using System;
using System.Web;
using System.Web.Security;
using DotNetOpenAuth.AspNet;
using Microsoft.AspNet.Membership.OpenAuth;

namespace WebSRM.Account
{
    public partial class RegisterExternalLogin : System.Web.UI.Page
    {
        protected string ProviderName
        {
            get { return (string)ViewState["ProviderName"] ?? String.Empty; }
            private set { ViewState["ProviderName"] = value; }
        }

        protected string ProviderDisplayName
        {
            get { return (string)ViewState["ProviderDisplayName"] ?? String.Empty; }
            private set { ViewState["ProviderDisplayName"] = value; }
        }

        protected string ProviderUserId
        {
            get { return (string)ViewState["ProviderUserId"] ?? String.Empty; }
            private set { ViewState["ProviderUserId"] = value; }
        }

        protected string ProviderUserName
        {
            get { return (string)ViewState["ProviderUserName"] ?? String.Empty; }
            private set { ViewState["ProviderUserName"] = value; }
        }

        protected void Page_Load()
        {
            if (!IsPostBack)
            {
                ProcessProviderResult();
            }
        }

        protected void logIn_Click(object sender, EventArgs e)
        {
            CreateAndLoginUser();
        }

        protected void cancel_Click(object sender, EventArgs e)
        {
            RedirectToReturnUrl();
        }

        private void ProcessProviderResult()
        {
            // 处理请求中的身份验证提供程序返回的结果
            ProviderName = OpenAuth.GetProviderNameFromCurrentRequest();

            if (String.IsNullOrEmpty(ProviderName))
            {
                Response.Redirect(FormsAuthentication.LoginUrl);
            }

            // 生成重定向 URL 以进行 OpenAuth 验证
            var redirectUrl = "~/Account/RegisterExternalLogin";
            var returnUrl = Request.QueryString["ReturnUrl"];
            if (!String.IsNullOrEmpty(returnUrl))
            {
                redirectUrl += "?ReturnUrl=" + HttpUtility.UrlEncode(returnUrl);
            }

            // 验证 OpenAuth 负载
            var authResult = OpenAuth.VerifyAuthentication(redirectUrl);
            ProviderDisplayName = OpenAuth.GetProviderDisplayName(ProviderName);
            if (!authResult.IsSuccessful)
            {
                Title = "外部登录失败";
                userNameForm.Visible = false;

                providerMessage.Text = String.Format("外部登录 {0} 失败，", ProviderDisplayName);

                // 若要查看此错误，请在 web.config 中启用页跟踪(<system.web><trace enabled="true"/></system.web>)，然后访问 ~/Trace.axd
                Trace.Warn("OpenAuth", String.Format("使用 {0}) 验证身份验证时出错", ProviderDisplayName), authResult.Error);
                return;
            }

            // 用户已成功地使用提供程序登录
            // 检查用户是否已在本地注册
            if (OpenAuth.Login(authResult.Provider, authResult.ProviderUserId, createPersistentCookie: false))
            {
                RedirectToReturnUrl();
            }

            // 在 ViewState 中存储提供程序详细信息
            ProviderName = authResult.Provider;
            ProviderUserId = authResult.ProviderUserId;
            ProviderUserName = authResult.UserName;

            // 从操作中去除查询字符串
            Form.Action = ResolveUrl(redirectUrl);

            if (User.Identity.IsAuthenticated)
            {
                // 用户已进行身份验证，请添加外部登录并重定向到返回 URL
                OpenAuth.AddAccountToExistingUser(ProviderName, ProviderUserId, ProviderUserName, User.Identity.Name);
                RedirectToReturnUrl();
            }
            else
            {
                // 这是新用户，请要求该用户提供所需的成员名称
                userName.Text = authResult.UserName;
            }
        }

        private void CreateAndLoginUser()
        {
            if (!IsValid)
            {
                return;
            }

            var createResult = OpenAuth.CreateUser(ProviderName, ProviderUserId, ProviderUserName, userName.Text);
            if (!createResult.IsSuccessful)
            {

                userNameMessage.Text = createResult.ErrorMessage;

            }
            else
            {
                // 已成功创建并关联用户
                if (OpenAuth.Login(ProviderName, ProviderUserId, createPersistentCookie: false))
                {
                    RedirectToReturnUrl();
                }
            }
        }

        private void RedirectToReturnUrl()
        {
            var returnUrl = Request.QueryString["ReturnUrl"];
            if (!String.IsNullOrEmpty(returnUrl) && OpenAuth.IsLocalUrl(returnUrl))
            {
                Response.Redirect(returnUrl);
            }
            else
            {
                Response.Redirect("~/");
            }
        }
    }
}