/***************************************************************************/
typedef struct {
  char   *unit;
  double mm;
} unit_type;

static unit_type units[] = {
  { "mm",                1.0     },
  { "cm",               10.0     },
  { "dm",              100.0     },
  { "m",              1000.0     },
  { "km",          1000000.0     },
  { "inch",             25.4     },
  { "ft",              304.8     },
  { "yard",            914.4     },
  { "mile",        1609300.0     },
  { "NM",          1853200.0     },
  { "tuuma(s)",         24.742   },
  { "kortteli",        148.45    },
  { "jalka(s)",        296.9     },
  { "kyynärä",         593.8     },
  { "syli",           1781.4     },
  { "virsta",      1068800.0     },
  { "peninkulma", 10688000.0     },
  { NULL,                0.0     }
};

#define MM 0
#define KM 4

#define DO_SHOW_OUT 1991
#define DO_SHOW_MAP 1992


/***************************************************************************/
BOOL do_command(HWND hDlg,WPARAM wParam)
{
  SendMessage(hDlg,WM_COMMAND,wParam,0);
  return TRUE;
}

typedef struct {
  int    map_unit;     
  double map_dist;     
  int    out_unit;     
  double out_dist;     
  double scale;        
  int    change_other;
} tLocalStruct, *pLocalStruct;   

#define DO_RETURN(ret)  { ret_val = ret; goto return_value; }

/***************************************************************************/
BOOL CALLBACK_E Scaling(HWND hDlg,unsigned message,WPARAM wParam,LPARAM lParam)
{
#pragma argsused
  int i,ret_val;
  pLocalStruct lp = (pLocalStruct)DialogLock(hDlg);

  if ( !lp ) {
    lp = (pLocalStruct)DialogAlloc(hDlg,sizeof(*lp)); 
    if ( !lp ) return FALSE;
    lp->map_unit     = MM;          /* mm */
    lp->map_dist     = 10.0;
    lp->out_unit     = KM;          /* km */
    lp->out_dist     = 2.0;
    lp->scale        = 200000.0;
    lp->change_other = 1;
  }

  switch (message) {

  case WM_PAINT:
    DO_RETURN(FALSE);

  case WM_INITDIALOG:
    for (i=0; units[i].unit; i++) {  /* Täytetään combo-listat */
      SendDlgItemMessage(hDlg,ID_MAP_UNIT,CB_INSERTSTRING,i,
         (LPARAM) ((LPSTR)units[i].unit));
      SendDlgItemMessage(hDlg,ID_OUT_UNIT,CB_INSERTSTRING,i,
         (LPARAM) ((LPSTR)units[i].unit));
    }

    SendDlgItemMessage(hDlg,ID_MAP_UNIT,CB_SETCURSEL,lp->map_unit,0); /* oletus yks  */
    SendDlgItemMessage(hDlg,ID_OUT_UNIT,CB_SETCURSEL,lp->out_unit,0); /* oletus yks  */
    SendDlgItemMessage(hDlg,IDR_OTHER,BM_SETCHECK,lp->change_other=1,0);/*oletus muut*/

    ShowDouble(hDlg,ID_SCALE,lp->scale);
    ShowDouble(hDlg,ID_MAP_DIST,lp->map_dist);
    ShowDouble(hDlg,ID_OUT_DIST,lp->out_dist);

    DO_RETURN(TRUE);

  case WM_COMMAND:
    switch ( wParam ) {

      case DO_SHOW_OUT:
        lp->out_dist = lp->map_dist*units[lp->map_unit].mm*lp->scale/
                        units[lp->out_unit].mm;
        ShowDouble(hDlg,ID_OUT_DIST,lp->out_dist);
        DO_RETURN(TRUE);

      case DO_SHOW_MAP:
        lp->map_dist = lp->out_dist/(units[lp->map_unit].mm*lp->scale/
                        units[lp->out_unit].mm);
        ShowDouble(hDlg,ID_MAP_DIST,lp->map_dist);
        DO_RETURN(TRUE);

      case ID_SCALE:
        if ( HIWORD(lParam) == EN_CHANGE ) {
          lp->scale = GetDouble(hDlg,wParam);
          if ( lp->scale <=0 ) lp->scale = 1;
          DO_RETURN( do_command(hDlg,DO_SHOW_OUT) );
        }
        break;

      case ID_MAP_DIST:
        if ( HIWORD(lParam) == EN_CHANGE ) {
          lp->map_dist = GetDouble(hDlg,wParam);
          DO_RETURN( do_command(hDlg,DO_SHOW_OUT) );
        }
        break;

      case ID_OUT_DIST:
        if ( HIWORD(lParam) == EN_CHANGE ) {
          lp->out_dist = GetDouble(hDlg,wParam);
          DO_RETURN( do_command(hDlg,DO_SHOW_MAP) );
        }
        break;

      case ID_MAP_UNIT:
        if ( HIWORD(lParam) == CBN_SELCHANGE ) {
            lp->map_unit = (int)SendDlgItemMessage(hDlg,ID_MAP_UNIT,CB_GETCURSEL,0,0);
            if ( lp->change_other ) DO_RETURN( do_command(hDlg,DO_SHOW_OUT) );
            DO_RETURN( do_command(hDlg,DO_SHOW_MAP) );
        }
        break;

      case ID_OUT_UNIT:
        if ( HIWORD(lParam) == CBN_SELCHANGE ) {
            lp->out_unit = (int)SendDlgItemMessage(hDlg,ID_OUT_UNIT,CB_GETCURSEL,0,0);
            if ( lp->change_other ) DO_RETURN( do_command(hDlg,DO_SHOW_MAP) );
            DO_RETURN( do_command(hDlg,DO_SHOW_OUT) );
        }
        break;

      case IDR_THIS:
        lp->change_other = 0;
        DO_RETURN(TRUE);

      case IDR_OTHER:
        lp->change_other = 1;
        DO_RETURN(TRUE);

      case IDOK:
        SetFocus(GetDlgItem(hDlg,ID_MAP_DIST));
        SendDlgItemMessage(hDlg,ID_MAP_DIST,EM_SETSEL,0,MAKELONG(0,-1));
        DO_RETURN(TRUE);

      case IDCANCEL:
        DestroyDialog(hDlg, TRUE);
        DO_RETURN(TRUE);

      default: break;
    }
    break;
  }
  DO_RETURN(FALSE);

return_value:
  DialogUnlock(hDlg);
  return ret_val;
}