using System;
using System.Threading.Tasks;
using Microsoft.Owin.Security.OAuth;
using Step.Database.Controllers;
using Step.Model.DatabaseModels;
using System.Security.Claims;
using static Step.Model.Constants;
using static Step.Config.ServerConfig;
using System.Linq;

namespace Step.Provider
{
    public class ApplicationOAuthProvider : OAuthAuthorizationServerProvider
    {
        public override async Task ValidateClientAuthentication(OAuthValidateClientAuthenticationContext context)
        {
            // Validate client
            context.Validated();
        }

        public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
        {
            using (UsersController usersController = new UsersController())
            {
                try
                {
                    // Check if credentials are correct
                    UserModel user = usersController.FindByUsernameAndPassword(context.UserName, context.Password);
                    // If not
                    if (user == null)
                    {
                        // Return 401
                        context.SetError("invalid_grant", "The user name or password is incorrect.");
                        return;
                    }
                    // Create a new Identity and insert custom claims
                    var identity = new ClaimsIdentity(context.Options.AuthenticationType);

                    // Add claims to token
                    identity.AddClaim(new Claim(USER_ID_KEY, user.UserId.ToString()));

                    using (MachinesUsersController machinesUsersController = new MachinesUsersController())
                    {
                        // Check if user can access to the machine
                        MachineUserModel machineUser = machinesUsersController.FindByUserId(MachineConfig.MachineId, user.UserId);

                        if (machineUser == null)
                        {
                            // Return 401 bad request
                            context.SetError("invalid_grant", "User has no access to this machine");
                            return;
                        }

                        // Add machine id 
                        identity.AddClaim(new Claim(MACHINE_ID_KEY, machineUser.MachineId.ToString()));
                    }

                    // Create Token with identity data
                    context.Validated(identity);

                    await base.GrantResourceOwnerCredentials(context);

                    return;
                }
                catch (Exception ex)
                {
                    // Return 401 bad request
                    context.SetError("invalid_grant", ex.Message);
                    return;
                }

            }
        }

        public override Task TokenEndpointResponse(OAuthTokenEndpointResponseContext context)
        {
            // Find userId and machineId from Claims
            var userId = context.Identity.Claims.Where(c => c.Type == USER_ID_KEY).FirstOrDefault();
            var machineId = context.Identity.Claims.Where(c => c.Type == MACHINE_ID_KEY).FirstOrDefault();

            using(MachinesUsersController machinesUsersController = new MachinesUsersController())
            {
                // Find machineUser Id from database by machineId and userId
                MachineUserModel machineUser = machinesUsersController.FindByUserId(Convert.ToInt32(machineId.Value), Convert.ToInt32(userId.Value));

                using (SessionsController sessionsController = new SessionsController())
                {
                    // Create new user session
                    sessionsController.Create(machineUser.MachineUserId, context.AccessToken);
                }
            }

            return base.TokenEndpointResponse(context);
        }
    }
}