#pragma once

namespace Guschin {

	using namespace System;
	using namespace System::ComponentModel;
	using namespace System::Collections;
	using namespace System::Windows::Forms;
	using namespace System::Data;
	using namespace System::Drawing;
	using namespace std;

	vec2 Vc;
	vec2 V;
	vec2 Vc_work, V_work;
	mat3 T;
	mat3 initT;

	public ref class MyForm : public System::Windows::Forms::Form
	{
	public:
		MyForm(void)
		{
			InitializeComponent();
		}

	protected:
		~MyForm()
		{
			if (components)
			{
				delete components;
			}
		}

	private:
		System::ComponentModel::Container ^components;

#pragma region Windows Form Designer generated code
		void InitializeComponent(void)
		{
			this->SuspendLayout();
			// 
			// MyForm
			// 
			this->AutoScaleDimensions = System::Drawing::SizeF(8, 16);
			this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
			this->ClientSize = System::Drawing::Size(737, 686);
			this->KeyPreview = true;
			this->Margin = System::Windows::Forms::Padding(4, 4, 4, 4);
			this->Name = L"MyForm";
			this->Text = L"MyForm";
			this->Load += gcnew System::EventHandler(this, &MyForm::MyForm_Load);
			this->Paint += gcnew System::Windows::Forms::PaintEventHandler(this, &MyForm::MyForm_Paint);
			this->KeyDown += gcnew System::Windows::Forms::KeyEventHandler(this, &MyForm::MyForm_KeyDown);
			this->Resize += gcnew System::EventHandler(this, &MyForm::MyForm_Resize);
			this->ResumeLayout(false);

		}
#pragma endregion
	private: 
		float left = 30, right = 100, top = 20, bottom = 50;
		float minX = left, maxX;
		float minY = top, maxY;
		float Wcx = left, Wcy;
		float Wx, Wy;

	private: 
		System::Void rectCalc() {
			maxX = ClientRectangle.Width - right;
			maxY = ClientRectangle.Height - bottom;
			Wcy = maxY;
			Wx = maxX - left;
			Wy = maxY - top;
		}
		System::Void worldRectCalc()
		{
			Vc_work = normalize(T * vec3(Vc, 1.f));
			V_work = mat2(T) * V;
		}
		float f(float x)
		{
			return tan(x);
		}
		bool f_exists(float x, float delta)
		{
			return fabs(2.f * acos(cos(x)) - Math::PI) > delta;
		}
	private: 
		System::Void MyForm_Resize(System::Object^ sender, System::EventArgs^ e) {
			rectCalc();
			Refresh();
		}
	private:
		System::Void MyForm_Paint(System::Object^ sender, System::Windows::Forms::PaintEventArgs^ e) {
			Graphics^ g = e->Graphics;
			g->Clear(Color::Aquamarine);

			Pen^ rectPen = gcnew Pen(Color::Black, 2);
			g->DrawRectangle(rectPen, left, top, Wx, Wy);

			Pen^ pen = gcnew Pen(Color::Blue, 1);
			
			float deltaX = V_work.x / Wx;
			bool hasStart, hasEnd;
			vec2 start, end;
			float x, y;

			start.x = Wcx;
			x = Vc_work.x;
			hasStart = f_exists(x, deltaX);
			if (hasStart)
			{
				y = f(x);
				start.y = Wcy - (y - Vc_work.y) / V_work.y * Wy;
			}

			while (start.x < maxX)
			{
				end.x = start.x + 1.f;
				x += deltaX;
				hasEnd = f_exists(x, deltaX);
				if (hasEnd)
				{
					y = f(x);
					end.y = Wcy - (y - Vc_work.y) / V_work.y * Wy;
				}

				vec2 tmpEnd = end;
				bool visible = hasStart && hasEnd && clip(start, end, minX, minY, maxX, maxY);
				if (visible) {
					g->DrawLine(pen, start.x, start.y, end.x, end.y);
				}
				start = tmpEnd;
                hasStart = hasEnd;
			}
		}
	private:
		System::Void MyForm_Load(System::Object^  sender, System::EventArgs^  e) {
			initT = mat3(1.f);
			T = initT;
			Vc = vec2(-2.f, -2.f);
			V = vec2(4.f, 4.f);
			rectCalc();
			worldRectCalc();
		}
	private:
		System::Void MyForm_KeyDown(System::Object^ sender, System::Windows::Forms::KeyEventArgs^ e) {
			float centerX = Vc_work.x + V_work.x / 2;
			float centerY = Vc_work.y + V_work.y / 2;

			switch (e->KeyCode) {
			case Keys::Escape:
				T = initT;
				break;
			case Keys::A:
				T = translate(-V_work.x / Wx, 0.f) * T;
				break;
			case Keys::Z:
				T = translate(-centerX, -centerY) * T;
				T = scale(1.1) * T;
				T = translate(centerX, centerY) * T;
				break;
			default:
				break;
			}
			worldRectCalc();
			Refresh();
		}
	};
}