/*
 * Copyright (C) 2013 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.dialer.smartdial;

import android.content.AsyncTaskLoader;
import android.content.Context;
import android.database.Cursor;
import android.database.MatrixCursor;
import com.android.contacts.common.list.PhoneNumberListAdapter.PhoneQuery;
import com.android.dialer.common.LogUtil;
import com.android.dialer.database.Database;
import com.android.dialer.database.DialerDatabaseHelper;
import com.android.dialer.database.DialerDatabaseHelper.ContactNumber;
import com.android.dialer.smartdial.util.SmartDialNameMatcher;
import com.android.dialer.util.PermissionsUtil;
import java.util.ArrayList;

/** Implements a Loader<Cursor> class to asynchronously load SmartDial search results. */
public class SmartDialCursorLoader extends AsyncTaskLoader<Cursor> {

  private static final String TAG = "SmartDialCursorLoader";
  private static final boolean DEBUG = false;

  private final Context context;

  private Cursor cursor;

  private String query;
  private SmartDialNameMatcher nameMatcher;

  private boolean showEmptyListForNullQuery = true;

  public SmartDialCursorLoader(Context context) {
    super(context);
    this.context = context;
  }

  /**
   * Configures the query string to be used to find SmartDial matches.
   *
   * @param query The query string user typed.
   */
  public void configureQuery(String query) {
    if (DEBUG) {
      LogUtil.v(TAG, "Configure new query to be " + query);
    }
    this.query = SmartDialNameMatcher.normalizeNumber(context, query);

    /** Constructs a name matcher object for matching names. */
    nameMatcher = new SmartDialNameMatcher(this.query);
    nameMatcher.setShouldMatchEmptyQuery(!showEmptyListForNullQuery);
  }

  /**
   * Queries the SmartDial database and loads results in background.
   *
   * @return Cursor of contacts that matches the SmartDial query.
   */
  @Override
  public Cursor loadInBackground() {
    if (DEBUG) {
      LogUtil.v(TAG, "Load in background " + query);
    }

    if (!PermissionsUtil.hasContactsReadPermissions(context)) {
      return new MatrixCursor(PhoneQuery.PROJECTION_PRIMARY);
    }

    /** Loads results from the database helper. */
    final DialerDatabaseHelper dialerDatabaseHelper =
        Database.get(context).getDatabaseHelper(context);
    final ArrayList<ContactNumber> allMatches =
        dialerDatabaseHelper.getLooseMatches(query, nameMatcher);

    if (DEBUG) {
      LogUtil.v(TAG, "Loaded matches " + allMatches.size());
    }

    /** Constructs a cursor for the returned array of results. */
    final MatrixCursor cursor = new MatrixCursor(PhoneQuery.PROJECTION_PRIMARY);
    Object[] row = new Object[PhoneQuery.PROJECTION_PRIMARY.length];
    for (ContactNumber contact : allMatches) {
      row[PhoneQuery.PHONE_ID] = contact.dataId;
      row[PhoneQuery.PHONE_NUMBER] = contact.phoneNumber;
      row[PhoneQuery.CONTACT_ID] = contact.id;
      row[PhoneQuery.LOOKUP_KEY] = contact.lookupKey;
      row[PhoneQuery.PHOTO_ID] = contact.photoId;
      row[PhoneQuery.DISPLAY_NAME] = contact.displayName;
      row[PhoneQuery.CARRIER_PRESENCE] = contact.carrierPresence;
      cursor.addRow(row);
    }
    return cursor;
  }

  @Override
  public void deliverResult(Cursor cursor) {
    if (isReset()) {
      /** The Loader has been reset; ignore the result and invalidate the data. */
      releaseResources(cursor);
      return;
    }

    /** Hold a reference to the old data so it doesn't get garbage collected. */
    Cursor oldCursor = this.cursor;
    this.cursor = cursor;

    if (isStarted()) {
      /** If the Loader is in a started state, deliver the results to the client. */
      super.deliverResult(cursor);
    }

    /** Invalidate the old data as we don't need it any more. */
    if (oldCursor != null && oldCursor != cursor) {
      releaseResources(oldCursor);
    }
  }

  @Override
  protected void onStartLoading() {
    if (cursor != null) {
      /** Deliver any previously loaded data immediately. */
      deliverResult(cursor);
    }
    if (cursor == null) {
      /** Force loads every time as our results change with queries. */
      forceLoad();
    }
  }

  @Override
  protected void onStopLoading() {
    /** The Loader is in a stopped state, so we should attempt to cancel the current load. */
    cancelLoad();
  }

  @Override
  protected void onReset() {
    /** Ensure the loader has been stopped. */
    onStopLoading();

    /** Release all previously saved query results. */
    if (cursor != null) {
      releaseResources(cursor);
      cursor = null;
    }
  }

  @Override
  public void onCanceled(Cursor cursor) {
    super.onCanceled(cursor);

    /** The load has been canceled, so we should release the resources associated with 'data'. */
    releaseResources(cursor);
  }

  private void releaseResources(Cursor cursor) {
    if (cursor != null) {
      cursor.close();
    }
  }

  public void setShowEmptyListForNullQuery(boolean show) {
    showEmptyListForNullQuery = show;
    if (nameMatcher != null) {
      nameMatcher.setShouldMatchEmptyQuery(!show);
    }
  }
}