/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of Qt Creator.
**
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** accordance with the commercial license agreement provided with the
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** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
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****************************************************************************/

#include "consoleprocess_p.h"

#include "qtcprocess.h"

#include <utils/hostosinfo.h>
#include <utils/qtcassert.h>

#include <QCoreApplication>
#include <QFileInfo>
#include <QSettings>
#include <QTimer>

#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>

namespace Utils {

ConsoleProcessPrivate::ConsoleProcessPrivate() :
    m_mode(ConsoleProcess::Run),
    m_appPid(0),
    m_stubSocket(0),
    m_tempFile(0),
    m_error(QProcess::UnknownError),
    m_settings(0),
    m_stubConnected(false),
    m_stubPid(0),
    m_stubConnectTimer(0)
{
}

ConsoleProcess::ConsoleProcess(QObject *parent)  :
    QObject(parent), d(new ConsoleProcessPrivate)
{
    connect(&d->m_stubServer, &QLocalServer::newConnection,
            this, &ConsoleProcess::stubConnectionAvailable);

    d->m_process.setProcessChannelMode(QProcess::ForwardedChannels);
}

qint64 ConsoleProcess::applicationMainThreadID() const
{
    return -1;
}

void ConsoleProcess::setSettings(QSettings *settings)
{
    d->m_settings = settings;
}

bool ConsoleProcess::start(const QString &program, const QString &args)
{
    if (isRunning())
        return false;

    d->m_errorString.clear();
    d->m_error = QProcess::UnknownError;

    QtcProcess::SplitError perr;
    QtcProcess::Arguments pargs = QtcProcess::prepareArgs(args, &perr, HostOsInfo::hostOs(),
                                                          &d->m_environment, &d->m_workingDir);
    QString pcmd;
    if (perr == QtcProcess::SplitOk) {
        pcmd = program;
    } else {
        if (perr != QtcProcess::FoundMeta) {
            emitError(QProcess::FailedToStart, tr("Quoting error in command."));
            return false;
        }
        if (d->m_mode == Debug) {
            // FIXME: QTCREATORBUG-2809
            emitError(QProcess::FailedToStart, tr("Debugging complex shell commands in a terminal"
                                 " is currently not supported."));
            return false;
        }
        pcmd = QLatin1String("/bin/sh");
        pargs = QtcProcess::Arguments::createUnixArgs(
                    QStringList({"-c", (QtcProcess::quoteArg(program) + ' ' + args)}));
    }

    QtcProcess::SplitError qerr;
    QtcProcess::Arguments xtermArgs = QtcProcess::prepareArgs(terminalEmulator(d->m_settings), &qerr,
                                                              HostOsInfo::hostOs(),
                                                              &d->m_environment, &d->m_workingDir);
    if (qerr != QtcProcess::SplitOk) {
        emitError(QProcess::FailedToStart, qerr == QtcProcess::BadQuoting
                          ? tr("Quoting error in terminal command.")
                          : tr("Terminal command may not be a shell command."));
        return false;
    }

    const QString err = stubServerListen();
    if (!err.isEmpty()) {
        emitError(QProcess::FailedToStart, msgCommChannelFailed(err));
        return false;
    }

    d->m_environment.unset(QLatin1String("TERM"));
    QStringList env = d->m_environment.toStringList();
    if (!env.isEmpty()) {
        d->m_tempFile = new QTemporaryFile();
        if (!d->m_tempFile->open()) {
            stubServerShutdown();
            emitError(QProcess::FailedToStart, msgCannotCreateTempFile(d->m_tempFile->errorString()));
            delete d->m_tempFile;
            d->m_tempFile = 0;
            return false;
        }
        QByteArray contents;
        foreach (const QString &var, env) {
            QByteArray l8b = var.toLocal8Bit();
            contents.append(l8b.constData(), l8b.size() + 1);
        }
        if (d->m_tempFile->write(contents) != contents.size() || !d->m_tempFile->flush()) {
            stubServerShutdown();
            emitError(QProcess::FailedToStart, msgCannotWriteTempFile());
            delete d->m_tempFile;
            d->m_tempFile = 0;
            return false;
        }
    }

    const QString stubPath = QCoreApplication::applicationDirPath()
            + QLatin1String("/" QTC_REL_TOOLS_PATH "/qtcreator_process_stub");
    QStringList allArgs = xtermArgs.toUnixArgs();
    allArgs << stubPath
              << modeOption(d->m_mode)
              << d->m_stubServer.fullServerName()
              << msgPromptToClose()
              << workingDirectory()
              << (d->m_tempFile ? d->m_tempFile->fileName() : QString())
              << QString::number(getpid())
              << pcmd << pargs.toUnixArgs();

    QString xterm = allArgs.takeFirst();
    d->m_process.start(xterm, allArgs);
    if (!d->m_process.waitForStarted()) {
        stubServerShutdown();
        emitError(QProcess::UnknownError, tr("Cannot start the terminal emulator \"%1\", change the setting in the "
                             "Environment options.").arg(xterm));
        delete d->m_tempFile;
        d->m_tempFile = 0;
        return false;
    }
    d->m_stubConnectTimer = new QTimer(this);
    connect(d->m_stubConnectTimer, &QTimer::timeout, this, &ConsoleProcess::stop);
    d->m_stubConnectTimer->setSingleShot(true);
    d->m_stubConnectTimer->start(10000);
    d->m_executable = program;
    return true;
}

void ConsoleProcess::killProcess()
{
    if (d->m_stubSocket && d->m_stubSocket->isWritable()) {
        d->m_stubSocket->write("k", 1);
        d->m_stubSocket->flush();
    }
    d->m_appPid = 0;
}

void ConsoleProcess::killStub()
{
    if (d->m_stubSocket && d->m_stubSocket->isWritable()) {
        d->m_stubSocket->write("s", 1);
        d->m_stubSocket->flush();
    }
    stubServerShutdown();
    d->m_stubPid = 0;
}

void ConsoleProcess::detachStub()
{
    if (d->m_stubSocket && d->m_stubSocket->isWritable()) {
        d->m_stubSocket->write("d", 1);
        d->m_stubSocket->flush();
    }
    stubServerShutdown();
    d->m_stubPid = 0;
}

void ConsoleProcess::stop()
{
    killProcess();
    killStub();
    if (isRunning()) {
        d->m_process.terminate();
        if (!d->m_process.waitForFinished(1000) && d->m_process.state() == QProcess::Running) {
            d->m_process.kill();
            d->m_process.waitForFinished();
        }
    }
}

bool ConsoleProcess::isRunning() const
{
    return d->m_process.state() != QProcess::NotRunning
            || (d->m_stubSocket && d->m_stubSocket->isOpen());
}

QString ConsoleProcess::stubServerListen()
{
    // We need to put the socket in a private directory, as some systems simply do not
    // check the file permissions of sockets.
    QString stubFifoDir;
    forever {
        {
            QTemporaryFile tf;
            if (!tf.open())
                return msgCannotCreateTempFile(tf.errorString());
            stubFifoDir = tf.fileName();
        }
        // By now the temp file was deleted again
        d->m_stubServerDir = QFile::encodeName(stubFifoDir);
        if (!::mkdir(d->m_stubServerDir.constData(), 0700))
            break;
        if (errno != EEXIST)
            return msgCannotCreateTempDir(stubFifoDir, QString::fromLocal8Bit(strerror(errno)));
    }
    const QString stubServer  = stubFifoDir + QLatin1String("/stub-socket");
    if (!d->m_stubServer.listen(stubServer)) {
        ::rmdir(d->m_stubServerDir.constData());
        return tr("Cannot create socket \"%1\": %2").arg(stubServer, d->m_stubServer.errorString());
    }
    return QString();
}

void ConsoleProcess::stubServerShutdown()
{
    if (d->m_stubSocket) {
        readStubOutput(); // we could get the shutdown signal before emptying the buffer
        d->m_stubSocket->disconnect(); // avoid getting queued readyRead signals
        d->m_stubSocket->deleteLater(); // we might be called from the disconnected signal of m_stubSocket
    }
    d->m_stubSocket = 0;
    if (d->m_stubServer.isListening()) {
        d->m_stubServer.close();
        ::rmdir(d->m_stubServerDir.constData());
    }
}

void ConsoleProcess::stubConnectionAvailable()
{
    if (d->m_stubConnectTimer) {
        delete d->m_stubConnectTimer;
        d->m_stubConnectTimer = 0;
    }
    d->m_stubConnected = true;
    emit stubStarted();
    d->m_stubSocket = d->m_stubServer.nextPendingConnection();
    connect(d->m_stubSocket, &QIODevice::readyRead, this, &ConsoleProcess::readStubOutput);
    connect(d->m_stubSocket, &QLocalSocket::disconnected, this, &ConsoleProcess::stubExited);
}

static QString errorMsg(int code)
{
    return QString::fromLocal8Bit(strerror(code));
}

void ConsoleProcess::readStubOutput()
{
    while (d->m_stubSocket->canReadLine()) {
        QByteArray out = d->m_stubSocket->readLine();
        out.chop(1); // \n
        if (out.startsWith("err:chdir ")) {
            emitError(QProcess::FailedToStart, msgCannotChangeToWorkDir(workingDirectory(), errorMsg(out.mid(10).toInt())));
        } else if (out.startsWith("err:exec ")) {
            emitError(QProcess::FailedToStart, msgCannotExecute(d->m_executable, errorMsg(out.mid(9).toInt())));
        } else if (out.startsWith("spid ")) {
            delete d->m_tempFile;
            d->m_tempFile = 0;

            d->m_stubPid = out.mid(4).toInt();
        } else if (out.startsWith("pid ")) {
            d->m_appPid = out.mid(4).toInt();
            emit processStarted();
        } else if (out.startsWith("exit ")) {
            d->m_appStatus = QProcess::NormalExit;
            d->m_appCode = out.mid(5).toInt();
            d->m_appPid = 0;
            emit processStopped(d->m_appCode, d->m_appStatus);
        } else if (out.startsWith("crash ")) {
            d->m_appStatus = QProcess::CrashExit;
            d->m_appCode = out.mid(6).toInt();
            d->m_appPid = 0;
            emit processStopped(d->m_appCode, d->m_appStatus);
        } else {
            emitError(QProcess::UnknownError, msgUnexpectedOutput(out));
            d->m_stubPid = 0;
            d->m_process.terminate();
            break;
        }
    }
}

void ConsoleProcess::stubExited()
{
    // The stub exit might get noticed before we read the error status.
    if (d->m_stubSocket && d->m_stubSocket->state() == QLocalSocket::ConnectedState)
        d->m_stubSocket->waitForDisconnected();
    stubServerShutdown();
    d->m_stubPid = 0;
    delete d->m_tempFile;
    d->m_tempFile = 0;
    if (d->m_appPid) {
        d->m_appStatus = QProcess::CrashExit;
        d->m_appCode = -1;
        d->m_appPid = 0;
        emit processStopped(d->m_appCode, d->m_appStatus); // Maybe it actually did not, but keep state consistent
    }
    emit stubStopped();
}

struct Terminal {
    const char *binary;
    const char *options;
};

static const Terminal knownTerminals[] =
{
    {"x-terminal-emulator", "-e"},
    {"xterm", "-e"},
    {"aterm", "-e"},
    {"Eterm", "-e"},
    {"rxvt", "-e"},
    {"urxvt", "-e"},
    {"xfce4-terminal", "-x"},
    {"konsole", "-e"},
    {"gnome-terminal", "-x"}
};

QString ConsoleProcess::defaultTerminalEmulator()
{
    if (HostOsInfo::isMacHost()) {
        QString termCmd = QCoreApplication::applicationDirPath() + QLatin1String("/../Resources/scripts/openTerminal.command");
        if (QFileInfo::exists(termCmd))
            return termCmd.replace(QLatin1Char(' '), QLatin1String("\\ "));
        return QLatin1String("/usr/X11/bin/xterm");
    }
    const Environment env = Environment::systemEnvironment();
    const int terminalCount = int(sizeof(knownTerminals) / sizeof(knownTerminals[0]));
    for (int i = 0; i < terminalCount; ++i) {
        QString result = env.searchInPath(QLatin1String(knownTerminals[i].binary)).toString();
        if (!result.isEmpty()) {
            result += QLatin1Char(' ');
            result += QLatin1String(knownTerminals[i].options);
            return result;
        }
    }
    return QLatin1String("xterm -e");
}

QStringList ConsoleProcess::availableTerminalEmulators()
{
    QStringList result;
    const Environment env = Environment::systemEnvironment();
    const int terminalCount = int(sizeof(knownTerminals) / sizeof(knownTerminals[0]));
    for (int i = 0; i < terminalCount; ++i) {
        QString terminal = env.searchInPath(QLatin1String(knownTerminals[i].binary)).toString();
        if (!terminal.isEmpty()) {
            terminal += QLatin1Char(' ');
            terminal += QLatin1String(knownTerminals[i].options);
            result.push_back(terminal);
        }
    }
    if (!result.contains(defaultTerminalEmulator()))
        result.append(defaultTerminalEmulator());
    result.sort();
    return result;
}

QString ConsoleProcess::terminalEmulator(const QSettings *settings, bool nonEmpty)
{
    if (settings) {
        const QString value = settings->value(QLatin1String("General/TerminalEmulator")).toString();
        if (!nonEmpty || !value.isEmpty())
            return value;
    }
    return defaultTerminalEmulator();
}

void ConsoleProcess::setTerminalEmulator(QSettings *settings, const QString &term)
{
    settings->setValue(QLatin1String("General/TerminalEmulator"), term);
}

bool ConsoleProcess::startTerminalEmulator(QSettings *settings, const QString &workingDir)
{
    const QString emu = QtcProcess::splitArgs(terminalEmulator(settings)).takeFirst();
    return QProcess::startDetached(emu, QStringList(), workingDir);
}

} // namespace Utils