/* Copyright 2013-2019 MultiMC Contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <QStringList>
#include <QString>
#include <QDir>
#include <QStringList>

#include <settings/Setting.h>

#include <QDebug>
#include "java/JavaUtils.h"
#include "java/JavaInstallList.h"
#include "FileSystem.h"

#define IBUS "@im=ibus"

JavaUtils::JavaUtils()
{
}

#ifdef Q_OS_LINUX
static QString processLD_LIBRARY_PATH(const QString & LD_LIBRARY_PATH)
{
    QDir mmcBin(QCoreApplication::applicationDirPath());
    auto items = LD_LIBRARY_PATH.split(':');
    QStringList final;
    for(auto & item: items)
    {
        QDir test(item);
        if(test == mmcBin)
        {
            qDebug() << "Env:LD_LIBRARY_PATH ignoring path" << item;
            continue;
        }
        final.append(item);
    }
    return final.join(':');
}
#endif

QProcessEnvironment CleanEnviroment()
{
    // prepare the process environment
    QProcessEnvironment rawenv = QProcessEnvironment::systemEnvironment();
    QProcessEnvironment env;

    QStringList ignored =
    {
        "JAVA_ARGS",
        "CLASSPATH",
        "CONFIGPATH",
        "JAVA_HOME",
        "JRE_HOME",
        "_JAVA_OPTIONS",
        "JAVA_OPTIONS",
        "JAVA_TOOL_OPTIONS"
    };
    for(auto key: rawenv.keys())
    {
        auto value = rawenv.value(key);
        // filter out dangerous java crap
        if(ignored.contains(key))
        {
            qDebug() << "Env: ignoring" << key << value;
            continue;
        }
        // filter MultiMC-related things
        if(key.startsWith("QT_"))
        {
            qDebug() << "Env: ignoring" << key << value;
            continue;
        }
#ifdef Q_OS_LINUX
        // Do not pass LD_* variables to java. They were intended for MultiMC
        if(key.startsWith("LD_"))
        {
            qDebug() << "Env: ignoring" << key << value;
            continue;
        }
        // Strip IBus
        // IBus is a Linux IME framework. For some reason, it breaks MC?
        if (key == "XMODIFIERS" && value.contains(IBUS))
        {
            QString save = value;
            value.replace(IBUS, "");
            qDebug() << "Env: stripped" << IBUS << "from" << save << ":" << value;
        }
        if(key == "GAME_PRELOAD")
        {
            env.insert("LD_PRELOAD", value);
            continue;
        }
        if(key == "GAME_LIBRARY_PATH")
        {
            env.insert("LD_LIBRARY_PATH", processLD_LIBRARY_PATH(value));
            continue;
        }
#endif
        // qDebug() << "Env: " << key << value;
        env.insert(key, value);
    }
#ifdef Q_OS_LINUX
    // HACK: Workaround for QTBUG42500
    if(!env.contains("LD_LIBRARY_PATH"))
    {
        env.insert("LD_LIBRARY_PATH", "");
    }
#endif

    return env;
}

JavaInstallPtr JavaUtils::MakeJavaPtr(QString path, QString id, QString arch)
{
    JavaInstallPtr javaVersion(new JavaInstall());

    javaVersion->id = id;
    javaVersion->arch = arch;
    javaVersion->path = path;

    return javaVersion;
}

JavaInstallPtr JavaUtils::GetDefaultJava()
{
    JavaInstallPtr javaVersion(new JavaInstall());

    javaVersion->id = "java";
    javaVersion->arch = "unknown";
#if defined(Q_OS_WIN32)
    javaVersion->path = "javaw";
#else
    javaVersion->path = "java";
#endif

    return javaVersion;
}

#if defined(Q_OS_WIN32)
QList<JavaInstallPtr> JavaUtils::FindJavaFromRegistryKey(DWORD keyType, QString keyName)
{
    QList<JavaInstallPtr> javas;

    QString archType = "unknown";
    if (keyType == KEY_WOW64_64KEY)
        archType = "64";
    else if (keyType == KEY_WOW64_32KEY)
        archType = "32";

    HKEY jreKey;
    if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, keyName.toStdString().c_str(), 0,
                      KEY_READ | keyType | KEY_ENUMERATE_SUB_KEYS, &jreKey) == ERROR_SUCCESS)
    {
        // Read the current type version from the registry.
        // This will be used to find any key that contains the JavaHome value.
        char *value = new char[0];
        DWORD valueSz = 0;
        if (RegQueryValueExA(jreKey, "CurrentVersion", NULL, NULL, (BYTE *)value, &valueSz) ==
            ERROR_MORE_DATA)
        {
            value = new char[valueSz];
            RegQueryValueExA(jreKey, "CurrentVersion", NULL, NULL, (BYTE *)value, &valueSz);
        }

        QString recommended = value;

        TCHAR subKeyName[255];
        DWORD subKeyNameSize, numSubKeys, retCode;

        // Get the number of subkeys
        RegQueryInfoKey(jreKey, NULL, NULL, NULL, &numSubKeys, NULL, NULL, NULL, NULL, NULL,
                        NULL, NULL);

        // Iterate until RegEnumKeyEx fails
        if (numSubKeys > 0)
        {
            for (DWORD i = 0; i < numSubKeys; i++)
            {
                subKeyNameSize = 255;
                retCode = RegEnumKeyEx(jreKey, i, subKeyName, &subKeyNameSize, NULL, NULL, NULL,
                                       NULL);
                if (retCode == ERROR_SUCCESS)
                {
                    // Now open the registry key for the version that we just got.
                    QString newKeyName = keyName + "\\" + subKeyName;

                    HKEY newKey;
                    if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, newKeyName.toStdString().c_str(), 0,
                                     KEY_READ | KEY_WOW64_64KEY, &newKey) == ERROR_SUCCESS)
                    {
                        // Read the JavaHome value to find where Java is installed.
                        value = new char[0];
                        valueSz = 0;
                        if (RegQueryValueEx(newKey, "JavaHome", NULL, NULL, (BYTE *)value,
                                            &valueSz) == ERROR_MORE_DATA)
                        {
                            value = new char[valueSz];
                            RegQueryValueEx(newKey, "JavaHome", NULL, NULL, (BYTE *)value,
                                            &valueSz);

                            // Now, we construct the version object and add it to the list.
                            JavaInstallPtr javaVersion(new JavaInstall());

                            javaVersion->id = subKeyName;
                            javaVersion->arch = archType;
                            javaVersion->path =
                                QDir(FS::PathCombine(value, "bin")).absoluteFilePath("javaw.exe");
                            javas.append(javaVersion);
                        }

                        RegCloseKey(newKey);
                    }
                }
            }
        }

        RegCloseKey(jreKey);
    }

    return javas;
}

QList<QString> JavaUtils::FindJavaPaths()
{
    QList<JavaInstallPtr> java_candidates;

    QList<JavaInstallPtr> JRE64s = this->FindJavaFromRegistryKey(
        KEY_WOW64_64KEY, "SOFTWARE\\JavaSoft\\Java Runtime Environment");
    QList<JavaInstallPtr> JDK64s = this->FindJavaFromRegistryKey(
        KEY_WOW64_64KEY, "SOFTWARE\\JavaSoft\\Java Development Kit");
    QList<JavaInstallPtr> JRE32s = this->FindJavaFromRegistryKey(
        KEY_WOW64_32KEY, "SOFTWARE\\JavaSoft\\Java Runtime Environment");
    QList<JavaInstallPtr> JDK32s = this->FindJavaFromRegistryKey(
        KEY_WOW64_32KEY, "SOFTWARE\\JavaSoft\\Java Development Kit");

    java_candidates.append(JRE64s);
    java_candidates.append(MakeJavaPtr("C:/Program Files/Java/jre8/bin/javaw.exe"));
    java_candidates.append(MakeJavaPtr("C:/Program Files/Java/jre7/bin/javaw.exe"));
    java_candidates.append(MakeJavaPtr("C:/Program Files/Java/jre6/bin/javaw.exe"));
    java_candidates.append(JDK64s);
    java_candidates.append(JRE32s);
    java_candidates.append(MakeJavaPtr("C:/Program Files (x86)/Java/jre8/bin/javaw.exe"));
    java_candidates.append(MakeJavaPtr("C:/Program Files (x86)/Java/jre7/bin/javaw.exe"));
    java_candidates.append(MakeJavaPtr("C:/Program Files (x86)/Java/jre6/bin/javaw.exe"));
    java_candidates.append(JDK32s);
    java_candidates.append(MakeJavaPtr(this->GetDefaultJava()->path));

    QList<QString> candidates;
    for(JavaInstallPtr java_candidate : java_candidates)
    {
        if(!candidates.contains(java_candidate->path))
        {
            candidates.append(java_candidate->path);
        }
    }

    return candidates;
}

#elif defined(Q_OS_MAC)
QList<QString> JavaUtils::FindJavaPaths()
{
    QList<QString> javas;
    javas.append(this->GetDefaultJava()->path);
    javas.append("/Applications/Xcode.app/Contents/Applications/Application Loader.app/Contents/MacOS/itms/java/bin/java");
    javas.append("/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java");
    javas.append("/System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands/java");
    QDir libraryJVMDir("/Library/Java/JavaVirtualMachines/");
    QStringList libraryJVMJavas = libraryJVMDir.entryList(QDir::Dirs | QDir::NoDotAndDotDot);
    foreach (const QString &java, libraryJVMJavas) {
        javas.append(libraryJVMDir.absolutePath() + "/" + java + "/Contents/Home/bin/java");
        javas.append(libraryJVMDir.absolutePath() + "/" + java + "/Contents/Home/jre/bin/java");
    }
    QDir systemLibraryJVMDir("/System/Library/Java/JavaVirtualMachines/");
    QStringList systemLibraryJVMJavas = systemLibraryJVMDir.entryList(QDir::Dirs | QDir::NoDotAndDotDot);
    foreach (const QString &java, systemLibraryJVMJavas) {
        javas.append(systemLibraryJVMDir.absolutePath() + "/" + java + "/Contents/Home/bin/java");
        javas.append(systemLibraryJVMDir.absolutePath() + "/" + java + "/Contents/Commands/java");
    }
    return javas;
}

#elif defined(Q_OS_LINUX)
QList<QString> JavaUtils::FindJavaPaths()
{
    qDebug() << "Linux Java detection incomplete - defaulting to \"java\"";

    QList<QString> javas;
    javas.append(this->GetDefaultJava()->path);
    auto scanJavaDir = [&](const QString & dirPath)
    {
        QDir dir(dirPath);
        if(!dir.exists())
            return;
        auto entries = dir.entryInfoList(QDir::Dirs | QDir::NoDotAndDotDot | QDir::NoSymLinks);
        for(auto & entry: entries)
        {

            QString prefix;
            if(entry.isAbsolute())
            {
                prefix = entry.absoluteFilePath();
            }
            else
            {
                prefix = entry.filePath();
            }

            javas.append(FS::PathCombine(prefix, "jre/bin/java"));
            javas.append(FS::PathCombine(prefix, "bin/java"));
        }
    };
    // oracle RPMs
    scanJavaDir("/usr/java");
    // general locations used by distro packaging
    scanJavaDir("/usr/lib/jvm");
    scanJavaDir("/usr/lib32/jvm");
    // javas stored in MultiMC's folder
    scanJavaDir("java");
    return javas;
}
#else
QList<QString> JavaUtils::FindJavaPaths()
{
    qDebug() << "Unknown operating system build - defaulting to \"java\"";

    QList<QString> javas;
    javas.append(this->GetDefaultJava()->path);

    return javas;
}
#endif