/*
 * 				Firetweet - Twitter client for Android
 * 
 *  Copyright (C) 2012-2014 Mariotaku Lee <mariotaku.lee@gmail.com>
 * 
 *  This program 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.
 * 
 *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.getlantern.firetweet.text.method;

import android.text.Layout;
import android.text.NoCopySpan;
import android.text.Selection;
import android.text.Spannable;
import android.text.method.ArrowKeyMovementMethod;
import android.text.method.MovementMethod;
import android.text.style.ClickableSpan;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TextView;

/**
 * A movement method that traverses links in the text buffer and scrolls if
 * necessary. Supports clicking on links with DPad Center or Enter.
 */
public class StatusContentMovementMethod extends ArrowKeyMovementMethod {

	private static StatusContentMovementMethod sInstance;

	private static Object FROM_BELOW = new NoCopySpan.Concrete();

	@Override
	public void initialize(final TextView widget, final Spannable text) {
		Selection.removeSelection(text);
		text.removeSpan(FROM_BELOW);
	}

	@Override
	public void onTakeFocus(final TextView view, final Spannable text, final int dir) {
		Selection.removeSelection(text);

		if ((dir & View.FOCUS_BACKWARD) != 0) {
			text.setSpan(FROM_BELOW, 0, 0, Spannable.SPAN_POINT_POINT);
		} else {
			text.removeSpan(FROM_BELOW);
		}
	}

	@Override
	public boolean onTouchEvent(final TextView widget, final Spannable buffer, final MotionEvent event) {
		final int action = event.getAction();

		if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_DOWN) {
			int x = (int) event.getX();
			int y = (int) event.getY();

			x -= widget.getTotalPaddingLeft();
			y -= widget.getTotalPaddingTop();

			x += widget.getScrollX();
			y += widget.getScrollY();

			final Layout layout = widget.getLayout();
			final int line = layout.getLineForVertical(y);
			final int off = layout.getOffsetForHorizontal(line, x);

			final ClickableSpan[] link = buffer.getSpans(off, off, ClickableSpan.class);

			if (link.length != 0) {
				if (action == MotionEvent.ACTION_UP) {
					link[0].onClick(widget);
				} else if (action == MotionEvent.ACTION_DOWN) {
					Selection.setSelection(buffer, buffer.getSpanStart(link[0]), buffer.getSpanEnd(link[0]));
				}

				return true;
			} else {
				Selection.removeSelection(buffer);
			}
		}

		return super.onTouchEvent(widget, buffer, event);
	}

	public static MovementMethod getInstance() {
		if (sInstance == null) {
			sInstance = new StatusContentMovementMethod();
		}

		return sInstance;
	}
}