using System.ComponentModel.DataAnnotations;
using System.Text.Json;
using System.Text.RegularExpressions;
using Microsoft.OpenApi.Models;

namespace NejCommon.Validation;

public class RegexAttribute : NejValidationAttribute
{
    public override string ExampleJson { get; }
    public string Pattern { get; }
    public RegexAttribute(string pattern, string example, string errorMsg = null)
    {
        Pattern = pattern;
        ExampleJson = JsonSerializer.Serialize(example);
        ErrorMessage = errorMsg ?? $"Invalid format (must match {pattern})";
    }

    protected override ValidationResult IsValid(object value, ValidationContext ctx)
    {
        if (value is null)
            return ValidationResult.Success!;
        
        var str = value as string;
        if (string.IsNullOrWhiteSpace(str) || !Regex.IsMatch(str, Pattern))
            return new ValidationResult(ErrorMessage);
        return ValidationResult.Success!;
    }

    public override void ApplySchema(OpenApiSchema schema)
    {
        base.ApplySchema(schema);
        schema.Pattern = Pattern;
    }
}