/*
 * Copyright (C) 2011 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 com.android.settings.location;

import android.app.ActionBar;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.location.LocationManager;
import android.location.SettingInjectorService;
import android.os.Bundle;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceCategory;
import android.preference.PreferenceGroup;
import android.preference.PreferenceScreen;
import android.provider.Settings;
import android.util.Log;
import android.view.Gravity;
import android.widget.CompoundButton;
import android.widget.Switch;

import com.android.settings.R;
import com.android.settings.fuelgauge.BatteryStatsHelper;

import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
 * Location access settings.
 */
public class LocationSettings extends LocationSettingsBase
        implements CompoundButton.OnCheckedChangeListener {

    private static final String TAG = "LocationSettings";

    /** Key for preference screen "Mode" */
    private static final String KEY_LOCATION_MODE = "location_mode";
    /** Key for preference category "Recent location requests" */
    private static final String KEY_RECENT_LOCATION_REQUESTS = "recent_location_requests";
    /** Key for preference category "Location services" */
    private static final String KEY_APP_SETTINGS = "app_settings";

    private Switch mSwitch;
    private boolean mValidListener;
    private Preference mLocationMode;
    private PreferenceCategory mCategoryRecentLocationRequests;
    private BatteryStatsHelper mStatsHelper;
    /** Receives UPDATE_INTENT  */
    private BroadcastReceiver mReceiver;

    public LocationSettings() {
        mValidListener = false;
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        createPreferenceHierarchy();
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        mStatsHelper = new BatteryStatsHelper(activity, null);
    }

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        mStatsHelper.create(icicle);
    }

    @Override
    public void onResume() {
        super.onResume();
        mSwitch = new Switch(getActivity());
        mSwitch.setOnCheckedChangeListener(this);
        mValidListener = true;
        createPreferenceHierarchy();
    }

    @Override
    public void onPause() {
        try {
            getActivity().unregisterReceiver(mReceiver);
        } catch (RuntimeException e) {
            // Ignore exceptions caused by race condition
        }
        super.onPause();
        mValidListener = false;
        mSwitch.setOnCheckedChangeListener(null);
        mStatsHelper.pause();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mStatsHelper.destroy();
    }

    private void addPreferencesSorted(List<Preference> prefs, PreferenceGroup container) {
        // If there's some items to display, sort the items and add them to the container.
        Collections.sort(prefs, new Comparator<Preference>() {
            @Override
            public int compare(Preference lhs, Preference rhs) {
                return lhs.getTitle().toString().compareTo(rhs.getTitle().toString());
            }
        });
        for (Preference entry : prefs) {
            container.addPreference(entry);
        }
    }

    private PreferenceScreen createPreferenceHierarchy() {
        final PreferenceActivity activity = (PreferenceActivity) getActivity();
        PreferenceScreen root = getPreferenceScreen();
        if (root != null) {
            root.removeAll();
        }
        addPreferencesFromResource(R.xml.location_settings);
        root = getPreferenceScreen();

        mLocationMode = root.findPreference(KEY_LOCATION_MODE);
        mLocationMode.setOnPreferenceClickListener(
                new Preference.OnPreferenceClickListener() {
                    @Override
                    public boolean onPreferenceClick(Preference preference) {
                        activity.startPreferencePanel(
                                LocationMode.class.getName(), null,
                                R.string.location_mode_screen_title, null, LocationSettings.this,
                                0);
                        return true;
                    }
                });

        mCategoryRecentLocationRequests =
                (PreferenceCategory) root.findPreference(KEY_RECENT_LOCATION_REQUESTS);
        RecentLocationApps recentApps = new RecentLocationApps(activity, mStatsHelper);
        List<Preference> recentLocationRequests = recentApps.getAppList();
        if (recentLocationRequests.size() > 0) {
            addPreferencesSorted(recentLocationRequests, mCategoryRecentLocationRequests);
        } else {
            // If there's no item to display, add a "No recent apps" item.
            Preference banner = new Preference(activity);
            banner.setLayoutResource(R.layout.location_list_no_item);
            banner.setTitle(R.string.location_no_recent_apps);
            banner.setSelectable(false);
            mCategoryRecentLocationRequests.addPreference(banner);
        }

        addAppSettings(activity, root);

        // Only show the master switch when we're not in multi-pane mode, and not being used as
        // Setup Wizard.
        if (activity.onIsHidingHeaders() || !activity.onIsMultiPane()) {
            final int padding = activity.getResources().getDimensionPixelSize(
                    R.dimen.action_bar_switch_padding);
            mSwitch.setPaddingRelative(0, 0, padding, 0);
            activity.getActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM,
                    ActionBar.DISPLAY_SHOW_CUSTOM);
            activity.getActionBar().setCustomView(mSwitch, new ActionBar.LayoutParams(
                    ActionBar.LayoutParams.WRAP_CONTENT,
                    ActionBar.LayoutParams.WRAP_CONTENT,
                    Gravity.CENTER_VERTICAL | Gravity.END));
        }

        setHasOptionsMenu(true);

        refreshLocationMode();
        return root;
    }

    /**
     * Add the settings injected by external apps into the "App Settings" category. Hides the
     * category if there are no injected settings.
     *
     * Reloads the settings whenever receives
     * {@link SettingInjectorService#ACTION_INJECTED_SETTING_CHANGED}. As a safety measure,
     * also reloads on {@link LocationManager#MODE_CHANGED_ACTION} to ensure the settings are
     * up-to-date after mode changes even if an affected app doesn't send the setting changed
     * broadcast.
     */
    private void addAppSettings(Context context, PreferenceScreen root) {
        PreferenceCategory categoryAppSettings =
                (PreferenceCategory) root.findPreference(KEY_APP_SETTINGS);
        final SettingsInjector injector = new SettingsInjector(context);
        List<Preference> appSettings = injector.getInjectedSettings();

        mReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                if (Log.isLoggable(TAG, Log.DEBUG)) {
                    Log.d(TAG, "Received settings change intent: " + intent);
                }
                injector.reloadStatusMessages();
            }
        };

        IntentFilter filter = new IntentFilter();
        filter.addAction(SettingInjectorService.ACTION_INJECTED_SETTING_CHANGED);
        filter.addAction(LocationManager.MODE_CHANGED_ACTION);
        context.registerReceiver(mReceiver, filter);

        if (appSettings.size() > 0) {
            addPreferencesSorted(appSettings, categoryAppSettings);
        } else {
            // If there's no item to display, remove the whole category.
            root.removePreference(categoryAppSettings);
        }
    }

    @Override
    public int getHelpResource() {
        return R.string.help_url_location_access;
    }

    @Override
    public void onModeChanged(int mode, boolean restricted) {
        switch (mode) {
            case Settings.Secure.LOCATION_MODE_OFF:
                mLocationMode.setSummary(R.string.location_mode_location_off_title);
                break;
            case Settings.Secure.LOCATION_MODE_SENSORS_ONLY:
                mLocationMode.setSummary(R.string.location_mode_sensors_only_title);
                break;
            case Settings.Secure.LOCATION_MODE_BATTERY_SAVING:
                mLocationMode.setSummary(R.string.location_mode_battery_saving_title);
                break;
            case Settings.Secure.LOCATION_MODE_HIGH_ACCURACY:
                mLocationMode.setSummary(R.string.location_mode_high_accuracy_title);
                break;
            default:
                break;
        }

        // Restricted user can't change the location mode, so disable the master switch. But in some
        // corner cases, the location might still be enabled. In such case the master switch should
        // be disabled but checked.
        boolean enabled = (mode != Settings.Secure.LOCATION_MODE_OFF);
        mSwitch.setEnabled(!restricted);
        mLocationMode.setEnabled(enabled && !restricted);
        mCategoryRecentLocationRequests.setEnabled(enabled);

        if (enabled != mSwitch.isChecked()) {
            // set listener to null so that that code below doesn't trigger onCheckedChanged()
            if (mValidListener) {
                mSwitch.setOnCheckedChangeListener(null);
            }
            mSwitch.setChecked(enabled);
            if (mValidListener) {
                mSwitch.setOnCheckedChangeListener(this);
            }
        }
    }

    /**
     * Listens to the state change of the location master switch.
     */
    @Override
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        if (isChecked) {
            setLocationMode(Settings.Secure.LOCATION_MODE_HIGH_ACCURACY);
        } else {
            setLocationMode(Settings.Secure.LOCATION_MODE_OFF);
        }
    }
}