/*
 * Copyright (C) 2022 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.quicksearchbox.util

import android.database.DataSetObservable
import android.os.Handler

/** A version of [DataSetObservable] that performs callbacks on given [Handler]. */
class AsyncDataSetObservable(handler: Handler?) : DataSetObservable() {
  private val mHandler: Handler?
  private val mChangedRunnable: Runnable =
    object : Runnable {
      override fun run() {
        super@AsyncDataSetObservable.notifyChanged()
      }
    }
  private val mInvalidatedRunnable: Runnable =
    object : Runnable {
      override fun run() {
        super@AsyncDataSetObservable.notifyInvalidated()
      }
    }

  @Override
  override fun notifyChanged() {
    if (mHandler == null) {
      super.notifyChanged()
    } else {
      mHandler.post(mChangedRunnable)
    }
  }

  @Override
  override fun notifyInvalidated() {
    if (mHandler == null) {
      super.notifyInvalidated()
    } else {
      mHandler.post(mInvalidatedRunnable)
    }
  }

  /** @param handler Handler to run callbacks on. */
  init {
    mHandler = handler
  }
}