// Copyright 2009-2022 Josh Close
// This file is a part of CsvHelper and is dual licensed under MS-PL and Apache 2.0.
// See LICENSE.txt for details or visit http://www.opensource.org/licenses/ms-pl.html for MS-PL and http://opensource.org/licenses/Apache-2.0 for Apache 2.0.
// https://github.com/JoshClose/CsvHelper
using System;
using System.Collections.Generic;
using System.Dynamic;

namespace CsvHelper.Expressions
{
	/// <summary>
	/// Creates dynamic records.
	/// </summary>
	public class DynamicRecordCreator : RecordCreator
	{
		/// <summary>
		/// Initializes a new instance.
		/// </summary>
		/// <param name="reader">The reader.</param>
		public DynamicRecordCreator(CsvReader reader) : base(reader) { }

		/// <summary>
		/// Creates a <see cref="Delegate"/> of type <see cref="Func{T}"/>
		/// that will create a record of the given type using the current
		/// reader row.
		/// </summary>
		/// <param name="recordType">The record type.</param>
		protected override Delegate CreateCreateRecordDelegate(Type recordType) => (Func<dynamic>)CreateDynamicRecord;

		/// <summary>
		/// Creates a dynamic record of the current reader row.
		/// </summary>
		protected virtual dynamic CreateDynamicRecord()
		{
			var obj = new ExpandoObject();
			var dict = obj as IDictionary<string, object>;
			if (Reader.HeaderRecord != null)
			{
				for (var i = 0; i < Reader.HeaderRecord.Length; i++)
				{
					var args = new GetDynamicPropertyNameArgs(i, Reader.Context);
					var propertyName = Reader.Configuration.GetDynamicPropertyName(args);
					Reader.TryGetField(i, out string field);
					dict.Add(propertyName, field);
				}
			}
			else
			{
				for (var i = 0; i < Reader.Parser.Count; i++)
				{
					var args = new GetDynamicPropertyNameArgs(i, Reader.Context);
					var propertyName = Reader.Configuration.GetDynamicPropertyName(args);
					var field = Reader.GetField(i);
					dict.Add(propertyName, field);
				}
			}

			return obj;
		}
	}
}