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

   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
{

//==============================================================================
FocusTraverser::FocusTraverser (SkipDisabledComponents skipDisabledComponentsIn)
    : skipDisabledComponents (skipDisabledComponentsIn)
{
}

Component* FocusTraverser::getNextComponent (Component* current)
{
    jassert (current != nullptr);

    return detail::FocusHelpers::navigateFocus (current,
                                                current->findFocusContainer(),
                                                detail::FocusHelpers::NavigationDirection::forwards,
                                                &Component::isFocusContainer,
                                                skipDisabledComponents);
}

Component* FocusTraverser::getPreviousComponent (Component* current)
{
    jassert (current != nullptr);

    return detail::FocusHelpers::navigateFocus (current,
                                                current->findFocusContainer(),
                                                detail::FocusHelpers::NavigationDirection::backwards,
                                                &Component::isFocusContainer,
                                                skipDisabledComponents);
}

Component* FocusTraverser::getDefaultComponent (Component* parentComponent)
{
    if (parentComponent != nullptr)
    {
        std::vector<Component*> components;

        detail::FocusHelpers::findAllComponents (parentComponent,
                                                 components,
                                                 &Component::isFocusContainer,
                                                 skipDisabledComponents);

        if (! components.empty())
            return components.front();
    }

    return nullptr;
}

std::vector<Component*> FocusTraverser::getAllComponents (Component* parentComponent)
{
    std::vector<Component*> components;
    detail::FocusHelpers::findAllComponents (parentComponent,
                                             components,
                                             &Component::isFocusContainer,
                                             skipDisabledComponents);

    return components;
}

//==============================================================================
//==============================================================================
#if JUCE_UNIT_TESTS

struct FocusTraverserTests final : public UnitTest
{
    FocusTraverserTests()
        : UnitTest ("FocusTraverser", UnitTestCategories::gui)
    {}

    void runTest() override
    {
        ScopedJuceInitialiser_GUI libraryInitialiser;
        const MessageManagerLock mml;

        testCase ("Basic traversal", [&]
        {
            TestComponent parent;

            expect (traverser.getDefaultComponent (&parent) == &parent.children.front());

            for (auto iter = parent.children.begin(); iter != parent.children.end(); ++iter)
                expect (traverser.getNextComponent (&(*iter)) == (iter == std::prev (parent.children.cend()) ? nullptr
                                                                                                             : &(*std::next (iter))));

            for (auto iter = parent.children.rbegin(); iter != parent.children.rend(); ++iter)
                expect (traverser.getPreviousComponent (&(*iter)) == (iter == std::prev (parent.children.rend()) ? nullptr
                                                                                                                 : &(*std::next (iter))));
            auto allComponents = traverser.getAllComponents (&parent);

            expect (std::equal (allComponents.cbegin(), allComponents.cend(), parent.children.cbegin(),
                                [] (const Component* c1, const Component& c2) { return c1 == &c2; }));
        });

        testCase ("Disabled components are not ignored by default", [&]
        {
            TestComponent parent;
            parent.children[2].setEnabled (false);
            parent.children[5].setEnabled (false);
            expect (traverser.getAllComponents (&parent).size() == parent.children.size());
        });

        testCase ("Disabled components can be ignored", [&]
        {
            FocusTraverser ignoringTraverser { FocusTraverser::SkipDisabledComponents::yes };
            checkIgnored ([] (Component& c) { c.setEnabled (false); }, ignoringTraverser);
        });

        testCase ("Invisible components are ignored", [&]
        {
            checkIgnored ([] (Component& c) { c.setVisible (false); }, traverser);
        });

        testCase ("Explicit focus order comes before unspecified", [&]
        {
            TestComponent parent;

            auto& explicitFocusComponent = parent.children[2];

            explicitFocusComponent.setExplicitFocusOrder (1);
            expect (traverser.getDefaultComponent (&parent) == &explicitFocusComponent);

            expect (traverser.getAllComponents (&parent).front() == &explicitFocusComponent);
        });

        testCase ("Explicit focus order comparison", [&]
        {
            checkComponentProperties ([this] (Component& child) { child.setExplicitFocusOrder (getRandom().nextInt ({ 1, 100 })); },
                                      [] (const Component& c1, const Component& c2) { return c1.getExplicitFocusOrder()
                                                                                               <= c2.getExplicitFocusOrder(); });
        });

        testCase ("Left to right", [&]
        {
            checkComponentProperties ([this] (Component& child) { child.setTopLeftPosition (getRandom().nextInt ({ 0, 100 }), 0); },
                                      [] (const Component& c1, const Component& c2) { return c1.getX() <= c2.getX(); });
        });

        testCase ("Top to bottom", [&]
        {
            checkComponentProperties ([this] (Component& child) { child.setTopLeftPosition (0, getRandom().nextInt ({ 0, 100 })); },
                                      [] (const Component& c1, const Component& c2) { return c1.getY() <= c2.getY(); });
        });

        testCase ("Focus containers have their own focus", [&]
        {
            Component root;

            TestComponent container;
            container.setFocusContainerType (Component::FocusContainerType::focusContainer);

            root.addAndMakeVisible (container);

            expect (traverser.getDefaultComponent (&root) == &container);
            expect (traverser.getNextComponent (&container) == nullptr);
            expect (traverser.getPreviousComponent (&container) == nullptr);

            expect (traverser.getDefaultComponent (&container) == &container.children.front());

            for (auto iter = container.children.begin(); iter != container.children.end(); ++iter)
                expect (traverser.getNextComponent (&(*iter)) == (iter == std::prev (container.children.cend()) ? nullptr
                                                                                                                : &(*std::next (iter))));

            for (auto iter = container.children.rbegin(); iter != container.children.rend(); ++iter)
                expect (traverser.getPreviousComponent (&(*iter)) == (iter == std::prev (container.children.rend()) ? nullptr
                                                                                                                    : &(*std::next (iter))));

            expect (traverser.getAllComponents (&root).size() == 1);

            auto allContainerComponents = traverser.getAllComponents (&container);

            expect (std::equal (allContainerComponents.cbegin(), allContainerComponents.cend(), container.children.cbegin(),
                                [] (const Component* c1, const Component& c2) { return c1 == &c2; }));
        });

        testCase ("Non-focus containers pass-through focus", [&]
        {
            Component root;

            TestComponent container;
            container.setFocusContainerType (Component::FocusContainerType::none);

            root.addAndMakeVisible (container);

            expect (traverser.getDefaultComponent (&root) == &container);
            expect (traverser.getNextComponent (&container) == &container.children.front());
            expect (traverser.getPreviousComponent (&container) == nullptr);

            expect (traverser.getDefaultComponent (&container) == &container.children.front());

            for (auto iter = container.children.begin(); iter != container.children.end(); ++iter)
                expect (traverser.getNextComponent (&(*iter)) == (iter == std::prev (container.children.cend()) ? nullptr
                                                                                                                : &(*std::next (iter))));

            for (auto iter = container.children.rbegin(); iter != container.children.rend(); ++iter)
                expect (traverser.getPreviousComponent (&(*iter)) == (iter == std::prev (container.children.rend()) ? &container
                                                                                                                    : &(*std::next (iter))));

            expect (traverser.getAllComponents (&root).size() == container.children.size() + 1);
        });
    }

private:
    struct TestComponent final : public Component
    {
        TestComponent()
        {
            for (auto& child : children)
                addAndMakeVisible (child);
        }

        std::array<Component, 10> children;
    };

    void checkComponentProperties (std::function<void (Component&)>&& childFn,
                                   std::function<bool (const Component&, const Component&)>&& testProperty)
    {
        TestComponent parent;

        for (auto& child : parent.children)
            childFn (child);

        auto* comp = traverser.getDefaultComponent (&parent);

        for (const auto& child : parent.children)
            if (&child != comp)
                expect (testProperty (*comp, child));

        for (;;)
        {
            auto* next = traverser.getNextComponent (comp);

            if (next == nullptr)
                break;

            expect (testProperty (*comp, *next));
            comp = next;
        }
    }

    void checkIgnored (const std::function<void (Component&)>& makeIgnored, FocusTraverser& traverserToUse)
    {
        TestComponent parent;

        auto iter = parent.children.begin();

        makeIgnored (*iter);
        expect (traverserToUse.getDefaultComponent (&parent) == std::addressof (*std::next (iter)));

        iter += 5;
        makeIgnored (*iter);
        expect (traverserToUse.getNextComponent (std::addressof (*std::prev (iter))) == std::addressof (*std::next (iter)));
        expect (traverserToUse.getPreviousComponent (std::addressof (*std::next (iter))) == std::addressof (*std::prev (iter)));

        auto allComponents = traverserToUse.getAllComponents (&parent);

        expect (std::find (allComponents.cbegin(), allComponents.cend(), &parent.children.front()) == allComponents.cend());
        expect (std::find (allComponents.cbegin(), allComponents.cend(), std::addressof (*iter)) == allComponents.cend());
    }

    FocusTraverser traverser;
};

static FocusTraverserTests focusTraverserTests;

#endif

} // namespace juce
