/*
    Windows ConPTY-based Pty implementation using ptyqt.
    Replaces the POSIX kpty/kptyprocess stack on Windows.
    Only compiled on Windows via win32{} block in lib.pri — no Q_OS_WIN guard needed.
*/

#include "Pty.h"
#include <conptyprocess.h>
#include <QProcess>
#include <QFileInfo>
#include <QIODevice>
#include <QtDebug>
#include <windows.h>

using namespace Konsole;

Pty::Pty(QObject *parent) : QObject(parent) {}
Pty::Pty(int /*ptyMasterFd*/, QObject *parent) : QObject(parent) {}

Pty::~Pty()
{
    if (_exitTimer) _exitTimer->stop();
    if (_ptyProcess) {
        _ptyProcess->kill();
        delete _ptyProcess;
    }
}

void Pty::kill()
{
    if (_ptyProcess)
        _ptyProcess->kill();
}

int Pty::start(const QString &program,
               const QStringList &arguments,
               const QStringList &environment,
               ulong /*winid*/,
               bool /*addToUtmp*/)
{
    _ptyProcess = new ConPtyProcess();
    if (!_ptyProcess->isAvailable()) {
        qWarning() << "Pty: ConPTY not available (requires Windows 10 build 1903+)";
        delete _ptyProcess;
        _ptyProcess = nullptr;
        return -1;
    }

    // ConPtyProcess::startProcess requires an absolute path to an existing executable.
    // Resolve relative names (e.g. "powershell.exe") via SearchPathW.
    auto findExe = [](const QString &name) -> QString {
        wchar_t buf[MAX_PATH] = {};
        std::wstring wname = name.toStdWString();
        if (SearchPathW(nullptr, wname.c_str(), L".exe", MAX_PATH, buf, nullptr) > 0)
            return QString::fromWCharArray(buf);
        return {};
    };

    QString exec = program;
    if (!QFileInfo(exec).isAbsolute()) {
        exec = findExe(exec);
        if (exec.isEmpty() || !QFileInfo::exists(exec)) {
            exec = findExe(QStringLiteral("cmd.exe"));
            if (exec.isEmpty())
                exec = QStringLiteral("C:\\Windows\\System32\\cmd.exe");
            qWarning() << "Pty: could not resolve" << program << "— falling back to" << exec;
        }
    }

    connect(_ptyProcess->notifier(), &QIODevice::readyRead,
            this, &Pty::onReadyRead);

    // ConPtyProcess inherits the parent-process CWD. Temporarily change it
    // to the requested working directory and restore immediately after.
    wchar_t prevDir[MAX_PATH] = {};
    const bool changedDir = !_workingDir.isEmpty()
        && GetCurrentDirectoryW(MAX_PATH, prevDir) != 0
        && SetCurrentDirectoryW(_workingDir.toStdWString().c_str());

    bool ok = _ptyProcess->startProcess(exec, environment,
                                        static_cast<qint16>(_windowColumns),
                                        static_cast<qint16>(_windowLines));

    if (changedDir)
        SetCurrentDirectoryW(prevDir);

    if (!ok) {
        qWarning() << "Pty: failed to start" << exec << _ptyProcess->lastError();
        delete _ptyProcess;
        _ptyProcess = nullptr;
        return -1;
    }

    // Poll every 500 ms to detect process exit (ConPTY has no exit signal)
    _exitTimer = new QTimer(this);
    _exitTimer->setInterval(500);
    connect(_exitTimer, &QTimer::timeout, this, &Pty::checkProcessExit);
    _exitTimer->start();

    emit started();
    return 0;
}

void Pty::sendData(const char *buffer, int length)
{
    if (_ptyProcess && length > 0)
        _ptyProcess->write(QByteArray(buffer, length));
}

void Pty::setWindowSize(int lines, int cols)
{
    _windowLines   = lines;
    _windowColumns = cols;
    if (_ptyProcess)
        _ptyProcess->resize(static_cast<qint16>(cols), static_cast<qint16>(lines));
}

QSize Pty::windowSize() const
{
    return {_windowColumns, _windowLines};
}

int Pty::foregroundProcessGroup() const
{
    return _ptyProcess ? static_cast<int>(_ptyProcess->pid()) : 0;
}

QProcess::ProcessState Pty::state() const
{
    if (!_ptyProcess || _ptyProcess->pid() == 0)
        return QProcess::NotRunning;
    HANDLE h = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, FALSE,
                           static_cast<DWORD>(_ptyProcess->pid()));
    if (!h) return QProcess::NotRunning;
    DWORD code = STILL_ACTIVE;
    GetExitCodeProcess(h, &code);
    CloseHandle(h);
    return (code == STILL_ACTIVE) ? QProcess::Running : QProcess::NotRunning;
}

qint64 Pty::processId() const
{
    return _ptyProcess ? _ptyProcess->pid() : -1;
}

void Pty::onReadyRead()
{
    if (!_ptyProcess) return;
    const QByteArray data = _ptyProcess->readAll();
    if (!data.isEmpty())
        emit receivedData(data.constData(), data.size());
}

void Pty::checkProcessExit()
{
    if (state() == QProcess::NotRunning) {
        _exitTimer->stop();
        emit finished(0, QProcess::NormalExit);
    }
}