// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
// SPDX-FileCopyrightText: 2021 Jorrit Rouwe
// SPDX-License-Identifier: MIT

#include <Samples.h>

#include <Tests/Character/CharacterVirtualTest.h>
#include <Jolt/Physics/Collision/Shape/CapsuleShape.h>
#include <Jolt/Physics/Collision/Shape/RotatedTranslatedShape.h>
#include <Layers.h>
#include <Utils/Log.h>
#include <Renderer/DebugRendererImp.h>
#include <Application/DebugUI.h>

//#define CHARACTER_TRACE_CONTACTS

JPH_IMPLEMENT_RTTI_VIRTUAL(CharacterVirtualTest)
{
	JPH_ADD_BASE_CLASS(CharacterVirtualTest, CharacterBaseTest)
}

void CharacterVirtualTest::Initialize()
{
	CharacterBaseTest::Initialize();

	// Create 'player' character
	Ref<CharacterVirtualSettings> settings = new CharacterVirtualSettings();
	settings->mMaxSlopeAngle = sMaxSlopeAngle;
	settings->mMaxStrength = sMaxStrength;
	settings->mShape = mStandingShape;
	settings->mBackFaceMode = sBackFaceMode;
	settings->mCharacterPadding = sCharacterPadding;
	settings->mPenetrationRecoverySpeed = sPenetrationRecoverySpeed;
	settings->mPredictiveContactDistance = sPredictiveContactDistance;
	settings->mSupportingVolume = Plane(Vec3::sAxisY(), -cCharacterRadiusStanding); // Accept contacts that touch the lower sphere of the capsule
	settings->mEnhancedInternalEdgeRemoval = sEnhancedInternalEdgeRemoval;
	settings->mInnerBodyShape = sCreateInnerBody? mInnerStandingShape : nullptr;
	settings->mInnerBodyLayer = Layers::MOVING;
	mCharacter = new CharacterVirtual(settings, RVec3::sZero(), Quat::sIdentity(), 0, mPhysicsSystem);
	mCharacter->SetCharacterVsCharacterCollision(&mCharacterVsCharacterCollision);
	mCharacterVsCharacterCollision.Add(mCharacter);

	// Install contact listener for all characters
	for (CharacterVirtual *character : mCharacterVsCharacterCollision.mCharacters)
		character->SetListener(this);

	// Draw labels on ramp blocks
	for (size_t i = 0; i < mRampBlocks.size(); ++i)
		SetBodyLabel(mRampBlocks[i], StringFormat("PushesPlayer: %s\nPushable: %s", (i & 1) != 0? "True" : "False", (i & 2) != 0? "True" : "False"));
}

void CharacterVirtualTest::PrePhysicsUpdate(const PreUpdateParams &inParams)
{
	CharacterBaseTest::PrePhysicsUpdate(inParams);

	// Draw character pre update (the sim is also drawn pre update)
	RMat44 com = mCharacter->GetCenterOfMassTransform();
	RMat44 world_transform = mCharacter->GetWorldTransform();
#ifdef JPH_DEBUG_RENDERER
	mCharacter->GetShape()->Draw(mDebugRenderer, com, Vec3::sOne(), Color::sGreen, false, true);
#endif // JPH_DEBUG_RENDERER

	DrawPaddedCharacter(mCharacter->GetShape(), mCharacter->GetCharacterPadding(), com);

	// Remember old position
	RVec3 old_position = mCharacter->GetPosition();

	// Settings for our update function
	CharacterVirtual::ExtendedUpdateSettings update_settings;
	if (!sEnableStickToFloor)
		update_settings.mStickToFloorStepDown = Vec3::sZero();
	else
		update_settings.mStickToFloorStepDown = -mCharacter->GetUp() * update_settings.mStickToFloorStepDown.Length();
	if (!sEnableWalkStairs)
		update_settings.mWalkStairsStepUp = Vec3::sZero();
	else
		update_settings.mWalkStairsStepUp = mCharacter->GetUp() * update_settings.mWalkStairsStepUp.Length();

	// Update the character position
	mCharacter->ExtendedUpdate(inParams.mDeltaTime,
		-mCharacter->GetUp() * mPhysicsSystem->GetGravity().Length(),
		update_settings,
		mPhysicsSystem->GetDefaultBroadPhaseLayerFilter(Layers::MOVING),
		mPhysicsSystem->GetDefaultLayerFilter(Layers::MOVING),
		{ },
		{ },
		*mTempAllocator);

#ifdef JPH_ENABLE_ASSERTS
	// Validate that our contact list is in sync with that of the character
	// Note that compound shapes could be non convex so we may detect more contacts than have been reported by the character
	// as the character only reports contacts as it is sliding through the world. If 2 sub shapes hit at the same time then
	// most likely only one will be reported as it stops the character and prevents the 2nd one from being seen.
	uint num_contacts = 0;
	for (const CharacterVirtual::Contact &c : mCharacter->GetActiveContacts())
		if (c.mHadCollision)
		{
			JPH_ASSERT(std::find(mActiveContacts.begin(), mActiveContacts.end(), c) != mActiveContacts.end());
			num_contacts++;
		}
	JPH_ASSERT(sShapeType == EType::Compound? num_contacts >= mActiveContacts.size() : num_contacts == mActiveContacts.size());
#endif

	// Calculate effective velocity
	RVec3 new_position = mCharacter->GetPosition();
	Vec3 velocity = Vec3(new_position - old_position) / inParams.mDeltaTime;

	// Draw state of character
	DrawCharacterState(mCharacter, world_transform, velocity);
}

void CharacterVirtualTest::HandleInput(Vec3Arg inMovementDirection, bool inJump, bool inSwitchStance, float inDeltaTime)
{
	bool player_controls_horizontal_velocity = sControlMovementDuringJump || mCharacter->IsSupported();
	if (player_controls_horizontal_velocity)
	{
		// Smooth the player input
		mDesiredVelocity = sEnableCharacterInertia? 0.25f * inMovementDirection * sCharacterSpeed + 0.75f * mDesiredVelocity : inMovementDirection * sCharacterSpeed;

		// True if the player intended to move
		mAllowSliding = !inMovementDirection.IsNearZero();
	}
	else
	{
		// While in air we allow sliding
		mAllowSliding = true;
	}

	// Update the character rotation and its up vector to match the up vector set by the user settings
	Quat character_up_rotation = Quat::sEulerAngles(Vec3(sUpRotationX, 0, sUpRotationZ));
	mCharacter->SetUp(character_up_rotation.RotateAxisY());
	mCharacter->SetRotation(character_up_rotation);

	// A cheaper way to update the character's ground velocity,
	// the platforms that the character is standing on may have changed velocity
	mCharacter->UpdateGroundVelocity();

	// Determine new basic velocity
	Vec3 current_vertical_velocity = mCharacter->GetLinearVelocity().Dot(mCharacter->GetUp()) * mCharacter->GetUp();
	Vec3 ground_velocity = mCharacter->GetGroundVelocity();
	Vec3 new_velocity;
	bool moving_towards_ground = (current_vertical_velocity.GetY() - ground_velocity.GetY()) < 0.1f;
	if (mCharacter->GetGroundState() == CharacterVirtual::EGroundState::OnGround	// If on ground
		&& (sEnableCharacterInertia?
			moving_towards_ground													// Inertia enabled: And not moving away from ground
			: !mCharacter->IsSlopeTooSteep(mCharacter->GetGroundNormal())))			// Inertia disabled: And not on a slope that is too steep
	{
		// Assume velocity of ground when on ground
		new_velocity = ground_velocity;

		// Jump
		if (inJump && moving_towards_ground)
			new_velocity += sJumpSpeed * mCharacter->GetUp();
	}
	else
		new_velocity = current_vertical_velocity;

	// Gravity
	new_velocity += (character_up_rotation * mPhysicsSystem->GetGravity()) * inDeltaTime;

	if (player_controls_horizontal_velocity)
	{
		// Player input
		new_velocity += character_up_rotation * mDesiredVelocity;
	}
	else
	{
		// Preserve horizontal velocity
		Vec3 current_horizontal_velocity = mCharacter->GetLinearVelocity() - current_vertical_velocity;
		new_velocity += current_horizontal_velocity;
	}

	// Update character velocity
	mCharacter->SetLinearVelocity(new_velocity);

	// Stance switch
	if (inSwitchStance)
	{
		bool is_standing = mCharacter->GetShape() == mStandingShape;
		const Shape *shape = is_standing? mCrouchingShape : mStandingShape;
		if (mCharacter->SetShape(shape, 1.5f * mPhysicsSystem->GetPhysicsSettings().mPenetrationSlop, mPhysicsSystem->GetDefaultBroadPhaseLayerFilter(Layers::MOVING), mPhysicsSystem->GetDefaultLayerFilter(Layers::MOVING), { }, { }, *mTempAllocator))
		{
			const Shape *inner_shape = is_standing? mInnerCrouchingShape : mInnerStandingShape;
			mCharacter->SetInnerBodyShape(inner_shape);
		}
	}
}

void CharacterVirtualTest::AddCharacterMovementSettings(DebugUI* inUI, UIElement* inSubMenu)
{
	inUI->CreateCheckBox(inSubMenu, "Enable Character Inertia", sEnableCharacterInertia, [](UICheckBox::EState inState) { sEnableCharacterInertia = inState == UICheckBox::STATE_CHECKED; });
	inUI->CreateCheckBox(inSubMenu, "Player Can Push Other Virtual Characters", sPlayerCanPushOtherCharacters, [](UICheckBox::EState inState) { sPlayerCanPushOtherCharacters = inState == UICheckBox::STATE_CHECKED; });
	inUI->CreateCheckBox(inSubMenu, "Other Virtual Characters Can Push Player", sOtherCharactersCanPushPlayer, [](UICheckBox::EState inState) { sOtherCharactersCanPushPlayer = inState == UICheckBox::STATE_CHECKED; });
}

void CharacterVirtualTest::AddConfigurationSettings(DebugUI *inUI, UIElement *inSubMenu)
{
	inUI->CreateComboBox(inSubMenu, "Back Face Mode", { "Ignore", "Collide" }, (int)sBackFaceMode, [=](int inItem) { sBackFaceMode = (EBackFaceMode)inItem; });
	inUI->CreateSlider(inSubMenu, "Up Rotation X (degrees)", RadiansToDegrees(sUpRotationX), -90.0f, 90.0f, 1.0f, [](float inValue) { sUpRotationX = DegreesToRadians(inValue); });
	inUI->CreateSlider(inSubMenu, "Up Rotation Z (degrees)", RadiansToDegrees(sUpRotationZ), -90.0f, 90.0f, 1.0f, [](float inValue) { sUpRotationZ = DegreesToRadians(inValue); });
	inUI->CreateSlider(inSubMenu, "Max Slope Angle (degrees)", RadiansToDegrees(sMaxSlopeAngle), 0.0f, 90.0f, 1.0f, [](float inValue) { sMaxSlopeAngle = DegreesToRadians(inValue); });
	inUI->CreateSlider(inSubMenu, "Max Strength (N)", sMaxStrength, 0.0f, 500.0f, 1.0f, [](float inValue) { sMaxStrength = inValue; });
	inUI->CreateSlider(inSubMenu, "Character Padding", sCharacterPadding, 0.01f, 0.5f, 0.01f, [](float inValue) { sCharacterPadding = inValue; });
	inUI->CreateSlider(inSubMenu, "Penetration Recovery Speed", sPenetrationRecoverySpeed, 0.0f, 1.0f, 0.05f, [](float inValue) { sPenetrationRecoverySpeed = inValue; });
	inUI->CreateSlider(inSubMenu, "Predictive Contact Distance", sPredictiveContactDistance, 0.01f, 1.0f, 0.01f, [](float inValue) { sPredictiveContactDistance = inValue; });
	inUI->CreateCheckBox(inSubMenu, "Enable Walk Stairs", sEnableWalkStairs, [](UICheckBox::EState inState) { sEnableWalkStairs = inState == UICheckBox::STATE_CHECKED; });
	inUI->CreateCheckBox(inSubMenu, "Enable Stick To Floor", sEnableStickToFloor, [](UICheckBox::EState inState) { sEnableStickToFloor = inState == UICheckBox::STATE_CHECKED; });
	inUI->CreateCheckBox(inSubMenu, "Enhanced Internal Edge Removal", sEnhancedInternalEdgeRemoval, [](UICheckBox::EState inState) { sEnhancedInternalEdgeRemoval = inState == UICheckBox::STATE_CHECKED; });
	inUI->CreateCheckBox(inSubMenu, "Create Inner Body", sCreateInnerBody, [](UICheckBox::EState inState) { sCreateInnerBody = inState == UICheckBox::STATE_CHECKED; });
}

void CharacterVirtualTest::SaveState(StateRecorder &inStream) const
{
	CharacterBaseTest::SaveState(inStream);

	mCharacter->SaveState(inStream);

	bool is_standing = mCharacter->GetShape() == mStandingShape;
	inStream.Write(is_standing);

	inStream.Write(mAllowSliding);
	inStream.Write(mDesiredVelocity);
	inStream.Write(mActiveContacts);
}

void CharacterVirtualTest::RestoreState(StateRecorder &inStream)
{
	CharacterBaseTest::RestoreState(inStream);

	mCharacter->RestoreState(inStream);

	bool is_standing = mCharacter->GetShape() == mStandingShape; // Initialize variable for validation mode
	inStream.Read(is_standing);
	const Shape *shape = is_standing? mStandingShape : mCrouchingShape;
	mCharacter->SetShape(shape, FLT_MAX, { }, { }, { }, { }, *mTempAllocator);
	const Shape *inner_shape = is_standing? mInnerStandingShape : mInnerCrouchingShape;
	mCharacter->SetInnerBodyShape(inner_shape);

	inStream.Read(mAllowSliding);
	inStream.Read(mDesiredVelocity);
	inStream.Read(mActiveContacts);
}

void CharacterVirtualTest::OnAdjustBodyVelocity(const CharacterVirtual *inCharacter, const Body &inBody2, Vec3 &ioLinearVelocity, Vec3 &ioAngularVelocity)
{
	// Apply artificial velocity to the character when standing on the conveyor belt
	if (inBody2.GetID() == mConveyorBeltBody)
		ioLinearVelocity += Vec3(0, 0, 2);
}

void CharacterVirtualTest::OnContactCommon(const CharacterVirtual *inCharacter, const BodyID &inBodyID2, const SubShapeID &inSubShapeID2, RVec3Arg inContactPosition, Vec3Arg inContactNormal, CharacterContactSettings &ioSettings)
{
	// Draw a box around the character when it enters the sensor
	if (inBodyID2 == mSensorBody)
	{
		AABox box = inCharacter->GetShape()->GetWorldSpaceBounds(inCharacter->GetCenterOfMassTransform(), Vec3::sOne());
		mDebugRenderer->DrawBox(box, Color::sGreen, DebugRenderer::ECastShadow::Off, DebugRenderer::EDrawMode::Wireframe);
	}

	// Dynamic boxes on the ramp go through all permutations
	Array<BodyID>::const_iterator i = find(mRampBlocks.begin(), mRampBlocks.end(), inBodyID2);
	if (i != mRampBlocks.end())
	{
		size_t index = i - mRampBlocks.begin();
		ioSettings.mCanPushCharacter = (index & 1) != 0;
		ioSettings.mCanReceiveImpulses = (index & 2) != 0;
	}

	// If we encounter an object that can push the player, enable sliding
	if (inCharacter == mCharacter
		&& ioSettings.mCanPushCharacter
		&& mPhysicsSystem->GetBodyInterface().GetMotionType(inBodyID2) != EMotionType::Static)
		mAllowSliding = true;
}

void CharacterVirtualTest::OnContactAdded(const CharacterVirtual *inCharacter, const BodyID &inBodyID2, const SubShapeID &inSubShapeID2, RVec3Arg inContactPosition, Vec3Arg inContactNormal, CharacterContactSettings &ioSettings)
{
	OnContactCommon(inCharacter, inBodyID2, inSubShapeID2, inContactPosition, inContactNormal, ioSettings);

	if (inCharacter == mCharacter)
	{
	#ifdef CHARACTER_TRACE_CONTACTS
		Trace("Contact added with body %08x, sub shape %08x", inBodyID2.GetIndexAndSequenceNumber(), inSubShapeID2.GetValue());
	#endif
		CharacterVirtual::ContactKey c(inBodyID2, inSubShapeID2);
		if (std::find(mActiveContacts.begin(), mActiveContacts.end(), c) != mActiveContacts.end())
			FatalError("Got an add contact that should have been a persisted contact");
		mActiveContacts.push_back(c);
	}
}

void CharacterVirtualTest::OnContactPersisted(const CharacterVirtual *inCharacter, const BodyID &inBodyID2, const SubShapeID &inSubShapeID2, RVec3Arg inContactPosition, Vec3Arg inContactNormal, CharacterContactSettings &ioSettings)
{
	OnContactCommon(inCharacter, inBodyID2, inSubShapeID2, inContactPosition, inContactNormal, ioSettings);

	if (inCharacter == mCharacter)
	{
	#ifdef CHARACTER_TRACE_CONTACTS
		Trace("Contact persisted with body %08x, sub shape %08x", inBodyID2.GetIndexAndSequenceNumber(), inSubShapeID2.GetValue());
	#endif
		if (std::find(mActiveContacts.begin(), mActiveContacts.end(), CharacterVirtual::ContactKey(inBodyID2, inSubShapeID2)) == mActiveContacts.end())
			FatalError("Got a persisted contact that should have been an add contact");
	}
}

void CharacterVirtualTest::OnContactRemoved(const CharacterVirtual *inCharacter, const BodyID &inBodyID2, const SubShapeID &inSubShapeID2)
{
	if (inCharacter == mCharacter)
	{
	#ifdef CHARACTER_TRACE_CONTACTS
		Trace("Contact removed with body %08x, sub shape %08x", inBodyID2.GetIndexAndSequenceNumber(), inSubShapeID2.GetValue());
	#endif
		ContactSet::iterator it = std::find(mActiveContacts.begin(), mActiveContacts.end(), CharacterVirtual::ContactKey(inBodyID2, inSubShapeID2));
		if (it == mActiveContacts.end())
			FatalError("Got a remove contact that has not been added");
		mActiveContacts.erase(it);
	}
}

void CharacterVirtualTest::OnCharacterContactCommon(const CharacterVirtual *inCharacter, const CharacterVirtual *inOtherCharacter, const SubShapeID &inSubShapeID2, RVec3Arg inContactPosition, Vec3Arg inContactNormal, CharacterContactSettings &ioSettings)
{
	// Characters can only be pushed in their own update
	if (sPlayerCanPushOtherCharacters)
		ioSettings.mCanPushCharacter = sOtherCharactersCanPushPlayer || inOtherCharacter == mCharacter;
	else if (sOtherCharactersCanPushPlayer)
		ioSettings.mCanPushCharacter = inCharacter == mCharacter;
	else
		ioSettings.mCanPushCharacter = false;

	// If the player can be pushed by the other virtual character, we allow sliding
	if (inCharacter == mCharacter && ioSettings.mCanPushCharacter)
		mAllowSliding = true;
}

void CharacterVirtualTest::OnCharacterContactAdded(const CharacterVirtual *inCharacter, const CharacterVirtual *inOtherCharacter, const SubShapeID &inSubShapeID2, RVec3Arg inContactPosition, Vec3Arg inContactNormal, CharacterContactSettings &ioSettings)
{
	OnCharacterContactCommon(inCharacter, inOtherCharacter, inSubShapeID2, inContactPosition, inContactNormal, ioSettings);

	if (inCharacter == mCharacter)
	{
	#ifdef CHARACTER_TRACE_CONTACTS
		Trace("Contact added with character %08x, sub shape %08x", inOtherCharacter->GetID().GetValue(), inSubShapeID2.GetValue());
	#endif
		CharacterVirtual::ContactKey c(inOtherCharacter->GetID(), inSubShapeID2);
		if (std::find(mActiveContacts.begin(), mActiveContacts.end(), c) != mActiveContacts.end())
			FatalError("Got an add contact that should have been a persisted contact");
		mActiveContacts.push_back(c);
	}
}

void CharacterVirtualTest::OnCharacterContactPersisted(const CharacterVirtual *inCharacter, const CharacterVirtual *inOtherCharacter, const SubShapeID &inSubShapeID2, RVec3Arg inContactPosition, Vec3Arg inContactNormal, CharacterContactSettings &ioSettings)
{
	OnCharacterContactCommon(inCharacter, inOtherCharacter, inSubShapeID2, inContactPosition, inContactNormal, ioSettings);

	if (inCharacter == mCharacter)
	{
	#ifdef CHARACTER_TRACE_CONTACTS
		Trace("Contact persisted with character %08x, sub shape %08x", inOtherCharacter->GetID().GetValue(), inSubShapeID2.GetValue());
	#endif
		if (std::find(mActiveContacts.begin(), mActiveContacts.end(), CharacterVirtual::ContactKey(inOtherCharacter->GetID(), inSubShapeID2)) == mActiveContacts.end())
			FatalError("Got a persisted contact that should have been an add contact");
	}
}

void CharacterVirtualTest::OnCharacterContactRemoved(const CharacterVirtual *inCharacter, const CharacterID &inOtherCharacterID, const SubShapeID &inSubShapeID2)
{
	if (inCharacter == mCharacter)
	{
	#ifdef CHARACTER_TRACE_CONTACTS
		Trace("Contact removed with character %08x, sub shape %08x", inOtherCharacterID.GetValue(), inSubShapeID2.GetValue());
	#endif
		ContactSet::iterator it = std::find(mActiveContacts.begin(), mActiveContacts.end(), CharacterVirtual::ContactKey(inOtherCharacterID, inSubShapeID2));
		if (it == mActiveContacts.end())
			FatalError("Got a remove contact that has not been added");
		mActiveContacts.erase(it);
	}
}

void CharacterVirtualTest::OnContactSolve(const CharacterVirtual *inCharacter, const BodyID &inBodyID2, const SubShapeID &inSubShapeID2, RVec3Arg inContactPosition, Vec3Arg inContactNormal, Vec3Arg inContactVelocity, const PhysicsMaterial *inContactMaterial, Vec3Arg inCharacterVelocity, Vec3 &ioNewCharacterVelocity)
{
	// Ignore callbacks for other characters than the player
	if (inCharacter != mCharacter)
		return;

	// Don't allow the player to slide down static not-too-steep surfaces when not actively moving and when not on a moving platform
	if (!mAllowSliding && inContactVelocity.IsNearZero() && !inCharacter->IsSlopeTooSteep(inContactNormal))
		ioNewCharacterVelocity = Vec3::sZero();
}
