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

public partial class Account_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()
    {
        // Process the result from an auth provider in the request
        ProviderName = OpenAuth.GetProviderNameFromCurrentRequest();

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

        ProviderDisplayName = OpenAuth.GetProviderDisplayName(ProviderName);

        // Build the redirect url for OpenAuth verification
        var redirectUrl = "~/Account/RegisterExternalLogin.aspx";
        var returnUrl = Request.QueryString["ReturnUrl"];
        if (!String.IsNullOrEmpty(returnUrl))
        {
            redirectUrl += "?ReturnUrl=" + HttpUtility.UrlEncode(returnUrl);
        }

        // Verify the OpenAuth payload
        var authResult = OpenAuth.VerifyAuthentication(redirectUrl);
        if (!authResult.IsSuccessful)
        {
            Title = "External login failed";
            userNameForm.Visible = false;
            
            ModelState.AddModelError("Provider", String.Format("External login {0} failed.", ProviderDisplayName));
            
            // To view this error, enable page tracing in web.config (<system.web><trace enabled="true"/></system.web>) and visit ~/Trace.axd
            Trace.Warn("OpenAuth", String.Format("There was an error verifying authentication with {0})", ProviderDisplayName), authResult.Error);
            return;
        }

        // User has logged in with provider successfully
        // Check if user is already registered locally
        if (OpenAuth.Login(authResult.Provider, authResult.ProviderUserId, createPersistentCookie: false))
        {
            RedirectToReturnUrl();
        }

        // Store the provider details in ViewState
        ProviderName = authResult.Provider;
        ProviderUserId = authResult.ProviderUserId;
        ProviderUserName = authResult.UserName;

        // Strip the query string from action
        Form.Action = ResolveUrl(redirectUrl);

        if (User.Identity.IsAuthenticated)
        {
            // User is already authenticated, add the external login and redirect to return url
            OpenAuth.AddAccountToExistingUser(ProviderName, ProviderUserId, ProviderUserName, User.Identity.Name);
            RedirectToReturnUrl();
        }
        else
        {
            // User is new, ask for their desired membership name
            userName.Text = authResult.UserName;
        }
    }

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

        var createResult = OpenAuth.CreateUser(ProviderName, ProviderUserId, ProviderUserName, userName.Text);
        if (!createResult.IsSuccessful)
        {
            
                ModelState.AddModelError("UserName", createResult.ErrorMessage);
                
        }
        else
        {
            // User created & associated OK
            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("~/");
        }
    }
}