/* 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;
using System.Collections.Generic;
using OpenSearch.Net.Utf8Json;

namespace OpenSearch.Client
{
	/// <summary>
	/// A bucket with a composite key
	/// </summary>
	public class CompositeBucket : BucketBase
	{
		public CompositeBucket(IReadOnlyDictionary<string, IAggregate> dict, CompositeKey key) : base(dict) =>
			Key = key;

		/// <summary>
		/// The count of documents
		/// </summary>
		public long? DocCount { get; set; }

		/// <summary>
		/// The bucket key
		/// </summary>
		public CompositeKey Key { get; }
	}

	/// <summary>
	/// A key for a <see cref="CompositeBucket" />
	/// </summary>
	[JsonFormatter(typeof(CompositeKeyFormatter))]
	public class CompositeKey : IsAReadOnlyDictionaryBase<string, object>
	{
		public CompositeKey(IReadOnlyDictionary<string, object> backingDictionary) : base(backingDictionary) { }

		/// <summary>
		/// Tries to get a value with the given key as a string. Returns <c>false</c> if the key does
		/// not exist or is not a string.
		/// </summary>
		public bool TryGetValue(string key, out string value) => TryGetValue<string>(key, out value);

		/// <summary>
		/// Tries to get a value with the given key as a double. Returns <c>false</c> if the key does
		/// not exist or is not a double.
		/// </summary>
		public bool TryGetValue(string key, out double value) => TryGetValue<double>(key, out value);

		/// <summary>
		/// Tries to get a value with the given key as a int. Returns <c>false</c> if the key does
		/// not exist or is not a int.
		/// </summary>
		public bool TryGetValue(string key, out int value) => TryGetValue<int>(key, out value);

		/// <summary>
		/// Tries to get a value with the given key as a long. Returns <c>false</c> if the key does
		/// not exist or is not a long.
		/// </summary>
		public bool TryGetValue(string key, out long value) => TryGetValue<long>(key, out value);

		/// <summary>
		/// Tries to get a value with the given key as a DateTime. Returns <c>false</c> if the key does
		/// not exist or cannot be converted to a DateTime.
		/// </summary>
		public bool TryGetValue(string key, out DateTime value)
		{
			if (TryGetValue(key, out DateTimeOffset dateTimeOffset))
			{
				value = dateTimeOffset.DateTime;
				return true;
			}

			value = default(DateTime);
			return false;
		}

		/// <summary>
		/// Tries to get a value with the given key as a DateTimeOffset. Returns <c>false</c> if the key does
		/// not exist or cannot be converted to a DateTimeOffset.
		/// </summary>
		public bool TryGetValue(string key, out DateTimeOffset value)
		{
			var exists = TryGetValue(key, out object o);
			if (!exists || !long.TryParse(o.ToString(), out var l))
			{
				value = default(DateTimeOffset);
				return false;
			}

			value = DateTimeUtil.UnixEpoch.AddMilliseconds(l);
			return true;
		}

		private bool TryGetValue<TValue>(string key, out TValue value)
		{
			if (!BackingDictionary.TryGetValue(key, out var obj))
			{
				value = default(TValue);
				return false;
			}

			try
			{
				value = (TValue)Convert.ChangeType(obj, typeof(TValue));
				return true;
			}
			catch
			{
				value = default(TValue);
				return false;
			}
		}
	}

	internal class CompositeKeyFormatter : IJsonFormatter<CompositeKey>
	{
		private static readonly VerbatimInterfaceReadOnlyDictionaryKeysPreservingNullFormatter<string, object> DictionaryFormatter =
			new VerbatimInterfaceReadOnlyDictionaryKeysPreservingNullFormatter<string, object>();

		public void Serialize(ref JsonWriter writer, CompositeKey value, IJsonFormatterResolver formatterResolver) =>
			DictionaryFormatter.Serialize(ref writer, value, formatterResolver);

		public CompositeKey Deserialize(ref JsonReader reader, IJsonFormatterResolver formatterResolver)
		{
			if (reader.ReadIsNull())
				return null;

			var dictionary = DictionaryFormatter.Deserialize(ref reader, formatterResolver);
			return new CompositeKey(dictionary);
		}
	}
}