/* 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 System.Runtime.Serialization;
using OpenSearch.Net.Utf8Json;

namespace OpenSearch.Client
{
	/// <summary>
	/// The completion suggester provides auto-complete/search-as-you-type functionality.
	/// This is a navigational feature to guide users to relevant results as they are typing, improving search precision.
	/// It is not meant for spell correction or did-you-mean functionality like the term or phrase suggesters.
	/// </summary>
	[InterfaceDataContract]
	[ReadAs(typeof(CompletionSuggester))]
	public interface ICompletionSuggester : ISuggester
	{
		/// <summary>
		/// Context mappings used to filter and/or boost suggestions
		/// </summary>
		[DataMember(Name = "contexts")]
		IDictionary<string, IList<ISuggestContextQuery>> Contexts { get; set; }

		/// <summary>
		/// Support fuzziness for the suggestions
		/// </summary>
		[DataMember(Name = "fuzzy")]
		ISuggestFuzziness Fuzzy { get; set; }

		/// <summary>
		/// Prefix used to search for suggestions
		/// </summary>
		[IgnoreDataMember]
		string Prefix { get; set; }

		/// <summary>
		/// Prefix as a regular expression used to search for suggestions
		/// </summary>
		[IgnoreDataMember]
		string Regex { get; set; }

		/// <summary>
		/// Whether duplicate suggestions should be filtered out. Defaults to <c>false</c>
		/// </summary>
		[DataMember(Name = "skip_duplicates")]
		bool? SkipDuplicates { get; set; }
	}

	/// <inheritdoc cref="ICompletionSuggester" />
	public class CompletionSuggester : SuggesterBase, ICompletionSuggester
	{
		/// <inheritdoc />
		public IDictionary<string, IList<ISuggestContextQuery>> Contexts { get; set; }

		/// <inheritdoc />
		public ISuggestFuzziness Fuzzy { get; set; }

		/// <inheritdoc />
		public string Prefix { get; set; }

		/// <inheritdoc />
		public string Regex { get; set; }

		/// <inheritdoc />
		public bool? SkipDuplicates { get; set; }
	}

	/// <inheritdoc cref="ICompletionSuggester" />
	public class CompletionSuggesterDescriptor<T>
		: SuggestDescriptorBase<CompletionSuggesterDescriptor<T>, ICompletionSuggester, T>, ICompletionSuggester
		where T : class
	{
		IDictionary<string, IList<ISuggestContextQuery>> ICompletionSuggester.Contexts { get; set; }
		ISuggestFuzziness ICompletionSuggester.Fuzzy { get; set; }
		string ICompletionSuggester.Prefix { get; set; }
		string ICompletionSuggester.Regex { get; set; }
		bool? ICompletionSuggester.SkipDuplicates { get; set; }

		/// <inheritdoc cref="ICompletionSuggester.Prefix" />
		public CompletionSuggesterDescriptor<T> Prefix(string prefix) => Assign(prefix, (a, v) => a.Prefix = v);

		/// <inheritdoc cref="ICompletionSuggester.Regex" />
		public CompletionSuggesterDescriptor<T> Regex(string regex) => Assign(regex, (a, v) => a.Regex = v);

		/// <inheritdoc cref="ICompletionSuggester.Fuzzy" />
		public CompletionSuggesterDescriptor<T> Fuzzy(Func<SuggestFuzzinessDescriptor<T>, ISuggestFuzziness> selector = null) =>
			Assign(selector.InvokeOrDefault(new SuggestFuzzinessDescriptor<T>()), (a, v) => a.Fuzzy = v);

		/// <inheritdoc cref="ICompletionSuggester.Contexts" />
		public CompletionSuggesterDescriptor<T> Contexts(
			Func<SuggestContextQueriesDescriptor<T>, IPromise<IDictionary<string, IList<ISuggestContextQuery>>>> contexts
		) =>
			Assign(contexts, (a, v) => a.Contexts = v?.Invoke(new SuggestContextQueriesDescriptor<T>()).Value);

		/// <inheritdoc cref="ICompletionSuggester.SkipDuplicates" />
		public CompletionSuggesterDescriptor<T> SkipDuplicates(bool? skipDuplicates = true) => Assign(skipDuplicates, (a, v) => a.SkipDuplicates = v);
	}
}