Download updates automatically, ask to install from a modeless dialog

src/engine/UpdateInstallDialog.cpp

Index: src/engine/UpdateInstallDialog.cpp
===================================================================
new file mode 100644
--- /dev/null
+++ b/src/engine/UpdateInstallDialog.cpp
@@ -0,0 +1,189 @@
+#include <sstream>
+#include <string>
+#include <Windows.h>
+
+#include "../shared/Dictionary.h"
+#include "../shared/Utils.h"
+#include "UpdateInstallDialog.h"
+
+namespace
+{
+  LRESULT CALLBACK ProcessWindowMessage(HWND window, UINT message,
+                                        WPARAM wParam, LPARAM lParam)
+  {
+    switch (message)
+    {
+    case WM_CLOSE:
+      PostQuitMessage(1);
+      return 0;
+    case WM_COMMAND:
+      switch (LOWORD(wParam))
+      {
+      case IDYES:
+        PostQuitMessage(0);
+        return 0;
+      case IDNO:
+        PostQuitMessage(1);
+        return 0;
+      }
+      break;
+    }
+    return DefWindowProc(window, message, wParam, lParam);
+  }
+
+  HWND CreateDialogWindow()
+  {
+    const std::wstring windowClassName = L"ABP_UPDATE_INSTALL_DIALOG";
+    WNDCLASSEXW windowClass = {};
+    windowClass.cbSize = sizeof(windowClass);
+    windowClass.lpfnWndProc = ProcessWindowMessage;
+    windowClass.hbrBackground = reinterpret_cast<HBRUSH>(COLOR_MENU + 1);
+    windowClass.lpszClassName = windowClassName.c_str();
+    RegisterClassEx(&windowClass);
+
+    Dictionary* dictionary = Dictionary::GetInstance();
+    std::wstring title =
+      dictionary->Lookup("updater", "install-question-title");
+
+    return CreateWindowExW(WS_EX_TOOLWINDOW | WS_EX_TOPMOST,
+                           windowClassName.c_str(), title.c_str(), WS_SYSMENU,
+                           0, 0, 0, 0, 0, 0, 0, 0);
+  }
+
+  int GetAverageCharacterWidth(HDC deviceContext)
+  {
+    std::wstring alphabet;
+    for (wchar_t letter = L'A'; letter != 'Z'; letter++)
+      alphabet += letter;
+    RECT alphabetRect = {};
+    DrawTextW(deviceContext, alphabet.c_str(), -1, &alphabetRect,
+              DT_CALCRECT | DT_NOPREFIX);
+    return alphabetRect.right / alphabet.length();
+  }
+
+  HWND CreateText(HWND parent)
+  {
+    Dictionary* dictionary = Dictionary::GetInstance();
+    std::wstring text = dictionary->Lookup("updater", "install-question-text");
+
+    HDC deviceContext = GetDC(parent);
+    const int characterWidth = GetAverageCharacterWidth(deviceContext);
+    const int lineLength = 40;
+    const int textWidth = lineLength * characterWidth;
+
+    RECT textRect = {};
+    textRect.right = textWidth;
+    DrawTextW(deviceContext, text.c_str(), -1, &textRect,
+              DT_CALCRECT | DT_NOPREFIX | DT_WORDBREAK);
+    const int textHeight = textRect.bottom;
+
+    return CreateWindowW(L"STATIC", text.c_str(),
+                         WS_CHILD | WS_VISIBLE| SS_LEFT, 0, 0,
+                         textWidth, textHeight, parent, 0, 0, 0);
+  }
+
+  HWND CreateButtons(HWND parent)
+  {
+    const std::wstring panelClassName = L"ABP_PANEL";
+    WNDCLASSW panelClass = {};
+    panelClass.lpfnWndProc =
+      reinterpret_cast<WNDPROC>(GetWindowLongPtr(parent, GWLP_WNDPROC));
+    panelClass.lpszClassName = panelClassName.c_str();
+    RegisterClass(&panelClass);
+
+    Dictionary* dictionary = Dictionary::GetInstance();
+    const std::wstring yesLabel = dictionary->Lookup("general", "button-yes");
+    const std::wstring noLabel = dictionary->Lookup("general", "button-no");
+
+    HDC deviceContext = GetDC(parent);
+    RECT yesButtonRect = {};
+    DrawTextW(deviceContext, yesLabel.c_str(), -1, &yesButtonRect,
+              DT_CALCRECT | DT_NOPREFIX);
+    RECT noButtonRect = {};
+    DrawTextW(deviceContext, noLabel.c_str(), -1, &noButtonRect,
+              DT_CALCRECT | DT_NOPREFIX);
+
+    const int minButtonWidth = 120;
+    const int minButtonHeight = 30;
+    const int buttonPadding = 5;
+    int yesButtonWidth = yesButtonRect.right + buttonPadding * 2;
+    yesButtonWidth = max(yesButtonWidth, minButtonWidth);
+    int noButtonWidth =  noButtonRect.right + buttonPadding * 2;
+    noButtonWidth = max(noButtonWidth, minButtonWidth);
+    int buttonHeight = max(yesButtonRect.bottom, noButtonRect.bottom)
+      + buttonPadding * 2;
+    buttonHeight = max(buttonHeight, minButtonHeight);
+
+    const int gap = 10;
+    const int panelWidth = yesButtonWidth + gap + noButtonWidth;
+    const int panelHeight = buttonHeight;
+
+    const DWORD flags = WS_CHILD | WS_VISIBLE;
+    HWND buttons = CreateWindowW(panelClassName.c_str(), 0, flags, 0, 0,
+                                 panelWidth, panelHeight, parent, 0, 0, 0);
+    CreateWindowW(L"BUTTON", yesLabel.c_str(), flags,
+                  0, 0, yesButtonWidth, buttonHeight,
+                  buttons, reinterpret_cast<HMENU>(IDYES), 0, 0);
+    CreateWindowW(L"BUTTON", noLabel.c_str(), flags,
+                  yesButtonWidth + gap, 0, noButtonWidth, buttonHeight,
+                  buttons, reinterpret_cast<HMENU>(IDNO), 0, 0);
+    return buttons;
+  }
+
+  void UpdateSizes(HWND window, const HWND text, const HWND buttons)
+  {
+    RECT textRect;
+    GetWindowRect(text, &textRect);
+
+    RECT buttonsRect;
+    GetWindowRect(buttons, &buttonsRect);
+
+    const int padding = 10;
+    const int margin = 10;
+    const int gap = 10;
+    const int contentWidth = max(textRect.right, buttonsRect.right);
+    const int contentHeight = textRect.bottom + buttonsRect.bottom + margin;
+    const int windowWidth = contentWidth + padding * 2;
+    const int windowHeight = contentHeight + padding * 2;
+
+    RECT workArea;
+    SystemParametersInfo(SPI_GETWORKAREA, 0, &workArea, 0);
+    const int windowX = workArea.right - windowWidth - margin;
+    const int windowY = workArea.bottom - windowHeight - margin;
+    SetWindowPos(window, 0, windowX, windowY, windowWidth, windowHeight, 0);
+
+    const int textX = padding;
+    const int textY = padding;
+    SetWindowPos(text, 0, padding, padding, 0, 0, SWP_NOSIZE);
+
+    const int buttonsX = windowWidth - buttonsRect.right - padding;
+    const int buttonsY = windowHeight - buttonsRect.bottom - padding;
+    SetWindowPos(buttons, 0, buttonsX, buttonsY, 0, 0, SWP_NOSIZE);
+  }
+}
+
+UpdateInstallDialog::UpdateInstallDialog()
+{
+  window = CreateDialogWindow();
+  HWND text = CreateText(window);
+  HWND buttons = CreateButtons(window);
+  UpdateSizes(window, text, buttons);
+}
+
+UpdateInstallDialog::~UpdateInstallDialog()
+{
+  DestroyWindow(window);
+}
+
+bool UpdateInstallDialog::Show()
+{
+  ShowWindow(window, SW_SHOW);
+  MSG message;
+  while(GetMessage(&message, 0, 0, 0) > 0)
+  {
+    TranslateMessage(&message);
+    DispatchMessage(&message);
+  }
+  ShowWindow(window, SW_HIDE);
+  return message.wParam == 0;
+}