using System;

using DL.MessageBroker.Contracts;

using DL.Extensions.Json;

​

#nullable enable

public class Program

{

    public static void Main()

    {

        var @event = new DeviceReplacedOnVehicleEvent(new DeviceReplacedDto("old-device-id", "new-device-id"), "TESTING");

        var eventJson = @event

            .ToJsonObjectBuilder()

            .TryReplace(e => e.Device.OldDeviceId, "OldDevice", new Device("product-id", "product-name"))

            .TryReplace(e => e.Device.NewDeviceId, "NewDevice", new Device("product-id", "product-name"))

            .ToJsonString();

        Console.WriteLine(eventJson);

    }

}

​

namespace DL.MessageBroker.Contracts

{

    public record DeviceReplacedOnVehicleEvent(DeviceReplacedDto Device, string DataSource);

    public record DeviceReplacedDto(string OldDeviceId, string NewDeviceId);

    public record Device(string Id, string Name);

}

​

namespace DL.Extensions

{

    using System.Linq.Expressions;

    using System.Text;

​

    public static class ExpressionExtensions

    {

        public static MemberExpression? GetMemberExpression(this Expression? expression)

        {

            if (expression != null)

            {

                Console.WriteLine($"DEBUG GetMemberExpression(): expression = {expression}");

                if (expression is MemberExpression)

                {

                    Console.WriteLine("DEBUG GetMemberExpression(): expression is a member expression");

                    return (MemberExpression)expression;

                }

​

                if (expression is LambdaExpression)

                {

                    Console.WriteLine("DEBUG GetMemberExpression(): expression is a Lambda expression");

                    var lambdaExpression = (LambdaExpression)expression;

                    Console.WriteLine($"DEBUG GetMemberExpression(): lambdaExpression = {lambdaExpression}");

​

                    if (lambdaExpression.Body is MemberExpression)

                    {

                        Console.WriteLine($"DEBUG GetMemberExpression(): lambdaExpression Body is a member expression {lambdaExpression.Body}");

                        return (MemberExpression)lambdaExpression.Body;

                    }

​

                    if (lambdaExpression.Body is UnaryExpression)

                    {

                        Console.WriteLine($"DEBUG GetMemberExpression(): lambdaExpression Body is an Unary expression {((UnaryExpression)lambdaExpression.Body).Operand}");

                        return (MemberExpression)((UnaryExpression)lambdaExpression.Body).Operand;

                    }

                }

            }

​

            return null;

        }

​

        public static string GetPropertyPath(this Expression expression)

        {

            var path = new StringBuilder();

            //Console.WriteLine($"DEBUG GetPropertyPath(): expression = {expression}");

​

            var memberExpression = expression.GetMemberExpression();

            while(memberExpression != null)

            {

                /*

                Console.WriteLine($"DEBUG GetPropertyPath(): memberExpression = {memberExpression}");

                Console.WriteLine($"DEBUG GetPropertyPath(): memberExpression.Member.Name = {memberExpression.Member.Name}");

                */

                if (path.Length > 0)

                {

                    path.Insert(0, ".");

                }

​

                path.Insert(0, memberExpression.Member.Name);

​

                memberExpression = memberExpression.Expression.GetMemberExpression();

            }

​

            return path.ToString();

        }

    }

}

​

namespace DL.Extensions.Json

{

    using System.Collections.Generic;

    using System.Linq.Expressions;

    using System.Text.Json;

    using System.Text.Json.Nodes;

​

    public class JsonObjectBuilder<TSource>

    {

        private readonly TSource? _source;

        private readonly JsonObject? _jsonObject;

​

        public JsonObjectBuilder(TSource? source)

        {

            _source = source;

​

            if (source != null)

            {

                _jsonObject = JsonSerializer.SerializeToNode(source)?.AsObject();

            }

        }

​

        public JsonObjectBuilder<TSource> TryReplace<TProperty>(Expression<Func<TSource, TProperty>> selectorExpression,

            string newPropertyName, object? newPropertyValue)

        {

            if (_jsonObject != null && newPropertyValue != null)

            {

                string oldPropertyNamePath = selectorExpression.GetPropertyPath();

                var nestedProperties = oldPropertyNamePath

                    .Split('.');

                /*

                Console.WriteLine();

                Console.WriteLine($"DEBUG: oldPropertyNamePath = {oldPropertyNamePath}");

                Console.WriteLine($"DEBUG: nestedProperties = {JsonSerializer.Serialize(nestedProperties)}");

                Console.WriteLine();

                */

​

                JsonObject? jsonObjectPointer = _jsonObject;

​

                // If the old property to replace is nested

                for (int i = 0; i < nestedProperties.Length - 1 && jsonObjectPointer != null; i++)

                {

                    string parentPropertyName = nestedProperties[i];

                    jsonObjectPointer = jsonObjectPointer[parentPropertyName]?.AsObject();

                }

​

                if (jsonObjectPointer != null)

                {

                    string oldPropertyName = nestedProperties[^1];

​

                    jsonObjectPointer.TryAdd(newPropertyName, JsonSerializer.SerializeToNode(newPropertyValue));

                    jsonObjectPointer.Remove(oldPropertyName);

                }

            }

​

            return this;

        }

​

        public JsonObjectBuilder<TSource> TryReplace<TProperty>(Expression<Func<TSource, TProperty>> selectorExpression,

            string newPropertyName, JsonNode? newPropertyValue)

        {

            if (_jsonObject != null && newPropertyValue != null)

            {

                string oldPropertyNamePath = selectorExpression.GetPropertyPath();

​

                var nestedProperties = oldPropertyNamePath

                    .Split('.');

​

                JsonObject? jsonObjectPointer = _jsonObject;

​

                // If the old property to replace is nested

                for (int i = 0; i < nestedProperties.Length - 1 && jsonObjectPointer != null; i++)

                {

                    string parentPropertyName = nestedProperties[i];

                    jsonObjectPointer = jsonObjectPointer[parentPropertyName]?.AsObject();

                }

​

                if (jsonObjectPointer != null)

                {

                    string oldPropertyName = nestedProperties[^1];

​

                    _jsonObject.TryAdd(newPropertyName, newPropertyValue);

                    _jsonObject.Remove(oldPropertyName);

                }

            }

​

            return this;

        }

​

        public JsonNode? ToJsonNode()

        {

            return JsonNode.Parse(ToJsonString());

        }

​

        public string ToJsonString(bool indented = true)

        {

            if (_jsonObject == null)

            {

                return JsonSerializer.Serialize(_source);

            }

​

            return _jsonObject.ToJsonString(new JsonSerializerOptions

            {

                WriteIndented = indented

            });

        }

    }

    public static class JsonSerializationExtensions

    {

        public static JsonObjectBuilder<TSource> ToJsonObjectBuilder<TSource>(this TSource? source)

        {

            return new JsonObjectBuilder<TSource>(source);

        }

    }

}