using System.IO.Pipelines;
using AyCode.Core.Serializers.Binaries;
using Microsoft.AspNetCore.Mvc.Formatters;
using Microsoft.Extensions.Logging;

namespace AyCode.Services.Mvc;

/// <summary>
/// ASP.NET Core MVC InputFormatter for AcBinary wire format. Reads request body via PipeReader,
/// drains into AsyncPipeReaderInput, deserializes to ModelType. Standard ProblemDetails error
/// flow on failure (ModelState.AddModelError → 400 + application/problem+json).
/// </summary>
public class AcBinaryInputFormatter : InputFormatter
{
    /// <summary>Vendor media type. <c>application/vnd.acbinary</c> by default.</summary>
    public const string DefaultMediaType = "application/vnd.acbinary";

    private readonly AcBinarySerializerOptions _options;
    private readonly ILogger<AcBinaryInputFormatter>? _logger;

    public AcBinaryInputFormatter(AcBinarySerializerOptions? options = null, ILogger<AcBinaryInputFormatter>? logger = null)
    {
        _options = options ?? AcBinarySerializerOptions.Default;
        _logger = logger;
        SupportedMediaTypes.Add(DefaultMediaType);
    }

    public override async Task<InputFormatterResult> ReadRequestBodyAsync(InputFormatterContext context)
    {
        if (context is null) throw new ArgumentNullException(nameof(context));

        var ct = context.HttpContext.RequestAborted;
        var reader = PipeReader.Create(context.HttpContext.Request.Body);
        try
        {
            var model = await AcBinaryDeserializer.DeserializeFromPipeReaderAsync(reader, context.ModelType, _options, ct).ConfigureAwait(false);
            return await InputFormatterResult.SuccessAsync(model).ConfigureAwait(false);
        }
        catch (OperationCanceledException) when (ct.IsCancellationRequested)
        {
            throw;
        }
        catch (Exception ex)
        {
            _logger?.LogWarning(ex, "AcBinary deserialization failed for type {ModelType}", context.ModelType);
            context.ModelState.TryAddModelError(context.ModelName ?? string.Empty, ex.Message);
            return await InputFormatterResult.FailureAsync().ConfigureAwait(false);
        }
        finally
        {
            await reader.CompleteAsync().ConfigureAwait(false);
        }
    }

    protected override bool CanReadType(Type type) => true;
}