#include <QFile>
#include <QMessageBox>
#include <FileSystem.h>
#include <updater/GoUpdate.h>
#include "UpdateController.h"
#include <QApplication>
#include <thread>
#include <chrono>
#include <LocalPeer.h>

// from <sys/stat.h>
#ifndef S_IRUSR
#define __S_IREAD 0400         /* Read by owner.  */
#define __S_IWRITE 0200        /* Write by owner.  */
#define __S_IEXEC 0100         /* Execute by owner.  */
#define S_IRUSR __S_IREAD      /* Read by owner.  */
#define S_IWUSR __S_IWRITE     /* Write by owner.  */
#define S_IXUSR __S_IEXEC      /* Execute by owner.  */

#define S_IRGRP (S_IRUSR >> 3) /* Read by group.  */
#define S_IWGRP (S_IWUSR >> 3) /* Write by group.  */
#define S_IXGRP (S_IXUSR >> 3) /* Execute by group.  */

#define S_IROTH (S_IRGRP >> 3) /* Read by others.  */
#define S_IWOTH (S_IWGRP >> 3) /* Write by others.  */
#define S_IXOTH (S_IXGRP >> 3) /* Execute by others.  */
#endif
static QFile::Permissions unixModeToPermissions(const int mode)
{
    QFile::Permissions perms;

    if (mode & S_IRUSR)
    {
        perms |= QFile::ReadUser;
    }
    if (mode & S_IWUSR)
    {
        perms |= QFile::WriteUser;
    }
    if (mode & S_IXUSR)
    {
        perms |= QFile::ExeUser;
    }

    if (mode & S_IRGRP)
    {
        perms |= QFile::ReadGroup;
    }
    if (mode & S_IWGRP)
    {
        perms |= QFile::WriteGroup;
    }
    if (mode & S_IXGRP)
    {
        perms |= QFile::ExeGroup;
    }

    if (mode & S_IROTH)
    {
        perms |= QFile::ReadOther;
    }
    if (mode & S_IWOTH)
    {
        perms |= QFile::WriteOther;
    }
    if (mode & S_IXOTH)
    {
        perms |= QFile::ExeOther;
    }
    return perms;
}

static const QLatin1String liveCheckFile("live.check");

UpdateController::UpdateController(QWidget * parent, const QString& root, const QString updateFilesDir, GoUpdate::OperationList operations)
{
    m_parent = parent;
    m_root = root;
    m_updateFilesDir = updateFilesDir;
    m_operations = operations;
}


void UpdateController::installUpdates()
{
    qint64 pid = -1;
    QStringList args;
    bool started = false;

    qDebug() << "Installing updates.";
#ifdef Q_OS_WIN
    QString finishCmd = QApplication::applicationFilePath();
#elif defined Q_OS_LINUX
    QString finishCmd = FS::PathCombine(m_root, "MultiMC");
#elif defined Q_OS_MAC
    QString finishCmd = QApplication::applicationFilePath();
#else
#error Unsupported operating system.
#endif

    QString backupPath = FS::PathCombine(m_root, "update", "backup");
    QDir origin(m_root);

    // clean up the backup folder. it should be empty before we start
    if(!FS::deletePath(backupPath))
    {
        qWarning() << "couldn't remove previous backup folder" << backupPath;
    }
    // and it should exist.
    if(!FS::ensureFolderPathExists(backupPath))
    {
        qWarning() << "couldn't create folder" << backupPath;
        return;
    }

    bool useXPHack = false;
    QString exePath;
    QString exeOrigin;
    QString exeBackup;

    // perform the update operations
    for(auto op: m_operations)
    {
        switch(op.type)
        {
            // replace = move original out to backup, if it exists, move the new file in its place
            case GoUpdate::Operation::OP_REPLACE:
            {
#ifdef Q_OS_WIN32
                // hack for people renaming the .exe because ... reasons :)
                if(op.destination == "MultiMC.exe")
                {
                    op.destination = QFileInfo(QApplication::applicationFilePath()).fileName();
                }
#endif
                QFileInfo destination (FS::PathCombine(m_root, op.destination));
#ifdef Q_OS_WIN32
                if(QSysInfo::windowsVersion() < QSysInfo::WV_VISTA)
                {
                    if(destination.fileName() == "MultiMC.exe")
                    {
                        QDir rootDir(m_root);
                        exeOrigin = rootDir.relativeFilePath(op.source);
                        exePath = rootDir.relativeFilePath(op.destination);
                        exeBackup = rootDir.relativeFilePath(FS::PathCombine(backupPath, destination.fileName()));
                        useXPHack = true;
                        continue;
                    }
                }
#endif
                if(destination.exists())
                {
                    QString backupName = op.destination;
                    backupName.replace('/', '_');
                    QString backupFilePath = FS::PathCombine(backupPath, backupName);
                    if(!QFile::rename(destination.absoluteFilePath(), backupFilePath))
                    {
                        qWarning() << "Couldn't move:" << destination.absoluteFilePath() << "to" << backupFilePath;
                        m_failedOperationType = Replace;
                        m_failedFile = op.destination;
                        fail();
                        return;
                    }
                    BackupEntry be;
                    be.original = destination.absoluteFilePath();
                    be.backup = backupFilePath;
                    be.update = op.source;
                    m_replace_backups.append(be);
                }
                // make sure the folder we are putting this into exists
                if(!FS::ensureFilePathExists(destination.absoluteFilePath()))
                {
                    qWarning() << "REPLACE: Couldn't create folder:" << destination.absoluteFilePath();
                    m_failedOperationType = Replace;
                    m_failedFile = op.destination;
                    fail();
                    return;
                }
                // now move the new file in
                if(!QFile::rename(op.source, destination.absoluteFilePath()))
                {
                    qWarning() << "REPLACE: Couldn't move:" << op.source << "to" << destination.absoluteFilePath();
                    m_failedOperationType = Replace;
                    m_failedFile = op.destination;
                    fail();
                    return;
                }
                QFile::setPermissions(destination.absoluteFilePath(), unixModeToPermissions(op.destinationMode));
            }
            break;
            // delete = move original to backup
            case GoUpdate::Operation::OP_DELETE:
            {
                QString destFilePath = FS::PathCombine(m_root, op.destination);
                if(QFile::exists(destFilePath))
                {
                    QString backupName = op.destination;
                    backupName.replace('/', '_');
                    QString trashFilePath = FS::PathCombine(backupPath, backupName);

                    if(!QFile::rename(destFilePath, trashFilePath))
                    {
                        qWarning() << "DELETE: Couldn't move:" << op.destination << "to" << trashFilePath;
                        m_failedFile = op.destination;
                        m_failedOperationType = Delete;
                        fail();
                        return;
                    }
                    BackupEntry be;
                    be.original = destFilePath;
                    be.backup = trashFilePath;
                    m_delete_backups.append(be);
                }
            }
            break;
        }
    }

    // try to start the new binary
    args = qApp->arguments();
    args.removeFirst();

    // on old Windows, do insane things... no error checking here, this is just to have something.
    if(useXPHack)
    {
        QString script;
        auto nativePath = QDir::toNativeSeparators(exePath);
        auto nativeOriginPath = QDir::toNativeSeparators(exeOrigin);
        auto nativeBackupPath = QDir::toNativeSeparators(exeBackup);

        // so we write this vbscript thing...
        QTextStream out(&script);
        out << "WScript.Sleep 1000\n";
        out << "Set fso=CreateObject(\"Scripting.FileSystemObject\")\n";
        out << "Set shell=CreateObject(\"WScript.Shell\")\n";
        out << "fso.MoveFile \"" << nativePath << "\", \"" << nativeBackupPath << "\"\n";
        out << "fso.MoveFile \"" << nativeOriginPath << "\", \"" << nativePath << "\"\n";
        out << "shell.Run \"" << nativePath << "\"\n";

        QString scriptPath = FS::PathCombine(m_root, "update", "update.vbs");

        // we save it
        QFile scriptFile(scriptPath);
        scriptFile.open(QIODevice::WriteOnly);
        scriptFile.write(script.toLocal8Bit().replace("\n", "\r\n"));
        scriptFile.close();

        // we run it
        started = QProcess::startDetached("wscript", {scriptPath}, m_root);

        // and we quit. conscious thought.
        qApp->quit();
        return;
    }
    bool doLiveCheck = true;
    bool startFailed = false;

    // remove live check file, if any
    if(QFile::exists(liveCheckFile))
    {
        if(!QFile::remove(liveCheckFile))
        {
            qWarning() << "Couldn't remove the" << liveCheckFile << "file! We will proceed without :(";
            doLiveCheck = false;
        }
    }

    if(doLiveCheck)
    {
        if(!args.contains("--alive"))
        {
            args.append("--alive");
        }
    }

    // FIXME: reparse args and construct a safe variant from scratch. This is a workaround for GH-1874:
    QStringList realargs;
    int skip = 0;
    for(auto & arg: args)
    {
        if(skip)
        {
            skip--;
            continue;
        }
        if(arg == "-l")
        {
            skip = 1;
            continue;
        }
        realargs.append(arg);
    }

    // start the updated application
    started = QProcess::startDetached(finishCmd, realargs, QDir::currentPath(), &pid);
    // much dumber check - just find out if the call
    if(!started || pid == -1)
    {
        qWarning() << "Couldn't start new process properly!";
        startFailed = true;
    }
    if(!startFailed && doLiveCheck)
    {
        int attempts = 0;
        while(attempts < 10)
        {
            attempts++;
            QString key;
            std::this_thread::sleep_for(std::chrono::milliseconds(250));
            if(!QFile::exists(liveCheckFile))
            {
                qWarning() << "Couldn't find the" << liveCheckFile << "file!";
                startFailed = true;
                continue;
            }
            try
            {
                key = QString::fromUtf8(FS::read(liveCheckFile));
                auto id = ApplicationId::fromRawString(key);
                LocalPeer peer(nullptr, id);
                if(peer.isClient())
                {
                    startFailed = false;
                    qDebug() << "Found process started with key " << key;
                    break;
                }
                else
                {
                    startFailed = true;
                    qDebug() << "Process started with key " << key << "apparently died or is not reponding...";
                    break;
                }
            }
            catch (const Exception &e)
            {
                qWarning() << "Couldn't read the" << liveCheckFile << "file!";
                startFailed = true;
                continue;
            }
        }
    }
    if(startFailed)
    {
        m_failedOperationType = Start;
        fail();
        return;
    }
    else
    {
        origin.rmdir(m_updateFilesDir);
        qApp->quit();
        return;
    }
}

void UpdateController::fail()
{
    qWarning() << "Update failed!";

    QString msg;
    bool doRollback = false;
    QString failTitle = QObject::tr("Update failed!");
    QString rollFailTitle = QObject::tr("Rollback failed!");
    switch (m_failedOperationType)
    {
        case Replace:
        {
            msg = QObject::tr("Couldn't replace file %1. Changes will be reverted.\n"
                "See the MultiMC log file for details.").arg(m_failedFile);
            doRollback = true;
            QMessageBox::critical(m_parent, failTitle, msg);
            break;
        }
        case Delete:
        {
            msg = QObject::tr("Couldn't remove file %1. Changes will be reverted.\n"
                "See the MultiMC log file for details.").arg(m_failedFile);
            doRollback = true;
            QMessageBox::critical(m_parent, failTitle, msg);
            break;
        }
        case Start:
        {
            msg = QObject::tr("The new version didn't start or is too old and doesn't respond to startup checks.\n"
                "\n"
                "Roll back to previous version?");
            auto result = QMessageBox::critical(
                m_parent,
                failTitle,
                msg,
                QMessageBox::Yes | QMessageBox::No,
                QMessageBox::Yes
            );
            doRollback = (result == QMessageBox::Yes);
            break;
        }
        case Nothing:
        default:
            return;
    }
    if(doRollback)
    {
        auto rollbackOK = rollback();
        if(!rollbackOK)
        {
            msg = QObject::tr("The rollback failed too.\n"
                "You will have to repair MultiMC manually.\n"
                "Please let us know why and how this happened.").arg(m_failedFile);
            QMessageBox::critical(m_parent, rollFailTitle, msg);
            qApp->quit();
        }
    }
    else
    {
        qApp->quit();
    }
}

bool UpdateController::rollback()
{
    bool revertOK = true;
    // if the above failed, roll back changes
    for(auto backup:m_replace_backups)
    {
        qWarning() << "restoring" << backup.original << "from" << backup.backup;
        if(!QFile::rename(backup.original, backup.update))
        {
            revertOK = false;
            qWarning() << "moving new" << backup.original << "back to" << backup.update << "failed!";
            continue;
        }

        if(!QFile::rename(backup.backup, backup.original))
        {
            revertOK = false;
            qWarning() << "restoring" << backup.original << "failed!";
        }
    }
    for(auto backup:m_delete_backups)
    {
        qWarning() << "restoring" << backup.original << "from" << backup.backup;
        if(!QFile::rename(backup.backup, backup.original))
        {
            revertOK = false;
            qWarning() << "restoring" << backup.original << "failed!";
        }
    }
    return revertOK;
}