/*
 * Copyright (C) 2013-2017 microG Project Team
 *
 * 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 org.microg.gms.gservices;

import android.content.ContentProvider;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.net.Uri;
import android.os.Build;
import android.util.Log;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/**
 * Originally found in Google Services Framework (com.google.android.gsf), this provides a generic
 * key-value store, that is written by the checkin service and read from various Google Apps.
 * <p/>
 * Google uses the checkin process to store various device or country specific settings and
 * if certain "experiments" are enabled on the device.
 */
public class GServicesProvider extends ContentProvider {
    public static final Uri CONTENT_URI = Uri.parse("content://com.mgoogle.android.gsf.gservices/");
    public static final Uri MAIN_URI = Uri.withAppendedPath(CONTENT_URI, "main");
    public static final Uri OVERRIDE_URI = Uri.withAppendedPath(CONTENT_URI, "override");
    public static final Uri PREFIX_URI = Uri.withAppendedPath(CONTENT_URI, "prefix");

    private static final String TAG = "GmsServicesProvider";

    private DatabaseHelper databaseHelper;
    private Map<String, String> cache = new HashMap<>();
    private Set<String> cachedPrefixes = new HashSet<>();

    @Override
    public boolean onCreate() {
        databaseHelper = new DatabaseHelper(getContext());
        return true;
    }

    private String getCallingPackageName() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            return getCallingPackage();
        } else {
            return "unknown";
        }
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
        MatrixCursor cursor = new MatrixCursor(new String[]{"name", "value"});
        if (PREFIX_URI.equals(uri)) {
            for (String prefix : selectionArgs) {
                if (!cachedPrefixes.contains(prefix)) {
                    cache.putAll(databaseHelper.search(prefix + "%"));
                    cachedPrefixes.add(prefix);
                }

                for (String name : cache.keySet()) {
                    if (name.startsWith(prefix)) {
                        String value = cache.get(name);
                        Log.d(TAG, "query caller=" + getCallingPackageName() + " prefix=" + prefix + " name=" + name + " value=" + value);
                        cursor.addRow(new String[]{name, value});
                    }
                }
            }
        } else {
            for (String name : selectionArgs) {
                String value;
                if (cache.containsKey(name)) {
                    value = cache.get(name);
                } else {
                    value = databaseHelper.get(name);
                    cache.put(name, value);
                }
                Log.d(TAG, "query caller=" + getCallingPackageName() + " name=" + name + " value=" + value);
                if (value != null) {
                    cursor.addRow(new String[]{name, value});
                }
            }
        }
        if (cursor.getCount() == 0) return null;
        return cursor;
    }

    @Override
    public String getType(Uri uri) {
        return null;
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        throw new UnsupportedOperationException();
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        throw new UnsupportedOperationException();
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
        Log.d(TAG, "update caller=" + getCallingPackageName() + " table=" + uri.getLastPathSegment()
                + " name=" + values.getAsString("name") + " value=" + values.getAsString("value"));
        if (uri.equals(MAIN_URI)) {
            databaseHelper.put("main", values);
        } else if (uri.equals(OVERRIDE_URI)) {
            databaseHelper.put("override", values);
        }
        String name = values.getAsString("name");
        cache.remove(name);
        Iterator<String> iterator = cachedPrefixes.iterator();
        while (iterator.hasNext()) if (name.startsWith(iterator.next())) iterator.remove();
        return 1;
    }
}