using System;
using System.Linq;
using System.Security.Claims;
using System.Web.Http;
using System.Web.Http.Controllers;
using Step.Database.Controllers;
using Step.Config;
using Step.Model.DatabaseModels;
using static Step.Config.ServerConfig;
using static Step.Model.Constants;

namespace Step
{
    class WebApiAuthorizeAttribute : AuthorizeAttribute
    {
        public string FunctionAccess;
        public ACTIONS Action;
        protected override bool IsAuthorized(HttpActionContext actionContext)
        {
            if (!base.IsAuthorized(actionContext))
                return false;

            // Get claims from token
            ClaimsPrincipal principal = actionContext.RequestContext.Principal as ClaimsPrincipal;
            // Get user id stored in the bearer token   
            var userId = principal.Claims.Where(c => c.Type == USER_ID_KEY).FirstOrDefault();

            // Get machine unique id stored in the bearer token
            var machineId = principal.Claims.Where(c => c.Type == MACHINE_ID_KEY).FirstOrDefault();

            //User data not found -> not authorized
            if (userId == null || machineId == null)
                return false;

            // Get token from headers
            string token = actionContext.Request.Headers.Authorization.ToString();
            token = token.Split(' ')[1];

            // check authorization
            if (!CheckAuthorization(Convert.ToInt32(machineId.Value), Convert.ToInt32(userId.Value), FunctionAccess, token))
                return false;

            return true;
        }

        private bool CheckAuthorization(int machineId, int userId, string functionName, string token)
        {                    
            // Check if the machine is the same where the user logged in
            if (machineId != MachineConfig.MachineId)
                return false;

            using (SessionsController sessionsController = new SessionsController())
            {
                // Find user session on this machine
                SessionModel session = sessionsController.FindSessionByToken(token);
                if (session == null)
                    return false;

                MachineUserModel machineUser = new MachineUserModel();
                using (MachinesUsersController machineUsersController = new MachinesUsersController())
                {
                    // Find machineUser data and joined to user data, role data, machine data 
                    machineUser = machineUsersController.FindByIdWithData(session.MachineUserId);
                }

                using (FunctionsAccessController acController = new FunctionsAccessController())
                {
                    // Read from db function levels
                    FunctionAccessModel functionAccess = acController.FindEnabledFunctionByName(functionName);
                    if (functionAccess != null && ServerConfigController.CheckAreaStatus(functionAccess.Area))
                    {
                        if (Action == ACTIONS.READ)
                        {   // Check read permissions 
                            if (functionAccess.ReadLevelMin > machineUser.Role.Level)
                                return false; // Not authorized
                        }
                        else
                        {   // Check write permissions
                            if (functionAccess.WriteLevelMin > machineUser.Role.Level)
                                return false; // Not authorized
                        }
                    }
                    else
                        return false;

                    // Authorized
                    return true;
                }
            }
        }
    }
}