/*
  ==============================================================================

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2020 - Raw Material Software Limited

   You may use this code under the terms of the GPL v3
   (see www.gnu.org/licenses).

   For this technical preview, this file is not subject to commercial licensing.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

#if JUCE_MODAL_LOOPS_PERMITTED
static bool exeIsAvailable (const char* const executable)
{
    ChildProcess child;
    const bool ok = child.start ("which " + String (executable))
                      && child.readAllProcessOutput().trim().isNotEmpty();

    child.waitForProcessToFinish (60 * 1000);
    return ok;
}


class FileChooser::Native    : public FileChooser::Pimpl,
                               private Timer
{
public:
    Native (FileChooser& fileChooser, int flags)
        : owner (fileChooser),
          isDirectory         ((flags & FileBrowserComponent::canSelectDirectories)   != 0),
          isSave              ((flags & FileBrowserComponent::saveMode)               != 0),
          selectMultipleFiles ((flags & FileBrowserComponent::canSelectMultipleItems) != 0),
          warnAboutOverwrite  ((flags & FileBrowserComponent::warnAboutOverwriting)   != 0)
    {
        const File previousWorkingDirectory (File::getCurrentWorkingDirectory());

        // use kdialog for KDE sessions or if zenity is missing
        if (exeIsAvailable ("kdialog") && (isKdeFullSession() || ! exeIsAvailable ("zenity")))
            addKDialogArgs();
        else
            addZenityArgs();
    }

    ~Native() override
    {
        finish (true);
    }

    void runModally() override
    {
        child.start (args, ChildProcess::wantStdOut);

        while (child.isRunning())
            if (! MessageManager::getInstance()->runDispatchLoopUntil(20))
                break;

        finish (false);
    }

    void launch() override
    {
        child.start (args, ChildProcess::wantStdOut);
        startTimer (100);
    }

private:
    FileChooser& owner;
    bool isDirectory, isSave, selectMultipleFiles, warnAboutOverwrite;

    ChildProcess child;
    StringArray args;
    String separator;

    void timerCallback() override
    {
        if (! child.isRunning())
        {
            stopTimer();
            finish (false);
        }
    }

    void finish (bool shouldKill)
    {
        String result;
        Array<URL> selection;

        if (shouldKill)
            child.kill();
        else
            result = child.readAllProcessOutput().trim();

        if (result.isNotEmpty())
        {
            StringArray tokens;

            if (selectMultipleFiles)
                tokens.addTokens (result, separator, "\"");
            else
                tokens.add (result);

            for (auto& token : tokens)
                selection.add (URL (File::getCurrentWorkingDirectory().getChildFile (token)));
        }

        if (! shouldKill)
        {
            child.waitForProcessToFinish (60 * 1000);
            owner.finished (selection);
        }
    }

    static uint64 getTopWindowID() noexcept
    {
        if (TopLevelWindow* top = TopLevelWindow::getActiveTopLevelWindow())
            return (uint64) (pointer_sized_uint) top->getWindowHandle();

        return 0;
    }

    static bool isKdeFullSession()
    {
        return SystemStats::getEnvironmentVariable ("KDE_FULL_SESSION", String())
                     .equalsIgnoreCase ("true");
    }

    void addKDialogArgs()
    {
        args.add ("kdialog");

        if (owner.title.isNotEmpty())
            args.add ("--title=" + owner.title);

        if (uint64 topWindowID = getTopWindowID())
        {
            args.add ("--attach");
            args.add (String (topWindowID));
        }

        if (selectMultipleFiles)
        {
            separator = "\n";
            args.add ("--multiple");
            args.add ("--separate-output");
            args.add ("--getopenfilename");
        }
        else
        {
            if (isSave)             args.add ("--getsavefilename");
            else if (isDirectory)   args.add ("--getexistingdirectory");
            else                    args.add ("--getopenfilename");
        }

        File startPath;

        if (owner.startingFile.exists())
        {
            startPath = owner.startingFile;
        }
        else if (owner.startingFile.getParentDirectory().exists())
        {
            startPath = owner.startingFile.getParentDirectory();
        }
        else
        {
            startPath = File::getSpecialLocation (File::userHomeDirectory);

            if (isSave)
                startPath = startPath.getChildFile (owner.startingFile.getFileName());
        }

        args.add (startPath.getFullPathName());
        args.add (owner.filters.replaceCharacter (';', ' '));
    }

    void addZenityArgs()
    {
        args.add ("zenity");
        args.add ("--file-selection");

        if (warnAboutOverwrite)
            args.add("--confirm-overwrite");

        if (owner.title.isNotEmpty())
            args.add ("--title=" + owner.title);

        if (selectMultipleFiles)
        {
            separator = ":";
            args.add ("--multiple");
            args.add ("--separator=" + separator);
        }
        else
        {
            if (isDirectory)  args.add ("--directory");
            if (isSave)       args.add ("--save");
        }

        if (owner.filters.isNotEmpty() && owner.filters != "*" && owner.filters != "*.*")
        {
            StringArray tokens;
            tokens.addTokens (owner.filters, ";,|", "\"");

            for (int i = 0; i < tokens.size(); ++i)
                args.add ("--file-filter=" + tokens[i]);
        }

        if (owner.startingFile.isDirectory())
            owner.startingFile.setAsCurrentWorkingDirectory();
        else if (owner.startingFile.getParentDirectory().exists())
            owner.startingFile.getParentDirectory().setAsCurrentWorkingDirectory();
        else
            File::getSpecialLocation (File::userHomeDirectory).setAsCurrentWorkingDirectory();

        auto filename = owner.startingFile.getFileName();

        if (! filename.isEmpty())
            args.add ("--filename=" + filename);

        // supplying the window ID of the topmost window makes sure that Zenity pops up..
        if (uint64 topWindowID = getTopWindowID())
            setenv ("WINDOWID", String (topWindowID).toRawUTF8(), true);
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Native)
};
#endif

bool FileChooser::isPlatformDialogAvailable()
{
   #if JUCE_DISABLE_NATIVE_FILECHOOSERS || ! JUCE_MODAL_LOOPS_PERMITTED
    return false;
   #else
    static bool canUseNativeBox = exeIsAvailable ("zenity") || exeIsAvailable ("kdialog");
    return canUseNativeBox;
   #endif
}

FileChooser::Pimpl* FileChooser::showPlatformDialog (FileChooser& owner, int flags, FilePreviewComponent*)
{
#if JUCE_MODAL_LOOPS_PERMITTED
    return new Native (owner, flags);
#else
    return nullptr;
#endif
}

} // namespace juce