using System.ComponentModel.DataAnnotations;
using System.Reflection;
using System.Text;

namespace IStation.Test
{
    public static class CsvHelper
    {
        /// <summary>
        /// 导出PumpViewModel集合到CSV文件
        /// </summary>
        public static void ExportToCsv<T>(IEnumerable<T> data, string filePath, Encoding encoding = null)
        {
            if (data == null || !data.Any())
                throw new ArgumentException("数据不能为空");

            encoding ??= Encoding.UTF8;

            var csvContent = GenerateCsvContent(data);
            File.WriteAllText(filePath, csvContent, encoding);
        }

        /// <summary>
        /// 生成CSV内容字符串
        /// </summary>
        public static string GenerateCsvContent<T>(IEnumerable<T> data)
        {
            var sb = new StringBuilder();

            // 添加标题行
            var headers = GetPropertyDisplayNames(typeof(T));
            sb.AppendLine(string.Join(",", headers.Select(EscapeCsvField)));

            // 添加数据行
            foreach (var item in data)
            {
                var values = GetPropertyValues(item);
                sb.AppendLine(string.Join(",", values.Select(EscapeCsvField)));
            }

            return sb.ToString();
        }

        private static List<string> GetPropertyDisplayNames(Type type)
        {
            return type.GetProperties()
                .Select(p => p.GetCustomAttribute<DisplayAttribute>()?.Name ?? p.Name)
                .ToList();
        }

        private static List<string> GetPropertyValues<T>(T item)
        {
            return typeof(T).GetProperties()
                .Select(p => p.GetValue(item)?.ToString() ?? "")
                .ToList();
        }

        private static string EscapeCsvField(string field)
        {
            if (string.IsNullOrEmpty(field))
                return "";

            // 如果字段包含逗号、引号或换行符，则用引号括起来
            if (field.Contains(",") || field.Contains("\"") || field.Contains("\r") || field.Contains("\n"))
            {
                return $"\"{field.Replace("\"", "\"\"")}\"";
            }

            return field;
        }
    }
}