using System.Collections.Generic;
using System.Linq;
using System.Text.Json;
using ModelContextProtocol.Protocol;
using ModelContextProtocol.Server;

namespace Sozsoft.Mcp;

/// <summary>
/// Model metin parametresine tirnaksiz deger (<c>section: 4.2</c>) ya da JSON metni yerine dogrudan
/// dizi/nesne (<c>filter: ["Status","=","Open"]</c>) gonderebilir. SDK her parametreyi ayri ayri
/// <c>string</c> olarak bagladigi icin bu deger <see cref="JsonException"/> ("Cannot get the value of a
/// token type 'Number' / 'StartArray' as a string") ile duser. Deger cagri araca ulasmadan, aracin kendi
/// semasina bakilarak ham JSON metnine cevrilir — JSON bekleyen parametre ayni metni alir; string icin
/// ozel converter kullanilmaz, cunku arac semasindaki <c>"type": "string"</c> bilgisini siler.
/// </summary>
internal static class McpToolArgumentNormalizer
{
    public static void Normalize(CallToolRequestParams? parameters, McpServerTool? tool)
    {
        if (parameters?.Arguments is not { Count: > 0 } arguments
            || tool is null
            || !tool.ProtocolTool.InputSchema.TryGetProperty("properties", out var properties)
            || properties.ValueKind != JsonValueKind.Object)
        {
            return;
        }

        Dictionary<string, JsonElement>? normalized = null;

        foreach (var (name, value) in arguments)
        {
            if (value.ValueKind is JsonValueKind.String or JsonValueKind.Null or JsonValueKind.Undefined
                || !properties.TryGetProperty(name, out var schema)
                || !IsStringOnly(schema))
            {
                continue;
            }

            normalized ??= new Dictionary<string, JsonElement>(arguments);
            normalized[name] = JsonSerializer.SerializeToElement(value.GetRawText());
        }

        if (normalized is not null)
        {
            parameters.Arguments = normalized;
        }
    }

    // Nullable metin parametresi semada ["string", "null"] olarak gelir; baska tip de kabul eden bir
    // birlesim tipi donusturulmez, degeri SDK oldugu gibi baglar.
    private static bool IsStringOnly(JsonElement schema)
    {
        if (!schema.TryGetProperty("type", out var type))
        {
            return false;
        }

        return type.ValueKind switch
        {
            JsonValueKind.String => type.GetString() == "string",
            JsonValueKind.Array => type.EnumerateArray()
                .Select(item => item.GetString())
                .Where(item => item != "null")
                .SequenceEqual(["string"]),
            _ => false
        };
    }
}