#include <DirectXMath.h>
#include <fstream>

class Camera {
public:
	Camera() {
		reset();
	}

	~Camera() {
	
	}

	void reset() {
		m_cameraViewUp = DirectX::XMFLOAT3(0.0f, 1.0f, 0.0f);
		m_cameraViewDirection = DirectX::XMFLOAT3(0.0f, 0.0f, -1.0f);
		m_cameraViewPosition = DirectX::XMFLOAT3(0.0f, 0.0f, 3.0f);
	}

	void translate(float us, float vs, float ws) {
		// RHS coordinate system U, V, W
		DirectX::XMVECTOR w = DirectX::XMVectorScale(DirectX::XMLoadFloat3(&m_cameraViewDirection), -1.0f);
		DirectX::XMVECTOR v = DirectX::XMLoadFloat3(&m_cameraViewUp);
		DirectX::XMVECTOR u = DirectX::XMVector3Normalize(DirectX::XMVector3Cross(v, w));

		DirectX::XMVECTOR p = XMLoadFloat3(&m_cameraViewPosition);

		DirectX::XMVECTOR wScaled = DirectX::XMVectorScale(u, us);
		DirectX::XMVECTOR vScaled = DirectX::XMVectorScale(v, vs);
		DirectX::XMVECTOR uScaled = DirectX::XMVectorScale(w, ws);

		DirectX::XMStoreFloat3(&m_cameraViewPosition, DirectX::XMVectorAdd(p, DirectX::XMVectorAdd(uScaled, DirectX::XMVectorAdd(vScaled, wScaled))));
	}

	void rotateAroundU(float theta) {
		// RHS coordinate system U, V, W
		DirectX::XMVECTOR w = DirectX::XMVectorScale(DirectX::XMLoadFloat3(&m_cameraViewDirection), -1.0f);
		DirectX::XMVECTOR v = DirectX::XMLoadFloat3(&m_cameraViewUp);
		DirectX::XMVECTOR u = DirectX::XMVector3Normalize(DirectX::XMVector3Cross(v, w));
		
		float cosTheta = std::cos(theta);
		float sinTheta = std::sin(theta);

		// Rodriguez rotation of W around U
		DirectX::XMVECTOR wNew = DirectX::XMVectorAdd(
			DirectX::XMVectorScale(w, cosTheta),
			DirectX::XMVectorScale(DirectX::XMVector3Normalize(DirectX::XMVector3Cross(u, w)), sinTheta));

		// Rodriguez rotation of V around U
		DirectX::XMVECTOR vNew = DirectX::XMVectorAdd(
			DirectX::XMVectorScale(v, cosTheta),
			DirectX::XMVectorScale(DirectX::XMVector3Normalize(DirectX::XMVector3Cross(u, v)), sinTheta));

		// Compute and store new view direction (-W)
		DirectX::XMStoreFloat3(&m_cameraViewDirection, DirectX::XMVectorScale(wNew, -1.0f));
		
		// Store new up vector
		DirectX::XMStoreFloat3(&m_cameraViewUp, vNew);
	}

	void rotateAroundV(float theta) {
		// RHS coordinate system U, V, W
		DirectX::XMVECTOR w = DirectX::XMVectorScale(DirectX::XMLoadFloat3(&m_cameraViewDirection), -1.0f);
		DirectX::XMVECTOR v = DirectX::XMLoadFloat3(&m_cameraViewUp);
		DirectX::XMVECTOR u = DirectX::XMVector3Normalize(DirectX::XMVector3Cross(v, w));
		
		float cosTheta = std::cos(theta);
		float sinTheta = std::sin(theta);

		// Rodriguez rotation of W around V
		DirectX::XMVECTOR wNew = DirectX::XMVectorAdd(
			DirectX::XMVectorScale(w, cosTheta),
			DirectX::XMVectorScale(DirectX::XMVector3Normalize(DirectX::XMVector3Cross(v, w)), sinTheta));
		
		// Compute and store new view direction (-W)
		DirectX::XMStoreFloat3(&m_cameraViewDirection, DirectX::XMVectorScale(wNew, -1.0f));
	}

	void rotateAroundW(float theta) {
		// RHS coordinate system U, V, W
		DirectX::XMVECTOR w = DirectX::XMVectorScale(DirectX::XMLoadFloat3(&m_cameraViewDirection), -1.0f);
		DirectX::XMVECTOR v = DirectX::XMLoadFloat3(&m_cameraViewUp);
		DirectX::XMVECTOR u = DirectX::XMVector3Normalize(DirectX::XMVector3Cross(v, w));
		
		float cosTheta = std::cos(theta);
		float sinTheta = std::sin(theta);

		// Rodriguez rotation of V around W
		DirectX::XMVECTOR vNew = DirectX::XMVectorAdd(
			DirectX::XMVectorScale(v, cosTheta),
			DirectX::XMVectorScale(DirectX::XMVector3Normalize(DirectX::XMVector3Cross(w, v)), sinTheta));
		
		// Store new up vector
		DirectX::XMStoreFloat3(&m_cameraViewUp, vNew);
	}


	const DirectX::XMFLOAT3& getViewUp() {
		return m_cameraViewUp;
	}

	const DirectX::XMFLOAT3& getViewPosition() {
		return m_cameraViewPosition;
	}

	const DirectX::XMFLOAT3& getViewDirection() {
		return m_cameraViewDirection;
	}

	void storeCamera(std::string cameraFilename) {
		std::ofstream outfile(cameraFilename.c_str(), std::ios::out | std::ios::binary);

		outfile.write(reinterpret_cast<char*>(&m_cameraViewUp), sizeof(DirectX::XMFLOAT3));
		outfile.write(reinterpret_cast<char*>(&m_cameraViewDirection), sizeof(DirectX::XMFLOAT3));
		outfile.write(reinterpret_cast<char*>(&m_cameraViewPosition), sizeof(DirectX::XMFLOAT3));

		outfile.close();
	}

	void loadCamera(std::string cameraFilename) {
		std::ifstream infile(cameraFilename.c_str(), std::ios::out | std::ios::binary);

		infile.read(reinterpret_cast<char*>(&m_cameraViewUp), sizeof(DirectX::XMFLOAT3));
		infile.read(reinterpret_cast<char*>(&m_cameraViewDirection), sizeof(DirectX::XMFLOAT3));
		infile.read(reinterpret_cast<char*>(&m_cameraViewPosition), sizeof(DirectX::XMFLOAT3));


		infile.close();
	}


protected:
	DirectX::XMFLOAT3 m_cameraViewUp; // Y
	DirectX::XMFLOAT3 m_cameraViewDirection; // -Z
	DirectX::XMFLOAT3 m_cameraViewPosition; // P

	float m_fovY;


};