/* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*
*  Licensed to Elasticsearch B.V. under one or more contributor
*  license agreements. See the NOTICE file distributed with
*  this work for additional information regarding copyright
*  ownership. Elasticsearch B.V. licenses this file to you 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.
*/

using System.Collections;
using System.Collections.Generic;
using OpenSearch.Net;

namespace OpenSearch.Client
{
	public abstract class IsAReadOnlyDictionaryBase<TKey, TValue> : IIsAReadOnlyDictionary<TKey, TValue>
	{
		protected IsAReadOnlyDictionaryBase(IReadOnlyDictionary<TKey, TValue> backingDictionary)
		{
			if (backingDictionary == null) return;

			var dictionary = new Dictionary<TKey, TValue>(backingDictionary.Count);
			foreach (var key in backingDictionary.Keys)
				// ReSharper disable once VirtualMemberCallInConstructor
				// expect all implementations of Sanitize to be pure
				dictionary[Sanitize(key)] = backingDictionary[key];

			BackingDictionary = dictionary;
		}

		public int Count => BackingDictionary.Count;

		public TValue this[TKey key] => BackingDictionary[key];

		public IEnumerable<TKey> Keys => BackingDictionary.Keys;

		public IEnumerable<TValue> Values => BackingDictionary.Values;
		protected internal IReadOnlyDictionary<TKey, TValue> BackingDictionary { get; } = EmptyReadOnly<TKey, TValue>.Dictionary;

		IEnumerator IEnumerable.GetEnumerator() => BackingDictionary.GetEnumerator();

		IEnumerator<KeyValuePair<TKey, TValue>> IEnumerable<KeyValuePair<TKey, TValue>>.GetEnumerator() =>
			BackingDictionary.GetEnumerator();

		public bool ContainsKey(TKey key) => BackingDictionary.ContainsKey(key);

		public bool TryGetValue(TKey key, out TValue value) =>
			BackingDictionary.TryGetValue(key, out value);

		protected virtual TKey Sanitize(TKey key) => key;
	}
}