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

   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
{

struct MarkerListScope  : public Expression::Scope
{
    MarkerListScope (Component& comp) : component (comp) {}

    Expression getSymbolValue (const String& symbol) const override
    {
        auto type = RelativeCoordinate::StandardStrings::getTypeOf (symbol);

        if (type == RelativeCoordinate::StandardStrings::width)   return Expression ((double) component.getWidth());
        if (type == RelativeCoordinate::StandardStrings::height)  return Expression ((double) component.getHeight());

        MarkerList* list;

        if (auto* marker = findMarker (component, symbol, list))
            return Expression (marker->position.getExpression().evaluate (*this));

        return Expression::Scope::getSymbolValue (symbol);
    }

    void visitRelativeScope (const String& scopeName, Visitor& visitor) const override
    {
        if (scopeName == RelativeCoordinate::Strings::parent)
        {
            if (auto* parent = component.getParentComponent())
            {
                visitor.visit (MarkerListScope (*parent));
                return;
            }
        }

        Expression::Scope::visitRelativeScope (scopeName, visitor);
    }

    String getScopeUID() const override
    {
        return String::toHexString ((pointer_sized_int) (void*) &component) + "m";
    }

    static const MarkerList::Marker* findMarker (Component& component, const String& name, MarkerList*& list)
    {
        const MarkerList::Marker* marker = nullptr;

        auto* mlh = dynamic_cast<MarkerList::MarkerListHolder*> (&component);

        if (mlh != nullptr)
        {
            list = mlh->getMarkers (true);

            if (list != nullptr)
                marker = list->getMarker (name);
        }

        if (marker == nullptr)
        {
            if (mlh != nullptr)
            {
                list = mlh->getMarkers (false);

                if (list != nullptr)
                    marker = list->getMarker (name);
            }
        }

        return marker;
    }

    Component& component;
};

//==============================================================================
RelativeCoordinatePositionerBase::ComponentScope::ComponentScope (Component& comp)
    : component (comp)
{
}

Expression RelativeCoordinatePositionerBase::ComponentScope::getSymbolValue (const String& symbol) const
{
    switch (RelativeCoordinate::StandardStrings::getTypeOf (symbol))
    {
        case RelativeCoordinate::StandardStrings::x:
        case RelativeCoordinate::StandardStrings::left:   return Expression ((double) component.getX());
        case RelativeCoordinate::StandardStrings::y:
        case RelativeCoordinate::StandardStrings::top:    return Expression ((double) component.getY());
        case RelativeCoordinate::StandardStrings::width:  return Expression ((double) component.getWidth());
        case RelativeCoordinate::StandardStrings::height: return Expression ((double) component.getHeight());
        case RelativeCoordinate::StandardStrings::right:  return Expression ((double) component.getRight());
        case RelativeCoordinate::StandardStrings::bottom: return Expression ((double) component.getBottom());
        case RelativeCoordinate::StandardStrings::parent:
        case RelativeCoordinate::StandardStrings::unknown:
        default: break;
    }

    if (Component* const parent = component.getParentComponent())
    {
        MarkerList* list;

        if (auto* marker = MarkerListScope::findMarker (*parent, symbol, list))
        {
            MarkerListScope scope (*parent);
            return Expression (marker->position.getExpression().evaluate (scope));
        }
    }

    return Expression::Scope::getSymbolValue (symbol);
}

void RelativeCoordinatePositionerBase::ComponentScope::visitRelativeScope (const String& scopeName, Visitor& visitor) const
{
    if (auto* targetComp = (scopeName == RelativeCoordinate::Strings::parent)
                               ? component.getParentComponent()
                               : findSiblingComponent (scopeName))
        visitor.visit (ComponentScope (*targetComp));
    else
        Expression::Scope::visitRelativeScope (scopeName, visitor);
}

String RelativeCoordinatePositionerBase::ComponentScope::getScopeUID() const
{
    return String::toHexString ((pointer_sized_int) (void*) &component);
}

Component* RelativeCoordinatePositionerBase::ComponentScope::findSiblingComponent (const String& componentID) const
{
    if (Component* const parent = component.getParentComponent())
        return parent->findChildWithID (componentID);

    return nullptr;
}

//==============================================================================
class RelativeCoordinatePositionerBase::DependencyFinderScope  : public ComponentScope
{
public:
    DependencyFinderScope (Component& comp, RelativeCoordinatePositionerBase& p, bool& result)
        : ComponentScope (comp), positioner (p), ok (result)
    {
    }

    Expression getSymbolValue (const String& symbol) const override
    {
        switch (RelativeCoordinate::StandardStrings::getTypeOf (symbol))
        {
            case RelativeCoordinate::StandardStrings::x:
            case RelativeCoordinate::StandardStrings::left:
            case RelativeCoordinate::StandardStrings::y:
            case RelativeCoordinate::StandardStrings::top:
            case RelativeCoordinate::StandardStrings::width:
            case RelativeCoordinate::StandardStrings::height:
            case RelativeCoordinate::StandardStrings::right:
            case RelativeCoordinate::StandardStrings::bottom:
                positioner.registerComponentListener (component);
                break;

            case RelativeCoordinate::StandardStrings::parent:
            case RelativeCoordinate::StandardStrings::unknown:
            default:
                if (auto* parent = component.getParentComponent())
                {
                    MarkerList* list;

                    if (MarkerListScope::findMarker (*parent, symbol, list) != nullptr)
                    {
                        positioner.registerMarkerListListener (list);
                    }
                    else
                    {
                        // The marker we want doesn't exist, so watch all lists in case they change and the marker appears later..
                        if (auto* mlh = dynamic_cast<MarkerList::MarkerListHolder*> (parent))
                        {
                            positioner.registerMarkerListListener (mlh->getMarkers (true));
                            positioner.registerMarkerListListener (mlh->getMarkers (false));
                        }

                        ok = false;
                    }
                }
                break;
        }

        return ComponentScope::getSymbolValue (symbol);
    }

    void visitRelativeScope (const String& scopeName, Visitor& visitor) const override
    {
        if (Component* const targetComp = (scopeName == RelativeCoordinate::Strings::parent)
                                                ? component.getParentComponent()
                                                : findSiblingComponent (scopeName))
        {
            visitor.visit (DependencyFinderScope (*targetComp, positioner, ok));
        }
        else
        {
            // The named component doesn't exist, so we'll watch the parent for changes in case it appears later..
            if (Component* const parent = component.getParentComponent())
                positioner.registerComponentListener (*parent);

            positioner.registerComponentListener (component);
            ok = false;
        }
    }

private:
    RelativeCoordinatePositionerBase& positioner;
    bool& ok;
};

//==============================================================================
RelativeCoordinatePositionerBase::RelativeCoordinatePositionerBase (Component& comp)
    : Component::Positioner (comp), registeredOk (false)
{
}

RelativeCoordinatePositionerBase::~RelativeCoordinatePositionerBase()
{
    unregisterListeners();
}

void RelativeCoordinatePositionerBase::componentMovedOrResized (Component&, bool /*wasMoved*/, bool /*wasResized*/)
{
    apply();
}

void RelativeCoordinatePositionerBase::componentParentHierarchyChanged (Component&)
{
    apply();
}

void RelativeCoordinatePositionerBase::componentChildrenChanged (Component& changed)
{
    if (getComponent().getParentComponent() == &changed && ! registeredOk)
        apply();
}

void RelativeCoordinatePositionerBase::componentBeingDeleted (Component& comp)
{
    jassert (sourceComponents.contains (&comp));
    sourceComponents.removeFirstMatchingValue (&comp);
    registeredOk = false;
}

void RelativeCoordinatePositionerBase::markersChanged (MarkerList*)
{
    apply();
}

void RelativeCoordinatePositionerBase::markerListBeingDeleted (MarkerList* markerList)
{
    jassert (sourceMarkerLists.contains (markerList));
    sourceMarkerLists.removeFirstMatchingValue (markerList);
}

void RelativeCoordinatePositionerBase::apply()
{
    if (! registeredOk)
    {
        unregisterListeners();
        registeredOk = registerCoordinates();
    }

    applyToComponentBounds();
}

bool RelativeCoordinatePositionerBase::addCoordinate (const RelativeCoordinate& coord)
{
    bool ok = true;
    DependencyFinderScope finderScope (getComponent(), *this, ok);
    coord.getExpression().evaluate (finderScope);
    return ok;
}

bool RelativeCoordinatePositionerBase::addPoint (const RelativePoint& point)
{
    const bool ok = addCoordinate (point.x);
    return addCoordinate (point.y) && ok;
}

void RelativeCoordinatePositionerBase::registerComponentListener (Component& comp)
{
    if (! sourceComponents.contains (&comp))
    {
        comp.addComponentListener (this);
        sourceComponents.add (&comp);
    }
}

void RelativeCoordinatePositionerBase::registerMarkerListListener (MarkerList* const list)
{
    if (list != nullptr && ! sourceMarkerLists.contains (list))
    {
        list->addListener (this);
        sourceMarkerLists.add (list);
    }
}

void RelativeCoordinatePositionerBase::unregisterListeners()
{
    for (int i = sourceComponents.size(); --i >= 0;)
        sourceComponents.getUnchecked(i)->removeComponentListener (this);

    for (int i = sourceMarkerLists.size(); --i >= 0;)
        sourceMarkerLists.getUnchecked(i)->removeListener (this);

    sourceComponents.clear();
    sourceMarkerLists.clear();
}

} // namespace juce