using System.Globalization;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace SIGCM2.Api.Json;

/// <summary>
/// JSON converter for <see cref="DateOnly"/> that uses the "yyyy-MM-dd" ISO format.
///
/// UDT-011: Ensures Cat2 date fields (VigenciaDesde, etc.) never serialize as
/// "2026-05-01T00:00:00" or with a UTC suffix "Z", which would mislead consumers
/// into treating civil Argentine dates as absolute UTC instants.
/// </summary>
public sealed class DateOnlyJsonConverter : JsonConverter<DateOnly>
{
    private const string DateFormat = "yyyy-MM-dd";

    public override DateOnly Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
    {
        var str = reader.GetString();
        if (str is null)
            throw new JsonException("DateOnly value cannot be null.");

        return DateOnly.ParseExact(str, DateFormat, CultureInfo.InvariantCulture);
    }

    public override void Write(Utf8JsonWriter writer, DateOnly value, JsonSerializerOptions options)
    {
        writer.WriteStringValue(value.ToString(DateFormat, CultureInfo.InvariantCulture));
    }
}