// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
#nullable enable
 
using System.Globalization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Core;
 
namespace Microsoft.AspNetCore.Mvc.ModelBinding;
 
/// <summary>
/// A <see cref="IValueProviderFactory"/> for <see cref="FormValueProvider"/>.
/// </summary>
public class FormValueProviderFactory : IValueProviderFactory
{
    /// <inheritdoc />
    public Task CreateValueProviderAsync(ValueProviderFactoryContext context)
    {
        ArgumentNullException.ThrowIfNull(context);
 
        var request = context.ActionContext.HttpContext.Request;
        if (request.HasFormContentType)
        {
            // Allocating a Task only when the body is form data.
            return AddValueProviderAsync(context);
        }
 
        return Task.CompletedTask;
    }
 
    private static async Task AddValueProviderAsync(ValueProviderFactoryContext context)
    {
        var request = context.ActionContext.HttpContext.Request;
        IFormCollection form;
 
        try
        {
            form = await request.ReadFormAsync();
        }
        catch (InvalidDataException ex)
        {
            // ReadFormAsync can throw InvalidDataException if the form content is malformed.
            // Wrap it in a ValueProviderException that the CompositeValueProvider special cases.
            throw new ValueProviderException(Resources.FormatFailedToReadRequestForm(ex.Message), ex);
        }
        catch (IOException ex)
        {
            // ReadFormAsync can throw IOException if the client disconnects.
            // Wrap it in a ValueProviderException that the CompositeValueProvider special cases.
            throw new ValueProviderException(Resources.FormatFailedToReadRequestForm(ex.Message), ex);
        }
 
        var valueProvider = new FormValueProvider(
            BindingSource.Form,
            form,
            CultureInfo.CurrentCulture);
 
        context.ValueProviders.Add(valueProvider);
    }
}