// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System.Linq;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.Diagnostics;

namespace Microsoft.AspNetCore.Mvc.Analyzers
{
    public class ApiControllerAnalyzerContext
    {
#pragma warning disable RS1012 // Start action has no registered actions.
        public ApiControllerAnalyzerContext(CompilationStartAnalysisContext context)
#pragma warning restore RS1012 // Start action has no registered actions.
        {
            Context = context;
            ApiControllerAttribute = context.Compilation.GetTypeByMetadataName(TypeNames.ApiControllerAttribute);
        }

        public CompilationStartAnalysisContext Context { get; }

        public INamedTypeSymbol ApiControllerAttribute { get; }

        private INamedTypeSymbol _routeAttribute;
        public INamedTypeSymbol RouteAttribute => GetType(TypeNames.IRouteTemplateProvider, ref _routeAttribute);

        private INamedTypeSymbol _actionResultOfT;
        public INamedTypeSymbol ActionResultOfT => GetType(TypeNames.ActionResultOfT, ref _actionResultOfT);

        private INamedTypeSymbol _systemThreadingTask;
        public INamedTypeSymbol SystemThreadingTask => GetType(TypeNames.Task, ref _systemThreadingTask);

        private INamedTypeSymbol _systemThreadingTaskOfT;
        public INamedTypeSymbol SystemThreadingTaskOfT => GetType(TypeNames.TaskOfT, ref _systemThreadingTaskOfT);

        private INamedTypeSymbol _objectResult;
        public INamedTypeSymbol ObjectResult => GetType(TypeNames.ObjectResult, ref _objectResult);

        private INamedTypeSymbol _iActionResult;
        public INamedTypeSymbol IActionResult => GetType(TypeNames.IActionResult, ref _iActionResult);

        public INamedTypeSymbol _modelState;
        public INamedTypeSymbol ModelStateDictionary => GetType(TypeNames.ModelStateDictionary, ref _modelState);

        public INamedTypeSymbol _nonActionAttribute;
        public INamedTypeSymbol NonActionAttribute => GetType(TypeNames.NonActionAttribute, ref _nonActionAttribute);


        private INamedTypeSymbol GetType(string name, ref INamedTypeSymbol cache) =>
            cache = cache ?? Context.Compilation.GetTypeByMetadataName(name);

        public bool IsApiAction(IMethodSymbol method)
        {
            return
                method.ContainingType.HasAttribute(ApiControllerAttribute, inherit: true) &&
                method.DeclaredAccessibility == Accessibility.Public &&
                !method.IsGenericMethod &&
                !method.IsAbstract &&
                !method.IsStatic &&
                !method.HasAttribute(NonActionAttribute);
        }
    }
}