Tiny Win32 Pomodoro Timer

Pomodoro.c

/*
==============================================================================

	Pomodoro.c - Tiny Win32 Pomodoro Timer

==============================================================================
*/

/*
==============================================================================
	NOTE:
	These defines are required in order for the compiler to properly use unicode
	strings. Not defining these results in malformed wchar_t strings and a single
	character window title
==============================================================================
*/
#ifndef UNICODE
	#define UNICODE
#endif
#ifndef _UNICODE
	#define _UNICODE
#endif

//==============================================================================

#include <windows.h>
#include <shellapi.h>
#include <shlwapi.h>
#include <assert.h>
#include <stdio.h>
#include <wchar.h>

//==============================================================================

/* Define the windows libraries that we want to link against. */
#pragma comment(lib, "user32.lib")
#pragma comment(lib, "kernel32.lib")
#pragma comment(lib, "gdi32.lib")
#pragma comment(lib, "shell32.lib") /* shellapi.h */
#pragma comment(lib, "shlwapi.lib")

//==============================================================================

#define kDefaultPomodoroDurationMins 25
const LPCWSTR		kClassName = L"Pomodoro";
const LPCWSTR		kWindowTitle = L"Pomodoro";
const int			kTimerRectX = 10;
const int			kTimerRectY = 10;
const int			kTimerRectW = 130;
const int			kTimerRectH = 50;

//==============================================================================

enum Element_ID {
	ELEMENTID_invalid,

	ELEMENTID_start_timer,
	ELEMENTID_one_second_timer,

	ELEMENTID_COUNT
};

typedef enum App_State App_State;
enum App_State {
	APPSTATE_idle,
	APPSTATE_timer_active,
	APPSTATE_completed,

	APPSTATE_COUNT
};

static App_State	gAppState = APPSTATE_idle;
static int			gPomodoroTimeLeftSeconds = 0;
static int			gPomodoroDurationMins = kDefaultPomodoroDurationMins;
static int			gCompletedCount = 0;
static HWND			gStartTimerButton = NULL;
static wchar_t		gTimerText[16] = {0};
static HFONT		gTimerFont = NULL;

//==============================================================================

LRESULT CALLBACK	WindowProc(HWND h_wnd, UINT u_msg, WPARAM w_param, LPARAM l_param);

//==============================================================================

int WINAPI wWinMain(HINSTANCE h_instance, HINSTANCE h_prev_instance, PWSTR p_cmd_line, int n_cmd_show) {
	int		return_value = 0;
	int		argc = 0;
	LPWSTR*	argv = NULL;

	argv = CommandLineToArgvW(p_cmd_line, &argc);
	if (argv != NULL) {
		for (int i = 0; i < argc; ++i) {
			if (wcscmp(argv[i], L"--duration") == 0) {
				++i;
				if (i < argc) {
					gPomodoroDurationMins = StrToIntW(argv[i]);
					wprintf(L"Default Duration: %d mins\n", gPomodoroDurationMins);
				}
			}
		}
		LocalFree(argv);

		WNDCLASSW wc = { 0 };
		wc.lpfnWndProc = WindowProc;
		wc.hInstance = h_instance;
		wc.lpszClassName = kClassName;

		RegisterClassW(&wc);

		HWND h_wnd = CreateWindowExW(
			WS_EX_TOPMOST,
			kClassName,
			kWindowTitle,
			WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU,
			CW_USEDEFAULT, CW_USEDEFAULT,
			165, 110,
			NULL,
			NULL,
			h_instance,
			NULL);

		if (h_wnd != NULL) {
			ShowWindow(h_wnd, n_cmd_show);

			MSG msg = { 0 };
			while (GetMessage(&msg, NULL, 0, 0)) {
				TranslateMessage(&msg);
				DispatchMessage(&msg);
			}
		} else {
			MessageBoxW(NULL, L"Failed to create window", L"Error", MB_OK);
			return_value = 1;
		}
	} else {
		MessageBoxW(NULL, L"Failed to parse command-line", L"Error", MB_OK);
		return_value = 1;
	}

	return(return_value);
}

//==============================================================================

void StartPomodoro(HWND h_wnd) {
	assert(gAppState == APPSTATE_idle);

	SetTimer(h_wnd, ELEMENTID_one_second_timer, 1000, NULL);
	ShowWindow(gStartTimerButton, SW_HIDE);
		
	gPomodoroTimeLeftSeconds = gPomodoroDurationMins * 60;
	swprintf(gTimerText, 16, L"%02d:%02d:%02d", (gPomodoroTimeLeftSeconds / (60 * 60)), (gPomodoroTimeLeftSeconds / 60) % 60, gPomodoroTimeLeftSeconds % 60);

	gAppState = APPSTATE_timer_active;
}

//==============================================================================

void StopPomodoro(HWND h_wnd, int did_complete) {
	assert(gAppState == APPSTATE_timer_active || gAppState == APPSTATE_completed);

	KillTimer(h_wnd, ELEMENTID_one_second_timer);

	if (did_complete) {
		++gCompletedCount;
		gAppState = APPSTATE_completed;
	} else {
		ShowWindow(gStartTimerButton, SW_SHOW);
		gAppState = APPSTATE_idle;
	}

	InvalidateRect(h_wnd, NULL, TRUE);
}

//==============================================================================

LRESULT CALLBACK WindowProc(HWND h_wnd, UINT u_msg, WPARAM w_param, LPARAM l_param) {
	switch (u_msg) {
		case WM_CREATE: {
			gStartTimerButton = CreateWindow(
				L"BUTTON",  // Predefined class; Unicode assumed 
				L"Start Timer",      // Button text 
				WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON,  // Styles 
				kTimerRectX,         // x position 
				kTimerRectY,         // y position 
				kTimerRectW,        // Button width
				kTimerRectH,        // Button height
				h_wnd,     // Parent window
				(HMENU)ELEMENTID_start_timer,       // Button ID.
				(HINSTANCE) GetWindowLongPtr(h_wnd, GWLP_HINSTANCE),
				NULL);

			gTimerFont = CreateFont(
				48,                        // Height of font
				0,                         // Width of font
				0,                         // Angle of escapement
				0,                         // Orientation angle
				FW_NORMAL,                 // Font weight
				FALSE,                     // Italic attribute option
				FALSE,                     // Underline attribute option
				FALSE,                     // Strikeout attribute option
				DEFAULT_CHARSET,           // Character set identifier
				OUT_DEFAULT_PRECIS,        // Output precision
				CLIP_DEFAULT_PRECIS,       // Clipping precision
				DEFAULT_QUALITY,           // Output quality
				DEFAULT_PITCH | FF_SWISS,  // Pitch and family
				L"Segoe UI");                 // Font name

			return(0);
		} break;

		case WM_COMMAND: {
			switch (LOWORD(w_param)) {
				case ELEMENTID_start_timer: {
					StartPomodoro(h_wnd);
					return(0);
				} break;

				default: break;
			}
		} break;

		case WM_KEYDOWN: {
			if (w_param == VK_ESCAPE) {
				DestroyWindow(h_wnd);
			} else if (w_param == VK_RETURN) {
				if (gAppState == APPSTATE_idle) {
					StartPomodoro(h_wnd);
				} else if (gAppState == APPSTATE_timer_active) {
					StopPomodoro(h_wnd, 0);
				} else if (gAppState == APPSTATE_completed) {
					StopPomodoro(h_wnd, 0);
				}

				return(0);
			}
		} break;

		case WM_DESTROY: {
			DeleteObject(gTimerFont);
			PostQuitMessage(0);
			return(0);
		} break;

		case WM_TIMER: {
			if (w_param == ELEMENTID_one_second_timer &&
				gAppState == APPSTATE_timer_active) {
				--gPomodoroTimeLeftSeconds;
				swprintf(gTimerText, 16, L"%02d:%02d:%02d", (gPomodoroTimeLeftSeconds / (60 * 60)), (gPomodoroTimeLeftSeconds / 60) % 60, gPomodoroTimeLeftSeconds % 60);

				if (gPomodoroTimeLeftSeconds <= 0) {
					StopPomodoro(h_wnd, 1);
				} else {
					InvalidateRect(h_wnd, NULL, TRUE);
				}
			}

			return(0);
		} break;

		case WM_PAINT: {
			PAINTSTRUCT ps;
			HDC hdc = BeginPaint(h_wnd, &ps);
			{
				SetBkColor(hdc, RGB(255, 255, 255));
				if (gAppState == APPSTATE_timer_active) {
					if (gPomodoroTimeLeftSeconds <= (gPomodoroDurationMins * 60) / 4) {
						HBRUSH dc_brush = (HBRUSH)GetStockObject(DC_BRUSH);
						SelectObject(hdc, dc_brush);
						SetDCBrushColor(hdc, RGB(255,255,0));
						SetBkColor(hdc, RGB(255, 255, 0));

						FillRect(hdc, &ps.rcPaint, dc_brush);
					} else {
						FillRect(hdc, &ps.rcPaint, (HBRUSH)(COLOR_WINDOW+1));
					}
				} else if (gAppState == APPSTATE_completed) {
					HBRUSH dc_brush = (HBRUSH)GetStockObject(DC_BRUSH);
					SelectObject(hdc, dc_brush);
					SetDCBrushColor(hdc, RGB(0,255,0));
					SetBkColor(hdc, RGB(0, 255, 0));

					FillRect(hdc, &ps.rcPaint, dc_brush);
				} else {
					FillRect(hdc, &ps.rcPaint, (HBRUSH)(COLOR_WINDOW+1));
				}

				if (gAppState == APPSTATE_timer_active ||
					gAppState == APPSTATE_completed) {
					RECT timer_rect = { kTimerRectX, kTimerRectY, kTimerRectX + kTimerRectW, kTimerRectY + kTimerRectH };
					HFONT old_font = (HFONT)SelectObject(hdc, gTimerFont);
					DrawText(hdc, gTimerText, -1, &timer_rect, DT_CENTER | DT_VCENTER | DT_SINGLELINE);
					SelectObject(hdc, old_font);
				}
			}
			EndPaint(h_wnd, &ps);
		} break;

		default: break;
	}

	return(DefWindowProc(h_wnd, u_msg, w_param, l_param));
}