Over-enthusiastic assertion introduced in the printing revamp was

[sgt/puzzles] / windows.c

/*
 * windows.c: Windows front end for my puzzle collection.
 */

#include <windows.h>
#include <commctrl.h>

#include <stdio.h>
#include <assert.h>
#include <ctype.h>
#include <stdarg.h>
#include <stdlib.h>
#include <limits.h>
#include <time.h>

#include "puzzles.h"

#define IDM_NEW       0x0010
#define IDM_RESTART   0x0020
#define IDM_UNDO      0x0030
#define IDM_REDO      0x0040
#define IDM_COPY      0x0050
#define IDM_SOLVE     0x0060
#define IDM_QUIT      0x0070
#define IDM_CONFIG    0x0080
#define IDM_DESC      0x0090
#define IDM_SEED      0x00A0
#define IDM_HELPC     0x00B0
#define IDM_GAMEHELP  0x00C0
#define IDM_ABOUT     0x00D0
#define IDM_SAVE      0x00E0
#define IDM_LOAD      0x00F0
#define IDM_PRINT     0x0100
#define IDM_PRESETS   0x0110

#define HELP_FILE_NAME  "puzzles.hlp"
#define HELP_CNT_NAME   "puzzles.cnt"

#ifdef DEBUGGING
static FILE *debug_fp = NULL;
static HANDLE debug_hdl = INVALID_HANDLE_VALUE;
static int debug_got_console = 0;

void dputs(char *buf)
{
    DWORD dw;

    if (!debug_got_console) {
        if (AllocConsole()) {
            debug_got_console = 1;
            debug_hdl = GetStdHandle(STD_OUTPUT_HANDLE);
        }
    }
    if (!debug_fp) {
        debug_fp = fopen("debug.log", "w");
    }

    if (debug_hdl != INVALID_HANDLE_VALUE) {
        WriteFile(debug_hdl, buf, strlen(buf), &dw, NULL);
    }
    fputs(buf, debug_fp);
    fflush(debug_fp);
}

void debug_printf(char *fmt, ...)
{
    char buf[4096];
    va_list ap;

    va_start(ap, fmt);
    vsprintf(buf, fmt, ap);
    dputs(buf);
    va_end(ap);
}
#endif

struct font {
    HFONT font;
    int type;
    int size;
};

struct cfg_aux {
    int ctlid;
};

struct blitter {
    HBITMAP bitmap;
    frontend *fe;
    int x, y, w, h;
};

enum { CFG_PRINT = CFG_FRONTEND_SPECIFIC };

struct frontend {
    midend *me;
    HWND hwnd, statusbar, cfgbox;
    HINSTANCE inst;
    HBITMAP bitmap, prevbm;
    HDC hdc;
    COLORREF *colours;
    HBRUSH *brushes;
    HPEN *pens;
    HRGN clip;
    UINT timer;
    DWORD timer_last_tickcount;
    int npresets;
    game_params **presets;
    struct font *fonts;
    int nfonts, fontsize;
    config_item *cfg;
    struct cfg_aux *cfgaux;
    int cfg_which, dlg_done;
    HFONT cfgfont;
    HBRUSH oldbr;
    HPEN oldpen;
    char *help_path;
    int help_has_contents;
    char *laststatus;
    enum { DRAWING, PRINTING, NOTHING } drawstatus;
    DOCINFO di;
    int printcount, printw, printh, printsolns, printcurr, printcolour;
    float printscale;
    int printoffsetx, printoffsety;
    float printpixelscale;
    int fontstart;
    int linewidth;
    drawing *dr;
};

void fatal(char *fmt, ...)
{
    char buf[2048];
    va_list ap;

    va_start(ap, fmt);
    vsprintf(buf, fmt, ap);
    va_end(ap);

    MessageBox(NULL, buf, "Fatal error", MB_ICONEXCLAMATION | MB_OK);

    exit(1);
}

char *geterrstr(void)
{
    LPVOID lpMsgBuf;
    DWORD dw = GetLastError();
    char *ret;

    FormatMessage(
        FORMAT_MESSAGE_ALLOCATE_BUFFER | 
        FORMAT_MESSAGE_FROM_SYSTEM,
        NULL,
        dw,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
        (LPTSTR) &lpMsgBuf,
        0, NULL );

    ret = dupstr(lpMsgBuf);

    LocalFree(lpMsgBuf);

    return ret;
}

void get_random_seed(void **randseed, int *randseedsize)
{
    time_t *tp = snew(time_t);
    time(tp);
    *randseed = (void *)tp;
    *randseedsize = sizeof(time_t);
}

static void win_status_bar(void *handle, char *text)
{
    frontend *fe = (frontend *)handle;
    char *rewritten;

    rewritten = midend_rewrite_statusbar(fe->me, text);
    if (!fe->laststatus || strcmp(rewritten, fe->laststatus)) {
        SetWindowText(fe->statusbar, rewritten);
        sfree(fe->laststatus);
        fe->laststatus = rewritten;
    } else {
        sfree(rewritten);
    }
}

static blitter *win_blitter_new(void *handle, int w, int h)
{
    blitter *bl = snew(blitter);

    memset(bl, 0, sizeof(blitter));
    bl->w = w;
    bl->h = h;
    bl->bitmap = 0;

    return bl;
}

static void win_blitter_free(void *handle, blitter *bl)
{
    if (bl->bitmap) DeleteObject(bl->bitmap);
    sfree(bl);
}

static void blitter_mkbitmap(frontend *fe, blitter *bl)
{
    HDC hdc = GetDC(fe->hwnd);
    bl->bitmap = CreateCompatibleBitmap(hdc, bl->w, bl->h);
    ReleaseDC(fe->hwnd, hdc);
}

/* BitBlt(dstDC, dstX, dstY, dstW, dstH, srcDC, srcX, srcY, dType) */

static void win_blitter_save(void *handle, blitter *bl, int x, int y)
{
    frontend *fe = (frontend *)handle;
    HDC hdc_win, hdc_blit;
    HBITMAP prev_blit;

    assert(fe->drawstatus == DRAWING);

    if (!bl->bitmap) blitter_mkbitmap(fe, bl);

    bl->x = x; bl->y = y;

    hdc_win = GetDC(fe->hwnd);
    hdc_blit = CreateCompatibleDC(hdc_win);
    if (!hdc_blit) fatal("hdc_blit failed: 0x%x", GetLastError());

    prev_blit = SelectObject(hdc_blit, bl->bitmap);
    if (prev_blit == NULL || prev_blit == HGDI_ERROR)
        fatal("SelectObject for hdc_main failed: 0x%x", GetLastError());

    if (!BitBlt(hdc_blit, 0, 0, bl->w, bl->h,
                fe->hdc, x, y, SRCCOPY))
        fatal("BitBlt failed: 0x%x", GetLastError());

    SelectObject(hdc_blit, prev_blit);
    DeleteDC(hdc_blit);
    ReleaseDC(fe->hwnd, hdc_win);
}

static void win_blitter_load(void *handle, blitter *bl, int x, int y)
{
    frontend *fe = (frontend *)handle;
    HDC hdc_win, hdc_blit;
    HBITMAP prev_blit;

    assert(fe->drawstatus == DRAWING);

    assert(bl->bitmap); /* we should always have saved before loading */

    if (x == BLITTER_FROMSAVED) x = bl->x;
    if (y == BLITTER_FROMSAVED) y = bl->y;

    hdc_win = GetDC(fe->hwnd);
    hdc_blit = CreateCompatibleDC(hdc_win);

    prev_blit = SelectObject(hdc_blit, bl->bitmap);

    BitBlt(fe->hdc, x, y, bl->w, bl->h,
           hdc_blit, 0, 0, SRCCOPY);

    SelectObject(hdc_blit, prev_blit);
    DeleteDC(hdc_blit);
    ReleaseDC(fe->hwnd, hdc_win);
}

void frontend_default_colour(frontend *fe, float *output)
{
    DWORD c = GetSysColor(COLOR_MENU); /* ick */

    output[0] = (float)(GetRValue(c) / 255.0);
    output[1] = (float)(GetGValue(c) / 255.0);
    output[2] = (float)(GetBValue(c) / 255.0);
}

static POINT win_transform_point(frontend *fe, int x, int y)
{
    POINT ret;

    assert(fe->drawstatus != NOTHING);

    if (fe->drawstatus == PRINTING) {
        ret.x = (int)(fe->printoffsetx + fe->printpixelscale * x);
        ret.y = (int)(fe->printoffsety + fe->printpixelscale * y);
    } else {
        ret.x = x;
        ret.y = y;
    }

    return ret;
}

static void win_text_colour(frontend *fe, int colour)
{
    assert(fe->drawstatus != NOTHING);

    if (fe->drawstatus == PRINTING) {
        int hatch;
        float r, g, b;
        print_get_colour(fe->dr, colour, &hatch, &r, &g, &b);
        if (fe->printcolour)
            SetTextColor(fe->hdc, RGB(r * 255, g * 255, b * 255));
        else
            SetTextColor(fe->hdc,
                         hatch == HATCH_CLEAR ? RGB(255,255,255) : RGB(0,0,0));
    } else {
        SetTextColor(fe->hdc, fe->colours[colour]);
    }
}

static void win_set_brush(frontend *fe, int colour)
{
    HBRUSH br;
    assert(fe->drawstatus != NOTHING);

    if (fe->drawstatus == PRINTING) {
        int hatch;
        float r, g, b;
        print_get_colour(fe->dr, colour, &hatch, &r, &g, &b);

        if (fe->printcolour)
            br = CreateSolidBrush(RGB(r * 255, g * 255, b * 255));
        else if (hatch == HATCH_SOLID)
            br = CreateSolidBrush(RGB(0,0,0));
        else if (hatch == HATCH_CLEAR)
            br = CreateSolidBrush(RGB(255,255,255));
        else
            br = CreateHatchBrush(hatch == HATCH_BACKSLASH ? HS_FDIAGONAL :
                                  hatch == HATCH_SLASH ? HS_BDIAGONAL :
                                  hatch == HATCH_HORIZ ? HS_HORIZONTAL :
                                  hatch == HATCH_VERT ? HS_VERTICAL :
                                  hatch == HATCH_PLUS ? HS_CROSS :
                                  /* hatch == HATCH_X ? */ HS_DIAGCROSS,
                                  RGB(0,0,0));
    } else {
        br = fe->brushes[colour];
    }
    fe->oldbr = SelectObject(fe->hdc, br);
}

static void win_reset_brush(frontend *fe)
{
    HBRUSH br;

    assert(fe->drawstatus != NOTHING);

    br = SelectObject(fe->hdc, fe->oldbr);
    if (fe->drawstatus == PRINTING)
        DeleteObject(br);
}

static void win_set_pen(frontend *fe, int colour, int thin)
{
    HPEN pen;
    assert(fe->drawstatus != NOTHING);

    if (fe->drawstatus == PRINTING) {
        int hatch;
        float r, g, b;
        int width = thin ? 0 : fe->linewidth;

        print_get_colour(fe->dr, colour, &hatch, &r, &g, &b);
        if (fe->printcolour)
            pen = CreatePen(PS_SOLID, width,
                            RGB(r * 255, g * 255, b * 255));
        else if (hatch == HATCH_SOLID)
            pen = CreatePen(PS_SOLID, width, RGB(0, 0, 0));
        else if (hatch == HATCH_CLEAR)
            pen = CreatePen(PS_SOLID, width, RGB(255,255,255));
        else {
            assert(!"This shouldn't happen");
            pen = CreatePen(PS_SOLID, 1, RGB(0, 0, 0));
        }
    } else {
        pen = fe->pens[colour];
    }
    fe->oldpen = SelectObject(fe->hdc, pen);
}

static void win_reset_pen(frontend *fe)
{
    HPEN pen;

    assert(fe->drawstatus != NOTHING);

    pen = SelectObject(fe->hdc, fe->oldpen);
    if (fe->drawstatus == PRINTING)
        DeleteObject(pen);
}

static void win_clip(void *handle, int x, int y, int w, int h)
{
    frontend *fe = (frontend *)handle;
    POINT p, q;

    if (fe->drawstatus == NOTHING)
        return;

    p = win_transform_point(fe, x, y);
    q = win_transform_point(fe, x+w, y+h);
    IntersectClipRect(fe->hdc, p.x, p.y, q.x, q.y);
}

static void win_unclip(void *handle)
{
    frontend *fe = (frontend *)handle;

    if (fe->drawstatus == NOTHING)
        return;

    SelectClipRgn(fe->hdc, NULL);
}

static void win_draw_text(void *handle, int x, int y, int fonttype,
                          int fontsize, int align, int colour, char *text)
{
    frontend *fe = (frontend *)handle;
    POINT xy;
    int i;

    if (fe->drawstatus == NOTHING)
        return;

    if (fe->drawstatus == PRINTING)
        fontsize = (int)(fontsize * fe->printpixelscale);

    xy = win_transform_point(fe, x, y);

    /*
     * Find or create the font.
     */
    for (i = fe->fontstart; i < fe->nfonts; i++)
        if (fe->fonts[i].type == fonttype && fe->fonts[i].size == fontsize)
            break;

    if (i == fe->nfonts) {
        if (fe->fontsize <= fe->nfonts) {
            fe->fontsize = fe->nfonts + 10;
            fe->fonts = sresize(fe->fonts, fe->fontsize, struct font);
        }

        fe->nfonts++;

        fe->fonts[i].type = fonttype;
        fe->fonts[i].size = fontsize;

        fe->fonts[i].font = CreateFont(-fontsize, 0, 0, 0,
                                       fe->drawstatus == PRINTING ? 0 : FW_BOLD,
                                       FALSE, FALSE, FALSE, DEFAULT_CHARSET,
                                       OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
                                       DEFAULT_QUALITY,
                                       (fonttype == FONT_FIXED ?
                                        FIXED_PITCH | FF_DONTCARE :
                                        VARIABLE_PITCH | FF_SWISS),
                                       NULL);
    }

    /*
     * Position and draw the text.
     */
    {
        HFONT oldfont;
        TEXTMETRIC tm;
        SIZE size;

        oldfont = SelectObject(fe->hdc, fe->fonts[i].font);
        if (GetTextMetrics(fe->hdc, &tm)) {
            if (align & ALIGN_VCENTRE)
                xy.y -= (tm.tmAscent+tm.tmDescent)/2;
            else
                xy.y -= tm.tmAscent;
        }
        if (GetTextExtentPoint32(fe->hdc, text, strlen(text), &size)) {
            if (align & ALIGN_HCENTRE)
                xy.x -= size.cx / 2;
            else if (align & ALIGN_HRIGHT)
                xy.x -= size.cx;
        }
        SetBkMode(fe->hdc, TRANSPARENT);
        win_text_colour(fe, colour);
        TextOut(fe->hdc, xy.x, xy.y, text, strlen(text));
        SelectObject(fe->hdc, oldfont);
    }
}

static void win_draw_rect(void *handle, int x, int y, int w, int h, int colour)
{
    frontend *fe = (frontend *)handle;
    POINT p, q;

    if (fe->drawstatus == NOTHING)
        return;

    if (fe->drawstatus == DRAWING && w == 1 && h == 1) {
        /*
         * Rectangle() appears to get uppity if asked to draw a 1x1
         * rectangle, presumably on the grounds that that's beneath
         * its dignity and you ought to be using SetPixel instead.
         * So I will.
         */
        SetPixel(fe->hdc, x, y, fe->colours[colour]);
    } else {
        win_set_brush(fe, colour);
        win_set_pen(fe, colour, TRUE);
        p = win_transform_point(fe, x, y);
        q = win_transform_point(fe, x+w, y+h);
        Rectangle(fe->hdc, p.x, p.y, q.x, q.y);
        win_reset_brush(fe);
        win_reset_pen(fe);
    }
}

static void win_draw_line(void *handle, int x1, int y1, int x2, int y2, int colour)
{
    frontend *fe = (frontend *)handle;
    POINT p, q;

    if (fe->drawstatus == NOTHING)
        return;

    win_set_pen(fe, colour, FALSE);
    p = win_transform_point(fe, x1, y1);
    q = win_transform_point(fe, x2, y2);
    MoveToEx(fe->hdc, p.x, p.y, NULL);
    LineTo(fe->hdc, q.x, q.y);
    if (fe->drawstatus == DRAWING)
        SetPixel(fe->hdc, q.x, q.y, fe->colours[colour]);
    win_reset_pen(fe);
}

static void win_draw_circle(void *handle, int cx, int cy, int radius,
                            int fillcolour, int outlinecolour)
{
    frontend *fe = (frontend *)handle;
    POINT p, q, r;

    assert(outlinecolour >= 0);

    if (fe->drawstatus == NOTHING)
        return;

    if (fillcolour >= 0) {
        win_set_brush(fe, fillcolour);
        win_set_pen(fe, outlinecolour, FALSE);
        p = win_transform_point(fe, cx - radius, cy - radius);
        q = win_transform_point(fe, cx + radius, cy + radius);
        Ellipse(fe->hdc, p.x, p.y, q.x+1, q.y+1);
        win_reset_brush(fe);
        win_reset_pen(fe);
    } else {
        win_set_pen(fe, outlinecolour, FALSE);
        p = win_transform_point(fe, cx - radius, cy - radius);
        q = win_transform_point(fe, cx + radius, cy + radius);
        r = win_transform_point(fe, cx - radius, cy);
        Arc(fe->hdc, p.x, p.y, q.x+1, q.y+1, r.x, r.y, r.x, r.y);
        win_reset_pen(fe);
    }
}

static void win_draw_polygon(void *handle, int *coords, int npoints,
                             int fillcolour, int outlinecolour)
{
    frontend *fe = (frontend *)handle;
    POINT *pts;
    int i;

    if (fe->drawstatus == NOTHING)
        return;

    pts = snewn(npoints+1, POINT);

    for (i = 0; i <= npoints; i++) {
        int j = (i < npoints ? i : 0);
        pts[i] = win_transform_point(fe, coords[j*2], coords[j*2+1]);
    }

    assert(outlinecolour >= 0);

    if (fillcolour >= 0) {
        win_set_brush(fe, fillcolour);
        win_set_pen(fe, outlinecolour, FALSE);
        Polygon(fe->hdc, pts, npoints);
        win_reset_brush(fe);
        win_reset_pen(fe);
    } else {
        win_set_pen(fe, outlinecolour, FALSE);
        Polyline(fe->hdc, pts, npoints+1);
        win_reset_pen(fe);
    }

    sfree(pts);
}

static void win_start_draw(void *handle)
{
    frontend *fe = (frontend *)handle;
    HDC hdc_win;

    assert(fe->drawstatus == NOTHING);

    hdc_win = GetDC(fe->hwnd);
    fe->hdc = CreateCompatibleDC(hdc_win);
    fe->prevbm = SelectObject(fe->hdc, fe->bitmap);
    ReleaseDC(fe->hwnd, hdc_win);
    fe->clip = NULL;
    SetMapMode(fe->hdc, MM_TEXT);
    fe->drawstatus = DRAWING;
}

static void win_draw_update(void *handle, int x, int y, int w, int h)
{
    frontend *fe = (frontend *)handle;
    RECT r;

    if (fe->drawstatus != DRAWING)
        return;

    r.left = x;
    r.top = y;
    r.right = x + w;
    r.bottom = y + h;

    InvalidateRect(fe->hwnd, &r, FALSE);
}

static void win_end_draw(void *handle)
{
    frontend *fe = (frontend *)handle;
    assert(fe->drawstatus == DRAWING);
    SelectObject(fe->hdc, fe->prevbm);
    DeleteDC(fe->hdc);
    if (fe->clip) {
        DeleteObject(fe->clip);
        fe->clip = NULL;
    }
    fe->drawstatus = NOTHING;
}

static void win_line_width(void *handle, float width)
{
    frontend *fe = (frontend *)handle;

    assert(fe->drawstatus != DRAWING);
    if (fe->drawstatus == NOTHING)
        return;

    fe->linewidth = (int)(width * fe->printpixelscale);
}

static void win_begin_doc(void *handle, int pages)
{
    frontend *fe = (frontend *)handle;

    assert(fe->drawstatus != DRAWING);
    if (fe->drawstatus == NOTHING)
        return;

    if (StartDoc(fe->hdc, &fe->di) <= 0) {
        char *e = geterrstr();
        MessageBox(fe->hwnd, e, "Error starting to print",
                   MB_ICONERROR | MB_OK);
        sfree(e);
        fe->drawstatus = NOTHING;
    }

    /*
     * Push a marker on the font stack so that we won't use the
     * same fonts for printing and drawing. (This is because
     * drawing seems to look generally better in bold, but printing
     * is better not in bold.)
     */
    fe->fontstart = fe->nfonts;
}

static void win_begin_page(void *handle, int number)
{
    frontend *fe = (frontend *)handle;

    assert(fe->drawstatus != DRAWING);
    if (fe->drawstatus == NOTHING)
        return;

    if (StartPage(fe->hdc) <= 0) {
        char *e = geterrstr();
        MessageBox(fe->hwnd, e, "Error starting a page",
                   MB_ICONERROR | MB_OK);
        sfree(e);
        fe->drawstatus = NOTHING;
    }
}

static void win_begin_puzzle(void *handle, float xm, float xc,
                             float ym, float yc, int pw, int ph, float wmm)
{
    frontend *fe = (frontend *)handle;
    int ppw, pph, pox, poy;
    float mmpw, mmph, mmox, mmoy;
    float scale;

    assert(fe->drawstatus != DRAWING);
    if (fe->drawstatus == NOTHING)
        return;

    ppw = GetDeviceCaps(fe->hdc, HORZRES);
    pph = GetDeviceCaps(fe->hdc, VERTRES);
    mmpw = (float)GetDeviceCaps(fe->hdc, HORZSIZE);
    mmph = (float)GetDeviceCaps(fe->hdc, VERTSIZE);

    /*
     * Compute the puzzle's position on the logical page.
     */
    mmox = xm * mmpw + xc;
    mmoy = ym * mmph + yc;

    /*
     * Work out what that comes to in pixels.
     */
    pox = (int)(mmox * (float)ppw / mmpw);
    poy = (int)(mmoy * (float)ppw / mmpw);

    /*
     * And determine the scale.
     * 
     * I need a scale such that the maximum puzzle-coordinate
     * extent of the rectangle (pw * scale) is equal to the pixel
     * equivalent of the puzzle's millimetre width (wmm * ppw /
     * mmpw).
     */
    scale = (wmm * ppw) / (mmpw * pw);

    /*
     * Now store pox, poy and scale for use in the main drawing
     * functions.
     */
    fe->printoffsetx = pox;
    fe->printoffsety = poy;
    fe->printpixelscale = scale;

    fe->linewidth = 1;
}

static void win_end_puzzle(void *handle)
{
    /* Nothing needs to be done here. */
}

static void win_end_page(void *handle, int number)
{
    frontend *fe = (frontend *)handle;

    assert(fe->drawstatus != DRAWING);

    if (fe->drawstatus == NOTHING)
        return;

    if (EndPage(fe->hdc) <= 0) {
        char *e = geterrstr();
        MessageBox(fe->hwnd, e, "Error finishing a page",
                   MB_ICONERROR | MB_OK);
        sfree(e);
        fe->drawstatus = NOTHING;
    }
}

static void win_end_doc(void *handle)
{
    frontend *fe = (frontend *)handle;

    assert(fe->drawstatus != DRAWING);

    /*
     * Free all the fonts created since we began printing.
     */
    while (fe->nfonts > fe->fontstart) {
        fe->nfonts--;
        DeleteObject(fe->fonts[fe->nfonts].font);
    }
    fe->fontstart = 0;

    /*
     * The MSDN web site sample code doesn't bother to call EndDoc
     * if an error occurs half way through printing. I expect doing
     * so would cause the erroneous document to actually be
     * printed, or something equally undesirable.
     */
    if (fe->drawstatus == NOTHING)
        return;

    if (EndDoc(fe->hdc) <= 0) {
        char *e = geterrstr();
        MessageBox(fe->hwnd, e, "Error finishing printing",
                   MB_ICONERROR | MB_OK);
        sfree(e);
        fe->drawstatus = NOTHING;
    }
}

const struct drawing_api win_drawing = {
    win_draw_text,
    win_draw_rect,
    win_draw_line,
    win_draw_polygon,
    win_draw_circle,
    win_draw_update,
    win_clip,
    win_unclip,
    win_start_draw,
    win_end_draw,
    win_status_bar,
    win_blitter_new,
    win_blitter_free,
    win_blitter_save,
    win_blitter_load,
    win_begin_doc,
    win_begin_page,
    win_begin_puzzle,
    win_end_puzzle,
    win_end_page,
    win_end_doc,
    win_line_width,
};

void print(frontend *fe)
{
    PRINTDLG pd;
    char doctitle[256];
    document *doc;
    midend *nme = NULL;  /* non-interactive midend for bulk puzzle generation */
    int i;
    char *err = NULL;

    /*
     * Create our document structure and fill it up with puzzles.
     */
    doc = document_new(fe->printw, fe->printh, fe->printscale / 100.0F);
    for (i = 0; i < fe->printcount; i++) {
        if (i == 0 && fe->printcurr) {
            err = midend_print_puzzle(fe->me, doc, fe->printsolns);
        } else {
            if (!nme) {
                game_params *params;

                nme = midend_new(NULL, &thegame, NULL, NULL);

                /*
                 * Set the non-interactive mid-end to have the same
                 * parameters as the standard one.
                 */
                params = midend_get_params(fe->me);
                midend_set_params(nme, params);
                thegame.free_params(params);
            }

            midend_new_game(nme);
            err = midend_print_puzzle(nme, doc, fe->printsolns);
        }
        if (err)
            break;
    }
    if (nme)
        midend_free(nme);

    if (err) {
        MessageBox(fe->hwnd, err, "Error preparing puzzles for printing",
                   MB_ICONERROR | MB_OK);
        document_free(doc);
        return;
    }

    memset(&pd, 0, sizeof(pd));
    pd.lStructSize = sizeof(pd);
    pd.hwndOwner = fe->hwnd;
    pd.hDevMode = NULL;
    pd.hDevNames = NULL;
    pd.Flags = PD_USEDEVMODECOPIESANDCOLLATE | PD_RETURNDC |
        PD_NOPAGENUMS | PD_NOSELECTION;
    pd.nCopies = 1;
    pd.nFromPage = pd.nToPage = 0xFFFF;
    pd.nMinPage = pd.nMaxPage = 1;

    if (!PrintDlg(&pd)) {
        document_free(doc);
        return;
    }

    /*
     * Now pd.hDC is a device context for the printer.
     */

    /*
     * FIXME: IWBNI we put up an Abort box here.
     */

    memset(&fe->di, 0, sizeof(fe->di));
    fe->di.cbSize = sizeof(fe->di);
    sprintf(doctitle, "Printed puzzles from %s (from Simon Tatham's"
            " Portable Puzzle Collection)", thegame.name);
    fe->di.lpszDocName = doctitle;
    fe->di.lpszOutput = NULL;
    fe->di.lpszDatatype = NULL;
    fe->di.fwType = 0;

    fe->drawstatus = PRINTING;
    fe->hdc = pd.hDC;

    fe->dr = drawing_init(&win_drawing, fe);
    document_print(doc, fe->dr);
    drawing_free(fe->dr);
    fe->dr = NULL;

    fe->drawstatus = NOTHING;

    DeleteDC(pd.hDC);
    document_free(doc);
}

void deactivate_timer(frontend *fe)
{
    if (!fe)
        return;                        /* for non-interactive midend */
    if (fe->hwnd) KillTimer(fe->hwnd, fe->timer);
    fe->timer = 0;
}

void activate_timer(frontend *fe)
{
    if (!fe)
        return;                        /* for non-interactive midend */
    if (!fe->timer) {
        fe->timer = SetTimer(fe->hwnd, fe->timer, 20, NULL);
        fe->timer_last_tickcount = GetTickCount();
    }
}

void write_clip(HWND hwnd, char *data)
{
    HGLOBAL clipdata;
    int len, i, j;
    char *data2;
    void *lock;

    /*
     * Windows expects CRLF in the clipboard, so we must convert
     * any \n that has come out of the puzzle backend.
     */
    len = 0;
    for (i = 0; data[i]; i++) {
        if (data[i] == '\n')
            len++;
        len++;
    }
    data2 = snewn(len+1, char);
    j = 0;
    for (i = 0; data[i]; i++) {
        if (data[i] == '\n')
            data2[j++] = '\r';
        data2[j++] = data[i];
    }
    assert(j == len);
    data2[j] = '\0';

    clipdata = GlobalAlloc(GMEM_DDESHARE | GMEM_MOVEABLE, len + 1);
    if (!clipdata)
        return;
    lock = GlobalLock(clipdata);
    if (!lock)
        return;
    memcpy(lock, data2, len);
    ((unsigned char *) lock)[len] = 0;
    GlobalUnlock(clipdata);

    if (OpenClipboard(hwnd)) {
        EmptyClipboard();
        SetClipboardData(CF_TEXT, clipdata);
        CloseClipboard();
    } else
        GlobalFree(clipdata);

    sfree(data2);
}

/*
 * See if we can find a help file.
 */
static void find_help_file(frontend *fe)
{
    char b[2048], *p, *q, *r;
    FILE *fp;
    if (!fe->help_path) {
        GetModuleFileName(NULL, b, sizeof(b) - 1);
        r = b;
        p = strrchr(b, '\\');
        if (p && p >= r) r = p+1;
        q = strrchr(b, ':');
        if (q && q >= r) r = q+1;
        strcpy(r, HELP_FILE_NAME);
        if ( (fp = fopen(b, "r")) != NULL) {
            fe->help_path = dupstr(b);
            fclose(fp);
        } else
            fe->help_path = NULL;
        strcpy(r, HELP_CNT_NAME);
        if ( (fp = fopen(b, "r")) != NULL) {
            fe->help_has_contents = TRUE;
            fclose(fp);
        } else
            fe->help_has_contents = FALSE;
    }
}

static void check_window_size(frontend *fe, int *px, int *py)
{
    RECT r;
    int x, y, sy;

    if (fe->statusbar) {
        RECT sr;
        GetWindowRect(fe->statusbar, &sr);
        sy = sr.bottom - sr.top;
    } else {
        sy = 0;
    }

    /*
     * See if we actually got the window size we wanted, and adjust
     * the puzzle size if not.
     */
    GetClientRect(fe->hwnd, &r);
    x = r.right - r.left;
    y = r.bottom - r.top - sy;
    midend_size(fe->me, &x, &y, FALSE);
    if (x != r.right - r.left || y != r.bottom - r.top) {
        /*
         * Resize the window, now we know what size we _really_
         * want it to be.
         */
        r.left = r.top = 0;
        r.right = x;
        r.bottom = y + sy;
        AdjustWindowRectEx(&r, WS_OVERLAPPEDWINDOW &~
                           (WS_THICKFRAME | WS_MAXIMIZEBOX | WS_OVERLAPPED),
                           TRUE, 0);
        SetWindowPos(fe->hwnd, NULL, 0, 0, r.right - r.left, r.bottom - r.top,
                     SWP_NOMOVE | SWP_NOZORDER);
    }

    if (fe->statusbar) {
        GetClientRect(fe->hwnd, &r);
        SetWindowPos(fe->statusbar, NULL, 0, r.bottom-r.top-sy, r.right-r.left,
                     sy, SWP_NOZORDER);
    }

    *px = x;
    *py = y;
}

static frontend *new_window(HINSTANCE inst, char *game_id, char **error)
{
    frontend *fe;
    int x, y;
    RECT r;
    HDC hdc;

    fe = snew(frontend);

    fe->me = midend_new(fe, &thegame, &win_drawing, fe);

    if (game_id) {
        *error = midend_game_id(fe->me, game_id);
        if (*error) {
            midend_free(fe->me);
            sfree(fe);
            return NULL;
        }
    }

    fe->help_path = NULL;
    find_help_file(fe);

    fe->inst = inst;

    fe->timer = 0;
    fe->hwnd = NULL;

    fe->drawstatus = NOTHING;
    fe->dr = NULL;
    fe->fontstart = 0;

    midend_new_game(fe->me);

    fe->fonts = NULL;
    fe->nfonts = fe->fontsize = 0;

    fe->laststatus = NULL;

    {
        int i, ncolours;
        float *colours;

        colours = midend_colours(fe->me, &ncolours);

        fe->colours = snewn(ncolours, COLORREF);
        fe->brushes = snewn(ncolours, HBRUSH);
        fe->pens = snewn(ncolours, HPEN);

        for (i = 0; i < ncolours; i++) {
            fe->colours[i] = RGB(255 * colours[i*3+0],
                                 255 * colours[i*3+1],
                                 255 * colours[i*3+2]);
            fe->brushes[i] = CreateSolidBrush(fe->colours[i]);
            fe->pens[i] = CreatePen(PS_SOLID, 1, fe->colours[i]);
        }
    }

    x = y = INT_MAX;                   /* find puzzle's preferred size */
    midend_size(fe->me, &x, &y, FALSE);

    r.left = r.top = 0;
    r.right = x;
    r.bottom = y;
    AdjustWindowRectEx(&r, WS_OVERLAPPEDWINDOW &~
                       (WS_THICKFRAME | WS_MAXIMIZEBOX | WS_OVERLAPPED),
                       TRUE, 0);

    fe->hwnd = CreateWindowEx(0, thegame.name, thegame.name,
                              WS_OVERLAPPEDWINDOW &~
                              (WS_THICKFRAME | WS_MAXIMIZEBOX),
                              CW_USEDEFAULT, CW_USEDEFAULT,
                              r.right - r.left, r.bottom - r.top,
                              NULL, NULL, inst, NULL);

    if (midend_wants_statusbar(fe->me)) {
        RECT sr;
        fe->statusbar = CreateWindowEx(0, STATUSCLASSNAME, "ooh",
                                       WS_CHILD | WS_VISIBLE,
                                       0, 0, 0, 0, /* status bar does these */
                                       fe->hwnd, NULL, inst, NULL);
        /*
         * Now resize the window to take account of the status bar.
         */
        GetWindowRect(fe->statusbar, &sr);
        GetWindowRect(fe->hwnd, &r);
        SetWindowPos(fe->hwnd, NULL, 0, 0, r.right - r.left,
                     r.bottom - r.top + sr.bottom - sr.top,
                     SWP_NOMOVE | SWP_NOZORDER);
    } else {
        fe->statusbar = NULL;
    }

    {
        HMENU bar = CreateMenu();
        HMENU menu = CreateMenu();

        AppendMenu(bar, MF_ENABLED|MF_POPUP, (UINT)menu, "Game");
        AppendMenu(menu, MF_ENABLED, IDM_NEW, "New");
        AppendMenu(menu, MF_ENABLED, IDM_RESTART, "Restart");
        AppendMenu(menu, MF_ENABLED, IDM_DESC, "Specific...");
        AppendMenu(menu, MF_ENABLED, IDM_SEED, "Random Seed...");

        if ((fe->npresets = midend_num_presets(fe->me)) > 0 ||
            thegame.can_configure) {
            HMENU sub = CreateMenu();
            int i;

            AppendMenu(bar, MF_ENABLED|MF_POPUP, (UINT)sub, "Type");

            fe->presets = snewn(fe->npresets, game_params *);

            for (i = 0; i < fe->npresets; i++) {
                char *name;

                midend_fetch_preset(fe->me, i, &name, &fe->presets[i]);

                /*
                 * FIXME: we ought to go through and do something
                 * with ampersands here.
                 */

                AppendMenu(sub, MF_ENABLED, IDM_PRESETS + 0x10 * i, name);
            }

            if (thegame.can_configure) {
                AppendMenu(sub, MF_ENABLED, IDM_CONFIG, "Custom...");
            }
        }

        AppendMenu(menu, MF_SEPARATOR, 0, 0);
        AppendMenu(menu, MF_ENABLED, IDM_LOAD, "Load");
        AppendMenu(menu, MF_ENABLED, IDM_SAVE, "Save");
        AppendMenu(menu, MF_SEPARATOR, 0, 0);
        if (thegame.can_print) {
            AppendMenu(menu, MF_ENABLED, IDM_PRINT, "Print");
            AppendMenu(menu, MF_SEPARATOR, 0, 0);
        }
        AppendMenu(menu, MF_ENABLED, IDM_UNDO, "Undo");
        AppendMenu(menu, MF_ENABLED, IDM_REDO, "Redo");
        if (thegame.can_format_as_text) {
            AppendMenu(menu, MF_SEPARATOR, 0, 0);
            AppendMenu(menu, MF_ENABLED, IDM_COPY, "Copy");
        }
        if (thegame.can_solve) {
            AppendMenu(menu, MF_SEPARATOR, 0, 0);
            AppendMenu(menu, MF_ENABLED, IDM_SOLVE, "Solve");
        }
        AppendMenu(menu, MF_SEPARATOR, 0, 0);
        AppendMenu(menu, MF_ENABLED, IDM_QUIT, "Exit");
        menu = CreateMenu();
        AppendMenu(bar, MF_ENABLED|MF_POPUP, (UINT)menu, "Help");
        AppendMenu(menu, MF_ENABLED, IDM_ABOUT, "About");
        if (fe->help_path) {
            AppendMenu(menu, MF_SEPARATOR, 0, 0);
            AppendMenu(menu, MF_ENABLED, IDM_HELPC, "Contents");
            if (thegame.winhelp_topic) {
                char *item;
                assert(thegame.name);
                item = snewn(9+strlen(thegame.name), char); /*ick*/
                sprintf(item, "Help on %s", thegame.name);
                AppendMenu(menu, MF_ENABLED, IDM_GAMEHELP, item);
                sfree(item);
            }
        }
        SetMenu(fe->hwnd, bar);
    }

    check_window_size(fe, &x, &y);

    hdc = GetDC(fe->hwnd);
    fe->bitmap = CreateCompatibleBitmap(hdc, x, y);
    ReleaseDC(fe->hwnd, hdc);

    SetWindowLong(fe->hwnd, GWL_USERDATA, (LONG)fe);

    ShowWindow(fe->hwnd, SW_NORMAL);
    SetForegroundWindow(fe->hwnd);

    midend_redraw(fe->me);

    return fe;
}

static int CALLBACK AboutDlgProc(HWND hwnd, UINT msg,
                                 WPARAM wParam, LPARAM lParam)
{
    frontend *fe = (frontend *)GetWindowLong(hwnd, GWL_USERDATA);

    switch (msg) {
      case WM_INITDIALOG:
        return 0;

      case WM_COMMAND:
        if ((HIWORD(wParam) == BN_CLICKED ||
             HIWORD(wParam) == BN_DOUBLECLICKED) &&
            LOWORD(wParam) == IDOK)
            fe->dlg_done = 1;
        return 0;

      case WM_CLOSE:
        fe->dlg_done = 1;
        return 0;
    }

    return 0;
}

/*
 * Wrappers on midend_{get,set}_config, which extend the CFG_*
 * enumeration to add CFG_PRINT.
 */
static config_item *frontend_get_config(frontend *fe, int which,
                                        char **wintitle)
{
    if (which < CFG_FRONTEND_SPECIFIC) {
        return midend_get_config(fe->me, which, wintitle);
    } else if (which == CFG_PRINT) {
        config_item *ret;
        int i;

        *wintitle = snewn(40 + strlen(thegame.name), char);
        sprintf(*wintitle, "%s print setup", thegame.name);

        ret = snewn(8, config_item);

        i = 0;

        ret[i].name = "Number of puzzles to print";
        ret[i].type = C_STRING;
        ret[i].sval = dupstr("1");
        ret[i].ival = 0;
        i++;

        ret[i].name = "Number of puzzles across the page";
        ret[i].type = C_STRING;
        ret[i].sval = dupstr("1");
        ret[i].ival = 0;
        i++;

        ret[i].name = "Number of puzzles down the page";
        ret[i].type = C_STRING;
        ret[i].sval = dupstr("1");
        ret[i].ival = 0;
        i++;

        ret[i].name = "Percentage of standard size";
        ret[i].type = C_STRING;
        ret[i].sval = dupstr("100.0");
        ret[i].ival = 0;
        i++;

        ret[i].name = "Include currently shown puzzle";
        ret[i].type = C_BOOLEAN;
        ret[i].sval = NULL;
        ret[i].ival = TRUE;
        i++;

        ret[i].name = "Print solutions";
        ret[i].type = C_BOOLEAN;
        ret[i].sval = NULL;
        ret[i].ival = FALSE;
        i++;

        if (thegame.can_print_in_colour) {
            ret[i].name = "Print in colour";
            ret[i].type = C_BOOLEAN;
            ret[i].sval = NULL;
            ret[i].ival = FALSE;
            i++;
        }

        ret[i].name = NULL;
        ret[i].type = C_END;
        ret[i].sval = NULL;
        ret[i].ival = 0;
        i++;

        return ret;
    } else {
        assert(!"We should never get here");
        return NULL;
    }
}

static char *frontend_set_config(frontend *fe, int which, config_item *cfg)
{
    if (which < CFG_FRONTEND_SPECIFIC) {
        return midend_set_config(fe->me, which, cfg);
    } else if (which == CFG_PRINT) {
        if ((fe->printcount = atoi(cfg[0].sval)) <= 0)
            return "Number of puzzles to print should be at least one";
        if ((fe->printw = atoi(cfg[1].sval)) <= 0)
            return "Number of puzzles across the page should be at least one";
        if ((fe->printh = atoi(cfg[2].sval)) <= 0)
            return "Number of puzzles down the page should be at least one";
        if ((fe->printscale = (float)atof(cfg[3].sval)) <= 0)
            return "Print size should be positive";
        fe->printcurr = cfg[4].ival;
        fe->printsolns = cfg[5].ival;
        fe->printcolour = thegame.can_print_in_colour && cfg[6].ival;
        return NULL;
    } else {
        assert(!"We should never get here");
        return "Internal error";
    }
}

static int CALLBACK ConfigDlgProc(HWND hwnd, UINT msg,
                                  WPARAM wParam, LPARAM lParam)
{
    frontend *fe = (frontend *)GetWindowLong(hwnd, GWL_USERDATA);
    config_item *i;
    struct cfg_aux *j;

    switch (msg) {
      case WM_INITDIALOG:
        return 0;

      case WM_COMMAND:
        /*
         * OK and Cancel are special cases.
         */
        if ((HIWORD(wParam) == BN_CLICKED ||
             HIWORD(wParam) == BN_DOUBLECLICKED) &&
            (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)) {
            if (LOWORD(wParam) == IDOK) {
                char *err = frontend_set_config(fe, fe->cfg_which, fe->cfg);

                if (err) {
                    MessageBox(hwnd, err, "Validation error",
                               MB_ICONERROR | MB_OK);
                } else {
                    fe->dlg_done = 2;
                }
            } else {
                fe->dlg_done = 1;
            }
            return 0;
        }

        /*
         * First find the control whose id this is.
         */
        for (i = fe->cfg, j = fe->cfgaux; i->type != C_END; i++, j++) {
            if (j->ctlid == LOWORD(wParam))
                break;
        }
        if (i->type == C_END)
            return 0;                  /* not our problem */

        if (i->type == C_STRING && HIWORD(wParam) == EN_CHANGE) {
            char buffer[4096];
            GetDlgItemText(fe->cfgbox, j->ctlid, buffer, lenof(buffer));
            buffer[lenof(buffer)-1] = '\0';
            sfree(i->sval);
            i->sval = dupstr(buffer);
        } else if (i->type == C_BOOLEAN && 
                   (HIWORD(wParam) == BN_CLICKED ||
                    HIWORD(wParam) == BN_DOUBLECLICKED)) {
            i->ival = IsDlgButtonChecked(fe->cfgbox, j->ctlid);
        } else if (i->type == C_CHOICES &&
                   HIWORD(wParam) == CBN_SELCHANGE) {
            i->ival = SendDlgItemMessage(fe->cfgbox, j->ctlid,
                                         CB_GETCURSEL, 0, 0);
        }

        return 0;

      case WM_CLOSE:
        fe->dlg_done = 1;
        return 0;
    }

    return 0;
}

HWND mkctrl(frontend *fe, int x1, int x2, int y1, int y2,
            char *wclass, int wstyle,
            int exstyle, const char *wtext, int wid)
{
    HWND ret;
    ret = CreateWindowEx(exstyle, wclass, wtext,
                         wstyle | WS_CHILD | WS_VISIBLE, x1, y1, x2-x1, y2-y1,
                         fe->cfgbox, (HMENU) wid, fe->inst, NULL);
    SendMessage(ret, WM_SETFONT, (WPARAM)fe->cfgfont, MAKELPARAM(TRUE, 0));
    return ret;
}

static void about(frontend *fe)
{
    int i;
    WNDCLASS wc;
    MSG msg;
    TEXTMETRIC tm;
    HDC hdc;
    HFONT oldfont;
    SIZE size;
    int gm, id;
    int winwidth, winheight, y;
    int height, width, maxwid;
    const char *strings[16];
    int lengths[16];
    int nstrings = 0;
    char titlebuf[512];

    sprintf(titlebuf, "About %.250s", thegame.name);

    strings[nstrings++] = thegame.name;
    strings[nstrings++] = "from Simon Tatham's Portable Puzzle Collection";
    strings[nstrings++] = ver;

    wc.style = CS_DBLCLKS | CS_SAVEBITS | CS_BYTEALIGNWINDOW;
    wc.lpfnWndProc = DefDlgProc;
    wc.cbClsExtra = 0;
    wc.cbWndExtra = DLGWINDOWEXTRA + 8;
    wc.hInstance = fe->inst;
    wc.hIcon = NULL;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH) (COLOR_BACKGROUND +1);
    wc.lpszMenuName = NULL;
    wc.lpszClassName = "GameAboutBox";
    RegisterClass(&wc);

    hdc = GetDC(fe->hwnd);
    SetMapMode(hdc, MM_TEXT);

    fe->dlg_done = FALSE;

    fe->cfgfont = CreateFont(-MulDiv(8, GetDeviceCaps(hdc, LOGPIXELSY), 72),
                             0, 0, 0, 0,
                             FALSE, FALSE, FALSE, DEFAULT_CHARSET,
                             OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
                             DEFAULT_QUALITY,
                             FF_SWISS,
                             "MS Shell Dlg");

    oldfont = SelectObject(hdc, fe->cfgfont);
    if (GetTextMetrics(hdc, &tm)) {
        height = tm.tmAscent + tm.tmDescent;
        width = tm.tmAveCharWidth;
    } else {
        height = width = 30;
    }

    /*
     * Figure out the layout of the About box by measuring the
     * length of each piece of text.
     */
    maxwid = 0;
    winheight = height/2;

    for (i = 0; i < nstrings; i++) {
        if (GetTextExtentPoint32(hdc, strings[i], strlen(strings[i]), &size))
            lengths[i] = size.cx;
        else
            lengths[i] = 0;            /* *shrug* */
        if (maxwid < lengths[i])
            maxwid = lengths[i];
        winheight += height * 3 / 2 + (height / 2);
    }

    winheight += height + height * 7 / 4;      /* OK button */
    winwidth = maxwid + 4*width;

    SelectObject(hdc, oldfont);
    ReleaseDC(fe->hwnd, hdc);

    /*
     * Create the dialog, now that we know its size.
     */
    {
        RECT r, r2;

        r.left = r.top = 0;
        r.right = winwidth;
        r.bottom = winheight;

        AdjustWindowRectEx(&r, (WS_OVERLAPPEDWINDOW /*|
                                DS_MODALFRAME | WS_POPUP | WS_VISIBLE |
                                WS_CAPTION | WS_SYSMENU*/) &~
                           (WS_MAXIMIZEBOX | WS_OVERLAPPED),
                           FALSE, 0);

        /*
         * Centre the dialog on its parent window.
         */
        r.right -= r.left;
        r.bottom -= r.top;
        GetWindowRect(fe->hwnd, &r2);
        r.left = (r2.left + r2.right - r.right) / 2;
        r.top = (r2.top + r2.bottom - r.bottom) / 2;
        r.right += r.left;
        r.bottom += r.top;

        fe->cfgbox = CreateWindowEx(0, wc.lpszClassName, titlebuf,
                                    DS_MODALFRAME | WS_POPUP | WS_VISIBLE |
                                    WS_CAPTION | WS_SYSMENU,
                                    r.left, r.top,
                                    r.right-r.left, r.bottom-r.top,
                                    fe->hwnd, NULL, fe->inst, NULL);
    }

    SendMessage(fe->cfgbox, WM_SETFONT, (WPARAM)fe->cfgfont, FALSE);

    SetWindowLong(fe->cfgbox, GWL_USERDATA, (LONG)fe);
    SetWindowLong(fe->cfgbox, DWL_DLGPROC, (LONG)AboutDlgProc);

    id = 1000;
    y = height/2;
    for (i = 0; i < nstrings; i++) {
        int border = width*2 + (maxwid - lengths[i]) / 2;
        mkctrl(fe, border, border+lengths[i], y+height*1/8, y+height*9/8,
               "Static", 0, 0, strings[i], id++);
        y += height*3/2;

        assert(y < winheight);
        y += height/2;
    }

    y += height/2;                     /* extra space before OK */
    mkctrl(fe, width*2, maxwid+width*2, y, y+height*7/4, "BUTTON",
           BS_PUSHBUTTON | BS_NOTIFY | WS_TABSTOP | BS_DEFPUSHBUTTON, 0,
           "OK", IDOK);

    SendMessage(fe->cfgbox, WM_INITDIALOG, 0, 0);

    EnableWindow(fe->hwnd, FALSE);
    ShowWindow(fe->cfgbox, SW_NORMAL);
    while ((gm=GetMessage(&msg, NULL, 0, 0)) > 0) {
        if (!IsDialogMessage(fe->cfgbox, &msg))
            DispatchMessage(&msg);
        if (fe->dlg_done)
            break;
    }
    EnableWindow(fe->hwnd, TRUE);
    SetForegroundWindow(fe->hwnd);
    DestroyWindow(fe->cfgbox);
    DeleteObject(fe->cfgfont);
}

static int get_config(frontend *fe, int which)
{
    config_item *i;
    struct cfg_aux *j;
    char *title;
    WNDCLASS wc;
    MSG msg;
    TEXTMETRIC tm;
    HDC hdc;
    HFONT oldfont;
    SIZE size;
    HWND ctl;
    int gm, id, nctrls;
    int winwidth, winheight, col1l, col1r, col2l, col2r, y;
    int height, width, maxlabel, maxcheckbox;

    wc.style = CS_DBLCLKS | CS_SAVEBITS | CS_BYTEALIGNWINDOW;
    wc.lpfnWndProc = DefDlgProc;
    wc.cbClsExtra = 0;
    wc.cbWndExtra = DLGWINDOWEXTRA + 8;
    wc.hInstance = fe->inst;
    wc.hIcon = NULL;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH) (COLOR_BACKGROUND +1);
    wc.lpszMenuName = NULL;
    wc.lpszClassName = "GameConfigBox";
    RegisterClass(&wc);

    hdc = GetDC(fe->hwnd);
    SetMapMode(hdc, MM_TEXT);

    fe->dlg_done = FALSE;

    fe->cfgfont = CreateFont(-MulDiv(8, GetDeviceCaps(hdc, LOGPIXELSY), 72),
                             0, 0, 0, 0,
                             FALSE, FALSE, FALSE, DEFAULT_CHARSET,
                             OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
                             DEFAULT_QUALITY,
                             FF_SWISS,
                             "MS Shell Dlg");

    oldfont = SelectObject(hdc, fe->cfgfont);
    if (GetTextMetrics(hdc, &tm)) {
        height = tm.tmAscent + tm.tmDescent;
        width = tm.tmAveCharWidth;
    } else {
        height = width = 30;
    }

    fe->cfg = frontend_get_config(fe, which, &title);
    fe->cfg_which = which;

    /*
     * Figure out the layout of the config box by measuring the
     * length of each piece of text.
     */
    maxlabel = maxcheckbox = 0;
    winheight = height/2;

    for (i = fe->cfg; i->type != C_END; i++) {
        switch (i->type) {
          case C_STRING:
          case C_CHOICES:
            /*
             * Both these control types have a label filling only
             * the left-hand column of the box.
             */
            if (GetTextExtentPoint32(hdc, i->name, strlen(i->name), &size) &&
                maxlabel < size.cx)
                maxlabel = size.cx;
            winheight += height * 3 / 2 + (height / 2);
            break;

          case C_BOOLEAN:
            /*
             * Checkboxes take up the whole of the box width.
             */
            if (GetTextExtentPoint32(hdc, i->name, strlen(i->name), &size) &&
                maxcheckbox < size.cx)
                maxcheckbox = size.cx;
            winheight += height + (height / 2);
            break;
        }
    }

    winheight += height + height * 7 / 4;      /* OK / Cancel buttons */

    col1l = 2*width;
    col1r = col1l + maxlabel;
    col2l = col1r + 2*width;
    col2r = col2l + 30*width;
    if (col2r < col1l+2*height+maxcheckbox)
        col2r = col1l+2*height+maxcheckbox;
    winwidth = col2r + 2*width;

    SelectObject(hdc, oldfont);
    ReleaseDC(fe->hwnd, hdc);

    /*
     * Create the dialog, now that we know its size.
     */
    {
        RECT r, r2;

        r.left = r.top = 0;
        r.right = winwidth;
        r.bottom = winheight;

        AdjustWindowRectEx(&r, (WS_OVERLAPPEDWINDOW /*|
                                DS_MODALFRAME | WS_POPUP | WS_VISIBLE |
                                WS_CAPTION | WS_SYSMENU*/) &~
                           (WS_MAXIMIZEBOX | WS_OVERLAPPED),
                           FALSE, 0);

        /*
         * Centre the dialog on its parent window.
         */
        r.right -= r.left;
        r.bottom -= r.top;
        GetWindowRect(fe->hwnd, &r2);
        r.left = (r2.left + r2.right - r.right) / 2;
        r.top = (r2.top + r2.bottom - r.bottom) / 2;
        r.right += r.left;
        r.bottom += r.top;

        fe->cfgbox = CreateWindowEx(0, wc.lpszClassName, title,
                                    DS_MODALFRAME | WS_POPUP | WS_VISIBLE |
                                    WS_CAPTION | WS_SYSMENU,
                                    r.left, r.top,
                                    r.right-r.left, r.bottom-r.top,
                                    fe->hwnd, NULL, fe->inst, NULL);
        sfree(title);
    }

    SendMessage(fe->cfgbox, WM_SETFONT, (WPARAM)fe->cfgfont, FALSE);

    SetWindowLong(fe->cfgbox, GWL_USERDATA, (LONG)fe);
    SetWindowLong(fe->cfgbox, DWL_DLGPROC, (LONG)ConfigDlgProc);

    /*
     * Count the controls so we can allocate cfgaux.
     */
    for (nctrls = 0, i = fe->cfg; i->type != C_END; i++)
        nctrls++;
    fe->cfgaux = snewn(nctrls, struct cfg_aux);

    id = 1000;
    y = height/2;
    for (i = fe->cfg, j = fe->cfgaux; i->type != C_END; i++, j++) {
        switch (i->type) {
          case C_STRING:
            /*
             * Edit box with a label beside it.
             */
            mkctrl(fe, col1l, col1r, y+height*1/8, y+height*9/8,
                   "Static", 0, 0, i->name, id++);
            ctl = mkctrl(fe, col2l, col2r, y, y+height*3/2,
                         "EDIT", WS_TABSTOP | ES_AUTOHSCROLL,
                         WS_EX_CLIENTEDGE, "", (j->ctlid = id++));
            SetWindowText(ctl, i->sval);
            y += height*3/2;
            break;

          case C_BOOLEAN:
            /*
             * Simple checkbox.
             */
            mkctrl(fe, col1l, col2r, y, y+height, "BUTTON",
                   BS_NOTIFY | BS_AUTOCHECKBOX | WS_TABSTOP,
                   0, i->name, (j->ctlid = id++));
            CheckDlgButton(fe->cfgbox, j->ctlid, (i->ival != 0));
            y += height;
            break;

          case C_CHOICES:
            /*
             * Drop-down list with a label beside it.
             */
            mkctrl(fe, col1l, col1r, y+height*1/8, y+height*9/8,
                   "STATIC", 0, 0, i->name, id++);
            ctl = mkctrl(fe, col2l, col2r, y, y+height*41/2,
                         "COMBOBOX", WS_TABSTOP |
                         CBS_DROPDOWNLIST | CBS_HASSTRINGS,
                         WS_EX_CLIENTEDGE, "", (j->ctlid = id++));
            {
                char c, *p, *q, *str;

                SendMessage(ctl, CB_RESETCONTENT, 0, 0);
                p = i->sval;
                c = *p++;
                while (*p) {
                    q = p;
                    while (*q && *q != c) q++;
                    str = snewn(q-p+1, char);
                    strncpy(str, p, q-p);
                    str[q-p] = '\0';
                    SendMessage(ctl, CB_ADDSTRING, 0, (LPARAM)str);
                    sfree(str);
                    if (*q) q++;
                    p = q;
                }
            }

            SendMessage(ctl, CB_SETCURSEL, i->ival, 0);

            y += height*3/2;
            break;
        }

        assert(y < winheight);
        y += height/2;
    }

    y += height/2;                     /* extra space before OK and Cancel */
    mkctrl(fe, col1l, (col1l+col2r)/2-width, y, y+height*7/4, "BUTTON",
           BS_PUSHBUTTON | BS_NOTIFY | WS_TABSTOP | BS_DEFPUSHBUTTON, 0,
           "OK", IDOK);
    mkctrl(fe, (col1l+col2r)/2+width, col2r, y, y+height*7/4, "BUTTON",
           BS_PUSHBUTTON | BS_NOTIFY | WS_TABSTOP, 0, "Cancel", IDCANCEL);

    SendMessage(fe->cfgbox, WM_INITDIALOG, 0, 0);

    EnableWindow(fe->hwnd, FALSE);
    ShowWindow(fe->cfgbox, SW_NORMAL);
    while ((gm=GetMessage(&msg, NULL, 0, 0)) > 0) {
        if (!IsDialogMessage(fe->cfgbox, &msg))
            DispatchMessage(&msg);
        if (fe->dlg_done)
            break;
    }
    EnableWindow(fe->hwnd, TRUE);
    SetForegroundWindow(fe->hwnd);
    DestroyWindow(fe->cfgbox);
    DeleteObject(fe->cfgfont);

    free_cfg(fe->cfg);
    sfree(fe->cfgaux);

    return (fe->dlg_done == 2);
}

static void new_game_size(frontend *fe)
{
    RECT r, sr;
    HDC hdc;
    int x, y;

    x = y = INT_MAX;
    midend_size(fe->me, &x, &y, FALSE);

    r.left = r.top = 0;
    r.right = x;
    r.bottom = y;
    AdjustWindowRectEx(&r, WS_OVERLAPPEDWINDOW &~
                       (WS_THICKFRAME | WS_MAXIMIZEBOX |
                        WS_OVERLAPPED),
                       TRUE, 0);

    if (fe->statusbar != NULL) {
        GetWindowRect(fe->statusbar, &sr);
    } else {
        sr.left = sr.right = sr.top = sr.bottom = 0;
    }
    SetWindowPos(fe->hwnd, NULL, 0, 0,
                 r.right - r.left,
                 r.bottom - r.top + sr.bottom - sr.top,
                 SWP_NOMOVE | SWP_NOZORDER);

    check_window_size(fe, &x, &y);

    if (fe->statusbar != NULL)
        SetWindowPos(fe->statusbar, NULL, 0, y, x,
                     sr.bottom - sr.top, SWP_NOZORDER);

    DeleteObject(fe->bitmap);

    hdc = GetDC(fe->hwnd);
    fe->bitmap = CreateCompatibleBitmap(hdc, x, y);
    ReleaseDC(fe->hwnd, hdc);

    midend_redraw(fe->me);
}

static void new_game_type(frontend *fe)
{
    midend_new_game(fe->me);
    new_game_size(fe);
}

static int is_alt_pressed(void)
{
    BYTE keystate[256];
    int r = GetKeyboardState(keystate);
    if (!r)
        return FALSE;
    if (keystate[VK_MENU] & 0x80)
        return TRUE;
    if (keystate[VK_RMENU] & 0x80)
        return TRUE;
    return FALSE;
}

static void savefile_write(void *wctx, void *buf, int len)
{
    FILE *fp = (FILE *)wctx;
    fwrite(buf, 1, len, fp);
}

static int savefile_read(void *wctx, void *buf, int len)
{
    FILE *fp = (FILE *)wctx;
    int ret;

    ret = fread(buf, 1, len, fp);
    return (ret == len);
}

static LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
                                WPARAM wParam, LPARAM lParam)
{
    frontend *fe = (frontend *)GetWindowLong(hwnd, GWL_USERDATA);
    int cmd;

    switch (message) {
      case WM_CLOSE:
        DestroyWindow(hwnd);
        return 0;
      case WM_COMMAND:
        cmd = wParam & ~0xF;           /* low 4 bits reserved to Windows */
        switch (cmd) {
          case IDM_NEW:
            if (!midend_process_key(fe->me, 0, 0, 'n'))
                PostQuitMessage(0);
            break;
          case IDM_RESTART:
            midend_restart_game(fe->me);
            break;
          case IDM_UNDO:
            if (!midend_process_key(fe->me, 0, 0, 'u'))
                PostQuitMessage(0);
            break;
          case IDM_REDO:
            if (!midend_process_key(fe->me, 0, 0, '\x12'))
                PostQuitMessage(0);
            break;
          case IDM_COPY:
            {
                char *text = midend_text_format(fe->me);
                if (text)
                    write_clip(hwnd, text);
                else
                    MessageBeep(MB_ICONWARNING);
                sfree(text);
            }
            break;
          case IDM_SOLVE:
            {
                char *msg = midend_solve(fe->me);
                if (msg)
                    MessageBox(hwnd, msg, "Unable to solve",
                               MB_ICONERROR | MB_OK);
            }
            break;
          case IDM_QUIT:
            if (!midend_process_key(fe->me, 0, 0, 'q'))
                PostQuitMessage(0);
            break;
          case IDM_CONFIG:
            if (get_config(fe, CFG_SETTINGS))
                new_game_type(fe);
            break;
          case IDM_SEED:
            if (get_config(fe, CFG_SEED))
                new_game_type(fe);
            break;
          case IDM_DESC:
            if (get_config(fe, CFG_DESC))
                new_game_type(fe);
            break;
          case IDM_PRINT:
            if (get_config(fe, CFG_PRINT))
                print(fe);
            break;
          case IDM_ABOUT:
            about(fe);
            break;
          case IDM_LOAD:
          case IDM_SAVE:
            {
                OPENFILENAME of;
                char filename[FILENAME_MAX];
                int ret;

                memset(&of, 0, sizeof(of));
                of.hwndOwner = hwnd;
                of.lpstrFilter = "All Files (*.*)\0*\0\0\0";
                of.lpstrCustomFilter = NULL;
                of.nFilterIndex = 1;
                of.lpstrFile = filename;
                filename[0] = '\0';
                of.nMaxFile = lenof(filename);
                of.lpstrFileTitle = NULL;
                of.lpstrTitle = (cmd == IDM_SAVE ?
                                 "Enter name of game file to save" :
                                 "Enter name of saved game file to load");
                of.Flags = 0;
#ifdef OPENFILENAME_SIZE_VERSION_400
                of.lStructSize = OPENFILENAME_SIZE_VERSION_400;
#else
                of.lStructSize = sizeof(of);
#endif
                of.lpstrInitialDir = NULL;

                if (cmd == IDM_SAVE)
                    ret = GetSaveFileName(&of);
                else
                    ret = GetOpenFileName(&of);

                if (ret) {
                    if (cmd == IDM_SAVE) {
                        FILE *fp;

                        if ((fp = fopen(filename, "r")) != NULL) {
                            char buf[256 + FILENAME_MAX];
                            fclose(fp);
                            /* file exists */

                            sprintf(buf, "Are you sure you want to overwrite"
                                    " the file \"%.*s\"?",
                                    FILENAME_MAX, filename);
                            if (MessageBox(hwnd, buf, "Question",
                                           MB_YESNO | MB_ICONQUESTION)
                                != IDYES)
                                break;
                        }

                        fp = fopen(filename, "w");

                        if (!fp) {
                            MessageBox(hwnd, "Unable to open save file",
                                       "Error", MB_ICONERROR | MB_OK);
                            break;
                        }

                        midend_serialise(fe->me, savefile_write, fp);

                        fclose(fp);
                    } else {
                        FILE *fp = fopen(filename, "r");
                        char *err;

                        if (!fp) {
                            MessageBox(hwnd, "Unable to open saved game file",
                                       "Error", MB_ICONERROR | MB_OK);
                            break;
                        }

                        err = midend_deserialise(fe->me, savefile_read, fp);

                        fclose(fp);

                        if (err) {
                            MessageBox(hwnd, err, "Error", MB_ICONERROR|MB_OK);
                            break;
                        }

                        new_game_size(fe);
                    }
                }
            }

            break;
          case IDM_HELPC:
            assert(fe->help_path);
            WinHelp(hwnd, fe->help_path,
                    fe->help_has_contents ? HELP_FINDER : HELP_CONTENTS, 0);
            break;
          case IDM_GAMEHELP:
            assert(fe->help_path);
            assert(thegame.winhelp_topic);
            {
                char *cmd = snewn(10+strlen(thegame.winhelp_topic), char);
                sprintf(cmd, "JI(`',`%s')", thegame.winhelp_topic);
                WinHelp(hwnd, fe->help_path, HELP_COMMAND, (DWORD)cmd);
                sfree(cmd);
            }
            break;
          default:
            {
                int p = ((wParam &~ 0xF) - IDM_PRESETS) / 0x10;

                if (p >= 0 && p < fe->npresets) {
                    midend_set_params(fe->me, fe->presets[p]);
                    new_game_type(fe);
                }
            }
            break;
        }
        break;
      case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
      case WM_PAINT:
        {
            PAINTSTRUCT p;
            HDC hdc, hdc2;
            HBITMAP prevbm;

            hdc = BeginPaint(hwnd, &p);
            hdc2 = CreateCompatibleDC(hdc);
            prevbm = SelectObject(hdc2, fe->bitmap);
            BitBlt(hdc,
                   p.rcPaint.left, p.rcPaint.top,
                   p.rcPaint.right - p.rcPaint.left,
                   p.rcPaint.bottom - p.rcPaint.top,
                   hdc2,
                   p.rcPaint.left, p.rcPaint.top,
                   SRCCOPY);
            SelectObject(hdc2, prevbm);
            DeleteDC(hdc2);
            EndPaint(hwnd, &p);
        }
        return 0;
      case WM_KEYDOWN:
        {
            int key = -1;
            BYTE keystate[256];
            int r = GetKeyboardState(keystate);
            int shift = (r && (keystate[VK_SHIFT] & 0x80)) ? MOD_SHFT : 0;
            int ctrl = (r && (keystate[VK_CONTROL] & 0x80)) ? MOD_CTRL : 0;

            switch (wParam) {
              case VK_LEFT:
                if (!(lParam & 0x01000000))
                    key = MOD_NUM_KEYPAD | '4';
                else
                    key = shift | ctrl | CURSOR_LEFT;
                break;
              case VK_RIGHT:
                if (!(lParam & 0x01000000))
                    key = MOD_NUM_KEYPAD | '6';
                else
                    key = shift | ctrl | CURSOR_RIGHT;
                break;
              case VK_UP:
                if (!(lParam & 0x01000000))
                    key = MOD_NUM_KEYPAD | '8';
                else
                    key = shift | ctrl | CURSOR_UP;
                break;
              case VK_DOWN:
                if (!(lParam & 0x01000000))
                    key = MOD_NUM_KEYPAD | '2';
                else
                    key = shift | ctrl | CURSOR_DOWN;
                break;
                /*
                 * Diagonal keys on the numeric keypad.
                 */
              case VK_PRIOR:
                if (!(lParam & 0x01000000)) key = MOD_NUM_KEYPAD | '9';
                break;
              case VK_NEXT:
                if (!(lParam & 0x01000000)) key = MOD_NUM_KEYPAD | '3';
                break;
              case VK_HOME:
                if (!(lParam & 0x01000000)) key = MOD_NUM_KEYPAD | '7';
                break;
              case VK_END:
                if (!(lParam & 0x01000000)) key = MOD_NUM_KEYPAD | '1';
                break;
              case VK_INSERT:
                if (!(lParam & 0x01000000)) key = MOD_NUM_KEYPAD | '0';
                break;
              case VK_CLEAR:
                if (!(lParam & 0x01000000)) key = MOD_NUM_KEYPAD | '5';
                break;
                /*
                 * Numeric keypad keys with Num Lock on.
                 */
              case VK_NUMPAD4: key = MOD_NUM_KEYPAD | '4'; break;
              case VK_NUMPAD6: key = MOD_NUM_KEYPAD | '6'; break;
              case VK_NUMPAD8: key = MOD_NUM_KEYPAD | '8'; break;
              case VK_NUMPAD2: key = MOD_NUM_KEYPAD | '2'; break;
              case VK_NUMPAD5: key = MOD_NUM_KEYPAD | '5'; break;
              case VK_NUMPAD9: key = MOD_NUM_KEYPAD | '9'; break;
              case VK_NUMPAD3: key = MOD_NUM_KEYPAD | '3'; break;
              case VK_NUMPAD7: key = MOD_NUM_KEYPAD | '7'; break;
              case VK_NUMPAD1: key = MOD_NUM_KEYPAD | '1'; break;
              case VK_NUMPAD0: key = MOD_NUM_KEYPAD | '0'; break;
            }

            if (key != -1) {
                if (!midend_process_key(fe->me, 0, 0, key))
                    PostQuitMessage(0);
            } else {
                MSG m;
                m.hwnd = hwnd;
                m.message = WM_KEYDOWN;
                m.wParam = wParam;
                m.lParam = lParam & 0xdfff;
                TranslateMessage(&m);
            }
        }
        break;
      case WM_LBUTTONDOWN:
      case WM_RBUTTONDOWN:
      case WM_MBUTTONDOWN:
        {
            int button;

            /*
             * Shift-clicks count as middle-clicks, since otherwise
             * two-button Windows users won't have any kind of
             * middle click to use.
             */
            if (message == WM_MBUTTONDOWN || (wParam & MK_SHIFT))
                button = MIDDLE_BUTTON;
            else if (message == WM_RBUTTONDOWN || is_alt_pressed())
                button = RIGHT_BUTTON;
            else
                button = LEFT_BUTTON;

            if (!midend_process_key(fe->me, (signed short)LOWORD(lParam),
                                    (signed short)HIWORD(lParam), button))
                PostQuitMessage(0);

            SetCapture(hwnd);
        }
        break;
      case WM_LBUTTONUP:
      case WM_RBUTTONUP:
      case WM_MBUTTONUP:
        {
            int button;

            /*
             * Shift-clicks count as middle-clicks, since otherwise
             * two-button Windows users won't have any kind of
             * middle click to use.
             */
            if (message == WM_MBUTTONUP || (wParam & MK_SHIFT))
                button = MIDDLE_RELEASE;
            else if (message == WM_RBUTTONUP || is_alt_pressed())
                button = RIGHT_RELEASE;
            else
                button = LEFT_RELEASE;

            if (!midend_process_key(fe->me, (signed short)LOWORD(lParam),
                                    (signed short)HIWORD(lParam), button))
                PostQuitMessage(0);

            ReleaseCapture();
        }
        break;
      case WM_MOUSEMOVE:
        {
            int button;

            if (wParam & (MK_MBUTTON | MK_SHIFT))
                button = MIDDLE_DRAG;
            else if (wParam & MK_RBUTTON || is_alt_pressed())
                button = RIGHT_DRAG;
            else
                button = LEFT_DRAG;
            
            if (!midend_process_key(fe->me, (signed short)LOWORD(lParam),
                                    (signed short)HIWORD(lParam), button))
                PostQuitMessage(0);
        }
        break;
      case WM_CHAR:
        if (!midend_process_key(fe->me, 0, 0, (unsigned char)wParam))
            PostQuitMessage(0);
        return 0;
      case WM_TIMER:
        if (fe->timer) {
            DWORD now = GetTickCount();
            float elapsed = (float) (now - fe->timer_last_tickcount) * 0.001F;
            midend_timer(fe->me, elapsed);
            fe->timer_last_tickcount = now;
        }
        return 0;
    }

    return DefWindowProc(hwnd, message, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE inst, HINSTANCE prev, LPSTR cmdline, int show)
{
    MSG msg;
    char *error;

    InitCommonControls();

    if (!prev) {
        WNDCLASS wndclass;

        wndclass.style = 0;
        wndclass.lpfnWndProc = WndProc;
        wndclass.cbClsExtra = 0;
        wndclass.cbWndExtra = 0;
        wndclass.hInstance = inst;
        wndclass.hIcon = LoadIcon(inst, IDI_APPLICATION);
        wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
        wndclass.hbrBackground = NULL;
        wndclass.lpszMenuName = NULL;
        wndclass.lpszClassName = thegame.name;

        RegisterClass(&wndclass);
    }

    while (*cmdline && isspace((unsigned char)*cmdline))
        cmdline++;

    if (!new_window(inst, *cmdline ? cmdline : NULL, &error)) {
        char buf[128];
        sprintf(buf, "%.100s Error", thegame.name);
        MessageBox(NULL, error, buf, MB_OK|MB_ICONERROR);
        return 1;
    }

    while (GetMessage(&msg, NULL, 0, 0)) {
        DispatchMessage(&msg);
    }

    return msg.wParam;
}