using System.Data;
using Validation.Core;

namespace Validation.Rule.Format
{
    /// <summary>
    /// 长度校验
    /// </summary>
    public class LengthValidationRule : IValidationRule
    {
        private readonly string columnName;
        private readonly int minLength;
        private readonly int maxLength;

        public string RuleName => $"Length_{columnName}";
        public string Description => $"检查列'{columnName}'的字符串长度[{minLength}, {maxLength}]";

        public LengthValidationRule(string columnName, int minLength, int maxLength)
        {
            this.columnName = columnName;
            this.minLength = minLength;
            this.maxLength = maxLength;
        }

        public ValidationResult Validate(DataTable dataTable)
        {
            var result = new ValidationResult { IsValid = true };

            if (!dataTable.Columns.Contains(columnName))
                return result;

            foreach (DataRow row in dataTable.Rows)
            {
                int rowIndex = dataTable.Rows.IndexOf(row);

                if (!row.IsNull(columnName))
                {
                    var value = row[columnName]?.ToString() ?? string.Empty;
                    if (value.Length < minLength || value.Length > maxLength)
                    {
                        result.AddError(rowIndex, $"第{rowIndex + 1}行，列'{columnName}'的长度{value.Length}超出范围[{minLength}, {maxLength}]");
                    }
                }
            }

            return result;
        }

        /// <inheritdoc />
        public ValidationResult Validate(string[] headers, int rowIndex, object[] values)
        {
            var result = new ValidationResult { IsValid = true };

            // 查找列索引
            int columnIndex = Array.IndexOf(headers, columnName);

            // 如果找不到列或值为空，则直接返回
            if (columnIndex < 0 || columnIndex >= values.Length || values[columnIndex] == null || values[columnIndex] == DBNull.Value)
            {
                return result;
            }

            var value = values[columnIndex]?.ToString() ?? string.Empty;
            if (value.Length < minLength || value.Length > maxLength)
            {
                result.AddError(rowIndex, $"第{rowIndex + 1}行，列'{columnName}'的长度{value.Length}超出范围[{minLength}, {maxLength}]");
            }

            return result;
        }
    }
}