = e ? ShortcutManager::instance().action(id, e) : nullptr;
	if (!action) return failure(QStringLiteral("no editor window has %1").arg(id));
	if (!action->isEnabled())
		return failure(QStringLiteral("%1 is not available right now (nothing "
					      "selected, or no project open)").arg(id));
	action->trigger();
	return {{QStringLiteral("ok"), true}, {QStringLiteral("action"), id}};
}

QJsonObject LiveServer::showFolio(int folio)
{
	QETDiagramEditor *e = editor();
	ProjectView *pv = e ? e->currentProjectView() : nullptr;
	if (!pv) return failure(QStringLiteral("no project is open in QElectroTech"));
	const QList<Diagram *> diagrams = pv->project()->diagrams();
	if (folio < 0 || folio >= diagrams.count())
		return failure(QStringLiteral("no folio %1: the project has %2, counted from 0")
			       .arg(folio).arg(diagrams.count()));
	pv->showDiagram(diagrams.at(folio));
	return {{QStringLiteral("ok"), true}, {QStringLiteral("folio"), folio}};
}

/**
	@brief LiveServer::undoLast
	Undo the newest step, only if the assistant made it: what the user did
	by hand stays theirs to undo.
*/
QJsonObject LiveServer::undoLast()
{
	QETDiagramEditor *e = editor();
	QETProject *project = e ? e->currentProject() : nullptr;
	if (!project) return failure(QStringLiteral("no project is open in QElectroTech"));
	QUndoStack *stack = project->undoStack();
	const QString text = stack->text(stack->index() - 1);
	const QString prefix = tr("Assistant : %1").arg(QString());
	if (!stack->canUndo() || !text.startsWith(prefix))
		return failure(QStringLiteral("the last step is not the assistant's (\"%1\"); "
					      "only the user undoes their own").arg(text));
	stack->undo();
	return {{QStringLiteral("ok"), true}, {QStringLiteral("undone"), text}};
}

QJsonObject LiveServer::screenshot()
{
	QETDiagramEditor *e = editor();
	DiagramView *view = e ? e->currentDiagramView() : nullptr;
	if (!view) return failure(QStringLiteral("no folio is shown in QElectroTech"));
		// Only the part of the folio (frame and title block) that is on
		// screen: a tall or wide window around a zoomed-out folio would
		// otherwise give mostly empty background. The whole viewport when
		// the folio is scrolled out of sight.
	QRect area = view->viewport()->rect();
	bool cropped = false;
	if (Diagram *diagram = view->diagram()) {
		const QRect folio = view->mapFromScene(
			diagram->border_and_titleblock.borderAndTitleBlockRect()).boundingRect()
			.adjusted(-1, -1, 1, 1).intersected(area);
		if (!folio.isEmpty()) {
			cropped = folio != area;
			area = folio;
		}
	}
	const QPixmap pixmap = view->viewport()->grab(area);
	QByteArray png;
	QBuffer buffer(&png);
	buffer.open(QIODevice::WriteOnly);
	pixmap.save(&buffer, "PNG");
	return {{QStringLiteral("ok"), true},
		{QStringLiteral("width"), pixmap.width()},
		{QStringLiteral("height"), pixmap.height()},
		{QStringLiteral("cropped_to_folio"), cropped},
		{QStringLiteral("png_base64"), QString::fromLatin1(png.toBase64())}};
}

/**
	@brief LiveServer::confirm
	Show the user the script the assistant wants to run, and ask.
	@return true to run it
*/
bool LiveServer::confirm(const QString &name, const QString &source)
{
	QDialog dialog(editor());
	dialog.setWindowTitle(tr("L'assistant veut exécuter un script"));
	auto *layout = new QVBoxLayout(&dialog);
	layout->addWidget(new QLabel(
		tr("« %1 » sur le projet ouvert. Une fois exécuté, Ctrl+Z l'annule.")
		.arg(name.isEmpty() ? tr("script") : name), &dialog));
	auto *text = new QPlainTextEdit(source, &dialog);
	text->setReadOnly(true);
	text->setFont(QFontDatabase::systemFont(QFontDatabase::FixedFont));
	text->setMinimumSize(520, 220);
	layout->addWidget(text);
	auto *buttons = new QDialogButtonBox(&dialog);
	QPushButton *run = buttons->addButton(tr("&Exécuter"), QDialogButtonBox::AcceptRole);
	buttons->addButton(tr("&Refuser"), QDialogButtonBox::RejectRole);
	QPushButton *always = buttons->addButton(tr("&Toujours pour cette session"),
						 QDialogButtonBox::AcceptRole);
	layout->addWidget(buttons);
	QPushButton *clicked = nullptr;
	connect(buttons, &QDialogButtonBox::clicked, &dialog, [&](QAbstractButton *b) {
		clicked = qobject_cast<QPushButton *>(b);
	});
	connect(buttons, &QDialogButtonBox::accepted, &dialog, &QDialog::accept);
	connect(buttons, &QDialogButtonBox::rejected, &dialog, &QDialog::reject);
	run->setDefault(true);
	dialog.exec();
	if (clicked == always) setAskFirst(false);
	return clicked == run || clicked == always;
}