#include <windows.h>
#include <math.h>
#include <cmath>
#include <tchar.h>
#include <strsafe.h>
#include <errno.h>

#define ID_XSTART	574
#define ID_XEND		399
#define ID_WIDTH	333
#define ID_COLORSIN	519
#define ID_COLORCOS	605
#define MAX_CHARS	16

HWND hGraph, hTools;
WINDOWINFO hwndInfo;
CHOOSECOLOR nColor;

TCHAR buf[MAX_CHARS];
int width, height, penWidth;
double sinx, cosx, sinxL, cosxL;
double start, end, tmp;
COLORREF sinColor = RGB(255, 0, 0), cosColor = RGB(0, 0, 255);

void RepaintGraph();
LONG WINAPI WndProc(HWND, UINT, WPARAM,LPARAM);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    MSG msg;
    WNDCLASS w;
    memset(&w, 0, sizeof(WNDCLASS));
    w.style = WS_TILED | CS_HREDRAW | CS_VREDRAW;
    w.lpfnWndProc = WndProc;
    w.hInstance = hInstance;
	w.hbrBackground = (HBRUSH)GetStockObject(LTGRAY_BRUSH);
    w.lpszClassName = L"Lab2";
	w.hIcon = LoadIcon(NULL, IDI_EXCLAMATION);
	w.hCursor = LoadCursor(NULL, IDC_ARROW);
    RegisterClass(&w);
	// graph window
    hGraph = CreateWindow(L"Lab2", L"Nepryakhin 3121", WS_OVERLAPPEDWINDOW, 200, 200, 600, 400, NULL, NULL, hInstance, NULL);
	// tools window
	hTools = CreateWindow(L"Lab2", L"Tools", WS_DLGFRAME, 200, 100, 280, 100, NULL, NULL, hInstance, NULL);

	// create 3 textboxes (x start, x end, line width)
	HWND hStart = CreateWindow(L"Edit", NULL, WS_BORDER | WS_CHILD | WS_VISIBLE | ES_LEFT, 70, 8, 50, 20, hTools, (HMENU)ID_XSTART, hInstance, 0);
	HWND hEnd = CreateWindow(L"Edit", NULL, WS_BORDER | WS_CHILD | WS_VISIBLE | ES_LEFT, 70, 38, 50, 20, hTools, (HMENU)ID_XEND, hInstance, 0);
	HWND hWidth = CreateWindow(L"Edit", NULL, WS_BORDER | WS_CHILD | WS_VISIBLE | ES_LEFT | ES_NUMBER, 200, 8, 50, 20, hTools, (HMENU)ID_WIDTH, hInstance, 0);
	SetWindowText(hStart, L"-5");	// def start -5
	SetWindowText(hEnd, L"10");		// def end 10
	SetWindowText(hWidth, L"1");	// def width 1
	// create buttons (picks line color)
	HWND hColorSin = CreateWindow(L"Button", NULL, WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 140, 38, 50, 20, hTools, (HMENU)ID_COLORSIN, hInstance, 0);
	HWND hColorCos = CreateWindow(L"Button", NULL, WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 200, 38, 50, 20, hTools, (HMENU)ID_COLORCOS, hInstance, 0);
	SetWindowText(hColorSin, L"sin clr");	// info
	SetWindowText(hColorCos, L"cos clr");

    ShowWindow(hGraph,nCmdShow);			// show graph window
    UpdateWindow(hGraph);
	
	ShowWindow(hTools,nCmdShow);			// show tools window
    UpdateWindow(hTools);

	RepaintGraph();

	while(GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    
	return msg.wParam;
}

void RepaintGraph()
{
	InvalidateRect (hGraph, NULL, TRUE);
	UpdateWindow (hGraph);
}

void RepaintTools()
{
	InvalidateRect (hTools, NULL, TRUE);
	UpdateWindow (hTools);
}

void SetText(int CID, LPCWSTR format, double data)
{
	if (CID != ID_WIDTH)
		StringCbPrintf(buf, sizeof(buf), format, data);
	else
		StringCbPrintf(buf, sizeof(buf), format, (int)data);

	SetDlgItemText(hTools, CID, buf);
}

void TextBoxHandle(WPARAM param)
{
	LPTSTR endPtr;
	errno = 0;

	if (LOWORD(param) == ID_XSTART)
	{
		// get text, convert to double
		GetDlgItemText(hTools, ID_XSTART, buf, MAX_CHARS);
		tmp = _tcstod(buf, &endPtr);
		
		// convert validation
		if (!(*endPtr) && errno != ERANGE && wcslen(buf) != 0 && end - tmp <= 100 && tmp <= end)
		{
			start = tmp;	// its ok, remember new value
			start--;
		}
		else
			SetText(ID_XSTART, L"%0.3f", start+1);	// incorrect, set last value to textbox
	}
	
	if (LOWORD(param)==ID_XEND)
	{
		GetDlgItemText(hTools, ID_XEND, buf, MAX_CHARS);
		tmp = _tcstod(buf, &endPtr);
			
		if (!(*endPtr) && errno != ERANGE && wcslen(buf) != 0 && tmp - start <= 100 && tmp >= start)
		{
			end = tmp;
			end++;
		}
		else
			SetText(ID_XEND, L"%0.3f", end-1);
	}

	if (LOWORD(param)==ID_WIDTH)
	{
		GetDlgItemText(hTools, ID_WIDTH, buf, MAX_CHARS);
		tmp = _tcstod(buf, &endPtr);
			
		if (!(*endPtr) && errno != ERANGE && wcslen(buf) != 0 && tmp > 0 && tmp < 100)
			penWidth = (int)tmp;
		else
			SetText(ID_WIDTH, L"%d", penWidth);
	}
		
	RepaintGraph();	// repaint graph
}

void CreateChooseColorDlg(WPARAM param)
{
	nColor.lStructSize = sizeof(CHOOSECOLOR);
	nColor.hwndOwner = hTools;
	COLORREF cc[16] = { 0 };
	nColor.lpCustColors = cc;

	if (ChooseColor(&nColor) == TRUE)
	{
		if (LOWORD(param) == ID_COLORSIN)
			sinColor = nColor.rgbResult;
		else
			cosColor = nColor.rgbResult;

		RepaintTools();
		RepaintGraph();
	}
}

LONG WINAPI WndProc(HWND hwnd, UINT Message, WPARAM wparam, LPARAM lparam)
{
	HDC hdc;
	PAINTSTRUCT ps;
	HPEN sinPen, cosPen, defPen;
	
	double xRatio = width / (end-start);
	double yRatio = height / 2;

    switch (Message){
    case WM_DESTROY: 
        PostQuitMessage(0);
        break;
	case WM_COMMAND:
		if (HIWORD(wparam) == EN_UPDATE)
			TextBoxHandle(wparam);
		
		if (HIWORD(wparam) == BN_CLICKED)
			CreateChooseColorDlg(wparam);
		
		break;
	case WM_PAINT:
		hdc = BeginPaint(hwnd, &ps);
		SetBkMode(hdc,TRANSPARENT);
		
		if (hwnd == hTools)
		{
			sinPen = CreatePen(0 | 0x00010000, 4, sinColor);
			cosPen = CreatePen(0 | 0x00010000, 4, cosColor);
	
			TextOut(hdc, 10, 10, L"x start:", 8);
			TextOut(hdc, 10, 40, L"x end:", 6);
			TextOut(hdc, 140, 10, L"width:", 6);

			SelectObject(hdc, sinPen);
			MoveToEx(hdc, 140, 60, (LPPOINT)NULL);
			LineTo(hdc, 190, 60);
			SelectObject(hdc, cosPen);
			MoveToEx(hdc, 200, 60, (LPPOINT)NULL);
			LineTo(hdc, 250, 60);
		}
		else
		{
			ZeroMemory(&hwndInfo, sizeof(WINDOWINFO));
			hwndInfo.cbSize = sizeof(WINDOWINFO);
			GetWindowInfo(hwnd, &hwndInfo);

			width = hwndInfo.rcClient.right - hwndInfo.rcClient.left;
			height = hwndInfo.rcClient.bottom - hwndInfo.rcClient.top;

			// х ось
			MoveToEx(hdc, 0, height/2, (LPPOINT)NULL);
			LineTo(hdc, width, height/2);
			TextOut(hdc, width-10, height/2-20, L"X", 1);
			// стрелка
			MoveToEx(hdc, width-8, height/2-4, (LPPOINT)NULL);
			LineTo(hdc, width, height/2);
			MoveToEx(hdc, width-8, height/2+4, (LPPOINT)NULL);
			LineTo(hdc, width, height/2);
			// у ось
			MoveToEx(hdc, width-16, 0, (LPPOINT)NULL);
			LineTo(hdc, width-16, height);
			TextOut(hdc, width-12, 5, L"Y", 1);
			
			TextOut(hdc, width-40, 0, L"1.0", 3);
			TextOut(hdc, width-42, height-14, L"-1.0", 4);
			// стрелка
			MoveToEx(hdc, width-16, 0, (LPPOINT)NULL);
			LineTo(hdc, width-8, 4);
			MoveToEx(hdc, width-16, 0, (LPPOINT)NULL);
			LineTo(hdc, width-24, 4);
			
			defPen = CreatePen(0 | 0x00010000, 1, RGB(128, 128, 128));
			SelectObject(hdc, defPen);

			for (double i = -0.9; i < 0.9; i += 0.1)
			{
				if (abs(i) <= 0.0001)
					continue;

				MoveToEx(hdc, 0, (int)(-yRatio * i + height / 2), (LPPOINT)NULL);
				LineTo(hdc, width, (int)(-yRatio * i + height / 2));
			}

			if (abs(start - 0.001) <= 0.0001)
				sinx = 0.002;
			else
				sinx = 0.001;
			
			sinxL = sin(start - sinx)/(start - sinx);
			cosxL = cos(start - sinx)/(start - sinx);

			sinPen = CreatePen(0 | 0x00010000, penWidth, sinColor);
			cosPen = CreatePen(0 | 0x00010000, penWidth, cosColor);
			defPen = CreatePen(0 | 0x00010000, 1, RGB(0, 0, 0));
		    
			// let's draw
			for (double i = start; i < end + 0.001; i+=0.001)
			{
				if (abs(i) <= 0.0001)			// exclude divide by 0, function doesn't exist
				{
					cosxL = 0.999;
					continue;
				}

				sinx = sin(i)/i;	// get sin(x)/x
				cosx = cos(i)/i;	// get cos(x)/x
			
				SelectObject(hdc, sinPen);
				MoveToEx(hdc, (int)(xRatio * (i - 0.001) - start * xRatio), (int)(-yRatio * sinxL + height / 2), (LPPOINT)NULL);
				LineTo(hdc, (int)(xRatio * i - start * xRatio), (int)(-yRatio * sinx + height / 2));

				SelectObject(hdc, cosPen);
				MoveToEx(hdc, (int)(xRatio * (i - 0.001) - start * xRatio), (int)(-yRatio * cosxL + height / 2), (LPPOINT)NULL);
				LineTo(hdc, (int)(xRatio * i - start * xRatio), (int)(-yRatio * cosx + height / 2));

				//SetPixel(hdc, (int)(xRatio * i - start * xRatio), (int)(-yRatio * sinx + height / 2), RGB(255,0,0));
				//SetPixel(hdc, (int)(xRatio * i - start * xRatio), (int)(-yRatio * cosx + height / 2), RGB(0,0,255));
			
				sinxL = sinx;
				cosxL = cosx;

				if (fabs(modf(i, &sinx)) < 0.001)
				{
					SelectObject(hdc, defPen);
					StringCbPrintf(buf, sizeof(buf), L"%d", (int)i);
					TextOut(hdc, (int)(xRatio * i - start * xRatio) - 4, (int)(height / 2 + 4), buf, wcslen(buf));
					MoveToEx(hdc, (int)(xRatio * i - start * xRatio), (int)(height / 2 - 4), (LPPOINT)NULL);
					LineTo(hdc, (int)(xRatio * i - start * xRatio), (int)(height / 2 + 4));
				}
			}
		
			DeleteObject(defPen);
		}
		
		DeleteObject(sinPen);
		DeleteObject(cosPen);
		DeleteDC(hdc);

		EndPaint(hwnd, &ps);
		break;
    default:
        return DefWindowProc(hwnd, Message, wparam, lparam);
    }

    return 0;
}