#include "alfpriv.h"

#include <objbase.h>

/* ALF App and Window */

static void
ALF_InitializeWindowPriv(HWND hwnd, ALFWindowPriv *priv, void *closure)
{
    priv->vtbl = (ALFWindowVTable*)GetClassLongPtr(hwnd, 0);
    priv->app = (ALFAPP)GetClassLongPtr(hwnd, sizeof(void*));
    priv->closure = closure;
    ALF_ListInit(&priv->widgets);
    priv->defid = (WORD)-1;
}

static void
ALF_DestroyWindowPriv(ALFWindowPriv *priv)
{
    if (priv->vtbl->postdestroy)
        priv->vtbl->postdestroy(priv->closure);

    ALF_FOR_LIST(ALFWidgetPriv, list, &priv->widgets, w) {
        HeapFree(GetProcessHeap(), 0, w);
    }
    ALF_ListInit(&priv->widgets);

    if (priv->fonts.hMessageFont)
        DeleteObject(priv->fonts.hMessageFont);

    HeapFree(GetProcessHeap(), 0, priv->layout.columns);
    HeapFree(GetProcessHeap(), 0, priv->layout.rows);
    HeapFree(GetProcessHeap(), 0, priv);
}

int
ALF_CentipointsToPxPriv(ALFWindowPriv *priv, int cptValue)
{
    return MulDiv(cptValue, priv->fonts.dpi, 7200);
}

static void
ALF_UpdateFontForWidget(ALFWindowPriv *priv, ALFWidgetPriv *widget)
{
    if (widget->hwnd && (widget->flags & ALF_MESSAGEFONT) == ALF_MESSAGEFONT) {
        SendMessage(widget->hwnd, WM_SETFONT, (WPARAM)priv->fonts.hMessageFont, (LPARAM)NULL);

        // XXX: Invalidating should IMHO be the decision of the control, but at
        // least the commctl32 V5 static control doesn't do it.
        InvalidateRect(widget->hwnd, NULL, TRUE);
    }
}

void
ALF_UpdateFonts(HWND win)
{
    SendMessage(win, ALF_WM_UPDATEFONTS, 0, 0);
}

void
ALF_UpdateFontsPriv(HWND win, ALFWindowPriv *priv)
{
    priv->fonts.dpi = priv->app->compatFn->GetDpiForWindow(win);

    if (LOBYTE(LOWORD(GetVersion())) < 4) {
        // NT 3.x uses System font for everything, we copy that
        priv->fonts.hMessageFont = (HFONT)GetStockObject(SYSTEM_FONT);
        GetObject(priv->fonts.hMessageFont, sizeof(priv->fonts.lfMessageFont), &priv->fonts.lfMessageFont);
    } else {
        // XXX: SystemParametersInfoForDpi needs the Vista+ NONCLIENTMETRICS,
        // but we want to be able to build with WINVER = 0x0500 and PSDK2003
        ALF_NONCLIENTMETRICS_VISTA ncm;
        ZeroMemory(&ncm, sizeof(ncm));
        ncm.cbSize = ALF_SizeOf_NONCLIENTMETRICS();

        if (priv->app->compatFn->SystemParametersInfoForDpi(SPI_GETNONCLIENTMETRICS, ncm.cbSize, &ncm, 0, priv->fonts.dpi)) {
            priv->fonts.lfMessageFont = ncm.lfMessageFont;
        } else {
            // FIXME! fallback to default font, 8pt MS Shell Dlg
            ZeroMemory(&priv->fonts.lfMessageFont, sizeof(priv->fonts.lfMessageFont));

            priv->fonts.lfMessageFont.lfHeight = -MulDiv(8, priv->fonts.dpi, 72);
            lstrcpy(priv->fonts.lfMessageFont.lfFaceName, TEXT("MS Shell Dlg"));
        }

        if (priv->fonts.hMessageFont) {
            DeleteObject(priv->fonts.hMessageFont);
        }
        priv->fonts.hMessageFont = CreateFontIndirect(&priv->fonts.lfMessageFont);
    }

    ALF_FOR_LIST(ALFWidgetPriv, list, &priv->widgets, i) {
        ALF_UpdateFontForWidget(priv, i);
    }

    if (priv->vtbl->updatefonts) {
        priv->vtbl->updatefonts(priv->closure, win, &priv->fonts);
    }
}

void
ALF_RecalculateLayout(HWND hwnd)
{
    SIZE dummy;
    SendMessage(hwnd, ALF_WM_QUERYSIZE, 0, (LPARAM)&dummy);
    SendMessage(hwnd, ALF_WM_APPLYLAYOUT, 0, 0);
}

static void
ALF_CalculateSizes(ALFWindowPriv *win)
{
    for (int i = 0; i < win->layout.nColumns; ++i) {
        ZeroMemory(&win->layout.columns[i], sizeof(win->layout.columns[i]));
    }
    for (int i = 0; i < win->layout.nRows; ++i) {
        ZeroMemory(&win->layout.rows[i], sizeof(win->layout.rows[i]));
    }

    ALF_FOR_LIST(ALFWidgetPriv, list, &win->widgets, c) {
        while ((int)c->x >= win->layout.nColumns) {
            // FIXME! overflow, use reallocarray(2) equivalent
            if (win->layout.nColumns == 0) {
                win->layout.nColumns = 1;
                win->layout.columns = (ALFRowOrColumn*)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY | HEAP_GENERATE_EXCEPTIONS, win->layout.nColumns*sizeof(win->layout.columns[0]));
            } else {
                win->layout.nColumns *= 2;
                win->layout.columns = (ALFRowOrColumn*)HeapReAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY | HEAP_GENERATE_EXCEPTIONS, win->layout.columns, win->layout.nColumns*sizeof(win->layout.columns[0]));
            }
        }
        while ((int)c->y >= win->layout.nRows) {
            // FIXME! overflow, use reallocarray(2) equivalent
            if (win->layout.nRows == 0) {
                win->layout.nRows = 1;
                win->layout.rows = (ALFRowOrColumn*)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY | HEAP_GENERATE_EXCEPTIONS, win->layout.nRows*sizeof(win->layout.rows[0]));
            } else {
                win->layout.nRows *= 2;
                win->layout.rows = (ALFRowOrColumn*)HeapReAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY | HEAP_GENERATE_EXCEPTIONS, win->layout.rows, win->layout.nRows*sizeof(win->layout.rows[0]));
            }
        }

        // TODO: ignore spanning cell

        SIZE qs = { ALF_CentipointsToPxPriv(win, c->cptWidth),
                    ALF_CentipointsToPxPriv(win, c->cptHeight) };
        if ((c->flags & ALF_QUERYSIZE) == ALF_QUERYSIZE) {
            SendMessage(c->hwnd, ALF_WM_QUERYSIZE, 0, (LPARAM)&qs);
        }

        qs.cx += ALF_CentipointsToPxPriv(win, c->cptMarginLeft);
        qs.cx += ALF_CentipointsToPxPriv(win, c->cptMarginRight);
        qs.cy += ALF_CentipointsToPxPriv(win, c->cptMarginTop);
        qs.cy += ALF_CentipointsToPxPriv(win, c->cptMarginBottom);

        if (qs.cx > win->layout.columns[c->x].minWidth)
            win->layout.columns[c->x].minWidth = qs.cx;
        if (qs.cy > win->layout.rows[c->y].minWidth)
            win->layout.rows[c->y].minWidth = qs.cy;

        // TODO: expand flag
    }

    // TODO: second pass for spanning cells

    // update min width bookkeeping
    win->layout.totalMinWidth = 0;
    win->layout.occupiedColumnCount = 0;
    for (int i = 0; i < win->layout.nColumns; ++i) {
        if (win->layout.columns[i].minWidth > 0) {
            win->layout.totalMinWidth += win->layout.columns[i].minWidth;
            win->layout.occupiedColumnCount++;
            // TODO: expand flag
        }
    }
    win->layout.totalMinHeight = 0;
    win->layout.occupiedRowCount = 0;
    for (int i = 0; i < win->layout.nRows; ++i) {
        if (win->layout.rows[i].minWidth > 0) {
            win->layout.totalMinHeight += win->layout.rows[i].minWidth;
            win->layout.occupiedRowCount++;
            // TODO: expand flag
        }
    }

    // TODO: split here into allocation function
}

static void
ALF_ApplyLayout(HWND hwnd, ALFWindowPriv *win)
{
    // allocate cell positions
    // distribute free space
    int extraWidth = 0;
    int extraHeight = 0;
    RECT client;
    if (GetClientRect(hwnd, &client)) {
        if (client.right - client.left > win->layout.totalMinWidth)
            extraWidth = client.right - client.left - win->layout.totalMinWidth;
        if (client.bottom - client.top > win->layout.totalMinHeight)
            extraHeight = client.bottom - client.top - win->layout.totalMinHeight;
    }

    int extraWidthPart = 0;
    int extraWidthError = 0;
    if (win->layout.occupiedColumnCount) {
        extraWidthPart = extraWidth / win->layout.occupiedColumnCount;
        extraWidthError = extraWidth - extraWidthPart * win->layout.occupiedColumnCount;
    }

    for (int i = 0; i < win->layout.nColumns; ++i) {
        win->layout.columns[i].allocatedWidth = win->layout.columns[i].minWidth;

        if (win->layout.columns[i].minWidth > 0) {
            win->layout.columns[i].allocatedWidth += extraWidthPart;
            if (extraWidthError) {
                win->layout.columns[i].allocatedWidth++;
                extraWidthError--;
            }
        }

        if (i == 0) {
            win->layout.columns[i].allocatedPosition = 0;
        } else {
            win->layout.columns[i].allocatedPosition =
                win->layout.columns[i-1].allocatedPosition + win->layout.columns[i-1].allocatedWidth;
        }
    }


    int extraHeightPart = 0;
    int extraHeightError = 0;
    if (win->layout.occupiedRowCount) {
        extraHeightPart = extraHeight / win->layout.occupiedRowCount;
        extraHeightError = extraHeight - extraHeightPart * win->layout.occupiedRowCount;
    }

    for (int i = 0; i < win->layout.nRows; ++i) {
        win->layout.rows[i].allocatedWidth = win->layout.rows[i].minWidth;

        if (win->layout.rows[i].minWidth > 0) {
            win->layout.rows[i].allocatedWidth += extraHeightPart;
            if (extraHeightError) {
                win->layout.rows[i].allocatedWidth++;
                extraHeightError--;
            }
        }

        if (i == 0) {
            win->layout.rows[i].allocatedPosition = 0;
        } else {
            win->layout.rows[i].allocatedPosition =
                win->layout.rows[i-1].allocatedPosition + win->layout.rows[i-1].allocatedWidth;
        }
    }

    HDWP hdwp = BeginDeferWindowPos(win->layout.occupiedColumnCount * win->layout.occupiedRowCount);

    ALF_FOR_LIST(ALFWidgetPriv, list, &win->widgets, c) {
        if ((int)c->x >= win->layout.nColumns || (int)c->y >= win->layout.nRows)
            continue;

        int marginleft   = ALF_CentipointsToPxPriv(win, c->cptMarginLeft);
        int marginright  = ALF_CentipointsToPxPriv(win, c->cptMarginRight);
        int margintop    = ALF_CentipointsToPxPriv(win, c->cptMarginTop);
        int marginbottom = ALF_CentipointsToPxPriv(win, c->cptMarginBottom);

        RECT r = { 0,0,0,0 };
        r.left = win->layout.columns[c->x].allocatedPosition + marginleft;
        r.right = r.left + win->layout.columns[c->x].allocatedWidth - marginleft - marginright;
        r.top = win->layout.rows[c->y].allocatedPosition + margintop;
        r.bottom = r.top + win->layout.rows[c->y].allocatedWidth - margintop - marginbottom;

        if (c->flags & ALF_APPLYSIZE) {
            hdwp = (HDWP)SendMessage(c->hwnd, ALF_WM_APPLYSIZE, (WPARAM)hdwp, (LPARAM)&r);
        } else {
            hdwp = DeferWindowPos(hdwp,
                                c->hwnd, 0,
                                r.left, r.top, r.right - r.left, r.bottom - r.top,
                                SWP_NOACTIVATE | SWP_NOZORDER);
        }
    }

    EndDeferWindowPos(hdwp);
}

static void
ALF_InternalAddWidget(HWND hwnd, ALFWindowPriv *priv, ALFWidgetLayoutParams *params)
{
    ALFWidgetPriv *w = (ALFWidgetPriv*)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY|HEAP_GENERATE_EXCEPTIONS, sizeof(ALFWidgetPriv));
    w->hwnd = params->hwnd;
    w->x = params->x;
    w->y = params->y;
    w->cptWidth = params->width;
    w->cptHeight = params->height;
    w->flags = params->flags;
    w->cptMarginTop = params->margins[0];
    w->cptMarginRight = params->margins[1];
    w->cptMarginBottom = params->margins[2];
    w->cptMarginLeft = params->margins[3];

    if (GetParent(w->hwnd) != hwnd)
        SetParent(w->hwnd, hwnd);

    // TODO: QUERYUISTATE on parent, then replicate in child. But wait, XP appears to do this automatically!??

    ALF_ListInsert(priv->widgets.prev, &w->list);
    ALF_UpdateFontForWidget(priv, w);
}

static BOOL
ALF_InternalSetLayoutParams(ALFWindowPriv *priv, HWND widget, const ALFWidgetLayoutParams *params)
{
    ALF_FOR_LIST(ALFWidgetPriv, list, &priv->widgets, w) {
        if (w->hwnd == widget) {
            w->hwnd = params->hwnd;
            w->x = params->x;
            w->y = params->y;
            w->cptWidth = params->width;
            w->cptHeight = params->height;
            w->flags = params->flags;
            w->cptMarginTop = params->margins[0];
            w->cptMarginRight = params->margins[1];
            w->cptMarginBottom = params->margins[2];
            w->cptMarginLeft = params->margins[3];

            return TRUE;
        }
    }

    return FALSE;
}

static BOOL
ALF_InternalGetLayoutParams(ALFWindowPriv *priv, HWND widget, ALFWidgetLayoutParams *params)
{
    ALF_FOR_LIST(ALFWidgetPriv, list, &priv->widgets, w) {
        if (w->hwnd == widget) {
            params->hwnd = w->hwnd;
            params->x = w->x;
            params->y = w->y;
            params->width = w->cptWidth;
            params->height = w->cptHeight;
            params->flags = w->flags;
            params->margins[0] = w->cptMarginTop;
            params->margins[1] = w->cptMarginRight;
            params->margins[2] = w->cptMarginBottom;
            params->margins[3] = w->cptMarginLeft;

            return TRUE;
        }
    }

    return FALSE;
}

static HWND
ALF_InternalGetWidgetAtPos(ALFWindowPriv *priv, UINT x, UINT y)
{
    ALF_FOR_LIST(ALFWidgetPriv, list, &priv->widgets, w) {
        if (w->x == x && w->y == y) {
            return w->hwnd;
        }
    }

    return NULL;
}

static void
ALF_ApplyFocus(HWND hwnd, ALFWindowPriv *priv, BOOL restoringFocus)
{
    if (priv->hwndFocus) {
        if (!restoringFocus && SendMessage(priv->hwndFocus, WM_GETDLGCODE, 0, 0) & DLGC_HASSETSEL)
            SendMessage(priv->hwndFocus, EM_SETSEL, 0, -1);

        if (GetForegroundWindow() == hwnd)
            SetFocus(priv->hwndFocus);
    } else {
        priv->hwndFocus = GetNextDlgTabItem(hwnd, NULL, FALSE);
        if (priv->hwndFocus)
            ALF_ApplyFocus(hwnd, priv, FALSE);
    }
}

LRESULT
ALF_DefWindowProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
    ALFWindowPriv *priv = (ALFWindowPriv*)GetWindowLongPtr(hwnd, 0);

    if (msg == ALF_WM_QUERYSIZE) {
        ALF_CalculateSizes(priv);
        SIZE *ps = (SIZE*)lparam;
        ps->cx = priv->layout.totalMinWidth;
        ps->cy = priv->layout.totalMinHeight;
        return 0;
    }

    if (msg == ALF_WM_APPLYLAYOUT) {
        ALF_ApplyLayout(hwnd, priv);
        return 0;
    }

    if (msg == ALF_WM_GETMODALRESULT) {
        return (LRESULT)priv->modalResult;
    }
    if (msg == ALF_WM_SETMODALRESULT) {
        priv->modalResult = (int)wparam;
        return 0;
    }

    if (msg == ALF_WM_CENTIPOINTTOPX) {
        return (LRESULT)ALF_CentipointsToPxPriv(priv, (int)wparam);
    }

    if (msg == ALF_WM_ADDWIDGET) {
        ALF_InternalAddWidget(hwnd, priv, (ALFWidgetLayoutParams *)lparam);
        return 0;
    }

    if (msg == ALF_WM_GETLAYOUTPARAMS) {
        return (LRESULT)ALF_InternalGetLayoutParams(priv, (HWND)wparam, (ALFWidgetLayoutParams *)lparam);
    }

    if (msg == ALF_WM_SETLAYOUTPARAMS) {
        return (LRESULT)ALF_InternalSetLayoutParams(priv, (HWND)wparam, (const ALFWidgetLayoutParams *)lparam);
    }

    if (msg == ALF_WM_GETWIDGETATPOS) {
        return (LRESULT)ALF_InternalGetWidgetAtPos(priv, ((UINT*)lparam)[0], ((UINT*)lparam)[1]);
    }

    if (msg == ALF_WM_SETFOCUS) {
        priv->hwndFocus = (HWND)lparam;
        ALF_ApplyFocus(hwnd, priv, FALSE);
        return 0;
    }

    if (msg == ALF_WM_GETAPPLICATION) {
        return (LRESULT)priv->app;
    }

    if (msg == ALF_WM_UPDATEFONTS) {
        ALF_UpdateFontsPriv(hwnd, priv);
        return 0;
    }

    if (msg == WM_COMMAND) {
        HWND source = (HWND)lparam;
        WORD code   = HIWORD(wparam);
        WORD id     = LOWORD(wparam);
        LRESULT ret = 0;
        if (source != 0)
            ret = SendMessage(source, 0x2000 + WM_COMMAND, wparam, lparam);

        if (ret == 0 && priv->vtbl->command)
            ret = priv->vtbl->command(priv->closure, hwnd, code, id, source);

        return ret;
    }

    if (msg == WM_NOTIFY) {
        NMHDR *nmhdr = (NMHDR *)lparam;
        LRESULT ret = 0;

        if (nmhdr->hwndFrom)
            ret = SendMessage(nmhdr->hwndFrom, 0x2000 + WM_NOTIFY, wparam, lparam);

        if (ret == 0 && priv->vtbl->notify)
            ret = priv->vtbl->notify(priv->closure, hwnd, wparam, nmhdr);

        return ret;
    }

    if (msg == WM_ACTIVATE) {
        if (!HIWORD(wparam)) { // if !minimized
            if (LOWORD(wparam)) {
                ALF_ApplyFocus(hwnd, priv, TRUE);
            } else {
                priv->hwndFocus = GetFocus();
            }
        }
        return 0;
    }

    if (msg == WM_SIZE) {
        ALF_ApplyLayout(hwnd, priv);
        return 0;
    }

    if (msg == WM_GETMINMAXINFO) {
        RECT tmp;
        ZeroMemory(&tmp, sizeof(tmp));
        tmp.right = priv->layout.totalMinWidth;
        tmp.bottom = priv->layout.totalMinHeight;

        if (priv->app->compatFn->AdjustWindowRectExForDpi(
                               &tmp,
                               GetWindowLong(hwnd, GWL_STYLE),
                               GetMenu(hwnd) != NULL,
                               GetWindowLong(hwnd, GWL_EXSTYLE),
                               priv->fonts.dpi)) {
            MINMAXINFO *i = (MINMAXINFO *)lparam;
            i->ptMinTrackSize.x = tmp.right - tmp.left;
            i->ptMinTrackSize.y = tmp.bottom - tmp.top;
            return 0;
        }
    }

    if (msg == WM_CREATE) {
        if (priv->vtbl->create) {
            priv->vtbl->create(priv->closure, hwnd);
        }
        BOOL alwaysUnderline = FALSE;
        SystemParametersInfo(SPI_GETKEYBOARDCUES, 0, &alwaysUnderline, 0);
        if (!alwaysUnderline) {
            SendMessage(hwnd, WM_UPDATEUISTATE, MAKEWPARAM(UIS_INITIALIZE, 0), 0);
        }
        ALF_UpdateFontsPriv(hwnd, priv);
        ALF_CalculateSizes(priv);
        ALF_ApplyLayout(hwnd, priv);
    }

    if (msg == WM_DESTROY && priv->vtbl->destroy) {
        priv->vtbl->destroy(priv->closure, hwnd);
    }

    if (msg == WM_CLOSE) {
        if (!priv->vtbl->close || !priv->vtbl->close(priv->closure, hwnd)) {
            priv->modalResult = 2;
            ShowWindow(hwnd, FALSE);
        }
        return TRUE;
    }

    if (msg == WM_NCDESTROY) {
        SetWindowLongPtr(hwnd, 0, 0);
        ALF_DestroyWindowPriv(priv);
    }

    if (msg == WM_DPICHANGED) {
        ALF_UpdateFontsPriv(hwnd, priv);
        ALF_CalculateSizes(priv);
        RECT *r = (RECT*)lparam;
        SetWindowPos(hwnd, NULL, r->left, r->top, r->right-r->left, r->bottom-r->top, SWP_NOACTIVATE|SWP_NOZORDER);
    }

    if (msg == WM_THEMECHANGED || msg == WM_SETTINGCHANGE) {
        ALF_UpdateFontsPriv(hwnd, priv);
        ALF_CalculateSizes(priv);
        ALF_ApplyLayout(hwnd, priv);
    }

    if (msg == DM_GETDEFID) {
        if (priv->defid == (WORD)-1) {
            return 0;
        } else {
            return MAKELONG(priv->defid, DC_HASDEFID);
        }
    }
    if (msg == DM_SETDEFID) {
        if (priv->defid != (WORD)-1) {
            HWND hwndOld = ALF_WidgetHwndById(hwnd, priv->defid);
            if (hwndOld && SendMessage(hwndOld, WM_GETDLGCODE, 0, 0) & DLGC_DEFPUSHBUTTON) {
                SendMessage(hwndOld, BM_SETSTYLE, BS_PUSHBUTTON, TRUE);
            }
        }

        priv->defid = (WORD)wparam;
        HWND hwndNew = ALF_WidgetHwndById(hwnd, priv->defid);
        if (hwndNew && SendMessage(hwndNew, WM_GETDLGCODE, 0, 0) & DLGC_UNDEFPUSHBUTTON) {
            SendMessage(hwndNew, BM_SETSTYLE, BS_DEFPUSHBUTTON, TRUE);
        }
        return TRUE;
    }

    return DefWindowProc(hwnd, msg, wparam, lparam);
}

void
ALF_AddWidget(HWND win, UINT x, UINT y, HWND widget, UINT minWidth, UINT minHeight, DWORD flags)
{
    ALFWidgetLayoutParams params;
    ZeroMemory(&params, sizeof(params));
    params.hwnd = widget;
    params.x = x;
    params.y = y;
    params.width = minWidth;
    params.height = minHeight;
    params.flags = flags;
    ALF_AddWidgetEx(win, &params);
}

void ALF_AddWidgetEx(HWND win, const ALFWidgetLayoutParams* params)
{
    SendMessage(win, ALF_WM_ADDWIDGET, 0, (LPARAM)params);
}

static LRESULT CALLBACK
ALF_WindowProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
    if (msg == WM_NCCREATE) {
        CREATESTRUCT *cs = (CREATESTRUCT*)(void*)lparam;
        if (cs->lpCreateParams) {
            ALFWindowPriv *priv = (ALFWindowPriv*)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY|HEAP_GENERATE_EXCEPTIONS, sizeof(ALFWindowPriv));
            SetWindowLongPtr(hwnd, 0, (LONG_PTR)priv);
            ALF_InitializeWindowPriv(hwnd, priv, *((void**)cs->lpCreateParams));
        }
    }

    ALFWindowPriv *priv = (ALFWindowPriv*)(void*)GetWindowLongPtr(hwnd, 0);
    if (priv != NULL) {
        if (priv->vtbl->message) {
            return priv->vtbl->message(priv->closure, hwnd, msg, wparam, lparam);
        } else {
            return ALF_DefWindowProc(hwnd, msg, wparam, lparam);
        }
    } else {
        return DefWindowProc(hwnd, msg, wparam, lparam);
    }
}

ALFAPP
ALF_CreateApplication(HINSTANCE hInstance)
{
    ALFAPP app = (ALFAPP)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY|HEAP_GENERATE_EXCEPTIONS, sizeof(struct ALFAppPriv));
    app->hInstance = hInstance;

    InitCommonControls();

    app->compatFn = ALF_CreateCompatFuncTable();
    ALF_RegisterComboClass(app);

    return app;
}

void
ALF_TeardownApplication(ALFAPP app)
{
    UnregisterClass(app->comboClass, app->hInstance);
    HeapFree(GetProcessHeap(), 0, app->compatFn);
    HeapFree(GetProcessHeap(), 0, app);
}

static void
ALF_IntToHex(TCHAR *buf, unsigned long num, int chars)
{
    char letters[] = { '0', '1', '2', '3', '4', '5', '6', '7',
                       '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
    for (int i = 0; i < chars; ++i) {
        buf[chars-i-1] = letters[(num >> (i*4)) & 0xf];
    }
}

static void
ALF_UuidToString(const GUID *guid, TCHAR *buf)
{
    ALF_IntToHex(buf, guid->Data1, 8);
    buf[8] = '-';
    ALF_IntToHex(buf + 9, guid->Data2, 4);
    buf[13] = '-';
    ALF_IntToHex(buf + 14, guid->Data3, 4);
    buf[18] = '-';
    for (int i = 0; i < 8; ++i) {
        ALF_IntToHex(buf + 19 + 2*i, guid->Data4[i], 2);
    }
    buf[35] = 0;
}

void
ALF_BuildRandomClassName(ALFAPP app, const TCHAR* prefix, TCHAR* buf)
{
    UUID uuid;
    app->compatFn->UuidCreate(&uuid);

    lstrcpy(buf, prefix);
    ALF_UuidToString(&uuid, &buf[lstrlen(buf)]);
}

LPTSTR
ALF_RegisterWindowClass(ALFAPP app, const ALFWindowClassParams *params)
{
    WNDCLASS cls;
    ZeroMemory(&cls, sizeof(cls));

    const TCHAR *classNamePtr = params->className;
    TCHAR  classNameBuf[256];
    if (!classNamePtr) {
        ZeroMemory(classNameBuf, sizeof(classNameBuf));
        classNamePtr = classNameBuf;

        ALF_BuildRandomClassName(app, TEXT("ALFWindow."), classNameBuf);
    }

    cls.style = params->classStyle;
    cls.hInstance = app->hInstance;
    cls.hCursor = LoadCursor(NULL, (LPTSTR)IDC_ARROW);
    if (LOBYTE(LOWORD(GetVersion())) >= 4) {
        cls.hbrBackground = (HBRUSH)(COLOR_BTNFACE+1);
    } else {
        // NT 3.x has white dialog backgrounds
        cls.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    }
    cls.lpszClassName = classNamePtr;
    cls.cbWndExtra = sizeof(void*);
    cls.cbClsExtra = sizeof(void*)*2;
    cls.lpfnWndProc = DefWindowProc;

    ATOM classatom = RegisterClass(&cls);
    if (!classatom)
        return NULL;

    ALFWindowVTable *pvtbl = (ALFWindowVTable*)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY|HEAP_GENERATE_EXCEPTIONS, sizeof(ALFWindowVTable));
    *pvtbl = params->vtbl;

    // XXX: This could have been a HWND_MESSAGE window, but Win95 doesn't support these
    HWND tmp = CreateWindowEx(0, MAKEINTATOM(classatom), TEXT("dummy"), 0, 0, 0, 0, 0, NULL, 0, app->hInstance, 0);
    SetClassLongPtr(tmp, 0, (LONG_PTR)pvtbl);
    SetClassLongPtr(tmp, sizeof(void*), (LONG_PTR)app);
    SetClassLongPtr(tmp, GCLP_WNDPROC, (LONG_PTR)ALF_WindowProc);
    DestroyWindow(tmp);

    return MAKEINTATOM(classatom);
}

void
ALF_UnregisterWindowClass(ALFAPP app, LPCTSTR className)
{
    HWND tmp = CreateWindowEx(0, className, TEXT("dummy"), 0, 0, 0, 0, 0, NULL, 0, app->hInstance, 0);
    ALFWindowVTable *pvtbl = (ALFWindowVTable*)GetClassLongPtr(tmp, 0);
    DestroyWindow(tmp);

    HeapFree(GetProcessHeap(), 0, pvtbl);

    UnregisterClass(className, app->hInstance);
}

HWND ALF_InstantiateWindow(ALFAPP app, LPCTSTR className, HWND hwndParent, void *closure)
{
    return CreateWindowEx(0,
                          className,
                          TEXT("Window"),
                          WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          300, 100, //FIXME
                          hwndParent,
                          NULL,
                          app->hInstance,
                          &closure);
}

void
ALF_DestroyWindow(HWND win)
{
    DestroyWindow(win);
}

ALFAPP
ALF_ApplicationFromWindow(HWND hwnd)
{
    return (ALFAPP)SendMessage(hwnd, ALF_WM_GETAPPLICATION, 0, 0);
}

int
ALF_ShowModal(HWND win)
{
    MSG msg;

    ALF_SetModalResult(win, 0);

    // TODO: disable parent window
    ShowWindow(win, SW_SHOW);

    while (GetMessage(&msg, NULL, 0, 0) > 0) {
        // TODO: call application message hooks
        // TODO: call preprocess message hook

        if (!IsDialogMessage(win, &msg)) {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }

        int mr = ALF_GetModalResult(win);
        if (mr)
            return mr;
    }

    return 0;
}


void
ALF_SetModalResult(HWND win, int result)
{
    SendMessage(win, ALF_WM_SETMODALRESULT, (WPARAM)result, 0);
}

int
ALF_GetModalResult(HWND win)
{
    return (int)SendMessage(win, ALF_WM_GETMODALRESULT, 0, 0);
}

int
ALF_CentipointsToPixels(HWND win, int cptValue)
{
    return (int)SendMessage(win, ALF_WM_CENTIPOINTTOPX, (WPARAM)cptValue, 0);
}

void
ALF_ResizeWindow(HWND win, int cptWidth, int cptHeight)
{
    int pxwidth = ALF_CentipointsToPixels(win, cptWidth);
    int pxheight = ALF_CentipointsToPixels(win, cptHeight);

    ALF_ResizeWindowPx(win, pxwidth, pxheight);
}

void
ALF_ResizeWindowPx(HWND win, int pxwidth, int pxheight)
{
    MINMAXINFO tmp = {
        { 0, 0 },
        { pxwidth, pxheight },
        { 0, 0 },
        { pxwidth, pxheight },
        { pxwidth, pxheight }
    };
    SendMessage(win, WM_GETMINMAXINFO, 0, (LPARAM)&tmp);

    if (tmp.ptMinTrackSize.x > pxwidth)
        pxwidth = tmp.ptMinTrackSize.x;
    if (tmp.ptMinTrackSize.y > pxheight)
        pxheight = tmp.ptMinTrackSize.y;

    SetWindowPos(win, NULL, 0, 0, pxwidth, pxheight, SWP_NOACTIVATE|SWP_NOMOVE|SWP_NOZORDER);
}

struct ALF_WidgetHwndById_Closure {
    HWND result;
    WORD needle;
};

static BOOL CALLBACK
ALF_WidgetHwndById_EnumChildProc(HWND hwnd, LPARAM lParam)
{
    struct ALF_WidgetHwndById_Closure *closure = (struct ALF_WidgetHwndById_Closure*)lParam;
    if ((WORD)GetWindowLongPtr(hwnd, GWLP_ID) == closure->needle) {
        closure->result = hwnd;
        return FALSE;
    }
    return TRUE;
}

HWND
ALF_WidgetHwndById(HWND win, WORD id)
{
    struct ALF_WidgetHwndById_Closure closure = { 0, id };
    EnumChildWindows(win, ALF_WidgetHwndById_EnumChildProc, (LPARAM)&closure);
    return closure.result;
}

void
ALF_SetText(HWND hwnd, const TCHAR *text)
{
    SendMessage(hwnd, WM_SETTEXT, 0, (LPARAM)text);
}

void
ALF_SetWidgetText(HWND parent, WORD id, const TCHAR *text)
{
    HWND h = ALF_WidgetHwndById(parent, id);
    if (h)
        ALF_SetText(h, text);
}

TCHAR * // free with HeapFree
ALF_Text(HWND hwnd)
{
    int len = (int)SendMessage(hwnd, WM_GETTEXTLENGTH, 0, 0);
    if (len > 0) {
        TCHAR *buf = (TCHAR*)HeapAlloc(GetProcessHeap(), HEAP_GENERATE_EXCEPTIONS|HEAP_ZERO_MEMORY, (len + 1)*sizeof(TCHAR));
        if (SendMessage(hwnd, WM_GETTEXT, 0, (LPARAM)buf)) {
            return buf;
        } else {
            HeapFree(GetProcessHeap(), 0, buf);
        }
    }

    return NULL;
}

TCHAR * // free with HeapFree
ALF_WidgetText(HWND parent, WORD id)
{
    HWND h = ALF_WidgetHwndById(parent, id);
    if (h)
        return ALF_Text(h);

    return NULL;
}

DWORD
ALF_WidgetLayoutFlags(HWND parent, HWND widget)
{
    ALFWidgetLayoutParams p;
    if (SendMessage(parent, ALF_WM_GETLAYOUTPARAMS, (WPARAM)widget, (LPARAM)&p)) {
        return p.flags;
    } else {
        return 0;
    }
}

BOOL
ALF_SetWidgetLayoutFlags(HWND parent, HWND widget, DWORD flags)
{
    ALFWidgetLayoutParams p;
    if (SendMessage(parent, ALF_WM_GETLAYOUTPARAMS, (WPARAM)widget, (LPARAM)&p)) {
        p.flags = flags;
        return SendMessage(parent, ALF_WM_SETLAYOUTPARAMS, (WPARAM)widget, (LPARAM)&p);
    }

    return FALSE;
}

BOOL
ALF_WidgetLayoutPosition(HWND parent, HWND widget, UINT *pX, UINT *pY)
{
    ALFWidgetLayoutParams p;
    if (SendMessage(parent, ALF_WM_GETLAYOUTPARAMS, (WPARAM)widget, (LPARAM)&p)) {
        *pX = p.x;
        *pY = p.y;
        return TRUE;
    } else {
        return FALSE;
    }
}

BOOL
ALF_SetWidgetLayoutPosition(HWND parent, HWND widget, UINT x, UINT y)
{
    ALFWidgetLayoutParams p;
    if (SendMessage(parent, ALF_WM_GETLAYOUTPARAMS, (WPARAM)widget, (LPARAM)&p)) {
        p.x = x;
        p.y = y;
        return SendMessage(parent, ALF_WM_SETLAYOUTPARAMS, (WPARAM)widget, (LPARAM)&p);
    }

    return FALSE;
}

BOOL
ALF_WidgetLayoutSize(HWND parent, HWND widget, UINT *pCptWidth, UINT *pCptHeight)
{
    ALFWidgetLayoutParams p;
    if (SendMessage(parent, ALF_WM_GETLAYOUTPARAMS, (WPARAM)widget, (LPARAM)&p)) {
        *pCptWidth  = p.width;
        *pCptHeight = p.height;
        return TRUE;
    } else {
        return FALSE;
    }
}

BOOL
ALF_SetWidgetLayoutSize(HWND parent, HWND widget, UINT cptWidth, UINT cptHeight)
{
    ALFWidgetLayoutParams p;
    if (SendMessage(parent, ALF_WM_GETLAYOUTPARAMS, (WPARAM)widget, (LPARAM)&p)) {
        p.width  = cptWidth;
        p.height = cptHeight;
        return SendMessage(parent, ALF_WM_SETLAYOUTPARAMS, (WPARAM)widget, (LPARAM)&p);
    }

    return FALSE;
}

HWND
ALF_WidgetAtLayoutPosition(HWND parent, UINT x, UINT y)
{
    UINT xy[2] = { x, y };

    return (HWND)SendMessage(parent, ALF_WM_GETWIDGETATPOS, 0, (LPARAM)&xy);
}