using System;
using System.Collections.Generic;
using System.Linq;
using Jellyfin.Api.Constants;
using Microsoft.AspNetCore.Authorization;
using Microsoft.OpenApi.Models;
using Swashbuckle.AspNetCore.SwaggerGen;

namespace Jellyfin.Server.Filters
{
    /// <summary>
    /// Security requirement operation filter.
    /// </summary>
    public class SecurityRequirementsOperationFilter : IOperationFilter
    {
        /// <inheritdoc />
        public void Apply(OpenApiOperation operation, OperationFilterContext context)
        {
            var requiredScopes = new List<string>();

            // Add all method scopes.
            foreach (var attribute in context.MethodInfo.GetCustomAttributes(true))
            {
                if (attribute is AuthorizeAttribute authorizeAttribute
                    && authorizeAttribute.Policy is not null
                    && !requiredScopes.Contains(authorizeAttribute.Policy, StringComparer.Ordinal))
                {
                    requiredScopes.Add(authorizeAttribute.Policy);
                }
            }

            // Add controller scopes if any.
            var controllerAttributes = context.MethodInfo.DeclaringType?.GetCustomAttributes(true);
            if (controllerAttributes is not null)
            {
                foreach (var attribute in controllerAttributes)
                {
                    if (attribute is AuthorizeAttribute authorizeAttribute
                        && authorizeAttribute.Policy is not null
                        && !requiredScopes.Contains(authorizeAttribute.Policy, StringComparer.Ordinal))
                    {
                        requiredScopes.Add(authorizeAttribute.Policy);
                    }
                }
            }

            if (requiredScopes.Count != 0)
            {
                if (!operation.Responses.ContainsKey("401"))
                {
                    operation.Responses.Add("401", new OpenApiResponse { Description = "Unauthorized" });
                }

                if (!operation.Responses.ContainsKey("403"))
                {
                    operation.Responses.Add("403", new OpenApiResponse { Description = "Forbidden" });
                }

                var scheme = new OpenApiSecurityScheme
                {
                    Reference = new OpenApiReference
                    {
                        Type = ReferenceType.SecurityScheme,
                        Id = AuthenticationSchemes.CustomAuthentication
                    }
                };

                operation.Security = new List<OpenApiSecurityRequirement>
                {
                    new OpenApiSecurityRequirement
                    {
                        [scheme] = requiredScopes
                    }
                };
            }
        }
    }
}