using System;

using System.Collections.Generic;

using System.Text.Json;

using System.Text.Json.Serialization;

var baseRule = JsonSerializer.Deserialize<BaseRule>(

    """

    {

        "combinator": "OR",

        "not": true,

        "criteria": [

            {

                "field": "path",

                "key": "",

                "value": "",

                "operator": "="

            },

            {

                "combinator": "AND",

                "not": false,

                "criteria": [

                    {

                        "field": "header",

                        "key": "",

                        "value": "",

                        "operator": "="

                    }

                ]

            }

        ]

    }

    """,

    new JsonSerializerOptions(JsonSerializerDefaults.Web)

);

​

baseRule.Dump();

public class RuleGroup : BaseRule

{

    public string Combinator { get; set; }

    public bool Not { get; set; }

    public List<BaseRule> Criteria { get; set; }

}

​

public class RuleCriteria : BaseRule

{

    public string Field { get; set; }

    public string Operator { get; set; }

    public string Key { get; set; }

    public string Value { get; set; }

}

​

[JsonConverter(typeof(RuleConverter))]

public class BaseRule;

​

public class RuleConverter : JsonConverter<BaseRule>

{

    public override BaseRule? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)

    {

        using var doc = JsonDocument.ParseValue(ref reader);

        if (doc.RootElement.TryGetProperty("combinator", out _))

        {

            return doc.Deserialize<RuleGroup>(options);

        }

​

        return doc.Deserialize<RuleCriteria>(options);

    }

​

    public override void Write(Utf8JsonWriter writer, BaseRule value, JsonSerializerOptions options) 

        => throw new NotImplementedException();

}