using System;
using System.Collections.Generic;
using System.Text;

namespace Apewer.Internals
{

    internal class CsvHelper
    {

        /// <summary>读取 .CSV 文件。</summary>
        public static List<List<string>> ReadCSV(string argText)
        {
            var result = new List<List<string>>();
            if (string.IsNullOrEmpty(argText)) return result;

            var rows = argText.Split('\n');
            var vramarray = new List<string[]>();
            foreach (var row in rows)
            {
                var list = ResolveCSV(row);
                if (list.Count > 0) result.Add(list);
            }

            return result;
        }

        /// <summary>解析 .CSV 文件。</summary>
        private static List<string> ResolveCSV(string argRowText)
        {
            if (string.IsNullOrEmpty(argRowText)) return new List<string>();

            var trim = argRowText.Trim();
            if (string.IsNullOrEmpty(trim)) return new List<string>();

            var list = new List<string>();
            var quote = false;
            var cell = "";
            for (int i = 0; i < argRowText.Length; i++)
            {
                var vchar = argRowText[i];
                switch (vchar)
                {
                    case '"':
                        if (!quote) cell = "";
                        quote = !quote;
                        break;
                    case ',':
                        if (quote)
                        {
                            cell += vchar;
                        }
                        else
                        {
                            list.Add(cell.Trim());
                            cell = "";
                        }
                        break;
                    default:
                        cell += vchar;
                        break;
                }
            }
            if (!string.IsNullOrEmpty(cell))
            {
                list.Add(cell.Trim());
                cell = "";
            }
            return list;
        }

    }

}