/*******************************************************************************
 * Copyright (c) 2007, 2017 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.widgets;

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.internal.*;
import org.eclipse.swt.internal.cocoa.*;

/**
 * Instances of this class represent input method editors.
 * These are typically in-line pre-edit text areas that allow
 * the user to compose characters from Far Eastern languages
 * such as Japanese, Chinese or Korean.
 *
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>(none)</dd>
 * <dt><b>Events:</b></dt>
 * <dd>ImeComposition</dd>
 * </dl>
 * <p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 *
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 *
 * @since 3.4
 * @noextend This class is not intended to be subclassed by clients.
 */
public class IME extends Widget {
	Canvas parent;
	int caretOffset;
	int startOffset;
	int commitCount;
	String text;
	int [] ranges;
	TextStyle [] styles;

	static final int UNDERLINE_THICK = 1 << 16;

/**
 * Prevents uninitialized instances from being created outside the package.
 */
IME () {
}

/**
 * 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 canvas control which will be the parent of the new instance (cannot be null)
 * @param style the style of control 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>
 *
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public IME (Canvas parent, int style) {
	super (parent, style);
	this.parent = parent;
	createWidget ();
}

@Override
long attributedSubstringFromRange (long id, long sel, long rangePtr) {
	Event event = new Event ();
	event.detail = SWT.COMPOSITION_SELECTION;
	sendEvent (SWT.ImeComposition, event);
	NSRange range = new NSRange ();
	OS.memmove (range, rangePtr, NSRange.sizeof);
	int start = (int)range.location;
	int end = (int)(range.location + range.length);
	if (event.start <= start && start <= event.end && event.start <= end && end <= event.end) {
		NSString str = (NSString) new NSString().alloc();
		str = str.initWithString(event.text.substring(start - event.start, end - event.start));
		NSAttributedString attriStr = ((NSAttributedString)new NSAttributedString().alloc()).initWithString(str, null);
		str.release();
		attriStr.autorelease ();
		return attriStr.id;
	}
	return 0;
}

@Override
long characterIndexForPoint (long id, long sel, long point) {
	if (!isInlineEnabled ()) return OS.NSNotFound();
	NSPoint pt = new NSPoint ();
	OS.memmove (pt, point, NSPoint.sizeof);
	NSView view = parent.view;
	pt = view.window ().convertScreenToBase (pt);
	pt = view.convertPoint_fromView_ (pt, null);
	Event event = new Event ();
	event.detail = SWT.COMPOSITION_OFFSET;
	event.x = (int) pt.x;
	event.y = (int) pt.y;
	sendEvent (SWT.ImeComposition, event);
	int offset = event.index + event.count;
	return offset != -1 ? offset : OS.NSNotFound();
}

@Override
void createWidget () {
	text = "";
	startOffset = -1;
	if (parent.getIME () == null) {
		parent.setIME (this);
	}
}

@Override
NSRect firstRectForCharacterRange(long id, long sel, long range) {
	NSRect rect = new NSRect ();
	Caret caret = parent.caret;
	if (caret != null) {
		NSView view = parent.view;
		NSPoint pt = new NSPoint ();
		pt.x = caret.x;
		pt.y = caret.y + caret.height;
		pt = view.convertPoint_toView_ (pt, null);
		pt = view.window ().convertBaseToScreen (pt);
		rect.x = pt.x;
		rect.y = pt.y;
		rect.width = caret.width;
		rect.height = caret.height;
	}
	return rect;
}

/**
 * Returns the offset of the caret from the start of the document.
 * -1 means that there is currently no active composition.
 * The caret is within the current composition.
 *
 * @return the caret offset
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getCaretOffset () {
	checkWidget ();
	return startOffset + caretOffset;
}

/**
 * Returns the commit count of the composition.  This is the
 * number of characters that have been composed.  When the
 * commit count is equal to the length of the composition
 * text, then the in-line edit operation is complete.
 *
 * @return the commit count
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see IME#getText
 */
public int getCommitCount () {
	checkWidget ();
	return commitCount;
}

/**
 * Returns the offset of the composition from the start of the document.
 * This is the start offset of the composition within the document and
 * in not changed by the input method editor itself during the in-line edit
 * session.
 *
 * @return the offset of the composition
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getCompositionOffset () {
	checkWidget ();
	return startOffset;
}

/**
 * Returns the ranges for the style that should be applied during the
 * in-line edit session.
 * <p>
 * The ranges array contains start and end pairs.  Each pair refers to
 * the corresponding style in the styles array.  For example, the pair
 * that starts at ranges[n] and ends at ranges[n+1] uses the style
 * at styles[n/2] returned by <code>getStyles()</code>.
 * </p>
 * @return the ranges for the styles
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see IME#getStyles
 */
public int [] getRanges () {
	checkWidget ();
	if (ranges == null) return new int [0];
	int [] result = new int [ranges.length];
	for (int i = 0; i < result.length; i++) {
		result [i] = ranges [i] + startOffset;
	}
	return result;
}

/**
 * Returns the styles for the ranges.
 * <p>
 * The ranges array contains start and end pairs.  Each pair refers to
 * the corresponding style in the styles array.  For example, the pair
 * that starts at ranges[n] and ends at ranges[n+1] uses the style
 * at styles[n/2].
 * </p>
 *
 * @return the ranges for the styles
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see IME#getRanges
 */
public TextStyle [] getStyles () {
	checkWidget ();
	if (styles == null) return new TextStyle [0];
	TextStyle [] result = new TextStyle [styles.length];
	System.arraycopy (styles, 0, result, 0, styles.length);
	return result;
}

TextStyle getStyle (NSDictionary attribs) {
	NSArray keys = attribs.allKeys ();
	long count = keys.count ();
	TextStyle style = new TextStyle ();
	for (int j = 0; j < count; j++) {
		NSString key = new NSString (keys.objectAtIndex (j));
		if (key.isEqual (OS.NSBackgroundColorAttributeName)) {
			NSColor color = new NSColor (attribs.objectForKey (key));
			style.background = Color.cocoa_new (display, display.getNSColorRGB(color));
		} else if (key.isEqual (OS.NSForegroundColorAttributeName)) {
			NSColor color = new NSColor (attribs.objectForKey (key));
			style.foreground = Color.cocoa_new (display, display.getNSColorRGB(color));
		} else if (key.isEqual (OS.NSUnderlineColorAttributeName)) {
			NSColor color = new NSColor (attribs.objectForKey (key));
			style.underlineColor = Color.cocoa_new (display, display.getNSColorRGB(color));
		} else if (key.isEqual (OS.NSUnderlineStyleAttributeName)) {
			NSNumber value = new NSNumber (attribs.objectForKey (key));
			switch (value.intValue ()) {
				case OS.NSUnderlineStyleSingle: style.underlineStyle = SWT.UNDERLINE_SINGLE; break;
				case OS.NSUnderlineStyleDouble: style.underlineStyle = SWT.UNDERLINE_DOUBLE; break;
				case OS.NSUnderlineStyleThick: style.underlineStyle = UNDERLINE_THICK; break;
			}
			style.underline = value.intValue () != OS.NSUnderlineStyleNone;
		} else if (key.isEqual (OS.NSStrikethroughColorAttributeName)) {
			NSColor color = new NSColor (attribs.objectForKey (key));
			style.strikeoutColor = Color.cocoa_new (display, display.getNSColorRGB(color));
		} else if (key.isEqual (OS.NSStrikethroughStyleAttributeName)) {
			NSNumber value = new NSNumber (attribs.objectForKey (key));
			style.strikeout = value.intValue () != OS.NSUnderlineStyleNone;
		} else if (key.isEqual (OS.NSFontAttributeName)) {
			NSFont font = new NSFont (attribs.objectForKey (key));
			font.retain();
			style.font = Font.cocoa_new (display, font);
		}
	}
	return style;
}

/**
 * Returns the composition text.
 * <p>
 * The text for an IME is the characters in the widget that
 * are in the current composition. When the commit count is
 * equal to the length of the composition text, then the
 * in-line edit operation is complete.
 * </p>
 *
 * @return the widget text
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public String getText () {
	checkWidget ();
	return text;
}

/**
 * Returns <code>true</code> if the caret should be wide, and
 * <code>false</code> otherwise.  In some languages, for example
 * Korean, the caret is typically widened to the width of the
 * current character in the in-line edit session.
 *
 * @return the wide caret state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public boolean getWideCaret() {
	return false;
}

@Override
boolean hasMarkedText (long id, long sel) {
	return text.length () != 0;
}

@Override
boolean insertText (long id, long sel, long string) {
	if (startOffset == -1) return true;
	NSString str = new NSString (string);
	if (str.isKindOfClass (OS.class_NSAttributedString)) {
		str = new NSAttributedString (string).string ();
	}
	int length = (int)str.length ();
	int end = startOffset + text.length ();
	resetStyles ();
	caretOffset = commitCount = length;
	Event event = new Event ();
	event.detail = SWT.COMPOSITION_CHANGED;
	event.start = startOffset;
	event.end = end;
	event.text = text = str.getString();
	sendEvent (SWT.ImeComposition, event);
	text = "";
	caretOffset = commitCount = 0;
	startOffset = -1;
	return event.doit;
}

boolean isInlineEnabled () {
	return hooks (SWT.ImeComposition);
}

@Override
NSRange markedRange (long id, long sel) {
	NSRange range = new NSRange ();
	if (startOffset != -1) {
		range.location = startOffset;
		range.length = text.length ();
	} else {
		range.location = OS.NSNotFound();
	}
	return range;
}

void resetStyles () {
	if (styles != null) {
		for (int i = 0; i < styles.length; i++) {
			TextStyle style = styles [i];
			Font font = style.font;
			if (font != null) font.handle.release ();
		}
	}
	styles = null;
	ranges = null;
}

@Override
void releaseParent () {
	super.releaseParent ();
	if (this == parent.getIME ()) parent.setIME (null);
}

@Override
void releaseWidget () {
	super.releaseWidget ();
	parent = null;
	text = null;
	resetStyles ();
}

@Override
NSRange selectedRange (long id, long sel) {
	Event event = new Event ();
	event.detail = SWT.COMPOSITION_SELECTION;
	sendEvent (SWT.ImeComposition, event);
	NSRange range = new NSRange ();
	range.location = event.start;
	range.length = event.text.length ();
	return range;
}

/**
 * Sets the offset of the composition from the start of the document.
 * This is the start offset of the composition within the document and
 * in not changed by the input method editor itself during the in-line edit
 * session but may need to be changed by clients of the IME.  For example,
 * if during an in-line edit operation, a text editor inserts characters
 * above the IME, then the IME must be informed that the composition
 * offset has changed.
 *
 * @param offset the offset of the composition
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setCompositionOffset (int offset) {
	checkWidget ();
	if (offset < 0) return;
	if (startOffset != -1) {
		startOffset = offset;
	}
}

@Override
boolean setMarkedText_selectedRange (long id, long sel, long string, long selRange) {
	if (!isInlineEnabled ()) return true;
	resetStyles ();
	caretOffset = commitCount = 0;
	int end = startOffset + text.length ();
	if (startOffset == -1) {
		Event event = new Event ();
		event.detail = SWT.COMPOSITION_SELECTION;
		sendEvent (SWT.ImeComposition, event);
		startOffset = event.start;
		end = event.end;
	}
	NSString str = new NSString (string);
	if (str.isKindOfClass (OS.class_NSAttributedString)) {
		NSAttributedString attribStr = new NSAttributedString (string);
		str = attribStr.string ();
		int length = (int)str.length ();
		styles = new TextStyle [length];
		ranges = new int [length * 2];
		NSRange rangeLimit = new NSRange (), effectiveRange = new NSRange ();
		rangeLimit.length = length;
		int rangeCount = 0;
		long ptr = C.malloc (NSRange.sizeof);
		for (int i = 0; i < length;) {
			NSDictionary attribs = attribStr.attributesAtIndex(i, ptr, rangeLimit);
			OS.memmove (effectiveRange, ptr, NSRange.sizeof);
			i = (int)(effectiveRange.location + effectiveRange.length);
			ranges [rangeCount * 2] = (int)effectiveRange.location;
			ranges [rangeCount * 2 + 1] = (int)(effectiveRange.location + effectiveRange.length - 1);
			styles [rangeCount++] = getStyle (attribs);
		}
		C.free (ptr);
		if (rangeCount != styles.length) {
			TextStyle [] newStyles = new TextStyle [rangeCount];
			System.arraycopy (styles, 0, newStyles, 0, newStyles.length);
			styles = newStyles;
			int [] newRanges = new int [rangeCount * 2];
			System.arraycopy (ranges, 0, newRanges, 0, newRanges.length);
			ranges = newRanges;
		}
	}
	int length = (int)str.length ();
	if (ranges == null && length > 0) {
		styles = new TextStyle []{getStyle (display.markedAttributes)};
		ranges = new int[]{0, length - 1};
	}
	NSRange range = new NSRange ();
	OS.memmove (range, selRange, NSRange.sizeof);

	/*
	 * Bug 427882: There is a macOS bug where it sends
	 * 'setMarkedText:selectedRange:' with 'markedText' that is incorrectly
	 * too short, which results in 'selectedRange.location' being outside it.
	 * If caret's position is already at the end, this will result in trying
	 * to set caret outside the text. The workaround is to correct 'location'
	 * so that it's always within 'markedText'.
	 */
	range.location = Math.min(range.location, length);

	caretOffset = (int)range.location;
	Event event = new Event ();
	event.detail = SWT.COMPOSITION_CHANGED;
	event.start = startOffset;
	event.end = end;
	event.text = text = str.getString();
	sendEvent (SWT.ImeComposition, event);
	if (isDisposed ()) return false;
	if (text.length () == 0) {
		Shell s = parent.getShell ();
		s.keyInputHappened = true;
		startOffset = -1;
		resetStyles ();
	}
	return true;
}

@Override
long validAttributesForMarkedText (long id, long sel) {
	NSMutableArray attribs = NSMutableArray.arrayWithCapacity (6);
	attribs.addObject (OS.NSForegroundColorAttributeName);
	attribs.addObject (OS.NSBackgroundColorAttributeName);
	attribs.addObject (OS.NSUnderlineStyleAttributeName);
	attribs.addObject (OS.NSUnderlineColorAttributeName);
	attribs.addObject (OS.NSStrikethroughStyleAttributeName);
	attribs.addObject (OS.NSStrikethroughColorAttributeName);
	return attribs.id;
}

}
