/*
 * Theming - Button control
 *
 * Copyright (c) 2008 by Reece H. Dunn
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 *
 */

#include <stdarg.h>
#include <string.h>
#include <stdlib.h>

#include "windef.h"
#include "winbase.h"
#include "wingdi.h"
#include "winuser.h"
#include "uxtheme.h"
#include "tmschema.h"
#include "comctl32.h"

#define BUTTON_TYPE 0x0f /* bit mask for the available button types */

/* These are indices into a states array to determine the theme state for a given theme part. */
typedef enum
{
	STATE_NORMAL,
	STATE_DISABLED,
	STATE_HOT,
	STATE_PRESSED,
	STATE_DEFAULTED
} ButtonState;

typedef void (*pfThemedPaint)(HTHEME theme, HWND hwnd, HDC hdc, ButtonState drawState, UINT dtFlags);

static UINT get_drawtext_flags(DWORD style, DWORD ex_style)
{
    UINT flags = 0;

    if (style & BS_PUSHLIKE)
        style &= ~BUTTON_TYPE;

    if (!(style & BS_MULTILINE))
        flags |= DT_SINGLELINE;
    else
        flags |= DT_WORDBREAK;

    switch (style & BS_CENTER)
    {
    case BS_LEFT:   flags |= DT_LEFT;   break;
    case BS_RIGHT:  flags |= DT_RIGHT;  break;
    case BS_CENTER: flags |= DT_CENTER; break;
    default:
        flags |= ((style & BUTTON_TYPE) <= BS_DEFPUSHBUTTON)
               ? DT_CENTER : DT_LEFT;
    }

    if (ex_style & WS_EX_RIGHT)
        flags = DT_RIGHT | (flags & ~(DT_LEFT | DT_CENTER));

    if ((style & BUTTON_TYPE) != BS_GROUPBOX)
    {
        switch (style & BS_VCENTER)
        {
        case BS_TOP:     flags |= DT_TOP;     break;
        case BS_BOTTOM:  flags |= DT_BOTTOM;  break;
        case BS_VCENTER: /* fall through */
        default:         flags |= DT_VCENTER; break;
        }
    }
    else
        /* GroupBox's text is always single line and is top aligned. */
        flags |= DT_SINGLELINE | DT_TOP;

    return flags;
}

static inline WCHAR *get_button_text(HWND hwnd)
{
    INT len = 512;
    WCHAR *text;
    text = HeapAlloc(GetProcessHeap(), 0, (len + 1) * sizeof(WCHAR));
    if (text) InternalGetWindowText(hwnd, text, len + 1);
    return text;
}

static void PB_draw(HTHEME theme, HWND hwnd, HDC hDC, ButtonState drawState, UINT dtFlags)
{
    static const int states[] = { PBS_NORMAL, PBS_DISABLED, PBS_HOT, PBS_PRESSED, PBS_DEFAULTED };

    RECT bgRect, textRect;
    HFONT font = (HFONT)SendMessageW(hwnd, WM_GETFONT, 0, 0);
    HFONT hPrevFont = font ? SelectObject(hDC, font) : NULL;
    int state = states[ drawState ];
    WCHAR *text = get_button_text(hwnd);

    GetClientRect(hwnd, &bgRect);
    GetThemeBackgroundContentRect(theme, hDC, BP_PUSHBUTTON, state, &bgRect, &textRect);

    if (IsThemeBackgroundPartiallyTransparent(theme, BP_PUSHBUTTON, state))
        DrawThemeParentBackground(hwnd, hDC, NULL);
    DrawThemeBackground(theme, hDC, BP_PUSHBUTTON, state, &bgRect, NULL);
    if (text)
    {
        DrawThemeText(theme, hDC, BP_PUSHBUTTON, state, text, lstrlenW(text), dtFlags, 0, &textRect);
        HeapFree(GetProcessHeap(), 0, text);
    }

    if (hPrevFont) SelectObject(hDC, hPrevFont);
}

static void CB_draw(HTHEME theme, HWND hwnd, HDC hDC, ButtonState drawState, UINT dtFlags)
{
    static const int cb_states[3][5] =
    {
        { CBS_UNCHECKEDNORMAL, CBS_UNCHECKEDDISABLED, CBS_UNCHECKEDHOT, CBS_UNCHECKEDPRESSED, CBS_UNCHECKEDNORMAL },
        { CBS_CHECKEDNORMAL, CBS_CHECKEDDISABLED, CBS_CHECKEDHOT, CBS_CHECKEDPRESSED, CBS_CHECKEDNORMAL },
        { CBS_MIXEDNORMAL, CBS_MIXEDDISABLED, CBS_MIXEDHOT, CBS_MIXEDPRESSED, CBS_MIXEDNORMAL }
    };

    static const int rb_states[2][5] =
    {
        { RBS_UNCHECKEDNORMAL, RBS_UNCHECKEDDISABLED, RBS_UNCHECKEDHOT, RBS_UNCHECKEDPRESSED, RBS_UNCHECKEDNORMAL },
        { RBS_CHECKEDNORMAL, RBS_CHECKEDDISABLED, RBS_CHECKEDHOT, RBS_CHECKEDPRESSED, RBS_CHECKEDNORMAL }
    };

    static const int cb_size = 13;

    RECT bgRect, textRect;
    HFONT font = (HFONT)SendMessageW(hwnd, WM_GETFONT, 0, 0);
    HFONT hPrevFont = font ? SelectObject(hDC, font) : NULL;
    LRESULT checkState = SendMessageW(hwnd, BM_GETCHECK, 0, 0);
    DWORD dwStyle = GetWindowLongW(hwnd, GWL_STYLE);
    int part = ((dwStyle & BUTTON_TYPE) == BS_RADIOBUTTON) || ((dwStyle & BUTTON_TYPE) == BS_AUTORADIOBUTTON)
             ? BP_RADIOBUTTON
             : BP_CHECKBOX;
    int state = (part == BP_CHECKBOX)
              ? cb_states[ checkState ][ drawState ]
              : rb_states[ checkState ][ drawState ];
    WCHAR *text = get_button_text(hwnd);

    GetClientRect(hwnd, &bgRect);
    GetThemeBackgroundContentRect(theme, hDC, part, state, &bgRect, &textRect);

    if (dtFlags & DT_SINGLELINE) /* Center the checkbox / radio button to the text. */
        bgRect.top = bgRect.top + (textRect.bottom - textRect.top - cb_size) / 2;

    /* adjust for the check/radio marker */
    bgRect.bottom = bgRect.top + cb_size;
    bgRect.right = bgRect.left + cb_size;
    textRect.left = bgRect.right + 6;

    if (IsThemeBackgroundPartiallyTransparent(theme, part, state))
        DrawThemeParentBackground(hwnd, hDC, NULL);
    DrawThemeBackground(theme, hDC, part, state, &bgRect, NULL);
    if (text)
    {
        DrawThemeText(theme, hDC, part, state, text, lstrlenW(text), dtFlags, 0, &textRect);
        HeapFree(GetProcessHeap(), 0, text);
    }

    if (hPrevFont) SelectObject(hDC, hPrevFont);
}

static void GB_draw(HTHEME theme, HWND hwnd, HDC hDC, ButtonState drawState, UINT dtFlags)
{
    static const int states[] = { GBS_NORMAL, GBS_DISABLED, GBS_NORMAL, GBS_NORMAL, GBS_NORMAL };

    RECT bgRect, textRect, contentRect;
    HFONT font = (HFONT)SendMessageW(hwnd, WM_GETFONT, 0, 0);
    HFONT hPrevFont = font ? SelectObject(hDC, font) : NULL;
    int state = states[ drawState ];
    WCHAR *text = get_button_text(hwnd);

    GetClientRect(hwnd, &bgRect);
    textRect = bgRect;

    if (text)
    {
        SIZE textExtent;
        GetTextExtentPoint32W(hDC, text, lstrlenW(text), &textExtent);
        bgRect.top += (textExtent.cy / 2);
        textRect.left += 10;
        textRect.bottom = textRect.top + textExtent.cy;
        textRect.right = textRect.left + textExtent.cx + 4;

        ExcludeClipRect(hDC, textRect.left, textRect.top, textRect.right, textRect.bottom);
    }

    GetThemeBackgroundContentRect(theme, hDC, BP_GROUPBOX, state, &bgRect, &contentRect);
    ExcludeClipRect(hDC, contentRect.left, contentRect.top, contentRect.right, contentRect.bottom);

    if (IsThemeBackgroundPartiallyTransparent(theme, BP_GROUPBOX, state))
        DrawThemeParentBackground(hwnd, hDC, NULL);
    DrawThemeBackground(theme, hDC, BP_GROUPBOX, state, &bgRect, NULL);

    SelectClipRgn(hDC, NULL);

    if (text)
    {
        textRect.left += 2;
        textRect.right -= 2;
        DrawThemeText(theme, hDC, BP_GROUPBOX, state, text, lstrlenW(text), 0, 0, &textRect);
        HeapFree(GetProcessHeap(), 0, text);
    }

    if (hPrevFont) SelectObject(hDC, hPrevFont);
}

static const pfThemedPaint btnThemedPaintFunc[BUTTON_TYPE + 1] =
{
    PB_draw, /* BS_PUSHBUTTON */
    PB_draw, /* BS_DEFPUSHBUTTON */
    CB_draw, /* BS_CHECKBOX */
    CB_draw, /* BS_AUTOCHECKBOX */
    CB_draw, /* BS_RADIOBUTTON */
    CB_draw, /* BS_3STATE */
    CB_draw, /* BS_AUTO3STATE */
    GB_draw, /* BS_GROUPBOX */
    NULL, /* BS_USERBUTTON */
    CB_draw, /* BS_AUTORADIOBUTTON */
    NULL, /* Not defined */
    NULL, /* BS_OWNERDRAW */
    NULL, /* Not defined */
    NULL, /* Not defined */
    NULL, /* Not defined */
    NULL, /* Not defined */
};

static BOOL BUTTON_Paint(HTHEME theme, HWND hwnd, HDC hParamDC)
{
    PAINTSTRUCT ps;
    HDC hDC;
    DWORD dwStyle = GetWindowLongW(hwnd, GWL_STYLE);
    DWORD dwStyleEx = GetWindowLongW(hwnd, GWL_EXSTYLE);
    UINT dtFlags = get_drawtext_flags(dwStyle, dwStyleEx);
    ButtonState drawState = IsWindowEnabled(hwnd) ? STATE_NORMAL : STATE_DISABLED;
    pfThemedPaint paint = btnThemedPaintFunc[ dwStyle & BUTTON_TYPE ];

    if (paint)
    {
        hDC = hParamDC ? hParamDC : BeginPaint(hwnd, &ps);
        paint(theme, hwnd, hDC, drawState, dtFlags);
        if (!hParamDC) EndPaint(hwnd, &ps);
        return TRUE;
    }

    return FALSE; /* Delegate drawing to the non-themed code. */
}

/**********************************************************************
 * The button control subclass window proc.
 */
LRESULT CALLBACK THEMING_ButtonSubclassProc(HWND hwnd, UINT msg,
                                            WPARAM wParam, LPARAM lParam,
                                            ULONG_PTR dwRefData)
{
    const WCHAR* themeClass = WC_BUTTONW;
    HTHEME theme;
    LRESULT result;

    switch (msg)
    {
    case WM_CREATE:
        result = THEMING_CallOriginalClass(hwnd, msg, wParam, lParam);
        OpenThemeData(hwnd, themeClass);
        return result;

    case WM_DESTROY:
        theme = GetWindowTheme(hwnd);
        CloseThemeData (theme);
        return THEMING_CallOriginalClass(hwnd, msg, wParam, lParam);

    case WM_THEMECHANGED:
        theme = GetWindowTheme(hwnd);
        CloseThemeData (theme);
        OpenThemeData(hwnd, themeClass);
        break;

    case WM_SYSCOLORCHANGE:
        theme = GetWindowTheme(hwnd);
	if (!theme) return THEMING_CallOriginalClass(hwnd, msg, wParam, lParam);
        /* Do nothing. When themed, a WM_THEMECHANGED will be received, too,
	 * which will do the repaint. */
        break;

    case WM_PAINT:
        theme = GetWindowTheme(hwnd);
        if (theme && BUTTON_Paint(theme, hwnd, (HDC)wParam))
            return 0;
        else
            return THEMING_CallOriginalClass(hwnd, msg, wParam, lParam);

    case WM_ENABLE:
        theme = GetWindowTheme(hwnd);
        if (theme) RedrawWindow(hwnd, NULL, NULL,
                                RDW_FRAME | RDW_INVALIDATE | RDW_UPDATENOW);
        return THEMING_CallOriginalClass(hwnd, msg, wParam, lParam);

    default:
	/* Call old proc */
	return THEMING_CallOriginalClass(hwnd, msg, wParam, lParam);
    }
    return 0;
}