/*
 * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
 * its licensors.
 *
 * For complete copyright and license terms please see the LICENSE at the root of this
 * distribution (the "License"). All use of this software is governed by the License,
 * or, if provided, by the license below or the license accompanying this file. Do not
 * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *
 */
#include <PhysX_precompiled.h>

#include <AzCore/Math/IntersectSegment.h>
#include <AzFramework/Entity/EntityDebugDisplayBus.h>
#include <AzFramework/Viewport/CameraState.h>
#include <AzToolsFramework/Viewport/ViewportMessages.h>
#include <AzToolsFramework/ViewportSelection/EditorVisibleEntityDataCache.h>

#include <Editor/EditorViewportEntityPicker.h>

namespace PhysX
{
    EditorViewportEntityPicker::EditorViewportEntityPicker()
    {
        m_entityDataCache = AZStd::make_unique<AzToolsFramework::EditorVisibleEntityDataCache>();
        AzFramework::ViewportDebugDisplayEventBus::Handler::BusConnect(AzToolsFramework::GetEntityContextId());
    }

    EditorViewportEntityPicker::~EditorViewportEntityPicker()
    {
        AzFramework::ViewportDebugDisplayEventBus::Handler::BusDisconnect();
    }

    AZ::EntityId EditorViewportEntityPicker::PickEntity(
        const AzFramework::CameraState& cameraState
        , const AzToolsFramework::ViewportInteraction::MouseInteractionEvent& mouseInteraction
        , AZ::Vector3& pickPosition
        , AZ::Aabb& pickAabb)
    {  
        const int viewportId = mouseInteraction.m_mouseInteraction.m_interactionId.m_viewportId;

        // set the widget context before calls to ViewportWorldToScreen so we are not
        // going to constantly be pushing/popping the widget context
        AzToolsFramework::ViewportInteraction::WidgetContextGuard widgetContextGuard(viewportId);

        // selecting new entities
        AZ::EntityId entityIdUnderCursor;
        pickPosition = AZ::Vector3::CreateZero();
        pickAabb = AZ::Aabb::CreateNull();
        AZ::VectorFloat closestDistance = AZ::g_fltMax;

        for (size_t entityCacheIndex = 0; entityCacheIndex < m_entityDataCache->VisibleEntityDataCount(); ++entityCacheIndex)
        {
            const AZ::EntityId entityId = m_entityDataCache->GetVisibleEntityId(entityCacheIndex);

            if (m_entityDataCache->IsVisibleEntityLocked(entityCacheIndex)
                || !m_entityDataCache->IsVisibleEntityVisible(entityCacheIndex))
            {
                continue;
            }

            // Ignore the case where the mouse hovers over an icon. Proceed to check for intersection with entity's AABB.
            AZ::EBusReduceResult<AZ::Aabb, AzToolsFramework::AabbAggregator> aabbResult(AZ::Aabb::CreateNull());
            AzToolsFramework::EditorComponentSelectionRequestsBus::EventResult(
                aabbResult, entityId, &AzToolsFramework::EditorComponentSelectionRequests::GetEditorSelectionBoundsViewport,
                AzFramework::ViewportInfo{ viewportId });
            AZ::Aabb aabb = aabbResult.value;

            if (aabb.IsValid())
            {
                const AZ::VectorFloat pickRayLength = AZ::VectorFloat(1000.0f);
                const AZ::Vector3 rayScaledDir =
                    mouseInteraction.m_mouseInteraction.m_mousePick.m_rayDirection * pickRayLength;

                AZ::Vector3 startNormal;
                AZ::VectorFloat t, end;
                int intersectResult = AZ::Intersect::IntersectRayAABB(
                    mouseInteraction.m_mouseInteraction.m_mousePick.m_rayOrigin, rayScaledDir,
                    rayScaledDir.GetReciprocal(), aabb, t, end, startNormal);
                if (intersectResult > 0)
                {
                    entityIdUnderCursor = entityId;
                    pickPosition = mouseInteraction.m_mouseInteraction.m_mousePick.m_rayOrigin 
                        + (mouseInteraction.m_mouseInteraction.m_mousePick.m_rayDirection * pickRayLength * t);
                    pickAabb = aabb;
                }
            }
        }

        return entityIdUnderCursor;
    }

    void EditorViewportEntityPicker::DisplayViewport(
        const AzFramework::ViewportInfo& viewportInfo,
        AzFramework::DebugDisplayRequests& debugDisplay)
    {
        AZ_UNUSED(debugDisplay);
        m_entityDataCache->CalculateVisibleEntityDatas(viewportInfo);
    }
} // namespace PhysX