///////////////////////////////////////////////////////////////
//  proto2.c   -  prototype Windows program for Project #2   //
//  ver 1.1                                                  //
//                                                           //
//  Language:     Visual C, ver 6.0                          //
//  Platform:     Micron Dual Pentium Pro 200, Win NT 4.0    //
//  Application:  CSE691 Project #1                          //
//  Author:       Jim Fawcett, Instructor, CSE691, Fall '99  //
//                CST 2-187, Syracuse Univ, (315) 443-3948   //
//                fawcett@ecs.syr.edu                        //
//  Sources:      modified from head.c, Chap 8,              //
//                Programming Windows 95, Charles Petzold,   //
//                Microsoft Press, 1996                      //
///////////////////////////////////////////////////////////////
/* 
    Module Operations:
    ==================
    This module is a prototype for project #2.  It illustrates how to
    draw a triangle, how to fill it with a shade, and how to implement
    a menu.

    There is no public interface since no other software component
    calls functions in this module.

///////////////////////////////////////////////////////////////
//  build process                                            //
///////////////////////////////////////////////////////////////
//  required files:                                          //
//    pr2c.c                                                 //
//                                                           //
//  building in IDE:                                         //
//    - build project that includes this file                //
//    - compile, line, and run                               //
///////////////////////////////////////////////////////////////

    Maintenance History:
    ====================
    ver 1.1 : 29 Sep 99
      - added version number
      - added manual page and maintenance page
    ver 1.0 : 22 Sep 99
      - first release

*/
/**/

#include <windows.h>
#include <string.h>
#include <direct.h>
#include <stdlib.h>
#include "resource.h"

LRESULT CALLBACK WndProc  (HWND, UINT, WPARAM, LPARAM);

typedef enum State { leftB, rightB } State;


//----< entry point >------------------------------------------

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
  HWND  hwnd;             // declare handle to window
  MSG   msg;              // declare message structure

// build window class structure

  WNDCLASSEX  wndclass;
  static char szAppName[] = "proto2";
  wndclass.cbSize         = sizeof (wndclass);
  wndclass.style          = CS_HREDRAW | CS_VREDRAW;
  wndclass.lpfnWndProc    = WndProc;
  wndclass.cbClsExtra     = 0;
  wndclass.cbWndExtra     = 0;
  wndclass.hInstance      = hInstance;
  wndclass.hIcon          = LoadIcon (NULL, IDI_APPLICATION);
  wndclass.hCursor        = LoadCursor (NULL, IDC_ARROW);
  wndclass.hbrBackground  = GetStockObject(WHITE_BRUSH);
  wndclass.lpszMenuName   = MAKEINTRESOURCE(IDR_MENU1);
  wndclass.lpszClassName  = szAppName;
  wndclass.hIconSm        = LoadIcon (NULL, IDI_APPLICATION);

//

// register window class
  
  RegisterClassEx (&wndclass);

// create main window at specified location with specified size
  
  hwnd = CreateWindow (szAppName, szAppName,
                       WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN,
                       200, 200, 550, 200,
                       NULL, NULL, hInstance, NULL);

// display window

  ShowWindow (hwnd, iCmdShow);
  UpdateWindow (hwnd);

// start message loop

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

//

//----< handle menu selections >-------------------------------
//
//  - doesn't do anything except show user that a selection was detected
//
int handleMenu(HWND hwnd, WPARAM wParam) {

  HMENU hmenu;
  hmenu = GetMenu(hwnd);
  switch(LOWORD(wParam)) {
    case ID_FILEOPEN :
      MessageBox(hwnd,
        "file open selected",
        "test menu",MB_OK);
      return 0;
    case ID_FILEEXIT :
      PostQuitMessage(0);
      return 0;
    case ID_ROTATEAZIMUTH :
      MessageBox(hwnd,
        "rotate azimuth selected",
        "test menu",MB_OK);
      return 0;
    case ID_ROTATEELEVATION :
      MessageBox(hwnd,
        "rotate elevation selected",
        "test menu",MB_OK);
      return 0;
    case ID_TRANSLATE_XAXIS :
      MessageBox(hwnd,
        "translate x-axis selected",
        "test menu",MB_OK);
      return 0;
    case ID_TRANSLATE_YAXIS :
      MessageBox(hwnd,
        "translate y-axis selected",
        "test menu",MB_OK);
      return 0;
    case ID_TRANSLATE_ZAXIS :
      MessageBox(hwnd,
        "translate z-axis selected",
        "test menu",MB_OK);
      return 0;
    case 65535 :
      MessageBox(hwnd,
        "scale selected",
        "test menu",MB_OK);
      return 0;
  }
  return 0;
}

//

//----< compute patch position and hue for display >-----------
//
//  - compute vertices of a triangular patch relative to mouse position
//  - change hue so it oscillates between 0 (black) and 255 (white)
//  - invalidate entire window
//
void doPositionAndHue(HWND hwnd, POINT position, POINT patch[], int *pHue) {

  #define MinHue   0
  #define MaxHue 255
  static enum State { up, down } state;
  patch[0].x = position.x;
  patch[0].y = position.y;
  patch[1].x = patch[0].x + 30;
  patch[1].y = patch[0].y - 10;
  patch[2].x = patch[0].x - 10;
  patch[2].y = patch[0].y - 45;
  InvalidateRect(hwnd,NULL,TRUE);
  if(state == up) {
    *pHue += 25;
    if(*pHue > MaxHue) {
      *pHue = MaxHue;
      state = down;
    }
  }
  else {
    *pHue -= 25;
    if(*pHue < MinHue) {
      *pHue = MinHue;
      state = up;
    }
  }
}

//----< compute mouse display string >-------------------------
//
//  - construct a display string showing mouse coordinates
//  - invalidate a small rectangle around the string
//
void doMouseDisplay(HWND hwnd, RECT smallRect, POINT position, char *staticText) {

  int size;
  staticText[0] = '[';
  itoa(position.x,&staticText[1],10);
  size = strlen(staticText);
  staticText[size] = ',';
  itoa(position.y,&staticText[size+1],10);
  size = strlen(staticText);
  staticText[size] = ']';
  staticText[size+1] = '\0';
  InvalidateRect(hwnd,&smallRect,TRUE);
}

//

//----< handle paint message >---------------------------------
//
//  - display message about using mouse buttons in middle of window
//    changing grayscale to match hue
//  - display mouse coordinates at upper left of window
//  - draw triangular patch attached to current mouse coordinates
//
void doPaint(
             HWND hwnd, 
             State state, 
             int hue, 
             char szText[], 
             char staticText[], 
             POINT patch[], 
             RECT rect
            ) {

  PAINTSTRUCT ps;   // structure to hold paint info
  HDC hdc;          // handle to device context
  HBRUSH hb;        // handle to brush used for filling closed regions

  hdc = BeginPaint (hwnd, &ps);
  SelectObject (hdc, GetStockObject (SYSTEM_FIXED_FONT));
  
// display message about mouse buttons in current hue

  SetTextColor (hdc, RGB(hue,hue,hue));
  SetBkColor   (hdc, RGB(255,255,255));
  if(hue < 255)
    DrawText(hdc, szText, strlen(szText), &rect, DT_CENTER);

// display mouse coordinates

  SetTextColor (hdc, RGB(0,0,0));
  TextOut(hdc,10,10,staticText,strlen(staticText));
  
// draw triangular patch

  if(state == rightB) {   // if right button don't fill
    SelectObject(hdc,GetStockObject(BLACK_PEN));
    Polygon(hdc,patch,3);
  }
  else {                  // if left button fill to match current hue
    hb = CreateSolidBrush(RGB(hue,hue,hue));
    SelectObject(hdc,hb);
    Polygon(hdc,patch,3);
    DeleteObject(hb);
  }
  EndPaint (hwnd, &ps);
}

//

//----< process messages for main window >---------------------

LRESULT CALLBACK WndProc (HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
{
  #define  MAXWRITE  256

  static RECT     rect;                   // client area
  static RECT     smallRect;              // paint mouse coordinates here
  static char     szText[MAXWRITE];       // buffer to hold output text
  static char     staticText[MAXWRITE];   // buffer to hold label text
  static POINT    position = {20,20}, patch[3];
  static State    state;
  static int      hue = 0;

  switch (iMsg)
  {
    HDC        hdc;  // handle to device context
    TEXTMETRIC tm;   // structure to hold font info
    case WM_CREATE :

    // define font and get text metrics for main window

      hdc = GetDC (hwnd);
      SelectObject (hdc, GetStockObject (DEFAULT_GUI_FONT));
      GetTextMetrics (hdc, &tm);
      ReleaseDC (hwnd, hdc);

    // define writing area in main window

      GetClientRect(hwnd,&rect);    // make rect have size of client area
      rect.top = 5 * tm.tmHeight;   // change top to 5 lines down
      strcpy(szText,"press either left or right mouse button");

    // define small region for fast updates to mouse coordinate display
    // -- do this so screen won't flicker

      smallRect.top = 10;  smallRect.bottom = smallRect.top + 2*tm.tmHeight;
      smallRect.left = 10; smallRect.right = smallRect.left + 15*tm.tmAveCharWidth;
      return 0;

    case WM_COMMAND :
      return handleMenu(hwnd,wParam);

    case WM_SIZE :
      rect.right  = LOWORD (lParam);
      rect.bottom = HIWORD (lParam);
      return 0;

//

    case WM_LBUTTONDOWN :

    // define triangluar patch coordinates

      state = leftB;
      doPositionAndHue(hwnd,position,patch,&hue);
      return 0;

    case WM_RBUTTONDOWN :

      state = rightB;
      doPositionAndHue(hwnd,position,patch,&hue);
      return 0;

    case WM_MOUSEMOVE :
      position.x = LOWORD(lParam);
      position.y = HIWORD(lParam);
      doMouseDisplay(hwnd,smallRect,position,staticText);
      return 0;

    case WM_PAINT :
      doPaint(hwnd,state,hue,szText,staticText,patch,rect);
      return 0;

    case WM_DESTROY :
      PostQuitMessage (0);
      return 0;
  }
  return DefWindowProc (hwnd, iMsg, wParam, lParam);
}