using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

using Simplify.DI;

using Simplify.Web.Model.Binding;

using Simplify.Web.Model.Binding.Binders;

using Simplify.Web.Model.Validation;

using Simplify.Web.Modules.Context;

namespace Simplify.Web.Model;

/// <summary>

/// Provides the model handling.

/// </summary>

/// <seealso cref="Simplify.Web.Model.IModelHandler" />

/// <remarks>

/// Initializes a new instance of the <see cref="HttpModelHandler" /> class.

/// </remarks>

/// <seealso cref="IModelHandler" />

/// <param name="resolver">The resolver.</param>

/// <param name="context">The context.</param>

public class HttpModelHandler(IDIResolver resolver, IWebContext context) : IModelHandler

{

private object? _model;

/// <summary>

/// Gets the model binders types.

/// </summary>

public static IList<Type> ModelBindersTypes { get; } =

[

// Default model binders

typeof(JsonModelBinder),

typeof(HttpQueryModelBinder),

typeof(HttpFormModelBinder)

];

/// <summary>

/// Gets the model validators types.

/// </summary>

public static IList<Type> ModelValidatorsTypes { get; } =

[

// Default model validators

typeof (ValidationAttributesExecutor)

];

/// <summary>

/// Gets a value indicating whether model has been processed (parsed/validated).

/// </summary>

public bool Processed { get; private set; }

/// <summary>

/// Adds the model binder into model binders list, this type should be registered in Simplify.DI container.

/// </summary>

/// <typeparam name="T">The model type.</typeparam>

public static void RegisterModelBinder<T>()

where T : IModelBinder =>

ModelBindersTypes.Add(typeof(T));

/// <summary>

/// Adds the model validator into model validators list, this type should be registered in Simplify.DI container.

/// </summary>

/// <typeparam name="T">The model type.</typeparam>

public static void RegisterModelValidator<T>()

where T : IModelValidator =>

ModelValidatorsTypes.Add(typeof(T));

/// <summary>

/// Parses model and validates it asynchronously

/// </summary>

/// <typeparam name="T">The model type.</typeparam>

public async Task ProcessAsync<T>()

{

var args = new ModelBinderEventArgs<T>(context);

foreach (var binder in ModelBindersTypes.Select(binderType => (IModelBinder)resolver.Resolve(binderType)))

{

await binder.BindAsync(args);

if (!args.IsBound)

continue;

Validate(args, resolver);

_model = args.Model;

Processed = true;

return;

}

throw new ModelBindingException($"Unrecognized request content type for binding: {context.Request.ContentType}");

}

/// <summary>

/// Gets the model.

/// </summary>

/// <typeparam name="T">The model type.</typeparam>

/// <exception cref="InvalidOperationException">Error getting model, model should be processed via ProcessAsync&lt;T&gt; method first</exception>

public T GetModel<T>()

{

if (_model == null)

throw new InvalidOperationException("Error getting model, model should be processed via ProcessAsync<T> method first");

return (T)_model;

}

private static void Validate<T>(ModelBinderEventArgs<T> args, IDIResolver resolver)

{

foreach (var validator in ModelValidatorsTypes.Select(x => (IModelValidator)resolver.Resolve(x)))

validator.Validate(args.Model, resolver);

}

}