using System;
using System.Collections.Generic;
using System.IO;
using CsvHelper;
using CsvHelper.Configuration;

namespace LeafWeb.Core.Parsers
{
	public class CsvParserBase : IDisposable
	{
		protected readonly FileSystemInfo CsvFile;
		private readonly StreamReader _reader;
		protected readonly CsvReader CsvReader;

		protected CsvParserBase(FileSystemInfo csvFile)
		{
			CsvFile = csvFile;
			if (!csvFile.Exists)
				throw new FileNotFoundException($"Cannot find file '{csvFile.Name}'");

			_reader = File.OpenText(csvFile.FullName);
			var csvConfiguration = new CsvConfiguration { HasHeaderRecord = false, IgnoreBlankLines = false};
			CsvReader = new CsvReader(_reader, csvConfiguration);
		}

		protected string[] GetNextCsvRowValues()
		{
			// get values from row
			if (!CsvReader.Read())
				return null;

			// put all the values from this row into an array
			var values = new List<string>();
			var index = 0;
			string value;
			while (CsvReader.TryGetField(index, out value))
			{
				values.Add(value);
				index++;
			}
			return values.ToArray();
		}

		public void Dispose()
		{
			_reader.Dispose();
		}
	}
}