/*
 *Copyright (C) 2003-2004 Harold L Hunt II All Rights Reserved.
 *Copyright (C) Colin Harrison 2005-2008
 *
 *Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 *"Software"), to deal in the Software without restriction, including
 *without limitation the rights to use, copy, modify, merge, publish,
 *distribute, sublicense, and/or sell copies of the Software, and to
 *permit persons to whom the Software is furnished to do so, subject to
 *the following conditions:
 *
 *The above copyright notice and this permission notice shall be
 *included in all copies or substantial portions of the Software.
 *
 *THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *NONINFRINGEMENT. IN NO EVENT SHALL HAROLD L HUNT II BE LIABLE FOR
 *ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
 *CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 *Except as contained in this notice, the name of the copyright holder(s)
 *and author(s) shall not be used in advertising or otherwise to promote
 *the sale, use or other dealings in this Software without prior written
 *authorization from the copyright holder(s) and author(s).
 *
 * Authors:	Harold L Hunt II
 *              Colin Harrison
 */

#ifdef HAVE_XWIN_CONFIG_H
#include <xwin-config.h>
#endif
#include <sys/types.h>
#include <sys/time.h>
#include "winclipboard.h"
#include "misc.h"

/*
 * Constants
 */

#define WIN_POLL_TIMEOUT	1

/*
 * References to external symbols
 */

extern Bool g_fUseUnicode;
extern Bool g_fUnicodeSupport;
extern void *g_pClipboardDisplay;
extern Window g_iClipboardWindow;
extern Atom g_atomLastOwnedSelection;

/* 
 * Local function prototypes
 */

static int

winProcessXEventsTimeout(HWND hwnd, int iWindow, Display * pDisplay,
                         Bool fUseUnicode, int iTimeoutSec);

/*
 * Process X events up to specified timeout
 */

static int
winProcessXEventsTimeout(HWND hwnd, int iWindow, Display * pDisplay,
                         Bool fUseUnicode, int iTimeoutSec)
{
    int iConnNumber;
    struct timeval tv;
    int iReturn;
    DWORD dwStopTime = (GetTickCount() / 1000) + iTimeoutSec;

    /* We need to ensure that all pending events are processed */
    XSync(pDisplay, FALSE);

    /* Get our connection number */
    iConnNumber = ConnectionNumber(pDisplay);

    /* Loop for X events */
    while (1) {
        fd_set fdsRead;

        /* Setup the file descriptor set */
        FD_ZERO(&fdsRead);
        FD_SET(iConnNumber, &fdsRead);

        /* Adjust timeout */
        tv.tv_sec = dwStopTime - (GetTickCount() / 1000);
        tv.tv_usec = 0;

        /* Break out if no time left */
        if (tv.tv_sec < 0)
            return WIN_XEVENTS_SUCCESS;

        /* Wait for an X event */
        iReturn = select(iConnNumber + 1,       /* Highest fds number */
                         &fdsRead,      /* Read mask */
                         NULL,  /* No write mask */
                         NULL,  /* No exception mask */
                         &tv);  /* No timeout */
        if (iReturn < 0) {
            ErrorF("winProcessXEventsTimeout - Call to select () failed: %d.  "
                   "Bailing.\n", iReturn);
            break;
        }

        /* Branch on which descriptor became active */
        if (FD_ISSET(iConnNumber, &fdsRead)) {
            /* Process X events */
            /* Exit when we see that server is shutting down */
            iReturn = winClipboardFlushXEvents(hwnd,
                                               iWindow, pDisplay, fUseUnicode);
            if (WIN_XEVENTS_NOTIFY == iReturn) {
                /* Bail out if notify processed */
                return iReturn;
            }
        }
    }

    return WIN_XEVENTS_SUCCESS;
}

/*
 * Process a given Windows message
 */

LRESULT CALLBACK
winClipboardWindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static HWND s_hwndNextViewer;
    static Bool s_fCBCInitialized;

    /* Branch on message type */
    switch (message) {
    case WM_DESTROY:
    {
        winDebug("winClipboardWindowProc - WM_DESTROY\n");

        /* Remove ourselves from the clipboard chain */
        ChangeClipboardChain(hwnd, s_hwndNextViewer);

        s_hwndNextViewer = NULL;

        PostQuitMessage(0);
    }
        return 0;

    case WM_CREATE:
    {
        HWND first, next;
        DWORD error_code = 0;

        winDebug("winClipboardWindowProc - WM_CREATE\n");

        first = GetClipboardViewer();   /* Get handle to first viewer in chain. */
        if (first == hwnd)
            return 0;           /* Make sure it's not us! */
        /* Add ourselves to the clipboard viewer chain */
        next = SetClipboardViewer(hwnd);
        error_code = GetLastError();
        if (SUCCEEDED(error_code) && (next == first))   /* SetClipboardViewer must have succeeded, and the handle */
            s_hwndNextViewer = next;    /* it returned must have been the first window in the chain */
        else
            s_fCBCInitialized = FALSE;
    }
        return 0;

    case WM_CHANGECBCHAIN:
    {
        winDebug("winClipboardWindowProc - WM_CHANGECBCHAIN: wParam(%x) "
                 "lParam(%x) s_hwndNextViewer(%x)\n",
                 wParam, lParam, s_hwndNextViewer);

        if ((HWND) wParam == s_hwndNextViewer) {
            s_hwndNextViewer = (HWND) lParam;
            if (s_hwndNextViewer == hwnd) {
                s_hwndNextViewer = NULL;
                winErrorFVerb(1, "winClipboardWindowProc - WM_CHANGECBCHAIN: "
                              "attempted to set next window to ourselves.");
            }
        }
        else if (s_hwndNextViewer)
            SendMessage(s_hwndNextViewer, message, wParam, lParam);

    }
        winDebug("winClipboardWindowProc - WM_CHANGECBCHAIN: Exit\n");
        return 0;

    case WM_WM_REINIT:
    {
        /* Ensure that we're in the clipboard chain.  Some apps,
         * WinXP's remote desktop for one, don't play nice with the
         * chain.  This message is called whenever we receive a
         * WM_ACTIVATEAPP message to ensure that we continue to
         * receive clipboard messages.
         *
         * It might be possible to detect if we're still in the chain
         * by calling SendMessage (GetClipboardViewer(),
         * WM_DRAWCLIPBOARD, 0, 0); and then seeing if we get the
         * WM_DRAWCLIPBOARD message.  That, however, might be more
         * expensive than just putting ourselves back into the chain.
         */

        HWND first, next;
        DWORD error_code = 0;

        winDebug("winClipboardWindowProc - WM_WM_REINIT: Enter\n");

        first = GetClipboardViewer();   /* Get handle to first viewer in chain. */
        if (first == hwnd)
            return 0;           /* Make sure it's not us! */
        winDebug("  WM_WM_REINIT: Replacing us(%x) with %x at head "
                 "of chain\n", hwnd, s_hwndNextViewer);
        s_fCBCInitialized = FALSE;
        ChangeClipboardChain(hwnd, s_hwndNextViewer);
        s_hwndNextViewer = NULL;
        s_fCBCInitialized = FALSE;
        winDebug("  WM_WM_REINIT: Putting us back at head of chain.\n");
        first = GetClipboardViewer();   /* Get handle to first viewer in chain. */
        if (first == hwnd)
            return 0;           /* Make sure it's not us! */
        next = SetClipboardViewer(hwnd);
        error_code = GetLastError();
        if (SUCCEEDED(error_code) && (next == first))   /* SetClipboardViewer must have succeeded, and the handle */
            s_hwndNextViewer = next;    /* it returned must have been the first window in the chain */
        else
            s_fCBCInitialized = FALSE;
    }
        winDebug("winClipboardWindowProc - WM_WM_REINIT: Exit\n");
        return 0;

    case WM_DRAWCLIPBOARD:
    {
        static Atom atomClipboard;
        static int generation;
        static Bool s_fProcessingDrawClipboard = FALSE;
        Display *pDisplay = g_pClipboardDisplay;
        Window iWindow = g_iClipboardWindow;
        int iReturn;

        winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD: Enter\n");

        if (generation != serverGeneration) {
            generation = serverGeneration;
            atomClipboard = XInternAtom(pDisplay, "CLIPBOARD", False);
        }

        /*
         * We've occasionally seen a loop in the clipboard chain.
         * Try and fix it on the first hint of recursion.
         */
        if (!s_fProcessingDrawClipboard) {
            s_fProcessingDrawClipboard = TRUE;
        }
        else {
            /* Attempt to break the nesting by getting out of the chain, twice?, and then fix and bail */
            s_fCBCInitialized = FALSE;
            ChangeClipboardChain(hwnd, s_hwndNextViewer);
            winFixClipboardChain();
            winErrorFVerb(1, "winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                          "Nested calls detected.  Re-initing.\n");
            winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD: Exit\n");
            s_fProcessingDrawClipboard = FALSE;
            return 0;
        }

        /* Bail on first message */
        if (!s_fCBCInitialized) {
            s_fCBCInitialized = TRUE;
            s_fProcessingDrawClipboard = FALSE;
            winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD: Exit\n");
            return 0;
        }

        /*
         * NOTE: We cannot bail out when NULL == GetClipboardOwner ()
         * because some applications deal with the clipboard in a manner
         * that causes the clipboard owner to be NULL when they are in
         * fact taking ownership.  One example of this is the Win32
         * native compile of emacs.
         */

        /* Bail when we still own the clipboard */
        if (hwnd == GetClipboardOwner()) {

            winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                     "We own the clipboard, returning.\n");
            winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD: Exit\n");
            s_fProcessingDrawClipboard = FALSE;
            if (s_hwndNextViewer)
                SendMessage(s_hwndNextViewer, message, wParam, lParam);
            return 0;
        }

        /*
         * Do not take ownership of the X11 selections when something
         * other than CF_TEXT or CF_UNICODETEXT has been copied
         * into the Win32 clipboard.
         */
        if (!IsClipboardFormatAvailable(CF_TEXT)
            && !IsClipboardFormatAvailable(CF_UNICODETEXT)) {

            winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                     "Clipboard does not contain CF_TEXT nor "
                     "CF_UNICODETEXT.\n");

            /*
             * We need to make sure that the X Server has processed
             * previous XSetSelectionOwner messages.
             */
            XSync(pDisplay, FALSE);

            winDebug("winClipboardWindowProc - XSync done.\n");

            /* Release PRIMARY selection if owned */
            iReturn = XGetSelectionOwner(pDisplay, XA_PRIMARY);
            if (iReturn == g_iClipboardWindow) {
                winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                         "PRIMARY selection is owned by us.\n");
                XSetSelectionOwner(pDisplay, XA_PRIMARY, None, CurrentTime);
            }
            else if (BadWindow == iReturn || BadAtom == iReturn)
                winErrorFVerb(1, "winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                              "XGetSelection failed for PRIMARY: %d\n",
                              iReturn);

            /* Release CLIPBOARD selection if owned */
            iReturn = XGetSelectionOwner(pDisplay, atomClipboard);
            if (iReturn == g_iClipboardWindow) {
                winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                         "CLIPBOARD selection is owned by us.\n");
                XSetSelectionOwner(pDisplay, atomClipboard, None, CurrentTime);
            }
            else if (BadWindow == iReturn || BadAtom == iReturn)
                winErrorFVerb(1, "winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                              "XGetSelection failed for CLIPBOARD: %d\n",
                              iReturn);

            winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD: Exit\n");
            s_fProcessingDrawClipboard = FALSE;
            if (s_hwndNextViewer)
                SendMessage(s_hwndNextViewer, message, wParam, lParam);
            return 0;
        }

        /* Reassert ownership of PRIMARY */
        iReturn = XSetSelectionOwner(pDisplay,
                                     XA_PRIMARY, iWindow, CurrentTime);
        if (iReturn == BadAtom || iReturn == BadWindow ||
            XGetSelectionOwner(pDisplay, XA_PRIMARY) != iWindow) {
            winErrorFVerb(1, "winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                          "Could not reassert ownership of PRIMARY\n");
        }
        else {
            winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                     "Reasserted ownership of PRIMARY\n");
        }

        /* Reassert ownership of the CLIPBOARD */
        iReturn = XSetSelectionOwner(pDisplay,
                                     atomClipboard, iWindow, CurrentTime);

        if (iReturn == BadAtom || iReturn == BadWindow ||
            XGetSelectionOwner(pDisplay, atomClipboard) != iWindow) {
            winErrorFVerb(1, "winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                          "Could not reassert ownership of CLIPBOARD\n");
        }
        else {
            winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD - "
                     "Reasserted ownership of CLIPBOARD\n");
        }

        /* Flush the pending SetSelectionOwner event now */
        XFlush(pDisplay);

        s_fProcessingDrawClipboard = FALSE;
    }
        winDebug("winClipboardWindowProc - WM_DRAWCLIPBOARD: Exit\n");
        /* Pass the message on the next window in the clipboard viewer chain */
        if (s_hwndNextViewer)
            SendMessage(s_hwndNextViewer, message, wParam, lParam);
        return 0;

    case WM_DESTROYCLIPBOARD:
        /*
         * NOTE: Intentionally do nothing.
         * Changes in the Win32 clipboard are handled by WM_DRAWCLIPBOARD
         * above.  We only process this message to conform to the specs
         * for delayed clipboard rendering in Win32.  You might think
         * that we need to release ownership of the X11 selections, but
         * we do not, because a WM_DRAWCLIPBOARD message will closely
         * follow this message and reassert ownership of the X11
         * selections, handling the issue for us.
         */
        winDebug("winClipboardWindowProc - WM_DESTROYCLIPBOARD - Ignored.\n");
        return 0;

    case WM_RENDERFORMAT:
    case WM_RENDERALLFORMATS:
    {
        int iReturn;
        Display *pDisplay = g_pClipboardDisplay;
        Window iWindow = g_iClipboardWindow;
        Bool fConvertToUnicode;

        winDebug("winClipboardWindowProc - WM_RENDER*FORMAT - Hello.\n");

        /* Flag whether to convert to Unicode or not */
        if (message == WM_RENDERALLFORMATS)
            fConvertToUnicode = FALSE;
        else
            fConvertToUnicode = g_fUnicodeSupport && (CF_UNICODETEXT == wParam);

        /* Request the selection contents */
        iReturn = XConvertSelection(pDisplay,
                                    g_atomLastOwnedSelection,
                                    XInternAtom(pDisplay,
                                                "COMPOUND_TEXT", False),
                                    XInternAtom(pDisplay,
                                                "CYGX_CUT_BUFFER", False),
                                    iWindow, CurrentTime);
        if (iReturn == BadAtom || iReturn == BadWindow) {
            winErrorFVerb(1, "winClipboardWindowProc - WM_RENDER*FORMAT - "
                          "XConvertSelection () failed\n");
            break;
        }

        /* Special handling for WM_RENDERALLFORMATS */
        if (message == WM_RENDERALLFORMATS) {
            /* We must open and empty the clipboard */

            /* Close clipboard if we have it open already */
            if (GetOpenClipboardWindow() == hwnd) {
                CloseClipboard();
            }

            if (!OpenClipboard(hwnd)) {
                winErrorFVerb(1, "winClipboardWindowProc - WM_RENDER*FORMATS - "
                              "OpenClipboard () failed: %08x\n",
                              GetLastError());
                break;
            }

            if (!EmptyClipboard()) {
                winErrorFVerb(1, "winClipboardWindowProc - WM_RENDER*FORMATS - "
                              "EmptyClipboard () failed: %08x\n",
                              GetLastError());
                break;
            }
        }

        /* Process the SelectionNotify event */
        iReturn = winProcessXEventsTimeout(hwnd,
                                           iWindow,
                                           pDisplay,
                                           fConvertToUnicode, WIN_POLL_TIMEOUT);

        /*
         * The last call to winProcessXEventsTimeout
         * from above had better have seen a notify event, or else we
         * are dealing with a buggy or old X11 app.  In these cases we
         * have to paste some fake data to the Win32 clipboard to
         * satisfy the requirement that we write something to it.
         */
        if (WIN_XEVENTS_NOTIFY != iReturn) {
            /* Paste no data, to satisfy required call to SetClipboardData */
            if (g_fUnicodeSupport)
                SetClipboardData(CF_UNICODETEXT, NULL);
            SetClipboardData(CF_TEXT, NULL);

            ErrorF
                ("winClipboardWindowProc - timed out waiting for WIN_XEVENTS_NOTIFY\n");
        }

        /* Special handling for WM_RENDERALLFORMATS */
        if (message == WM_RENDERALLFORMATS) {
            /* We must close the clipboard */

            if (!CloseClipboard()) {
                winErrorFVerb(1,
                              "winClipboardWindowProc - WM_RENDERALLFORMATS - "
                              "CloseClipboard () failed: %08x\n",
                              GetLastError());
                break;
            }
        }

        winDebug("winClipboardWindowProc - WM_RENDER*FORMAT - Returning.\n");
        return 0;
    }
    }

    /* Let Windows perform default processing for unhandled messages */
    return DefWindowProc(hwnd, message, wParam, lParam);
}

/*
 * Process any pending Windows messages
 */

BOOL
winClipboardFlushWindowsMessageQueue(HWND hwnd)
{
    MSG msg;

    /* Flush the messaging window queue */
    /* NOTE: Do not pass the hwnd of our messaging window to PeekMessage,
     * as this will filter out many non-window-specific messages that
     * are sent to our thread, such as WM_QUIT.
     */
    while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) {
        /* Dispatch the message if not WM_QUIT */
        if (msg.message == WM_QUIT)
            return FALSE;
        else
            DispatchMessage(&msg);
    }

    return TRUE;
}