/*
 *  This file is part of RawTherapee.
 *
 *  Copyright (c) 2004-2010 Gabor Horvath <hgabor@rawtherapee.com>
 *
 *  RawTherapee is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  RawTherapee is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with RawTherapee.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "windirmonitor.h"
#include "options.h"

static void CALLBACK current_directory_monitor_callback (DWORD error, DWORD nBytes, LPOVERLAPPED lpOverlapped)
{
    DWORD dwOffset = 0;
    FILE_NOTIFY_INFORMATION* pInfo = NULL;

    WinDirMonitor::MonitorData* monData = (WinDirMonitor::MonitorData*)lpOverlapped;

    if (!nBytes) {
        delete monData;
        return;
    }

    bool notify = false;

    // Analysis of the modifications. Let only parsed file extensions emit a notify, not PP3 changes
    do {
        // Get a pointer to the first change record...
        pInfo = (FILE_NOTIFY_INFORMATION*) &monData->file_notify_buffer[dwOffset];

        char fnameC[(MAX_PATH + 1) * 2] = {0};
        int strLen = WideCharToMultiByte(CP_UTF8, 0, pInfo->FileName, pInfo->FileNameLength / sizeof(WCHAR), fnameC, sizeof(fnameC), 0, 0);
        fnameC[strLen] = 0;
        Glib::ustring fname = fnameC;

        if (options.has_retained_extention(fname)) {
            notify = true;
        }

        // More than one change may happen at the same time. Load the next change and continue...
        dwOffset += pInfo->NextEntryOffset;
    } while (!notify && pInfo->NextEntryOffset != 0);

    // ReadDirectoryChangesW sometimes emits multiple events per change (one for each change type)
    // To make sure it's not flooding update, this gets filtered.
    DWORD curTick = GetTickCount();

    if (notify && monData->listener && (curTick - monData->lastTimeUpdateTick) > 500) {
        monData->lastTimeUpdateTick = curTick;
        monData->listener->winDirChanged ();
    }

    ReadDirectoryChangesW (monData->hDirectory,
                           monData->file_notify_buffer,
                           monData->buffer_allocated_bytes,
                           FALSE,
                           FILE_NOTIFY_CHANGE_FILE_NAME |
                           FILE_NOTIFY_CHANGE_DIR_NAME |
                           FILE_NOTIFY_CHANGE_LAST_WRITE,
                           &monData->buffer_filled_bytes,
                           &monData->overlapped,
                           current_directory_monitor_callback);
}

WinDirMonitor::WinDirMonitor (Glib::ustring dirName, WinDirChangeListener* listener)  : monData(NULL)
{
    wchar_t* wdirname = (wchar_t*)g_utf8_to_utf16 (dirName.c_str(), -1, NULL, NULL, NULL);
    HANDLE hDirectory = CreateFileW (wdirname, FILE_LIST_DIRECTORY, FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED, NULL);
    g_free (wdirname);

    if (hDirectory != INVALID_HANDLE_VALUE) {

        monData = new MonitorData ();
        monData->listener = listener;
        monData->buffer_allocated_bytes = 32768;
        monData->file_notify_buffer = new char [monData->buffer_allocated_bytes];
        monData->hDirectory = hDirectory;
        monData->lastTimeUpdateTick = GetTickCount();

        ReadDirectoryChangesW (monData->hDirectory,
                               monData->file_notify_buffer,
                               monData->buffer_allocated_bytes,
                               FALSE,
                               FILE_NOTIFY_CHANGE_FILE_NAME |
                               FILE_NOTIFY_CHANGE_DIR_NAME |
                               FILE_NOTIFY_CHANGE_LAST_WRITE,
                               &monData->buffer_filled_bytes,
                               &monData->overlapped,
                               current_directory_monitor_callback);
    }
}

WinDirMonitor::~WinDirMonitor ()
{

    if (monData && monData->hDirectory != INVALID_HANDLE_VALUE) {
        CloseHandle (monData->hDirectory);
    }
}