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

namespace OpenSearch.Client.Specification.IngestApi
{
	/// <summary>
	/// Extracts fields from CSV line out of a single text field within a document.
	/// Any empty field in CSV will be skipped.
	/// </summary>
	[InterfaceDataContract]
	public interface ICsvProcessor : IProcessor
	{
		/// <summary>
		/// The field to extract data from
		/// </summary>
		[DataMember(Name ="field")]
		Field Field { get; set; }

		/// <summary>
		/// The array of fields to assign extracted values to.
		/// </summary>
		[DataMember(Name ="target_fields")]
		Fields TargetFields { get; set; }

		/// <summary>
		/// Separator used in CSV, has to be single character string. Defaults to <c>,</c>
		/// </summary>
		[DataMember(Name = "separator")]
		string Separator { get; set; }

		/// <summary>
		/// Quote used in CSV, has to be single character string. Defaults to <c>"</c>
		/// </summary>
		[DataMember(Name = "quote")]
		string Quote { get; set; }

		/// <summary>
		/// If <c>true</c> and <see cref="Field" /> does not exist or is null,
		/// the processor quietly exits without modifying the document. Default is <c>false</c>
		/// </summary>
		[DataMember(Name = "ignore_missing")]
		bool? IgnoreMissing { get; set; }

		/// <summary>
		/// Trim whitespaces in unquoted fields. Default is <c>false</c>;
		/// </summary>
		[DataMember(Name = "trim")]
		bool? Trim { get; set; }

		/// <summary>
		/// Value used to fill empty fields, empty fields will be skipped if this is not provided.
		/// Empty field is one with no value (2 consecutive separators) or empty quotes (`""`)
		/// </summary>
		[DataMember(Name = "empty_value")]
		object EmptyValue  { get; set; }
	}

	/// <inheritdoc cref="ICsvProcessor"/>
	public class CsvProcessor : ProcessorBase, ICsvProcessor
	{
		/// <inheritdoc />
		public Field Field { get; set; }
		/// <inheritdoc />
		public Fields TargetFields { get; set; }
		/// <inheritdoc />
		public string Separator { get; set; }
		/// <inheritdoc />
		public string Quote { get; set; }
		/// <inheritdoc />
		public bool? IgnoreMissing { get; set; }
		/// <inheritdoc />
		public bool? Trim { get; set; }
		/// <inheritdoc />
		public object EmptyValue { get; set; }
		/// <inheritdoc />
		protected override string Name => "csv";
	}

	/// <inheritdoc cref="ICsvProcessor"/>
	public class CsvProcessorDescriptor<T> : ProcessorDescriptorBase<CsvProcessorDescriptor<T>, ICsvProcessor>, ICsvProcessor
		where T : class
	{
		protected override string Name => "csv";
		Field ICsvProcessor.Field { get; set; }
		Fields ICsvProcessor.TargetFields { get; set; }
		bool? ICsvProcessor.IgnoreMissing { get; set; }
		string ICsvProcessor.Quote { get; set; }
		string ICsvProcessor.Separator { get; set; }
		bool? ICsvProcessor.Trim { get; set; }
		object ICsvProcessor.EmptyValue { get; set; }

		/// <inheritdoc cref="ICsvProcessor.Field" />
		public CsvProcessorDescriptor<T> Field(Field field) => Assign(field, (a, v) => a.Field = v);

		/// <inheritdoc cref="ICsvProcessor.Field" />
		public CsvProcessorDescriptor<T> Field<TValue>(Expression<Func<T, TValue>> objectPath) =>
			Assign(objectPath, (a, v) => a.Field = v);

		/// <inheritdoc cref="ICsvProcessor.TargetFields" />
		public CsvProcessorDescriptor<T> TargetFields(Func<FieldsDescriptor<T>, IPromise<Fields>> targetFields) =>
			Assign(targetFields, (a, v) => a.TargetFields = v?.Invoke(new FieldsDescriptor<T>())?.Value);

		/// <inheritdoc cref="ICsvProcessor.TargetFields" />
		public CsvProcessorDescriptor<T> TargetFields(Fields targetFields) => Assign(targetFields, (a, v) => a.TargetFields = v);

		/// <inheritdoc cref="ICsvProcessor.IgnoreMissing" />
		public CsvProcessorDescriptor<T> IgnoreMissing(bool? ignoreMissing = true) => Assign(ignoreMissing, (a, v) => a.IgnoreMissing = v);

		/// <inheritdoc cref="ICsvProcessor.Trim" />
		public CsvProcessorDescriptor<T> Trim(bool? trim = true) => Assign(trim, (a, v) => a.Trim = v);

		/// <inheritdoc cref="ICsvProcessor.Quote" />
		public CsvProcessorDescriptor<T> Quote(string quote) => Assign(quote, (a, v) => a.Quote = v);

		/// <inheritdoc cref="ICsvProcessor.Separator" />
		public CsvProcessorDescriptor<T> Separator(string separator) => Assign(separator, (a, v) => a.Separator = v);

		/// <inheritdoc cref="ICsvProcessor.EmptyValue" />
		public CsvProcessorDescriptor<T> EmptyValue(object value) => Assign(value, (a, v) => a.EmptyValue = v);
	}
}