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

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2017 - ROLI Ltd.

   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
{

// Win32NativeFileChooser needs to be a reference counted object as there
// is no way for the parent to know when the dialog HWND has actually been
// created without pumping the message thread (which is forbidden when modal
// loops are disabled). However, the HWND pointer is the only way to cancel
// the dialog box. This means that the actual native FileChooser HWND may
// not have been created yet when the user deletes JUCE's FileChooser class. If this
// occurs the Win32NativeFileChooser will still have a reference count of 1 and will
// simply delete itself immediately once the HWND will have been created a while later.
class Win32NativeFileChooser  : public ReferenceCountedObject,
                                private Thread
{
public:
    using Ptr = ReferenceCountedObjectPtr<Win32NativeFileChooser>;

    enum { charsAvailableForResult = 32768 };

    Win32NativeFileChooser (Component* parent, int flags, FilePreviewComponent* previewComp,
                            const File& startingFile, const String& titleToUse,
                            const String& filtersToUse)
        : Thread ("Native Win32 FileChooser"),
          owner (parent), title (titleToUse), filtersString (filtersToUse),
          selectsDirectories ((flags & FileBrowserComponent::canSelectDirectories)   != 0),
          selectsFiles       ((flags & FileBrowserComponent::canSelectFiles)         != 0),
          isSave             ((flags & FileBrowserComponent::saveMode)               != 0),
          warnAboutOverwrite ((flags & FileBrowserComponent::warnAboutOverwriting)   != 0),
          selectMultiple     ((flags & FileBrowserComponent::canSelectMultipleItems) != 0),
          nativeDialogRef (nullptr), shouldCancel (0)
    {
        auto parentDirectory = startingFile.getParentDirectory();

        // Handle nonexistent root directories in the same way as existing ones
        files.calloc (static_cast<size_t> (charsAvailableForResult) + 1);

        if (startingFile.isDirectory() ||startingFile.isRoot())
        {
            initialPath = startingFile.getFullPathName();
        }
        else
        {
            startingFile.getFileName().copyToUTF16 (files,
                                                    static_cast<size_t> (charsAvailableForResult) * sizeof (WCHAR));
            initialPath = parentDirectory.getFullPathName();
        }

        if (! selectsDirectories)
        {
            if (previewComp != nullptr)
                customComponent.reset (new CustomComponentHolder (previewComp));

            setupFilters();
        }
    }

    ~Win32NativeFileChooser()
    {
        signalThreadShouldExit();
        waitForThreadToExit (-1);
    }

    void open (bool async)
    {
        results.clear();

        // the thread should not be running
        nativeDialogRef.set (nullptr);

        if (async)
        {
            jassert (! isThreadRunning());

            threadHasReference.reset();
            startThread();

            threadHasReference.wait (-1);
        }
        else
        {
            results = openDialog (false);
            owner->exitModalState (results.size() > 0 ? 1 : 0);
        }
    }

    void cancel()
    {
        ScopedLock lock (deletingDialog);

        customComponent = nullptr;
        shouldCancel.set (1);

        if (auto hwnd = nativeDialogRef.get())
            EndDialog (hwnd, 0);
    }

    Component* getCustomComponent()    { return customComponent.get(); }

    Array<URL> results;

private:
    //==============================================================================
    class CustomComponentHolder  : public Component
    {
    public:
        CustomComponentHolder (Component* const customComp)
        {
            setVisible (true);
            setOpaque (true);
            addAndMakeVisible (customComp);
            setSize (jlimit (20, 800, customComp->getWidth()), customComp->getHeight());
        }

        void paint (Graphics& g) override
        {
            g.fillAll (Colours::lightgrey);
        }

        void resized() override
        {
            if (Component* const c = getChildComponent(0))
                c->setBounds (getLocalBounds());
        }

    private:
        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (CustomComponentHolder)
    };

    //==============================================================================
    Component::SafePointer<Component> owner;
    String title, filtersString;
    std::unique_ptr<CustomComponentHolder> customComponent;
    String initialPath, returnedString, defaultExtension;

    WaitableEvent threadHasReference;
    CriticalSection deletingDialog;

    bool selectsDirectories, selectsFiles, isSave, warnAboutOverwrite, selectMultiple;

    HeapBlock<WCHAR> files;
    HeapBlock<WCHAR> filters;

    Atomic<HWND> nativeDialogRef;
    Atomic<int>  shouldCancel;

    //==============================================================================
    Array<URL> openDialog (bool async)
    {
        Array<URL> selections;

        if (selectsDirectories)
        {
            BROWSEINFO bi = { 0 };
            bi.hwndOwner = (HWND) (async ? nullptr : owner->getWindowHandle());
            bi.pszDisplayName = files;
            bi.lpszTitle = title.toWideCharPointer();
            bi.lParam = (LPARAM) this;
            bi.lpfn = browseCallbackProc;
           #ifdef BIF_USENEWUI
            bi.ulFlags = BIF_USENEWUI | BIF_VALIDATE;
           #else
            bi.ulFlags = 0x50;
           #endif

            LPITEMIDLIST list = SHBrowseForFolder (&bi);

            if (! SHGetPathFromIDListW (list, files))
            {
                files[0] = 0;
                returnedString.clear();
            }

            LPMALLOC al;

            if (list != nullptr && SUCCEEDED (SHGetMalloc (&al)))
                al->Free (list);

            if (files[0] != 0)
            {
                File result (String (files.get()));

                if (returnedString.isNotEmpty())
                    result = result.getSiblingFile (returnedString);

                selections.add (URL (result));
            }
        }
        else
        {
            OPENFILENAMEW of = { 0 };

            #ifdef OPENFILENAME_SIZE_VERSION_400W
            of.lStructSize = OPENFILENAME_SIZE_VERSION_400W;
           #else
            of.lStructSize = sizeof (of);
           #endif
            of.hwndOwner = (HWND) (async ? nullptr : owner->getWindowHandle());
            of.lpstrFilter = filters.getData();
            of.nFilterIndex = 1;
            of.lpstrFile = files;
            of.nMaxFile = (DWORD) charsAvailableForResult;
            of.lpstrInitialDir = initialPath.toWideCharPointer();
            of.lpstrTitle = title.toWideCharPointer();
            of.Flags = getOpenFilenameFlags (async);
            of.lCustData = (LPARAM) this;
            of.lpfnHook = &openCallback;

            if (isSave)
            {
                StringArray tokens;
                tokens.addTokens (filtersString, ";,", "\"'");
                tokens.trim();
                tokens.removeEmptyStrings();

                if (tokens.size() == 1 && tokens[0].removeCharacters ("*.").isNotEmpty())
                {
                    defaultExtension = tokens[0].fromFirstOccurrenceOf (".", false, false);
                    of.lpstrDefExt = defaultExtension.toWideCharPointer();
                }

                if (! GetSaveFileName (&of))
                    return {};
            }
            else
            {
                if (! GetOpenFileName (&of))
                    return {};
            }

            if (selectMultiple && of.nFileOffset > 0 && files [of.nFileOffset - 1] == 0)
            {
                const WCHAR* filename = files + of.nFileOffset;

                while (*filename != 0)
                {
                    selections.add (URL (File (String (files.get())).getChildFile (String (filename))));
                    filename += wcslen (filename) + 1;
                }
            }
            else if (files[0] != 0)
            {
                selections.add (URL (File (String (files.get()))));
            }
        }

        getNativeDialogList().removeValue (this);

        return selections;
    }

    void run() override
    {
        // as long as the thread is running, don't delete this class
        Ptr safeThis (this);
        threadHasReference.signal();

        Array<URL> r = openDialog (true);
        MessageManager::callAsync ([safeThis, r]
        {
            safeThis->results = r;

            if (safeThis->owner != nullptr)
                safeThis->owner->exitModalState (r.size() > 0 ? 1 : 0);
        });
    }

    static HashMap<HWND, Win32NativeFileChooser*>& getNativeDialogList()
    {
        static HashMap<HWND, Win32NativeFileChooser*> dialogs;
        return dialogs;
    }

    static Win32NativeFileChooser* getNativePointerForDialog (HWND hWnd)
    {
        return getNativeDialogList()[hWnd];
    }

    //==============================================================================
    void setupFilters()
    {
        const size_t filterSpaceNumChars = 2048;
        filters.calloc (filterSpaceNumChars);

        const size_t bytesWritten = filtersString.copyToUTF16 (filters.getData(), filterSpaceNumChars * sizeof (WCHAR));
        filtersString.copyToUTF16 (filters + (bytesWritten / sizeof (WCHAR)),
                                   ((filterSpaceNumChars - 1) * sizeof (WCHAR) - bytesWritten));

        for (size_t i = 0; i < filterSpaceNumChars; ++i)
            if (filters[i] == '|')
                filters[i] = 0;
    }

    DWORD getOpenFilenameFlags (bool async)
    {
        DWORD ofFlags = OFN_EXPLORER | OFN_PATHMUSTEXIST | OFN_NOCHANGEDIR | OFN_HIDEREADONLY | OFN_ENABLESIZING;

        if (warnAboutOverwrite)
            ofFlags |= OFN_OVERWRITEPROMPT;

        if (selectMultiple)
            ofFlags |= OFN_ALLOWMULTISELECT;

        if (async || customComponent != nullptr)
            ofFlags |= OFN_ENABLEHOOK;

        return ofFlags;
    }

    //==============================================================================
    void initialised (HWND hWnd)
    {
        SendMessage (hWnd, BFFM_SETSELECTIONW, TRUE, (LPARAM) initialPath.toWideCharPointer());
        initDialog (hWnd);
    }

    void validateFailed (const String& path)
    {
        returnedString = path;
    }

    void initDialog (HWND hdlg)
    {
        ScopedLock lock (deletingDialog);
        getNativeDialogList().set (hdlg, this);

        if (shouldCancel.get() != 0)
        {
            EndDialog (hdlg, 0);
        }
        else
        {
            nativeDialogRef.set (hdlg);

            if (customComponent != nullptr)
            {
                Component::SafePointer<Component> safeCustomComponent (customComponent.get());

                RECT dialogScreenRect, dialogClientRect;
                GetWindowRect (hdlg, &dialogScreenRect);
                GetClientRect (hdlg, &dialogClientRect);

                auto screenRectangle = Rectangle<int>::leftTopRightBottom (dialogScreenRect.left,  dialogScreenRect.top,
                                                                           dialogScreenRect.right, dialogScreenRect.bottom);

                auto scale = Desktop::getInstance().getDisplays().findDisplayForRect (screenRectangle, true).scale;
                auto physicalComponentWidth = roundToInt (safeCustomComponent->getWidth() * scale);

                SetWindowPos (hdlg, 0, screenRectangle.getX(), screenRectangle.getY(),
                              physicalComponentWidth + jmax (150, screenRectangle.getWidth()),
                              jmax (150, screenRectangle.getHeight()),
                              SWP_NOACTIVATE | SWP_NOOWNERZORDER | SWP_NOZORDER);

                auto appendCustomComponent = [safeCustomComponent, dialogClientRect, scale, hdlg]() mutable
                {
                    if (safeCustomComponent != nullptr)
                    {
                        auto scaledClientRectangle = Rectangle<int>::leftTopRightBottom (dialogClientRect.left, dialogClientRect.top,
                                                                                         dialogClientRect.right, dialogClientRect.bottom) / scale;

                        safeCustomComponent->setBounds (scaledClientRectangle.getRight(), scaledClientRectangle.getY(),
                                                        safeCustomComponent->getWidth(), scaledClientRectangle.getHeight());
                        safeCustomComponent->addToDesktop (0, hdlg);
                    }
                };

                if (MessageManager::getInstance()->isThisTheMessageThread())
                    appendCustomComponent();
                else
                    MessageManager::callAsync (appendCustomComponent);
            }
        }
    }

    void destroyDialog (HWND hdlg)
    {
        ScopedLock exiting (deletingDialog);

        getNativeDialogList().remove (hdlg);
        nativeDialogRef.set (nullptr);

        if (MessageManager::getInstance()->isThisTheMessageThread())
            customComponent = nullptr;
        else
            MessageManager::callAsync ([this] { customComponent = nullptr; });
    }

    void selectionChanged (HWND hdlg)
    {
        ScopedLock lock (deletingDialog);

        if (customComponent != nullptr && shouldCancel.get() == 0)
        {
            if (FilePreviewComponent* comp = dynamic_cast<FilePreviewComponent*> (customComponent->getChildComponent(0)))
            {
                WCHAR path [MAX_PATH * 2] = { 0 };
                CommDlg_OpenSave_GetFilePath (hdlg, (LPARAM) &path, MAX_PATH);

                if (MessageManager::getInstance()->isThisTheMessageThread())
                {
                    comp->selectedFileChanged (File (path));
                }
                else
                {
                    Component::SafePointer<FilePreviewComponent> safeComp (comp);

                    File selectedFile (path);
                    MessageManager::callAsync ([safeComp, selectedFile]() mutable
                                               {
                                                    safeComp->selectedFileChanged (selectedFile);
                                               });
                }
            }
        }
    }

    //==============================================================================
    static int CALLBACK browseCallbackProc (HWND hWnd, UINT msg, LPARAM lParam, LPARAM lpData)
    {
        auto* self = reinterpret_cast<Win32NativeFileChooser*> (lpData);

        switch (msg)
        {
            case BFFM_INITIALIZED:       self->initialised (hWnd);                             break;
            case BFFM_VALIDATEFAILEDW:   self->validateFailed (String ((LPCWSTR)     lParam)); break;
            case BFFM_VALIDATEFAILEDA:   self->validateFailed (String ((const char*) lParam)); break;
            default: break;
        }

        return 0;
    }

    static UINT_PTR CALLBACK openCallback (HWND hwnd, UINT uiMsg, WPARAM /*wParam*/, LPARAM lParam)
    {
        auto hdlg = getDialogFromHWND (hwnd);

        switch (uiMsg)
        {
            case WM_INITDIALOG:
            {
                if (auto* self = reinterpret_cast<Win32NativeFileChooser*> (((OPENFILENAMEW*) lParam)->lCustData))
                    self->initDialog (hdlg);

                break;
            }

            case WM_DESTROY:
            {
                if (auto* self = getNativeDialogList()[hdlg])
                    self->destroyDialog (hdlg);

                break;
            }

            case WM_NOTIFY:
            {
                auto ofn = reinterpret_cast<LPOFNOTIFY> (lParam);

                if (ofn->hdr.code == CDN_SELCHANGE)
                    if (auto* self = reinterpret_cast<Win32NativeFileChooser*> (ofn->lpOFN->lCustData))
                        self->selectionChanged (hdlg);

                break;
            }

            default:
                break;
        }

        return 0;
    }

    static HWND getDialogFromHWND (HWND hwnd)
    {
        if (hwnd == nullptr)
            return nullptr;

        HWND dialogH = GetParent (hwnd);

        if (dialogH == 0)
            dialogH = hwnd;

        return dialogH;
    }

    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Win32NativeFileChooser)
};

class FileChooser::Native     : public Component,
                                public FileChooser::Pimpl
{
public:

    Native (FileChooser& fileChooser, int flags, FilePreviewComponent* previewComp)
        : owner (fileChooser),
          nativeFileChooser (new Win32NativeFileChooser (this, flags, previewComp, fileChooser.startingFile,
                                                         fileChooser.title, fileChooser.filters))
    {
        auto mainMon = Desktop::getInstance().getDisplays().getMainDisplay().userArea;

        setBounds (mainMon.getX() + mainMon.getWidth() / 4,
                   mainMon.getY() + mainMon.getHeight() / 4,
                   0, 0);

        setOpaque (true);
        setAlwaysOnTop (juce_areThereAnyAlwaysOnTopWindows());
        addToDesktop (0);
    }

    ~Native()
    {
        exitModalState (0);
        nativeFileChooser->cancel();
        nativeFileChooser = nullptr;
    }

    void launch() override
    {
        SafePointer<Native> safeThis (this);

        enterModalState (true, ModalCallbackFunction::create (
                         [safeThis] (int)
                         {
                             if (safeThis != nullptr)
                                 safeThis->owner.finished (safeThis->nativeFileChooser->results);
                         }));

        nativeFileChooser->open (true);
    }

    void runModally() override
    {
        enterModalState (true);
        nativeFileChooser->open (false);
        exitModalState (nativeFileChooser->results.size() > 0 ? 1 : 0);
        nativeFileChooser->cancel();

        owner.finished (nativeFileChooser->results);
    }

    bool canModalEventBeSentToComponent (const Component* targetComponent) override
    {
        if (targetComponent == nullptr)
            return false;

        if (targetComponent == nativeFileChooser->getCustomComponent())
            return true;

        return targetComponent->findParentComponentOfClass<FilePreviewComponent>() != nullptr;
    }

private:
    FileChooser& owner;
    Win32NativeFileChooser::Ptr nativeFileChooser;
};

//==============================================================================
bool FileChooser::isPlatformDialogAvailable()
{
   #if JUCE_DISABLE_NATIVE_FILECHOOSERS
    return false;
   #else
    return true;
   #endif
}

FileChooser::Pimpl* FileChooser::showPlatformDialog (FileChooser& owner, int flags,
                                                     FilePreviewComponent* preview)
{
    return new FileChooser::Native (owner, flags, preview);
}

} // namespace juce