using System;
using System.Collections.Generic;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace Tango.Portal.Chat.Web.Models
{
    public sealed class FlexibleStringListConverter : JsonConverter<List<string>>
    {
        public override List<string> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            if (reader.TokenType == JsonTokenType.Null)
                return new List<string>();

            if (reader.TokenType == JsonTokenType.String)
                return new List<string> { reader.GetString() ?? string.Empty };

            if (reader.TokenType == JsonTokenType.StartArray)
            {
                var list = new List<string>();
                while (reader.Read())
                {
                    if (reader.TokenType == JsonTokenType.EndArray) break;
                    if (reader.TokenType == JsonTokenType.String)
                        list.Add(reader.GetString() ?? string.Empty);
                    else
                    {
                        using var doc = JsonDocument.ParseValue(ref reader);
                        list.Add(doc.RootElement.GetRawText());
                    }
                }
                return list;
            }

            using var any = JsonDocument.ParseValue(ref reader);
            return new List<string> { any.RootElement.GetRawText() };
        }

        public override void Write(Utf8JsonWriter writer, List<string> value, JsonSerializerOptions options)
        {
            writer.WriteStartArray();
            foreach (var s in value) writer.WriteStringValue(s);
            writer.WriteEndArray();
        }
    }
}