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

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

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

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

namespace juce
{

class NSViewAttachment final : public ReferenceCountedObject,
                               public ComponentMovementWatcher
{
public:
    NSViewAttachment (NSView* v, Component& comp)
        : ComponentMovementWatcher (&comp),
          view (v), owner (comp)
    {
        [view retain];
        [view setPostsFrameChangedNotifications: YES];
        updateAlpha();

        if (owner.isShowing())
            componentPeerChanged();
    }

    ~NSViewAttachment() override
    {
        removeFromParent();
        [view release];
    }

    void componentMovedOrResized (Component& comp, bool wasMoved, bool wasResized) override
    {
        ComponentMovementWatcher::componentMovedOrResized (comp, wasMoved, wasResized);

        // The ComponentMovementWatcher version of this method avoids calling
        // us when the top-level comp is resized, but if we're listening to the
        // top-level comp we still want the NSView to track its size.
        if (comp.isOnDesktop() && wasResized)
            componentMovedOrResized (wasMoved, wasResized);
    }

    void componentMovedOrResized (bool /*wasMoved*/, bool /*wasResized*/) override
    {
        if (auto* peer = owner.getTopLevelComponent()->getPeer())
        {
            const auto newArea = peer->getAreaCoveredBy (owner);

            if (convertToRectInt ([view frame]) != newArea)
                [view setFrame: makeCGRect (newArea)];
        }
    }

    void componentPeerChanged() override
    {
        auto* peer = owner.getPeer();

        if (std::exchange (currentPeer, peer) != peer)
        {
            if (peer != nullptr)
            {
                auto peerView = (NSView*) peer->getNativeHandle();
                [peerView addSubview: view];

                componentMovedOrResized (false, false);
            }
            else
            {
                removeFromParent();
            }
        }

        [view setHidden: ! owner.isShowing()];
    }

    void componentVisibilityChanged() override
    {
        componentPeerChanged();
    }

    void updateAlpha()
    {
        [view setAlphaValue: (CGFloat) owner.getAlpha()];
    }

    NSView* const view;

    using Ptr = ReferenceCountedObjectPtr<NSViewAttachment>;

private:
    Component& owner;
    ComponentPeer* currentPeer = nullptr;
    NSViewFrameWatcher frameWatcher { view, [this] { owner.childBoundsChanged (nullptr); } };

    void removeFromParent()
    {
        if ([view superview] != nil)
            [view removeFromSuperview]; // Must be careful not to call this unless it's required - e.g. some Apple AU views
                                        // override the call and use it as a sign that they're being deleted, which breaks everything.
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (NSViewAttachment)
};

//==============================================================================
NSViewComponent::NSViewComponent() = default;
NSViewComponent::~NSViewComponent()
{
    AccessibilityHandler::setNativeChildForComponent (*this, nullptr);
}

void NSViewComponent::setView (void* view)
{
    if (view != getView())
    {
        auto old = attachment;

        attachment = nullptr;

        if (view != nullptr)
            attachment = attachViewToComponent (*this, view);

        old = nullptr;

        AccessibilityHandler::setNativeChildForComponent (*this, getView());
    }
}

void* NSViewComponent::getView() const
{
    return attachment != nullptr ? static_cast<NSViewAttachment*> (attachment.get())->view
                                 : nullptr;
}

void NSViewComponent::resizeToFitView()
{
    if (attachment != nullptr)
    {
        auto* view = static_cast<NSViewAttachment*> (attachment.get())->view;
        auto r = [view frame];
        setBounds (Rectangle<int> ((int) r.size.width, (int) r.size.height));

        if (auto* peer = getTopLevelComponent()->getPeer())
        {
            const auto position = peer->getAreaCoveredBy (*this).getPosition();
            [view setFrameOrigin: convertToCGPoint (position)];
        }
    }
}

void NSViewComponent::resizeViewToFit()
{
    if (attachment != nullptr)
        static_cast<NSViewAttachment*> (attachment.get())->componentMovedOrResized (true, true);
}

void NSViewComponent::paint (Graphics&) {}

void NSViewComponent::alphaChanged()
{
    if (attachment != nullptr)
        (static_cast<NSViewAttachment*> (attachment.get()))->updateAlpha();
}

ReferenceCountedObject* NSViewComponent::attachViewToComponent (Component& comp, void* view)
{
    return new NSViewAttachment ((NSView*) view, comp);
}

std::unique_ptr<AccessibilityHandler> NSViewComponent::createAccessibilityHandler()
{
    return std::make_unique<AccessibilityHandler> (*this, AccessibilityRole::group);
}

} // namespace juce
