// 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;
using System.Globalization;
using System.Text.Encodings.Web;
using Microsoft.AspNetCore.Authentication.OAuth;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.DataProtection;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Microsoft.AspNetCore.Authentication;

namespace Winsoft.GOV.XF.WXCore.OAuth
{
    /// <summary>
    /// An ASP.NET Core middleware for authenticating users using WeChat.
    /// </summary>
    public class WeChatMiddleware : OAuthMiddleware<WeChatOptions>
    {
        /// <summary>
        /// Initializes a new <see cref="WeChatMiddleware"/>.
        /// </summary>
        /// <param name="next">The next middleware in the HTTP pipeline to invoke.</param>
        /// <param name="dataProtectionProvider"></param>
        /// <param name="loggerFactory"></param>
        /// <param name="encoder"></param>
        /// <param name="sharedOptions"></param>
        /// <param name="options">Configuration options for the middleware.</param>
        public WeChatMiddleware(
            RequestDelegate next,
            IDataProtectionProvider dataProtectionProvider,
            ILoggerFactory loggerFactory,
            UrlEncoder encoder,
            IOptions<SharedAuthenticationOptions> sharedOptions,
            IOptions<WeChatOptions> options)
            : base(next, dataProtectionProvider, loggerFactory, encoder, sharedOptions, options)
        {
            if (next == null)
            {
                throw new ArgumentNullException(nameof(next));
            }

            if (dataProtectionProvider == null)
            {
                throw new ArgumentNullException(nameof(dataProtectionProvider));
            }

            if (loggerFactory == null)
            {
                throw new ArgumentNullException(nameof(loggerFactory));
            }

            if (encoder == null)
            {
                throw new ArgumentNullException(nameof(encoder));
            }

            if (sharedOptions == null)
            {
                throw new ArgumentNullException(nameof(sharedOptions));
            }

            if (options == null)
            {
                throw new ArgumentNullException(nameof(options));
            }

            if (string.IsNullOrEmpty(Options.AppId))
            {
                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, nameof(Options.AppId)));
            }

            if (string.IsNullOrEmpty(Options.AppSecret))
            {
                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, nameof(Options.AppSecret)));
            }
        }

        /// <summary>
        /// Provides the <see cref="AuthenticationHandler{T}"/> object for processing authentication-related requests.
        /// </summary>
        /// <returns>An <see cref="AuthenticationHandler{T}"/> configured with the <see cref="WeChatOptions"/> supplied to the constructor.</returns>
        protected override AuthenticationHandler<WeChatOptions> CreateHandler()
        {
            return new WeChatHandler(Backchannel);
        }
    }
}