/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * 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 com.examples.abelanav2.ui;

import android.app.Activity;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.v4.app.Fragment;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ListView;

import com.examples.abelanav2.R;
import com.examples.abelanav2.ui.utils.DrawerListAdapter;
import com.examples.abelanav2.ui.utils.NavItem;

import java.util.ArrayList;

/**
 * Fragment used for managing interactions for and presentation of a navigation
 * drawer.
 * See the <a href=
 * "https://developer.android.com/design/patterns/navigation-drawer.html">
 * design guidelines</a> for a complete explanation of the behaviors implemented
 * here.
 */
public class NavigationDrawerFragment extends Fragment {

    /**
     * Remember the position of the selected item.
     */
    private static final String STATE_SELECTED_POSITION
            = "selected_navigation_drawer_position";

    /**
     * Per the design guidelines, you should show the drawer on launch until the
     * user manually expands it. This shared preference tracks this.
     */
    private static final String PREF_USER_LEARNED_DRAWER
            = "navigation_drawer_learned";

    /**
     * The navigation drawer items.
     */
    private ArrayList<NavItem> mNavItems = new ArrayList<>();
    /**
     * A pointer to the current callbacks instance (the Activity).
     */
    private NavigationDrawerCallbacks mCallbacks;
    /**
     * Helper component that ties the action bar to the navigation drawer.
     */
    private ActionBarDrawerToggle mDrawerToggle;
    /**
     * The navigation drawer layout.
     */
    private DrawerLayout mDrawerLayout;
    /**
     * The navigation drawer ListView.
     */
    private ListView mDrawerListView;
    /**
     * The fragment container view.
     */
    private View mFragmentContainerView;
    /**
     * The currently selected item.
     */
    private int mCurrentSelectedPosition = 0;
    /**
     * Indicates if the drawer was restored or not.
     */
    private boolean mFromSavedInstanceState;
    /**
     * Indicates if the user has understood that the application uses a drawer.
     */
    private boolean mUserLearnedDrawer;

    /**
     * Constructor.
     */
    public NavigationDrawerFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mNavItems.add(new NavItem(getString(R.string.title_section1),
                R.drawable.ic_home_black_24dp));
        mNavItems.add(new NavItem(getString(R.string.title_section2),
                R.drawable.ic_file_upload_black_24dp));
        mNavItems.add(new NavItem(getString(R.string.title_section3),
                R.drawable.ic_image_black_24dp));
        mNavItems.add(new NavItem(getString(R.string.title_section4),
                R.drawable.ic_favorite_black_24dp));
        mNavItems.add(new NavItem("New Section", -1));
        mNavItems.add(new NavItem(getString(R.string.title_sign_out),
                R.drawable.ic_exit_to_app_black_24dp));


        // Read in the flag indicating whether or not the user has demonstrated
        // awareness of the drawer. See PREF_USER_LEARNED_DRAWER for details.
        SharedPreferences sp = PreferenceManager
                .getDefaultSharedPreferences(getActivity());
        mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false);

        if (savedInstanceState != null) {
            mCurrentSelectedPosition = savedInstanceState
                    .getInt(STATE_SELECTED_POSITION);
            mFromSavedInstanceState = true;
        }

        // Select either the default item (0) or the last selected item.
        selectItem(mCurrentSelectedPosition);

    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        // Indicate that this fragment would like to influence the set of
        // actions in the action bar.
        setHasOptionsMenu(true);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        mDrawerListView = (ListView) inflater.inflate(
                R.layout.fragment_navigation_drawer, container, false);
        mDrawerListView
                .setOnItemClickListener(new AdapterView.OnItemClickListener() {
                    @Override
                    public void onItemClick(AdapterView<?> parent, View view,
                                            int position, long id) {
                        selectItem(position);
                    }
                });

        DrawerListAdapter adapter = new DrawerListAdapter(getActivity()
                .getApplicationContext(), mNavItems);
        mDrawerListView.setAdapter(adapter);
        mDrawerListView.setItemChecked(mCurrentSelectedPosition, true);
        mDrawerListView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
        return mDrawerListView;
    }

    /**
     * Indicates whether the drawer is open or not.
     * @return a boolean indicating whether the drawer is open or not.
     */
    public boolean isDrawerOpen() {
        return mDrawerLayout != null && mDrawerLayout
                .isDrawerOpen(mFragmentContainerView);
    }

    /**
     * Users of this fragment must call this method to set up the navigation
     * drawer interactions.
     *
     * @param fragmentId   The android:id of this fragment in its activity's
     *                     layout.
     * @param drawerLayout The DrawerLayout containing this fragment's UI.
     */
    public void setUp(int fragmentId, DrawerLayout drawerLayout) {
        mFragmentContainerView = getActivity().findViewById(fragmentId);
        mDrawerLayout = drawerLayout;
        mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow,
                GravityCompat.START);
        ActionBar actionBar = getActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setHomeButtonEnabled(true);
        mDrawerToggle = new ActionBarDrawerToggle(
                getActivity(),                   // host Activity
                mDrawerLayout,                   // DrawerLayout object
                R.string.navigation_drawer_open, // "open drawer" description
                R.string.navigation_drawer_close        // "close drawer"
        ) {
            @Override
            public void onDrawerClosed(View drawerView) {
                super.onDrawerClosed(drawerView);
                if (!isAdded()) {
                    return;
                }
                getActivity().supportInvalidateOptionsMenu();
            }

            @Override
            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);
                if (!isAdded()) {
                    return;
                }
                if (!mUserLearnedDrawer) {
                    mUserLearnedDrawer = true;
                    SharedPreferences sp = PreferenceManager
                            .getDefaultSharedPreferences(getActivity());
                    sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true)
                            .apply();
                }
                getActivity().supportInvalidateOptionsMenu();
            }
        };
        if (!mUserLearnedDrawer && !mFromSavedInstanceState) {
            mDrawerLayout.openDrawer(mFragmentContainerView);
        }
        mDrawerLayout.post(new Runnable() {
            @Override
            public void run() {
                mDrawerToggle.syncState();
            }
        });
        mDrawerLayout.setDrawerListener(mDrawerToggle);
    }

    /**
     * Called when an item is selected.
     * @param position the item position in the list.
     */
    private void selectItem(int position) {
        mCurrentSelectedPosition = position;
        if (mDrawerListView != null) {
            mDrawerListView.setItemChecked(position, true);
        }
        if (mDrawerLayout != null) {
            mDrawerLayout.closeDrawer(mFragmentContainerView);
        }
        if (mCallbacks != null) {
            mCallbacks.onNavigationDrawerItemSelected(position);
        }
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            mCallbacks = (NavigationDrawerCallbacks) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(
                    "Activity must implement NavigationDrawerCallbacks.");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mCallbacks = null;
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition);
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        // Forward the new configuration the drawer toggle component.
        mDrawerToggle.onConfigurationChanged(newConfig);
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        // If the drawer is open, show the global app actions in the action bar.
        // See also showGlobalContextActionBar, which controls the top-left
        // area of the action bar.
        if (mDrawerLayout != null && isDrawerOpen()) {
            inflater.inflate(R.menu.global, menu);
            showGlobalContextActionBar();
        }
        super.onCreateOptionsMenu(menu, inflater);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        return mDrawerToggle.onOptionsItemSelected(item)
                || super.onOptionsItemSelected(item);
    }

    /**
     * Per the navigation drawer design guidelines, updates the action bar to
     * show the global app 'context', rather than just what's in the current
     * screen.
     */
    private void showGlobalContextActionBar() {
        ActionBar actionBar = getActionBar();
        actionBar.setDisplayShowTitleEnabled(true);
        actionBar.setTitle(R.string.app_name);
    }

    /**
     * @return the ActionBar.
     */
    private ActionBar getActionBar() {
        return ((AppCompatActivity) getActivity()).getSupportActionBar();
    }

    /**
     * Callbacks interface that all activities using this fragment must
     * implement.
     */
    public interface NavigationDrawerCallbacks {

        /**
         * Called when an item in the navigation drawer is selected.
         * @param position the position in the list.
         */
        void onNavigationDrawerItemSelected(int position);
    }
}