using ModelContextProtocol.Protocol.Messages;
using ModelContextProtocol.Protocol.Types;
using System.Diagnostics.CodeAnalysis;
using System.Text.Json;
using System.Text.Json.Nodes;
using System.Text.Json.Serialization;
using System.Text.Json.Serialization.Metadata;

namespace ModelContextProtocol.Utils.Json;

/// <summary>
/// Extensions for configuring System.Text.Json serialization options for MCP.
/// </summary>
internal static partial class JsonSerializerOptionsExtensions
{
    public static JsonSerializerOptions DefaultOptions { get; } = CreateDefaultOptions();

    /// <summary>
    /// Creates default options to use for MCP-related serialization.
    /// </summary>
    /// <returns>The configured options.</returns>
    [UnconditionalSuppressMessage("AotAnalysis", "IL3050", Justification = "DefaultJsonTypeInfoResolver is only used when reflection-based serialization is enabled")]
    [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026", Justification = "DefaultJsonTypeInfoResolver is only used when reflection-based serialization is enabled")]
    private static JsonSerializerOptions CreateDefaultOptions()
    {
        // If reflection-based serialization is enabled by default, use it, as it's the most permissive in terms of what it can serialize,
        // and we want to be flexible in terms of what can be put into the various collections in the object model.
        // Otherwise, use the source-generated options to enable trimming and Native AOT.

        if (JsonSerializer.IsReflectionEnabledByDefault)
        {
            // Keep in sync with the JsonSourceGenerationOptions attribute on JsonContext below.
            JsonSerializerOptions options = new(JsonSerializerDefaults.Web)
            {
                TypeInfoResolver = new DefaultJsonTypeInfoResolver(),
                Converters = { new JsonStringEnumConverter() },
                DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
                NumberHandling = JsonNumberHandling.AllowReadingFromString
            };

            options.MakeReadOnly();
            return options;
        }

        return JsonContext.Default.Options;
    }

    internal static JsonTypeInfo<T> GetTypeInfo<T>(this JsonSerializerOptions options) =>
        (JsonTypeInfo<T>)options.GetTypeInfo(typeof(T));

    // Keep in sync with CreateDefaultOptions above.
    [JsonSourceGenerationOptions(JsonSerializerDefaults.Web,
        UseStringEnumConverter = true,
        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
        NumberHandling = JsonNumberHandling.AllowReadingFromString)]
    [JsonSerializable(typeof(JsonDocument))]
    [JsonSerializable(typeof(JsonElement))]
    [JsonSerializable(typeof(JsonNode))]
    [JsonSerializable(typeof(IJsonRpcMessage))]
    [JsonSerializable(typeof(JsonRpcRequest))]
    [JsonSerializable(typeof(JsonRpcNotification))]
    [JsonSerializable(typeof(JsonRpcResponse))]
    [JsonSerializable(typeof(JsonRpcError))]
    [JsonSerializable(typeof(ServerCapabilities))]
    [JsonSerializable(typeof(Implementation))]
    [JsonSerializable(typeof(CreateMessageResult))]
    [JsonSerializable(typeof(ListRootsResult))]
    [JsonSerializable(typeof(InitializeResult))]
    [JsonSerializable(typeof(JsonSchema))]
    [JsonSerializable(typeof(CallToolResponse))]
    internal sealed partial class JsonContext : JsonSerializerContext;
}