#include "BsDockManager.h"
#include "BsEditorWidgetContainer.h"
#include "CmMath.h"
#include "CmException.h"
#include "CmMesh.h"
#include "CmMaterial.h"
#include "CmVector2.h"
#include "CmRenderQueue.h"
#include "CmApplication.h"
#include "CmRendererManager.h"
#include "CmRenderer.h"
#include "CmSceneObject.h"
#include "BsGUIManager.h"
#include "BsBuiltinMaterialManager.h"
#include "BsGUIWidget.h"
#include "BsCamera.h"
#include "CmVertexDataDesc.h"

using namespace CamelotFramework;
using namespace BansheeEngine;

namespace BansheeEditor
{
	const CM::UINT32 DockManager::DockContainer::SliderSize = 4;
	const CM::Color DockManager::TINT_COLOR = Color(0.44f, 0.44f, 0.44f, 0.22f);
	const CM::Color DockManager::HIGHLIGHT_COLOR = Color(0.44f, 0.44f, 0.44f, 0.42f);

	DockManager::DockContainer::DockContainer()
		:mIsLeaf(false), mWidgets(nullptr), mX(0), mY(0), mWidth(0), mHeight(0), mSplitPosition(0.5f),
		mIsHorizontal(false)
	{
		mChildren[0] = nullptr;
		mChildren[1] = nullptr;
	}

	DockManager::DockContainer::~DockContainer()
	{
		if(mIsLeaf && mWidgets != nullptr)
			cm_delete(mWidgets);

		if(!mIsLeaf)
		{
			if(mChildren[0] != nullptr)
				cm_delete(mChildren[0]);

			if(mChildren[1] != nullptr)
				cm_delete(mChildren[1]);
		}

		// TODO - Clean up slider
	}

	void DockManager::DockContainer::setArea(CM::INT32 x, CM::INT32 y, UINT32 width, UINT32 height)
	{
		mX = x;
		mY = y;
		mWidth = width;
		mHeight = height;

		if(mIsLeaf)
		{
			if(mWidgets != nullptr)
			{
				mWidgets->setPosition(x, y);
				mWidgets->setSize(width, height);
			}
		}
		else if(mChildren[0] != nullptr && mChildren[1] != nullptr)
		{
			if(mIsHorizontal)
			{
				UINT32 remainingSize = (UINT32)std::max(0, (INT32)mHeight - (INT32)SliderSize);
				UINT32 sizeTop = Math::FloorToInt(remainingSize * mSplitPosition);
				UINT32 sizeBottom = remainingSize - sizeTop;

				mChildren[0]->setArea(mX, mY, mWidth, sizeTop);
				mChildren[1]->setArea(mX, mY + sizeTop + SliderSize, mWidth, sizeBottom);

				// TODO - Set slider position
			}
			else
			{
				UINT32 remainingSize = (UINT32)std::max(0, (INT32)mWidth - (INT32)SliderSize);
				UINT32 sizeLeft = Math::FloorToInt(remainingSize * mSplitPosition);
				UINT32 sizeRight = remainingSize - sizeLeft;

				mChildren[0]->setArea(mX, mY, sizeLeft, mHeight);
				mChildren[1]->setArea(mX + sizeLeft + SliderSize, mY, sizeRight, mHeight);

				// TODO - Set slider position
			}
		}
	}

	void DockManager::DockContainer::makeLeaf(GUIWidget* widgetParent, RenderWindow* parentWindow, EditorWidget* widget)
	{
		mIsLeaf = true;
		mWidgets = cm_new<EditorWidgetContainer>(widgetParent, parentWindow);

		mWidgets->add(*widget);
		mWidgets->setPosition(mX, mY);
		mWidgets->setSize(mWidth, mHeight);
	}

	void DockManager::DockContainer::addLeft(BS::GUIWidget* widgetParent, RenderWindow* parentWindow, EditorWidget* widget)
	{
		splitContainer(widgetParent, parentWindow, widget, false, true);
	}

	void DockManager::DockContainer::addRight(BS::GUIWidget* widgetParent, RenderWindow* parentWindow, EditorWidget* widget)
	{
		splitContainer(widgetParent, parentWindow, widget, false, false);
	}

	void DockManager::DockContainer::addTop(BS::GUIWidget* widgetParent, RenderWindow* parentWindow, EditorWidget* widget)
	{
		splitContainer(widgetParent, parentWindow, widget, true, true);
	}

	void DockManager::DockContainer::addBottom(BS::GUIWidget* widgetParent, RenderWindow* parentWindow, EditorWidget* widget)
	{
		splitContainer(widgetParent, parentWindow, widget, true, false);
	}

	void DockManager::DockContainer::splitContainer(BS::GUIWidget* widgetParent, RenderWindow* parentWindow, EditorWidget* widget, bool horizontal, bool newChildIsFirst)
	{
		UINT32 idxA = newChildIsFirst ? 0 : 1;
		UINT32 idxB = (idxA + 1) % 2;

		mChildren[idxA] = cm_new<DockContainer>();
		mChildren[idxB] = cm_new<DockContainer>(*this);

		mChildren[idxA]->makeLeaf(widgetParent, parentWindow, widget);

		mIsLeaf = false;
		mIsHorizontal = horizontal;
		mWidgets = nullptr;
		mSplitPosition = 0.5f;

		// TODO - Add slider

		setArea(mX, mY, mWidth, mHeight);
	}

	DockManager::DockContainer* DockManager::DockContainer::find(EditorWidgetContainer* widgetContainer)
	{
		if(mIsLeaf)
		{
			if(mWidgets == widgetContainer)
				return this;
			else
				return nullptr;
		}
		else
		{
			if(mChildren[0] != nullptr && mChildren[0]->find(widgetContainer) != nullptr)
				return mChildren[0];

			if(mChildren[1] != nullptr && mChildren[1]->find(widgetContainer) != nullptr)
				return mChildren[1];
		}

		return nullptr;
	}

	DockManager::DockContainer* DockManager::DockContainer::findAtPos(const CM::Int2& pos)
	{
		if(mIsLeaf)
		{
			if(pos.x >= (float)mX && pos.x < (float)(mX + mWidth) &&
				pos.y >= (float)mY && pos.y < (float)(mY + mHeight))
			{
				return this;
			}
		}
		else
		{
			if(mChildren[0] != nullptr && mChildren[0]->findAtPos(pos) != nullptr)
				return mChildren[0];

			if(mChildren[1] != nullptr && mChildren[1]->findAtPos(pos) != nullptr)
				return mChildren[1];
		}

		return nullptr;
	}

	DockManager::DockManager(BS::GUIWidget* parent, CM::RenderWindow* parentWindow)
		:mParent(parent), mParentWindow(parentWindow), mMouseOverContainer(nullptr), mHighlightedDropLoc(DockLocation::None)
	{
		mTopDropPolygon = cm_newN<Vector2>(4);
		mBotDropPolygon = cm_newN<Vector2>(4);
		mLeftDropPolygon = cm_newN<Vector2>(4);
		mRightDropPolygon = cm_newN<Vector2>(4);

		mDropOverlayMat = BuiltinMaterialManager::instance().createDockDropOverlayMaterial();

		RendererManager::instance().getActive()->addRenderCallback(parent->getTarget(), boost::bind(&DockManager::render, this, _1, _2));

		GUIManager::instance().mouseEventFilter.connect(boost::bind(&DockManager::onGUIMouseEvent, this, _1, _2, _3));
	}

	DockManager::~DockManager()
	{
		cm_deleteN(mTopDropPolygon, 4);
		cm_deleteN(mBotDropPolygon, 4);
		cm_deleteN(mLeftDropPolygon, 4);
		cm_deleteN(mRightDropPolygon, 4);
	}

	void DockManager::render(const Viewport* viewport, CM::RenderQueue& renderQueue)
	{
		float invViewportWidth = 1.0f / (viewport->getWidth() * 0.5f);
		float invViewportHeight = 1.0f / (viewport->getHeight() * 0.5f);

		if(mDropOverlayMesh == nullptr || !mDropOverlayMesh.isLoaded() || !mDropOverlayMesh->isInitialized())
			return;

		if(mDropOverlayMat == nullptr || !mDropOverlayMat.isLoaded() || !mDropOverlayMat->isInitialized())
			return;

		mDropOverlayMat->setFloat("invViewportWidth", invViewportWidth);
		mDropOverlayMat->setFloat("invViewportHeight", invViewportHeight);

		mDropOverlayMat->setColor("tintColor", TINT_COLOR);
		mDropOverlayMat->setColor("highlightColor", HIGHLIGHT_COLOR);

		Color highlightColor;
		switch(mHighlightedDropLoc)
		{
		case DockLocation::Top:
			highlightColor = Color(1.0f, 0.0f, 0.0f, 0.0f);
			break;
		case DockLocation::Bottom:
			highlightColor = Color(0.0f, 1.0f, 0.0f, 0.0f);
			break;
		case DockLocation::Left:
			highlightColor = Color(0.0f, 0.0f, 1.0f, 0.0f);
			break;
		case DockLocation::Right:
			highlightColor = Color(0.0f, 0.0f, 0.0f, 1.0f);
			break;
		case DockLocation::None:
			highlightColor = Color(0.0f, 0.0f, 0.0f, 0.0f);
			break;
		}

		mDropOverlayMat->setColor("highlightActive", highlightColor);

		renderQueue.add(mDropOverlayMat, mDropOverlayMesh, 0, Vector3::ZERO);
	}

	void DockManager::insert(EditorWidgetContainer* relativeTo, EditorWidget* widgetToInsert, DockLocation location)
	{
		if(relativeTo != nullptr)
		{
			DockContainer* container = mRootContainer.find(relativeTo);
			if(container == nullptr)
				CM_EXCEPT(InternalErrorException, "Cannot find the wanted widget container relative to which the widget should be inserted.");

			switch(location)
			{
			case DockLocation::Left:
				container->addLeft(mParent, mParentWindow, widgetToInsert);
				break;
			case DockLocation::Right:
				container->addRight(mParent, mParentWindow, widgetToInsert);
				break;
			case DockLocation::Top:
				container->addTop(mParent, mParentWindow, widgetToInsert);
				break;
			case DockLocation::Bottom:
				container->addBottom(mParent, mParentWindow, widgetToInsert);
				break;
			}
		}
		else
		{
			if(mRootContainer.mWidgets != nullptr)
				CM_EXCEPT(InternalErrorException, "Trying to insert a widget into dock manager root container but one already exists.");

			mRootContainer.makeLeaf(mParent, mParentWindow, widgetToInsert);
		}
	}

	void DockManager::setArea(INT32 x, INT32 y, UINT32 width, UINT32 height)
	{
		mRootContainer.setArea(x, y, width, height);

		updateDropOverlay(x, y, width, height);
	}

	void DockManager::updateDropOverlay(INT32 x, INT32 y, UINT32 width, UINT32 height)
	{
		const static int spacing = 10;
		const static float innerScale = 0.75f;

		UINT32 outWidth = std::max(0, (INT32)width - spacing * 2);
		UINT32 outHeight = std::max(0, (INT32)height - spacing * 2);
		UINT32 inWidth = (UINT32)Math::FloorToInt(innerScale * outWidth);
		UINT32 inHeight = (UINT32)Math::FloorToInt(innerScale * outHeight);
		INT32 inXOffset = Math::FloorToInt((outWidth - inWidth) * 0.5f);
		INT32 inYOffset = Math::FloorToInt((outHeight - inHeight) * 0.5f);

		Vector2 outTopLeft((float)x, (float)y);
		Vector2 outTopRight((float)(x + outWidth), (float)y);
		Vector2 outBotLeft((float)x, (float)(y + outHeight));
		Vector2 outBotRight((float)(x + outWidth), (float)(y + outHeight));

		Vector2 inTopLeft((float)(x + inXOffset), (float)(y + inYOffset));
		Vector2 inTopRight((float)(x + inXOffset + inWidth), (float)(y + inYOffset));
		Vector2 inBotLeft((float)(x + inXOffset), (float)(y + inYOffset + inHeight));
		Vector2 inBotRight((float)(x + inXOffset + inWidth), (float)(y + inYOffset + inHeight));

		VertexDataDescPtr vertexDesc = cm_shared_ptr<VertexDataDesc>();
		
		vertexDesc->addVertElem(VET_FLOAT2, VES_POSITION);
		vertexDesc->addVertElem(VET_COLOR, VES_COLOR);

		MeshDataPtr meshData = cm_shared_ptr<MeshData, ScratchAlloc>(16, 24, vertexDesc);

		auto vertIter = meshData->getVec2DataIter(VES_POSITION);
		auto colIter = meshData->getDWORDDataIter(VES_COLOR);

		// Top
		Vector2 topOffset((float)spacing, 0.0f);

		mTopDropPolygon[0] = outTopLeft + topOffset;
		mTopDropPolygon[1] = outTopRight + topOffset;
		mTopDropPolygon[2] = inTopRight + topOffset;
		mTopDropPolygon[3] = inTopLeft + topOffset;

		vertIter.addValue(mTopDropPolygon[0]);
		vertIter.addValue(mTopDropPolygon[1]);
		vertIter.addValue(mTopDropPolygon[2]);
		vertIter.addValue(mTopDropPolygon[3]);

		Color color(1.0f, 0.0f, 0.0f, 0.0f);
		UINT32 color32 = color.getAsRGBA();
		colIter.addValue(color32);
		colIter.addValue(color32);
		colIter.addValue(color32);
		colIter.addValue(color32);

		// Bottom
		Vector2 botOffset((float)spacing, (float)spacing * 2.0f);

		mBotDropPolygon[0] = inBotLeft + botOffset;
		mBotDropPolygon[1] = inBotRight + botOffset;
		mBotDropPolygon[2] = outBotRight + botOffset;
		mBotDropPolygon[3] = outBotLeft + botOffset;

		vertIter.addValue(mBotDropPolygon[0]);
		vertIter.addValue(mBotDropPolygon[1]);
		vertIter.addValue(mBotDropPolygon[2]);
		vertIter.addValue(mBotDropPolygon[3]);

		color = Color(0.0f, 1.0f, 0.0f, 0.0f);
		color32 = color.getAsRGBA();
		colIter.addValue(color32);
		colIter.addValue(color32);
		colIter.addValue(color32);
		colIter.addValue(color32);

		// Left
		Vector2 leftOffset(0.0f, (float)spacing);

		mLeftDropPolygon[0] = outTopLeft + leftOffset;
		mLeftDropPolygon[1] = inTopLeft + leftOffset;
		mLeftDropPolygon[2] = inBotLeft + leftOffset;
		mLeftDropPolygon[3] = outBotLeft + leftOffset;

		vertIter.addValue(mLeftDropPolygon[0]);
		vertIter.addValue(mLeftDropPolygon[1]);
		vertIter.addValue(mLeftDropPolygon[2]);
		vertIter.addValue(mLeftDropPolygon[3]);

		color = Color(0.0f, 0.0f, 1.0f, 0.0f);
		color32 = color.getAsRGBA();
		colIter.addValue(color32);
		colIter.addValue(color32);
		colIter.addValue(color32);
		colIter.addValue(color32);

		// Right
		Vector2 rightOffset((float)spacing * 2.0f, (float)spacing);

		mRightDropPolygon[0] = inTopRight + rightOffset;
		mRightDropPolygon[1] = outTopRight + rightOffset;
		mRightDropPolygon[2] = outBotRight + rightOffset;
		mRightDropPolygon[3] = inBotRight + rightOffset;

		vertIter.addValue(mRightDropPolygon[0]);
		vertIter.addValue(mRightDropPolygon[1]);
		vertIter.addValue(mRightDropPolygon[2]);
		vertIter.addValue(mRightDropPolygon[3]);

		color = Color(0.0f, 0.0f, 0.0f, 1.0f);
		color32 = color.getAsRGBA();
		colIter.addValue(color32);
		colIter.addValue(color32);
		colIter.addValue(color32);
		colIter.addValue(color32);

		UINT32* indexData = meshData->getIndices32();

		// Top
		indexData[0] = 0;
		indexData[1] = 1;
		indexData[2] = 2;

		indexData[3] = 0;
		indexData[4] = 2;
		indexData[5] = 3;

		// Bottom
		indexData[6] = 4;
		indexData[7] = 5;
		indexData[8] = 6;

		indexData[9] = 4;
		indexData[10] = 6;
		indexData[11] = 7;

		// Left
		indexData[12] = 8;
		indexData[13] = 9;
		indexData[14] = 10;

		indexData[15] = 8;
		indexData[16] = 10;
		indexData[17] = 11;

		// Right
		indexData[18] = 12;
		indexData[19] = 13;
		indexData[20] = 14;

		indexData[21] = 12;
		indexData[22] = 14;
		indexData[23] = 15;

		mDropOverlayMesh = Mesh::create();

		gMainSyncedCA().writeSubresource(mDropOverlayMesh.getInternalPtr(), 0, meshData);
	}

	void DockManager::onGUIMouseEvent(GUIWidget* widget, GUIElement* element, const GUIMouseEvent& event)
	{
		if(event.getType() != GUIMouseEventType::MouseMove) // TODO - Replace with DragAndDrop event
			return;

		if(widget->getTarget() != mParent->getTarget())
			return;

		const Int2& widgetRelPos = event.getPosition();

		const Matrix4& worldTfrm = widget->SO()->getWorldTfrm();

		Vector4 tfrmdPos = worldTfrm * Vector4((float)widgetRelPos.x, (float)widgetRelPos.y, 0.0f, 1.0f);
		Vector2 windowPosVec(tfrmdPos.x, tfrmdPos.y);
		Int2 windowPos(Math::RoundToInt(windowPosVec.x), Math::RoundToInt(windowPosVec.y));

		DockContainer* mouseOverContainer = mRootContainer.findAtPos(windowPos);





		// DEBUG ONLY
		mouseOverContainer = &mRootContainer;
		// END DEBUG ONLY






		// Check if we need to highlight any drop locations
		if(mouseOverContainer)
		{
			if(insidePolygon(mTopDropPolygon, 4, windowPosVec))
				mHighlightedDropLoc = DockLocation::Top;
			else if(insidePolygon(mBotDropPolygon, 4, windowPosVec))
				mHighlightedDropLoc = DockLocation::Bottom;
			else if(insidePolygon(mLeftDropPolygon, 4, windowPosVec))
				mHighlightedDropLoc = DockLocation::Left;
			else if(insidePolygon(mRightDropPolygon, 4, windowPosVec))
				mHighlightedDropLoc = DockLocation::Right;
			else
				mHighlightedDropLoc = DockLocation::None;
		}

		// Update mesh if needed
		if(mouseOverContainer == mMouseOverContainer)
			return;

		mMouseOverContainer = mouseOverContainer;

		if(mMouseOverContainer == nullptr)
		{
			mDropOverlayMesh = HMesh();
		}
		else
		{
			updateDropOverlay(mMouseOverContainer->mX, mMouseOverContainer->mY, mMouseOverContainer->mWidth, mMouseOverContainer->mHeight);
		}
	}

	// TODO - Move to a separate Polygon class?
	bool DockManager::insidePolygon(CM::Vector2* polyPoints, CM::UINT32 numPoints, CM::Vector2 point) const
	{
		bool isInside = false;
		for (UINT32 i = 0, j = numPoints - 1; i < numPoints; j = i++) 
		{
			float lineVal = (polyPoints[j].x - polyPoints[i].x) * (point.y - polyPoints[i].y) / (polyPoints[j].y - polyPoints[i].y) + polyPoints[i].x;

			if (((polyPoints[i].y > point.y) != (polyPoints[j].y > point.y)) && (point.x < lineVal))
				isInside = !isInside;
		}

		return isInside;
	}
}