using NCC.Dependency;
using NCC.Localization;
using NCC.SensitiveDetection;
using System.Reflection;

namespace System.ComponentModel.DataAnnotations
{
    /// <summary>
    /// 脱敏词汇检查（脱敏处理）
    /// </summary>
    [SuppressSniffer]
    public class SensitiveDetectionAttribute : ValidationAttribute
    {
        /// <summary>
        /// 构造函数
        /// </summary>
        public SensitiveDetectionAttribute()
        {
        }

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="transfer"></param>
        public SensitiveDetectionAttribute(char transfer)
        {
            Transfer = transfer;
        }

        /// <summary>
        /// 替换为指定字符
        /// </summary>
        public char Transfer { get; set; }

        /// <summary>
        /// 验证逻辑
        /// </summary>
        /// <param name="value"></param>
        /// <param name="validationContext"></param>
        /// <returns></returns>
        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            // null 、非字符串和空字符串跳过检查
            if (value == null || value.GetType() != typeof(string) || (value is string s && string.IsNullOrWhiteSpace(s))) return ValidationResult.Success;

            // 获取脱敏提供器（如果未注册，直接跳过，而不是抛异常）
            if (validationContext.GetService(typeof(ISensitiveDetectionProvider)) is not ISensitiveDetectionProvider sensitiveWordsProvider) return ValidationResult.Success;

            var strValue = value.ToString();

            // 如果没有传入替换字符，则直接校验
            if (Transfer == default)
            {
                // 判断符合
                var isVaild = sensitiveWordsProvider.VaildedAsync(strValue).GetAwaiter().GetResult();

                if (!isVaild)
                {
                    // 进行多语言处理
                    var errorMessage = !string.IsNullOrWhiteSpace(ErrorMessage) ? ErrorMessage : "Characters contain sensitive words.";

                    return new ValidationResult(string.Format(L.Text == null ? errorMessage : L.Text[errorMessage], validationContext.MemberName));
                }

                // 验证成功
                return ValidationResult.Success;
            }
            // 替换敏感词汇
            else
            {
                // 不支持单个值替换（有知道方法的朋友可以提交 PR）
                if (validationContext.ObjectType == typeof(string))
                    throw new NotSupportedException("Single value sensitive word substitution is not supported.");

                // 替换字符
                var newValue = sensitiveWordsProvider.ReplaceAsync(strValue, Transfer).GetAwaiter().GetResult();

                // 如果不包含敏感词汇直接返回
                if (newValue == strValue) return ValidationResult.Success;

                // 对象类型替换
                validationContext.ObjectType
                                    .GetProperty(validationContext.MemberName, BindingFlags.Public | BindingFlags.Instance)
                                    .SetValue(validationContext.ObjectInstance, newValue);

                // 验证成功
                return ValidationResult.Success;
            }
        }
    }
}