/*******************************************************************************
 * Copyright (c) 2000, 2007 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwt.widgets.Group;


import dwt.DWT;
import dwt.DWTException;
import dwt.graphics.Font;
import dwt.graphics.Point;
import dwt.graphics.Rectangle;
import dwt.internal.win32.OS;
import dwt.widgets.Composite;

import dwt.dwthelper.utils;

/**
 * Instances of this class provide an etched border
 * with an optional title.
 * <p>
 * Shadow styles are hints and may not be honoured
 * by the platform.  To create a group with the
 * default shadow style for the platform, do not
 * specify a shadow style.
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>SHADOW_ETCHED_IN, SHADOW_ETCHED_OUT, SHADOW_IN, SHADOW_OUT, SHADOW_NONE</dd>
 * <dt><b>Events:</b></dt>
 * <dd>(none)</dd>
 * </dl>
 * <p>
 * Note: Only one of the above styles may be specified.
 * </p><p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 */

public class Group : Composite {

    alias Composite.computeSize computeSize;
    alias Composite.windowProc windowProc;

    String text = "";
    static const int CLIENT_INSET = 3;
    private static /+const+/ WNDPROC GroupProc;
    static if( OS.IsWinCE ){
        static const TCHAR[] GroupClass = "BUTTON\0";
    }
    else{
        static const TCHAR[] GroupClass = "SWT_GROUP\0";
    }

    private static bool static_this_completed = false;
    private static void static_this() {
        if( static_this_completed ){
            return;
        }
        synchronized {
            if( static_this_completed ){
                return;
            }
            /*
            * Feature in Windows.  The group box window class
            * uses the CS_HREDRAW and CS_VREDRAW style bits to
            * force a full redraw of the control and all children
            * when resized.  This causes flashing.  The fix is to
            * register a new window class without these bits and
            * implement special code that damages only the control.
            *
            * Feature in WinCE.  On certain devices, defining
            * a new window class which looks like BUTTON causes
            * CreateWindowEx() to crash.  The workaround is to use
            * the class Button directly.
            */
            WNDCLASS lpWndClass;
            static if (OS.IsWinCE) {
                OS.GetClassInfo (null, GroupClass.ptr, &lpWndClass);
                GroupProc = lpWndClass.lpfnWndProc;
            } else {
                TCHAR[] WC_BUTTON = "BUTTON\0";
                OS.GetClassInfo (null, WC_BUTTON.ptr, &lpWndClass);
                GroupProc = lpWndClass.lpfnWndProc;
                auto hInstance = OS.GetModuleHandle (null);
                if (!OS.GetClassInfo (hInstance, GroupClass.ptr, &lpWndClass)) {
                    auto hHeap = OS.GetProcessHeap ();
                    lpWndClass.hInstance = hInstance;
                    lpWndClass.style &= ~(OS.CS_HREDRAW | OS.CS_VREDRAW);
                    int byteCount = GroupClass.length * TCHAR.sizeof;
                    auto lpszClassName = cast(TCHAR*)OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount);
                    OS.MoveMemory (lpszClassName, GroupClass.ptr, byteCount);
                    lpWndClass.lpszClassName = lpszClassName;
                    OS.RegisterClass (&lpWndClass);
                    OS.HeapFree (hHeap, 0, lpszClassName);
                }
            }
            static_this_completed = true;
        }
    }

/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>DWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>DWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a composite control which will be the parent of the new instance (cannot be null)
 * @param style the style of control to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 *
 * @see DWT#SHADOW_ETCHED_IN
 * @see DWT#SHADOW_ETCHED_OUT
 * @see DWT#SHADOW_IN
 * @see DWT#SHADOW_OUT
 * @see DWT#SHADOW_NONE
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public this (Composite parent, int style) {
    static_this();
    super (parent, checkStyle (style));
}

override int callWindowProc (HWND hwnd, int msg, int wParam, int lParam) {
    if (handle is null) return 0;
    /*
    * Feature in Windows.  When the user clicks on the group
    * box label, the group box takes focus.  This is unwanted.
    * The fix is to avoid calling the group box window proc.
    */
    switch (msg) {
        case OS.WM_LBUTTONDOWN:
        case OS.WM_LBUTTONDBLCLK:
            return OS.DefWindowProc (hwnd, msg, wParam, lParam);
        default:
    }
    return OS.CallWindowProc (GroupProc, hwnd, msg, wParam, lParam);
}

static int checkStyle (int style) {
    style |= DWT.NO_FOCUS;
    /*
    * Even though it is legal to create this widget
    * with scroll bars, they serve no useful purpose
    * because they do not automatically scroll the
    * widget's client area.  The fix is to clear
    * the DWT style.
    */
    return style & ~(DWT.H_SCROLL | DWT.V_SCROLL);
}

override protected void checkSubclass () {
    if (!isValidSubclass ()) error (DWT.ERROR_INVALID_SUBCLASS);
}

override public Point computeSize (int wHint, int hHint, bool changed) {
    checkWidget ();
    Point size = super.computeSize (wHint, hHint, changed);
    int length = text.length;
    if (length !is 0) {
        /*
        * Bug in Windows.  When a group control is right-to-left and
        * is disabled, the first pixel of the text is clipped.  The
        * fix is to add a space to both sides of the text.  Note that
        * the work around must run all the time to stop the preferred
        * size from changing when a group is enabled and disabled.
        */
        String string = text;
        if ((style & DWT.RIGHT_TO_LEFT) !is 0) {
            if (OS.COMCTL32_MAJOR < 6 || !OS.IsAppThemed ()) {
                string = " " ~ string ~ " ";
            }
        }
        /*
        * If the group has text, and the text is wider than the
        * client area, pad the width so the text is not clipped.
        */
        TCHAR* buffer = StrToTCHARz (/+getCodePage (),+/ string);
        HFONT newFont, oldFont;
        auto hDC = OS.GetDC (handle);
        newFont = cast(HFONT) OS.SendMessage (handle, OS.WM_GETFONT, 0, 0);
        if (newFont !is null) oldFont = OS.SelectObject (hDC, newFont);
        RECT rect;
        int flags = OS.DT_CALCRECT | OS.DT_SINGLELINE;
        OS.DrawText (hDC, buffer, -1, &rect, flags);
        if (newFont !is null) OS.SelectObject (hDC, oldFont);
        OS.ReleaseDC (handle, hDC);
        size.x = Math.max (size.x, rect.right - rect.left + CLIENT_INSET * 6);
    }
    return size;
}

override public Rectangle computeTrim (int x, int y, int width, int height) {
    checkWidget ();
    Rectangle trim = super.computeTrim (x, y, width, height);
    HFONT newFont, oldFont;
    auto hDC = OS.GetDC (handle);
    newFont = cast(HFONT) OS.SendMessage (handle, OS.WM_GETFONT, 0, 0);
    if (newFont !is null) oldFont = OS.SelectObject (hDC, newFont);
    TEXTMETRIC tm;
    OS.GetTextMetrics (hDC, &tm);
    if (newFont !is null) OS.SelectObject (hDC, oldFont);
    OS.ReleaseDC (handle, hDC);
    trim.x -= CLIENT_INSET;
    trim.y -= tm.tmHeight;
    trim.width += CLIENT_INSET * 2;
    trim.height += tm.tmHeight + CLIENT_INSET;
    return trim;
}

override void createHandle () {
    super.createHandle ();
    state |= DRAW_BACKGROUND;
    state &= ~CANVAS;
}

override void enableWidget (bool enabled) {
    super.enableWidget (enabled);
    /*
    * Bug in Windows.  When a group control is right-to-left and
    * is disabled, the first pixel of the text is clipped.  The
    * fix is to add a space to both sides of the text.
    */
    if ((style & DWT.RIGHT_TO_LEFT) !is 0) {
        if (OS.COMCTL32_MAJOR < 6 || !OS.IsAppThemed ()) {
            String string = enabled || text.length is 0 ? text : " " ~ text ~ " ";
            TCHAR* buffer = StrToTCHARz (/+getCodePage (),+/ string);
            OS.SetWindowText (handle, buffer);
        }
    }
}

override public Rectangle getClientArea () {
    checkWidget ();
    forceResize ();
    RECT rect;
    OS.GetClientRect (handle, &rect);
    HFONT newFont, oldFont;
    auto hDC = OS.GetDC (handle);
    newFont = cast(HFONT) OS.SendMessage (handle, OS.WM_GETFONT, 0, 0);
    if (newFont !is null) oldFont = OS.SelectObject (hDC, newFont);
    TEXTMETRIC tm;
    OS.GetTextMetrics (hDC, &tm);
    if (newFont !is null) OS.SelectObject (hDC, oldFont);
    OS.ReleaseDC (handle, hDC);
    int x = CLIENT_INSET, y = tm.tmHeight;
    int width = Math.max (0, rect.right - CLIENT_INSET * 2);
    int height = Math.max (0, rect.bottom - y - CLIENT_INSET);
    return new Rectangle (x, y, width, height);
}

override String getNameText () {
    return getText ();
}

/**
 * Returns the receiver's text, which is the string that the
 * is used as the <em>title</em>. If the text has not previously
 * been set, returns an empty string.
 *
 * @return the text
 *
 * @exception DWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public String getText () {
    checkWidget ();
    return text;
}

override bool mnemonicHit (wchar key) {
    return setFocus ();
}

override bool mnemonicMatch (wchar key) {
    wchar mnemonic = findMnemonic (getText ());
    if (mnemonic is '\0') return false;
    return CharacterToUpper (key) is CharacterToUpper (mnemonic);
}

override void releaseWidget () {
    super.releaseWidget ();
    text = null;
}

override public void setFont (Font font) {
    checkWidget ();
    Rectangle oldRect = getClientArea ();
    super.setFont (font);
    Rectangle newRect = getClientArea ();
    if (oldRect!=newRect) sendResize ();
}

/**
 * Sets the receiver's text, which is the string that will
 * be displayed as the receiver's <em>title</em>, to the argument,
 * which may not be null. The string may include the mnemonic character.
 * </p>
 * Mnemonics are indicated by an '&amp;' that causes the next
 * character to be the mnemonic.  When the user presses a
 * key sequence that matches the mnemonic, focus is assigned
 * to the first child of the group. On most platforms, the
 * mnemonic appears underlined but may be emphasised in a
 * platform specific manner.  The mnemonic indicator character
 * '&amp;' can be escaped by doubling it in the string, causing
 * a single '&amp;' to be displayed.
 * </p>
 * @param string the new text
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the text is null</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setText (String string) {
    checkWidget ();
    if (string is null) error (DWT.ERROR_NULL_ARGUMENT);
    text = string;
    /*
    * Bug in Windows.  When a group control is right-to-left and
    * is disabled, the first pixel of the text is clipped.  The
    * fix is to add a space to both sides of the text.
    */
    if ((style & DWT.RIGHT_TO_LEFT) !is 0) {
        if (OS.COMCTL32_MAJOR < 6 || !OS.IsAppThemed ()) {
            if (!OS.IsWindowEnabled (handle)) {
                if (string.length !is 0) string = " " ~ string ~ " ";
            }
        }
    }
    TCHAR* buffer = StrToTCHARz(/+getCodePage (),+/ string);
    OS.SetWindowText (handle, buffer);
}

override int widgetStyle () {
    /*
    * Bug in Windows.  When GetDCEx() is called with DCX_INTERSECTUPDATE,
    * the HDC that is returned does not include the current update region.
    * This was confirmed under DEBUG Windows when GetDCEx() complained about
    * invalid flags.  Therefore, it is not easily possible to get an HDC from
    * outside of WM_PAINT that includes the current damage and clips children.
    * Because the receiver has children and draws a frame and label, it is
    * necessary that the receiver always draw clipped, in the current damaged
    * area.  The fix is to force the receiver to be fully clipped by including
    * WS_CLIPCHILDREN and WS_CLIPSIBLINGS in the default style bits.
    */
    return super.widgetStyle () | OS.BS_GROUPBOX | OS.WS_CLIPCHILDREN | OS.WS_CLIPSIBLINGS;
}

override String windowClass () {
    return TCHARsToStr( GroupClass );
}

override int windowProc () {
    return cast(int) GroupProc;
}

override LRESULT WM_ERASEBKGND (int wParam, int lParam) {
    LRESULT result = super.WM_ERASEBKGND (wParam, lParam);
    if (result !is null) return result;
    /*
    * Feature in Windows.  Group boxes do not erase
    * the background before drawing.  The fix is to
    * fill the background.
    */
    drawBackground (cast(HANDLE) wParam);
    return LRESULT.ONE;
}

override LRESULT WM_NCHITTEST (int wParam, int lParam) {
    LRESULT result = super.WM_NCHITTEST (wParam, lParam);
    if (result !is null) return result;
    /*
    * Feature in Windows.  The window proc for the group box
    * returns HTTRANSPARENT indicating that mouse messages
    * should not be delivered to the receiver and any children.
    * Normally, group boxes in Windows do not have children and
    * this is the correct behavior for this case.  Because we
    * allow children, answer HTCLIENT to allow mouse messages
    * to be delivered to the children.
    */
    int code = callWindowProc (handle, OS.WM_NCHITTEST, wParam, lParam);
    if (code is OS.HTTRANSPARENT) code = OS.HTCLIENT;
    return new LRESULT (code);
}

override LRESULT WM_MOUSEMOVE (int wParam, int lParam) {
    LRESULT result = super.WM_MOUSEMOVE (wParam, lParam);
    if (result !is null) return result;
    /*
    * Feature in Windows.  In version 6.00 of COMCTL32.DLL,
    * every time the mouse moves, the group title redraws.
    * This only happens when WM_NCHITTEST returns HTCLIENT.
    * The fix is to avoid calling the group window proc.
    */
    return LRESULT.ZERO;
}

override LRESULT WM_PRINTCLIENT (int wParam, int lParam) {
    LRESULT result = super.WM_PRINTCLIENT (wParam, lParam);
    if (result !is null) return result;
    /*
    * Feature in Windows.  In version 6.00 of COMCTL32.DLL,
    * when WM_PRINTCLIENT is sent from a child BS_GROUP
    * control to a parent BS_GROUP, the parent BS_GROUP
    * clears the font from the HDC.  Normally, group boxes
    * in Windows do not have children so this behavior is
    * undefined.  When the parent of a BS_GROUP is not a
    * BS_GROUP, there is no problem.  The fix is to save
    * and restore the current font.
    */
    if (OS.COMCTL32_MAJOR >= 6 && OS.IsAppThemed ()) {
        auto nSavedDC = OS.SaveDC (cast(HDC)wParam);
        int code = callWindowProc (handle, OS.WM_PRINTCLIENT, wParam, lParam);
        OS.RestoreDC (cast(HDC)wParam, nSavedDC);
        return new LRESULT (code);
    }
    return result;
}

override LRESULT WM_UPDATEUISTATE (int wParam, int lParam) {
    LRESULT result = super.WM_UPDATEUISTATE (wParam, lParam);
    if (result !is null) return result;
    /*
    * Feature in Windows.  When WM_UPDATEUISTATE is sent to
    * a group, it sends WM_CTLCOLORBTN to get the foreground
    * and background.  If drawing happens in WM_CTLCOLORBTN,
    * it will overwrite the contents of the control.  The
    * fix is draw the group without drawing the background
    * and avoid the group window proc.
    */
    bool redraw = findImageControl () !is null;
    if (!redraw) {
        if ((state & THEME_BACKGROUND) !is 0) {
            if (OS.COMCTL32_MAJOR >= 6 && OS.IsAppThemed ()) {
                redraw = findThemeControl () !is null;
            }
        }
        if (!redraw) redraw = findBackgroundControl () !is null;
    }
    if (redraw) {
        OS.InvalidateRect (handle, null, false);
        int code = OS.DefWindowProc (handle, OS.WM_UPDATEUISTATE, wParam, lParam);
        return new LRESULT (code);
    }
    return result;
}

override LRESULT WM_WINDOWPOSCHANGING (int wParam, int lParam) {
    LRESULT result = super.WM_WINDOWPOSCHANGING (wParam, lParam);
    if (result !is null) return result;
    /*
    * Invalidate the portion of the group widget that needs to
    * be redrawn.  Note that for some reason, invalidating the
    * group from inside WM_SIZE causes pixel corruption for
    * radio button children.
    */
    static if (OS.IsWinCE) return result;
    if (!OS.IsWindowVisible (handle)) return result;
    WINDOWPOS* lpwp = cast(WINDOWPOS*)lParam;
    //OS.MoveMemory (lpwp, lParam, WINDOWPOS.sizeof);
    if ((lpwp.flags & (OS.SWP_NOSIZE | OS.SWP_NOREDRAW)) !is 0) {
        return result;
    }
    RECT rect;
    OS.SetRect (&rect, 0, 0, lpwp.cx, lpwp.cy);
    OS.SendMessage (handle, OS.WM_NCCALCSIZE, 0, &rect);
    int newWidth = rect.right - rect.left;
    int newHeight = rect.bottom - rect.top;
    OS.GetClientRect (handle, &rect);
    int oldWidth = rect.right - rect.left;
    int oldHeight = rect.bottom - rect.top;
    if (newWidth is oldWidth && newHeight is oldHeight) {
        return result;
    }
    if (newWidth !is oldWidth) {
        int left = oldWidth;
        if (newWidth < oldWidth) left = newWidth;
        OS.SetRect (&rect, left - CLIENT_INSET, 0, newWidth, newHeight);
        OS.InvalidateRect (handle, &rect, true);
    }
    if (newHeight !is oldHeight) {
        int bottom = oldHeight;
        if (newHeight < oldHeight) bottom = newHeight;
        if (newWidth < oldWidth) oldWidth -= CLIENT_INSET;
        OS.SetRect (&rect, 0, bottom - CLIENT_INSET, oldWidth, newHeight);
        OS.InvalidateRect (handle, &rect, true);
    }
    return result;
}
}