/*
 * Copyright (C) 2014 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.search;

import android.annotation.XmlRes;
import android.content.Context;
import android.content.res.XmlResourceParser;
import android.provider.SearchIndexableResource;
import android.support.annotation.CallSuper;
import android.support.annotation.VisibleForTesting;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.Log;
import android.util.Xml;

import com.android.settings.core.BasePreferenceController;
import com.android.settings.core.PreferenceControllerListHelper;
import com.android.settings.core.PreferenceControllerMixin;
import com.android.settings.core.PreferenceXmlParserUtils;
import com.android.settingslib.core.AbstractPreferenceController;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * A basic SearchIndexProvider that returns no data to index.
 */
public class BaseSearchIndexProvider implements Indexable.SearchIndexProvider {

    private static final String TAG = "BaseSearchIndex";

    public BaseSearchIndexProvider() {
    }

    @Override
    public List<SearchIndexableResource> getXmlResourcesToIndex(Context context, boolean enabled) {
        return null;
    }

    @Override
    public List<SearchIndexableRaw> getRawDataToIndex(Context context, boolean enabled) {
        return null;
    }

    @Override
    @CallSuper
    public List<String> getNonIndexableKeys(Context context) {
        if (!isPageSearchEnabled(context)) {
            // Entire page should be suppressed, mark all keys from this page as non-indexable.
            return getNonIndexableKeysFromXml(context);
        }
        final List<AbstractPreferenceController> controllers = getPreferenceControllers(context);
        if (controllers != null && !controllers.isEmpty()) {
            final List<String> nonIndexableKeys = new ArrayList<>();
            for (AbstractPreferenceController controller : controllers) {
                if (controller instanceof PreferenceControllerMixin) {
                    ((PreferenceControllerMixin) controller)
                            .updateNonIndexableKeys(nonIndexableKeys);
                } else if (controller instanceof BasePreferenceController) {
                    ((BasePreferenceController) controller).updateNonIndexableKeys(
                            nonIndexableKeys);
                } else {
                    Log.e(TAG, controller.getClass().getName()
                            + " must implement " + PreferenceControllerMixin.class.getName()
                            + " treating the key non-indexable");
                    nonIndexableKeys.add(controller.getPreferenceKey());
                }
            }
            return nonIndexableKeys;
        } else {
            return new ArrayList<>();
        }
    }

    @Override
    public List<AbstractPreferenceController> getPreferenceControllers(Context context) {
        final List<AbstractPreferenceController> controllersFromCode =
                createPreferenceControllers(context);
        final List<SearchIndexableResource> res = getXmlResourcesToIndex(context, true);
        if (res == null || res.isEmpty()) {
            return controllersFromCode;
        }
        List<BasePreferenceController> controllersFromXml = new ArrayList<>();
        for (SearchIndexableResource sir : res) {
            controllersFromXml.addAll(PreferenceControllerListHelper
                    .getPreferenceControllersFromXml(context, sir.xmlResId));
        }
        controllersFromXml = PreferenceControllerListHelper.filterControllers(controllersFromXml,
                controllersFromCode);
        final List<AbstractPreferenceController> allControllers = new ArrayList<>();
        if (controllersFromCode != null) {
            allControllers.addAll(controllersFromCode);
        }
        allControllers.addAll(controllersFromXml);
        return allControllers;
    }

    /**
     * Creates a list of {@link AbstractPreferenceController} programatically.
     * <p/>
     * This list should create controllers that are not defined in xml as a Slice controller.
     */
    public List<AbstractPreferenceController> createPreferenceControllers(Context context) {
        return null;
    }

    /**
     * Returns true if the page should be considered in search query. If return false, entire page
     * will be suppressed during search query.
     */
    protected boolean isPageSearchEnabled(Context context) {
        return true;
    }

    private List<String> getNonIndexableKeysFromXml(Context context) {
        final List<SearchIndexableResource> resources = getXmlResourcesToIndex(
                context, true /* not used*/);
        if (resources == null || resources.isEmpty()) {
            return new ArrayList<>();
        }
        final List<String> nonIndexableKeys = new ArrayList<>();
        for (SearchIndexableResource res : resources) {
            nonIndexableKeys.addAll(getNonIndexableKeysFromXml(context, res.xmlResId));
        }
        return nonIndexableKeys;
    }

    @VisibleForTesting(otherwise = VisibleForTesting.PROTECTED)
    public List<String> getNonIndexableKeysFromXml(Context context, @XmlRes int xmlResId) {
        final List<String> nonIndexableKeys = new ArrayList<>();
        final XmlResourceParser parser = context.getResources().getXml(xmlResId);
        final AttributeSet attrs = Xml.asAttributeSet(parser);
        try {
            while (parser.next() != XmlPullParser.END_DOCUMENT) {
                final String key = PreferenceXmlParserUtils.getDataKey(context, attrs);
                if (!TextUtils.isEmpty(key)) {
                    nonIndexableKeys.add(key);
                }
            }
        } catch (IOException | XmlPullParserException e) {
            Log.w(TAG, "Error parsing non-indexable from xml " + xmlResId);
        }
        return nonIndexableKeys;
    }

}