/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package no.nordicsemi.android.nrftoolbox.app;

import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.View;
import android.view.View.OnCreateContextMenuListener;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.SimpleCursorTreeAdapter;
import android.widget.SimpleExpandableListAdapter;

import java.util.List;
import java.util.Map;

import no.nordicsemi.android.nrftoolbox.R;

/**
 * An activity that displays an expandable list of items by binding to a data source implementing the ExpandableListAdapter, and exposes event handlers when the
 * user selects an item.
 * <p>
 * ExpandableListActivity hosts a {@link android.widget.ExpandableListView ExpandableListView} object that can be bound to different data sources that provide a
 * two-levels of data (the top-level is group, and below each group are children). Binding, screen layout, and row layout are discussed in the following
 * sections.
 * <p>
 * <strong>Screen Layout</strong>
 * </p>
 * <p>
 * ExpandableListActivity has a default layout that consists of a single, full-screen, centered expandable list. However, if you desire, you can customize the
 * screen layout by setting your own view layout with setContentView() in onCreate(). To do this, your own view MUST contain an ExpandableListView object with
 * the id "@android:id/list" (or {@link android.R.id#list} if it's in code)
 * <p>
 * Optionally, your custom view can contain another view object of any type to display when the list view is empty. This "empty list" notifier must have an id
 * "android:empty". Note that when an empty view is present, the expandable list view will be hidden when there is no data to display.
 * <p>
 * The following code demonstrates an (ugly) custom screen layout. It has a list with a green background, and an alternate red "no data" message.
 * </p>
 * 
 * <pre>
 * &lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
 * &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 *         android:orientation=&quot;vertical&quot;
 *         android:layout_width=&quot;match_parent&quot; 
 *         android:layout_height=&quot;match_parent&quot;
 *         android:paddingLeft=&quot;8dp&quot;
 *         android:paddingRight=&quot;8dp&quot;&gt;
 * 
 *     &lt;ExpandableListView android:id=&quot;@id/android:list&quot;
 *               android:layout_width=&quot;match_parent&quot; 
 *               android:layout_height=&quot;match_parent&quot;
 *               android:background=&quot;#00FF00&quot;
 *               android:layout_weight=&quot;1&quot;
 *               android:drawSelectorOnTop=&quot;false&quot;/&gt;
 * 
 *     &lt;TextView android:id=&quot;@id/android:empty&quot;
 *               android:layout_width=&quot;match_parent&quot; 
 *               android:layout_height=&quot;match_parent&quot;
 *               android:background=&quot;#FF0000&quot;
 *               android:text=&quot;No data&quot;/&gt;
 * &lt;/LinearLayout&gt;
 * </pre>
 * 
 * <p>
 * <strong>Row Layout</strong>
 * </p>
 * The {@link ExpandableListAdapter} set in the {@link ExpandableListActivity} via {@link #setListAdapter(ExpandableListAdapter)} provides the {@link View}s for
 * each row. This adapter has separate methods for providing the group {@link View}s and child {@link View}s. There are a couple provided
 * {@link ExpandableListAdapter}s that simplify use of adapters: {@link SimpleCursorTreeAdapter} and {@link SimpleExpandableListAdapter}.
 * <p>
 * With these, you can specify the layout of individual rows for groups and children in the list. These constructor takes a few parameters that specify layout
 * resources for groups and children. It also has additional parameters that let you specify which data field to associate with which object in the row layout
 * resource. The {@link SimpleCursorTreeAdapter} fetches data from {@link Cursor}s and the {@link SimpleExpandableListAdapter} fetches data from {@link List}s
 * of {@link Map}s.
 * </p>
 * <p>
 * Android provides some standard row layout resources. These are in the {@link android.R.layout} class, and have names such as simple_list_item_1,
 * simple_list_item_2, and two_line_list_item. The following layout XML is the source for the resource two_line_list_item, which displays two data fields,one
 * above the other, for each list row.
 * </p>
 * 
 * <pre>
 * &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
 * &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 *     android:layout_width=&quot;match_parent&quot;
 *     android:layout_height=&quot;wrap_content&quot;
 *     android:orientation=&quot;vertical&quot;&gt;
 * 
 *     &lt;TextView android:id=&quot;@+id/text1&quot;
 *         android:textSize=&quot;16sp&quot;
 *         android:textStyle=&quot;bold&quot;
 *         android:layout_width=&quot;match_parent&quot;
 *         android:layout_height=&quot;wrap_content&quot;/&gt;
 * 
 *     &lt;TextView android:id=&quot;@+id/text2&quot;
 *         android:textSize=&quot;16sp&quot;
 *         android:layout_width=&quot;match_parent&quot;
 *         android:layout_height=&quot;wrap_content&quot;/&gt;
 * &lt;/LinearLayout&gt;
 * </pre>
 * 
 * <p>
 * You must identify the data bound to each TextView object in this layout. The syntax for this is discussed in the next section.
 * </p>
 * <p>
 * <strong>Binding to Data</strong>
 * </p>
 * <p>
 * You bind the ExpandableListActivity's ExpandableListView object to data using a class that implements the {@link android.widget.ExpandableListAdapter
 * ExpandableListAdapter} interface. Android provides two standard list adapters: {@link android.widget.SimpleExpandableListAdapter SimpleExpandableListAdapter}
 * for static data (Maps), and {@link android.widget.SimpleCursorTreeAdapter SimpleCursorTreeAdapter} for Cursor query results.
 * </p>
 * 
 * @see #setListAdapter
 * @see android.widget.ExpandableListView
 */
public class ExpandableListActivity extends AppCompatActivity implements
		OnCreateContextMenuListener,
		ExpandableListView.OnChildClickListener, ExpandableListView.OnGroupCollapseListener,
		ExpandableListView.OnGroupExpandListener {
	ExpandableListAdapter mAdapter;
	ExpandableListView mList;
	boolean mFinishedStart = false;

	/**
	 * Override this to populate the context menu when an item is long pressed. menuInfo will contain an
	 * {@link android.widget.ExpandableListView.ExpandableListContextMenuInfo} whose packedPosition is a packed position that should be used with
	 * {@link ExpandableListView#getPackedPositionType(long)} and the other similar methods.
	 * <p>
	 * {@inheritDoc}
	 */
	@Override
	public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
	}

	/**
	 * Override this for receiving callbacks when a child has been clicked.
	 * <p>
	 * {@inheritDoc}
	 */
	@Override
	public boolean onChildClick(ExpandableListView parent, View v, int groupPosition,
			int childPosition, long id) {
		return false;
	}

	/**
	 * Override this for receiving callbacks when a group has been collapsed.
	 */
	@Override
	public void onGroupCollapse(int groupPosition) {
	}

	/**
	 * Override this for receiving callbacks when a group has been expanded.
	 */
	@Override
	public void onGroupExpand(int groupPosition) {
	}

	/**
	 * Ensures the expandable list view has been created before Activity restores all of the view states.
	 * 
	 * @see Activity#onRestoreInstanceState(Bundle)
	 */
	@Override
	protected void onRestoreInstanceState(@NonNull Bundle state) {
		ensureList();
		super.onRestoreInstanceState(state);
	}

	/**
	 * Updates the screen state (current list and other views) when the content changes.
	 * 
	 * @see android.support.v7.app.AppCompatActivity#onContentChanged()
	 */
	@Override
	public void onContentChanged() {
		super.onContentChanged();
		View emptyView = findViewById(R.id.empty);
		mList = findViewById(R.id.list);
		if (mList == null) {
			throw new RuntimeException(
					"Your content must have a ExpandableListView whose id attribute is " +
							"'R.id.list'");
		}
		if (emptyView != null) {
			mList.setEmptyView(emptyView);
		}
		mList.setOnChildClickListener(this);
		mList.setOnGroupExpandListener(this);
		mList.setOnGroupCollapseListener(this);

		if (mFinishedStart) {
			setListAdapter(mAdapter);
		}
		mFinishedStart = true;
	}

	/**
	 * Provide the adapter for the expandable list.
	 */
	public void setListAdapter(ExpandableListAdapter adapter) {
		synchronized (this) {
			ensureList();
			mAdapter = adapter;
			mList.setAdapter(adapter);
		}
	}

	/**
	 * Get the activity's expandable list view widget. This can be used to get the selection, set the selection, and many other useful functions.
	 * 
	 * @see ExpandableListView
	 */
	public ExpandableListView getExpandableListView() {
		ensureList();
		return mList;
	}

	/**
	 * Get the ExpandableListAdapter associated with this activity's ExpandableListView.
	 */
	public ExpandableListAdapter getExpandableListAdapter() {
		return mAdapter;
	}

	private void ensureList() {
		if (mList != null) {
			return;
		}
		setContentView(R.layout.expandable_list_content);
	}

	/**
	 * Gets the ID of the currently selected group or child.
	 * 
	 * @return The ID of the currently selected group or child.
	 */
	public long getSelectedId() {
		return mList.getSelectedId();
	}

	/**
	 * Gets the position (in packed position representation) of the currently selected group or child. Use {@link ExpandableListView#getPackedPositionType},
	 * {@link ExpandableListView#getPackedPositionGroup}, and {@link ExpandableListView#getPackedPositionChild} to unpack the returned packed position.
	 * 
	 * @return A packed position representation containing the currently selected group or child's position and type.
	 */
	public long getSelectedPosition() {
		return mList.getSelectedPosition();
	}

	/**
	 * Sets the selection to the specified child. If the child is in a collapsed group, the group will only be expanded and child subsequently selected if
	 * shouldExpandGroup is set to true, otherwise the method will return false.
	 * 
	 * @param groupPosition
	 *            The position of the group that contains the child.
	 * @param childPosition
	 *            The position of the child within the group.
	 * @param shouldExpandGroup
	 *            Whether the child's group should be expanded if it is collapsed.
	 * @return Whether the selection was successfully set on the child.
	 */
	public boolean setSelectedChild(int groupPosition, int childPosition, boolean shouldExpandGroup) {
		return mList.setSelectedChild(groupPosition, childPosition, shouldExpandGroup);
	}

	/**
	 * Sets the selection to the specified group.
	 * 
	 * @param groupPosition
	 *            The position of the group that should be selected.
	 */
	public void setSelectedGroup(int groupPosition) {
		mList.setSelectedGroup(groupPosition);
	}

}
