/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.widgets;


import org.eclipse.swt.internal.*;
import org.eclipse.swt.internal.win32.*;
import org.eclipse.swt.*;

/**
 * Instances of this class allow the user to navigate
 * the file system and select or enter a file name.
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>SAVE, OPEN, MULTI</dd>
 * <dt><b>Events:</b></dt>
 * <dd>(none)</dd>
 * </dl>
 * <p>
 * Note: Only one of the styles SAVE and OPEN may be specified.
 * </p><p>
 * IMPORTANT: This class is intended to be subclassed <em>only</em>
 * within the SWT implementation.
 * </p>
 * 
 * @see <a href="http://www.eclipse.org/swt/snippets/#filedialog">FileDialog snippets</a>
 * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample, Dialog tab</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */
public class FileDialog extends Dialog {
	String [] filterNames = new String [0];
	String [] filterExtensions = new String [0];
	String [] fileNames = new String [0];
	String filterPath = "", fileName = "";
	int filterIndex = 0;
	boolean overwrite = false;
	static final String FILTER = "*.*";
	static int BUFFER_SIZE = 1024 * 32;
	static boolean USE_HOOK = true;
	static {
		/*
		*  Feature in Vista.  When OFN_ENABLEHOOK is set in the
		*  save or open file dialog,  Vista uses the old XP look
		*  and feel.  OFN_ENABLEHOOK is used to grow the file
		*  name buffer in a multi-select file dialog.  The fix
		*  is to only use OFN_ENABLEHOOK when the buffer has
		*  overrun.
		*/
		if (!OS.IsWinCE && OS.WIN32_VERSION >= OS.VERSION (6, 0)) {
			USE_HOOK = false;
		}
	}

/**
 * Constructs a new instance of this class given only its parent.
 *
 * @param parent a shell which will be the parent of the new instance
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 */
public FileDialog (Shell parent) {
	this (parent, SWT.APPLICATION_MODAL);
}

/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together 
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a shell which will be the parent of the new instance
 * @param style the style of dialog to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 */
public FileDialog (Shell parent, int style) {
	super (parent, checkStyle (parent, style));
	checkSubclass ();
}

/**
 * Returns the path of the first file that was
 * selected in the dialog relative to the filter path, or an
 * empty string if no such file has been selected.
 * 
 * @return the relative path of the file
 */
public String getFileName () {
	return fileName;
}

/**
 * Returns a (possibly empty) array with the paths of all files
 * that were selected in the dialog relative to the filter path.
 * 
 * @return the relative paths of the files
 */
public String [] getFileNames () {
	return fileNames;
}

/**
 * Returns the file extensions which the dialog will
 * use to filter the files it shows.
 *
 * @return the file extensions filter
 */
public String [] getFilterExtensions () {
	return filterExtensions;
}

/**
 * Get the 0-based index of the file extension filter
 * which was selected by the user, or -1 if no filter
 * was selected.
 * <p>
 * This is an index into the FilterExtensions array and
 * the FilterNames array.
 * </p>
 *
 * @return index the file extension filter index
 * 
 * @see #getFilterExtensions
 * @see #getFilterNames
 * 
 * @since 3.4
 */
public int getFilterIndex () {
	return filterIndex;
}

/**
 * Returns the names that describe the filter extensions
 * which the dialog will use to filter the files it shows.
 *
 * @return the list of filter names
 */
public String [] getFilterNames () {
	return filterNames;
}

/**
 * Returns the directory path that the dialog will use, or an empty
 * string if this is not set.  File names in this path will appear
 * in the dialog, filtered according to the filter extensions.
 *
 * @return the directory path string
 * 
 * @see #setFilterExtensions
 */
public String getFilterPath () {
	return filterPath;
}

/**
 * Returns the flag that the dialog will use to
 * determine whether to prompt the user for file
 * overwrite if the selected file already exists.
 *
 * @return true if the dialog will prompt for file overwrite, false otherwise
 * 
 * @since 3.4
 */
public boolean getOverwrite () {
	return overwrite;
}

int /*long*/ OFNHookProc (int /*long*/ hdlg, int /*long*/ uiMsg, int /*long*/ wParam, int /*long*/ lParam) {
	switch ((int)/*64*/uiMsg) {
		case OS.WM_NOTIFY:
			OFNOTIFY ofn = new OFNOTIFY ();
			OS.MoveMemory (ofn, lParam, OFNOTIFY.sizeof);
			if (ofn.code == OS.CDN_SELCHANGE) {
				int lResult = (int)/*64*/OS.SendMessage (ofn.hwndFrom, OS.CDM_GETSPEC, 0, 0);
				if (lResult > 0) {
					lResult += OS.MAX_PATH;
					OPENFILENAME lpofn = new OPENFILENAME ();
					OS.MoveMemory (lpofn, ofn.lpOFN, OPENFILENAME.sizeof);
					if (lpofn.nMaxFile < lResult) {
						int /*long*/ hHeap = OS.GetProcessHeap ();
						int /*long*/ lpstrFile = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, lResult * TCHAR.sizeof);
						if (lpstrFile != 0) {
							if (lpofn.lpstrFile != 0) OS.HeapFree (hHeap, 0, lpofn.lpstrFile);
							lpofn.lpstrFile = lpstrFile;
							lpofn.nMaxFile = lResult;
							OS.MoveMemory (ofn.lpOFN, lpofn, OPENFILENAME.sizeof);
						}
					}
			  }
		  }
		  break;
	}
	return 0;
}

/**
 * Makes the dialog visible and brings it to the front
 * of the display.
 *
 * @return a string describing the absolute path of the first selected file,
 *         or null if the dialog was cancelled or an error occurred
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the dialog has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the dialog</li>
 * </ul>
 */
public String open () {
	int /*long*/ hHeap = OS.GetProcessHeap ();
	
	/* Get the owner HWND for the dialog */
	int /*long*/ hwndOwner = parent.handle;
	int /*long*/ hwndParent = parent.handle;
	
	/*
	* Feature in Windows.  There is no API to set the orientation of a
	* file dialog.  It is always inherited from the parent.  The fix is
	* to create a hidden parent and set the orientation in the hidden
	* parent for the dialog to inherit.
	*/
	boolean enabled = false;
	if (!OS.IsWinCE && OS.WIN32_VERSION >= OS.VERSION(4, 10)) {
		int dialogOrientation = style & (SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT);
		int parentOrientation = parent.style & (SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT);
		if (dialogOrientation != parentOrientation) {
			int exStyle = OS.WS_EX_NOINHERITLAYOUT;
			if (dialogOrientation == SWT.RIGHT_TO_LEFT) exStyle |= OS.WS_EX_LAYOUTRTL;
			hwndOwner = OS.CreateWindowEx (
				exStyle,
				Shell.DialogClass,
				null,
				0,
				OS.CW_USEDEFAULT, 0, OS.CW_USEDEFAULT, 0,
				hwndParent,
				0,
				OS.GetModuleHandle (null),
				null);
			enabled = OS.IsWindowEnabled (hwndParent);
			if (enabled) OS.EnableWindow (hwndParent, false);
		}
	}
		
	/* Convert the title and copy it into lpstrTitle */
	if (title == null) title = "";	
	/* Use the character encoding for the default locale */
	TCHAR buffer3 = new TCHAR (0, title, true);
	int byteCount3 = buffer3.length () * TCHAR.sizeof;
	int /*long*/ lpstrTitle = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount3);
	OS.MoveMemory (lpstrTitle, buffer3, byteCount3); 

	/* Compute filters and copy into lpstrFilter */
	String strFilter = "";
	if (filterNames == null) filterNames = new String [0];
	if (filterExtensions == null) filterExtensions = new String [0];
	for (int i=0; i<filterExtensions.length; i++) {
		String filterName = filterExtensions [i];
		if (i < filterNames.length) filterName = filterNames [i];
		strFilter = strFilter + filterName + '\0' + filterExtensions [i] + '\0';
	}
	if (filterExtensions.length == 0) {
		strFilter = strFilter + FILTER + '\0' + FILTER + '\0';
	}
	/* Use the character encoding for the default locale */
	TCHAR buffer4 = new TCHAR (0, strFilter, true);
	int byteCount4 = buffer4.length () * TCHAR.sizeof;
	int /*long*/ lpstrFilter = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount4);
	OS.MoveMemory (lpstrFilter, buffer4, byteCount4);
	
	/* Convert the fileName and filterName to C strings */
	if (fileName == null) fileName = "";
	/* Use the character encoding for the default locale */
	TCHAR name = new TCHAR (0, fileName, true);

	/*
	* Copy the name into lpstrFile and ensure that the
	* last byte is NULL and the buffer does not overrun.
	*/
	int nMaxFile = OS.MAX_PATH;
	if ((style & SWT.MULTI) != 0) nMaxFile = Math.max (nMaxFile, BUFFER_SIZE);
	int byteCount = nMaxFile * TCHAR.sizeof;
	int /*long*/ lpstrFile = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount);
	int byteCountFile = Math.min (name.length () * TCHAR.sizeof, byteCount - TCHAR.sizeof);
	OS.MoveMemory (lpstrFile, name, byteCountFile);

	/*
	* Copy the path into lpstrInitialDir and ensure that
	* the last byte is NULL and the buffer does not overrun.
	*/
	if (filterPath == null) filterPath = "";
	/* Use the character encoding for the default locale */
	TCHAR path = new TCHAR (0, filterPath.replace ('/', '\\'), true);
	int byteCount5 = OS.MAX_PATH * TCHAR.sizeof;
	int /*long*/ lpstrInitialDir = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount5);
	int byteCountDir = Math.min (path.length () * TCHAR.sizeof, byteCount5 - TCHAR.sizeof);
	OS.MoveMemory (lpstrInitialDir, path, byteCountDir);

	/* Create the file dialog struct */
	OPENFILENAME struct = new OPENFILENAME ();
	struct.lStructSize = OPENFILENAME.sizeof;
	struct.Flags = OS.OFN_HIDEREADONLY | OS.OFN_NOCHANGEDIR;
	boolean save = (style & SWT.SAVE) != 0;
	if (save && overwrite) struct.Flags |= OS.OFN_OVERWRITEPROMPT;
	Callback callback = null;
	if ((style & SWT.MULTI) != 0) {
		struct.Flags |= OS.OFN_ALLOWMULTISELECT | OS.OFN_EXPLORER;
		if (!OS.IsWinCE && USE_HOOK) {
			callback = new Callback (this, "OFNHookProc", 4); //$NON-NLS-1$
			int /*long*/ lpfnHook = callback.getAddress ();
			if (lpfnHook == 0) SWT.error (SWT.ERROR_NO_MORE_CALLBACKS);
			struct.lpfnHook = lpfnHook;
			struct.Flags |= OS.OFN_ENABLEHOOK;
		}
	}
	struct.hwndOwner = hwndOwner;
	struct.lpstrTitle = lpstrTitle;
	struct.lpstrFile = lpstrFile;
	struct.nMaxFile = nMaxFile;
	struct.lpstrInitialDir = lpstrInitialDir;
	struct.lpstrFilter = lpstrFilter;
	struct.nFilterIndex = filterIndex == 0 ? filterIndex : filterIndex + 1;

	/*
	* Set the default extension to an empty string.  If the
	* user fails to type an extension and this extension is
	* empty, Windows uses the current value of the filter
	* extension at the time that the dialog is closed.
	*/
	int /*long*/ lpstrDefExt = 0;
	if (save) {
		lpstrDefExt = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, TCHAR.sizeof);
		struct.lpstrDefExt = lpstrDefExt;
	}
	
	/* Make the parent shell be temporary modal */
	Dialog oldModal = null;
	Display display = parent.getDisplay ();
	if ((style & (SWT.APPLICATION_MODAL | SWT.SYSTEM_MODAL)) != 0) {
		oldModal = display.getModalDialog ();
		display.setModalDialog (this);
	}
	
	/*
	* Feature in Windows.  For some reason, the WH_MSGFILTER filter
	* does not run for GetSaveFileName() or GetOpenFileName().  The
	* fix is to allow async messages to run in the WH_FOREGROUNDIDLE
	* hook instead.
	* 
	* Bug in Windows 98.  For some reason, when certain operating
	* system calls such as Shell_NotifyIcon(), GetOpenFileName()
	* and GetSaveFileName() are made during the WH_FOREGROUNDIDLE
	* hook, Windows hangs.  The fix is to disallow async messages
	* during WH_FOREGROUNDIDLE.
	*/
	boolean oldRunMessagesInIdle = display.runMessagesInIdle;
	display.runMessagesInIdle = !OS.IsWin95;
	/*
	* Open the dialog.  If the open fails due to an invalid
	* file name, use an empty file name and open it again.
	*/
	boolean success = (save) ? OS.GetSaveFileName (struct) : OS.GetOpenFileName (struct);
	switch (OS.CommDlgExtendedError ()) {
		case OS.FNERR_INVALIDFILENAME:
			OS.MoveMemory (lpstrFile, new TCHAR (0, "", true), TCHAR.sizeof);
			success = (save) ? OS.GetSaveFileName (struct) : OS.GetOpenFileName (struct);
			break;
		case OS.FNERR_BUFFERTOOSMALL: 
			USE_HOOK = true;
			break;
	}
	display.runMessagesInIdle = oldRunMessagesInIdle;
	
	/* Clear the temporary dialog modal parent */
	if ((style & (SWT.APPLICATION_MODAL | SWT.SYSTEM_MODAL)) != 0) {
		display.setModalDialog (oldModal);
	}

	/* Dispose the callback and reassign the buffer */
	if (callback != null) callback.dispose ();
	lpstrFile = struct.lpstrFile;

	/* Set the new path, file name and filter */
	fileNames = new String [0];
	String fullPath = null;
	if (success) {
		
		/* Use the character encoding for the default locale */
		TCHAR buffer = new TCHAR (0, struct.nMaxFile);
		int byteCount1 = buffer.length () * TCHAR.sizeof;
		OS.MoveMemory (buffer, lpstrFile, byteCount1);
		
		/*
		* Bug in WinCE.  For some reason, nFileOffset and nFileExtension
		* are always zero on WinCE HPC. nFileOffset is always zero on
		* WinCE PPC when using GetSaveFileName().  nFileOffset is correctly
		* set on WinCE PPC when using OpenFileName().  The fix is to parse
		* lpstrFile to calculate nFileOffset.
		* 
		* Note: WinCE does not support multi-select file dialogs.
		*/
		int nFileOffset = struct.nFileOffset;
		if (OS.IsWinCE && nFileOffset == 0) {
			int index = 0; 
			while (index < buffer.length ()) {
				int ch = buffer.tcharAt (index);
				if (ch == 0) break;
				if (ch == '\\') nFileOffset = index + 1;
				index++;
			}
		}
		if (nFileOffset > 0) {
		
			/* Use the character encoding for the default locale */
			TCHAR prefix = new TCHAR (0, nFileOffset - 1);
			int byteCount2 = prefix.length () * TCHAR.sizeof;
			OS.MoveMemory (prefix, lpstrFile, byteCount2);
			filterPath = prefix.toString (0, prefix.length ());
			
			/*
			* Get each file from the buffer.  Files are delimited
			* by a NULL character with 2 NULL characters at the end.
			*/
			int count = 0;
			fileNames = new String [(style & SWT.MULTI) != 0 ? 4 : 1];
			int start = nFileOffset;
			do {
				int end = start;
				while (end < buffer.length () && buffer.tcharAt (end) != 0) end++;
				String string = buffer.toString (start, end - start);
				start = end;
				if (count == fileNames.length) {
					String [] newFileNames = new String [fileNames.length + 4];
					System.arraycopy (fileNames, 0, newFileNames, 0, fileNames.length);
					fileNames = newFileNames;
				}
				fileNames [count++] = string;
				if ((style & SWT.MULTI) == 0) break;
				start++;
			} while (start < buffer.length () && buffer.tcharAt (start) != 0);
			
			if (fileNames.length > 0) fileName = fileNames  [0];
			String separator = "";
			int length = filterPath.length ();
			if (length > 0 && filterPath.charAt (length - 1) != '\\') {
				separator = "\\";
			}
			fullPath = filterPath + separator + fileName;
			if (count < fileNames.length) {
				String [] newFileNames = new String [count];
				System.arraycopy (fileNames, 0, newFileNames, 0, count);
				fileNames = newFileNames;
			}
		}
		filterIndex = struct.nFilterIndex - 1;
	}
	
	/* Free the memory that was allocated. */
	OS.HeapFree (hHeap, 0, lpstrFile);
	OS.HeapFree (hHeap, 0, lpstrFilter);
	OS.HeapFree (hHeap, 0, lpstrInitialDir);
	OS.HeapFree (hHeap, 0, lpstrTitle);
	if (lpstrDefExt != 0) OS.HeapFree (hHeap, 0, lpstrDefExt);

	/* Destroy the BIDI orientation window */
	if (hwndParent != hwndOwner) {
		if (enabled) OS.EnableWindow (hwndParent, true);
		OS.SetActiveWindow (hwndParent);
		OS.DestroyWindow (hwndOwner);
	}
	
	/*
	* This code is intentionally commented.  On some
	* platforms, the owner window is repainted right
	* away when a dialog window exits.  This behavior
	* is currently unspecified.
	*/
//	if (hwndOwner != 0) OS.UpdateWindow (hwndOwner);
	
	/* Answer the full path or null */
	return fullPath;
}

/**
 * Set the initial filename which the dialog will
 * select by default when opened to the argument,
 * which may be null.  The name will be prefixed with
 * the filter path when one is supplied.
 * 
 * @param string the file name
 */
public void setFileName (String string) {
	fileName = string;
}

/**
 * Set the file extensions which the dialog will
 * use to filter the files it shows to the argument,
 * which may be null.
 * <p>
 * The strings are platform specific. For example, on
 * some platforms, an extension filter string is typically
 * of the form "*.extension", where "*.*" matches all files.
 * For filters with multiple extensions, use semicolon as
 * a separator, e.g. "*.jpg;*.png".
 * </p>
 *
 * @param extensions the file extension filter
 * 
 * @see #setFilterNames to specify the user-friendly
 * names corresponding to the extensions
 */
public void setFilterExtensions (String [] extensions) {
	filterExtensions = extensions;
}

/**
 * Set the 0-based index of the file extension filter
 * which the dialog will use initially to filter the files
 * it shows to the argument.
 * <p>
 * This is an index into the FilterExtensions array and
 * the FilterNames array.
 * </p>
 *
 * @param index the file extension filter index
 * 
 * @see #setFilterExtensions
 * @see #setFilterNames
 * 
 * @since 3.4
 */
public void setFilterIndex (int index) {
	filterIndex = index;
}

/**
 * Sets the names that describe the filter extensions
 * which the dialog will use to filter the files it shows
 * to the argument, which may be null.
 * <p>
 * Each name is a user-friendly short description shown for
 * its corresponding filter. The <code>names</code> array must
 * be the same length as the <code>extensions</code> array.
 * </p>
 *
 * @param names the list of filter names, or null for no filter names
 * 
 * @see #setFilterExtensions
 */
public void setFilterNames (String [] names) {
	filterNames = names;
}

/**
 * Sets the directory path that the dialog will use
 * to the argument, which may be null. File names in this
 * path will appear in the dialog, filtered according
 * to the filter extensions. If the string is null,
 * then the operating system's default filter path
 * will be used.
 * <p>
 * Note that the path string is platform dependent.
 * For convenience, either '/' or '\' can be used
 * as a path separator.
 * </p>
 *
 * @param string the directory path
 * 
 * @see #setFilterExtensions
 */
public void setFilterPath (String string) {
	filterPath = string;
}

/**
 * Sets the flag that the dialog will use to
 * determine whether to prompt the user for file
 * overwrite if the selected file already exists.
 *
 * @param overwrite true if the dialog will prompt for file overwrite, false otherwise
 * 
 * @since 3.4
 */
public void setOverwrite (boolean overwrite) {
	this.overwrite = overwrite;
}
}
