using System.Linq;
using System.Security.Claims;
using gehGassi.Domain.Users;
using gehGassi.Permissions;

namespace gehGassi.Web.Auth
{
    /// <summary>
    /// Erweiterungen für  ClaimsPrincipal für Abfrage von Permissions
    /// </summary>
    public static class PermissionExtensions
    {
        /// <summary>
        /// True wenn der Benutzer über zumindest eine Permission verfügt. Prüft gegen die Datenbank.
        /// </summary>
        /// <param name="user">ClaimsPrincipal User</param>
        /// <param name="permissions">Gesuchte permissions</param>
        /// <returns>true wenn verfügbar, false sonst</returns>
        public static bool HasPermission(this ApplicationUser user, params Permission[] permissions)
        {
            var permissionClaim = user?.Permissions;
            if (string.IsNullOrWhiteSpace(permissionClaim))
                return false;
            var permissionList = permissions.ToList();
            var permissionsGranted = permissionClaim.UnpackPermissionsFromString();
            foreach (var permission in permissionList)
            {
                if (permissionsGranted.Contains(permission))
                    return true;
            }
            return false;
        }

        /// <summary>
        /// True wenn der Benutzer über alle Permissions verfügt. Prüft gegen die Datenbank.
        /// </summary>
        /// <param name="user">ClaimsPrincipal User</param>
        /// <param name="permissions">Gesuchte permissions</param>
        /// <returns>true wenn verfügbar, false sonst</returns>
        public static bool HasPermissions(this ApplicationUser user, params Permission[] permissions)
        {
            var permissionClaim = user?.Permissions;
            if (string.IsNullOrWhiteSpace(permissionClaim))
                return false;
            var permissionList = permissions.ToList();
            var permissionsGranted = permissionClaim.UnpackPermissionsFromString();
            foreach (var permission in permissionList)
            {
                if (!permissionsGranted.Contains(permission))
                    return false;
            }
            return true;
        }

        /// <summary>
        /// True wenn der Benutzer über zumindest eine Permission verfügt. Prüft gegen Claims.
        /// </summary>
        /// <param name="user">ClaimsPrincipal User</param>
        /// <param name="permissions">Gesuchte permissions</param>
        /// <returns>true wenn verfügbar, false sonst</returns>
        public static bool HasPermission(this ClaimsPrincipal user, params Permission[] permissions)
        {
            var permissionClaim = user?.Claims.SingleOrDefault(x => x.Type == ClaimConstants.PackedPermissionClaimType);
            if (permissionClaim != null)
            {
                var permissionList = permissions.ToList();
                var permissionsGranted = permissionClaim.Value.UnpackPermissionsFromString();
                foreach (var permission in permissionList)
                {
                    if (permissionsGranted.Contains(permission))
                        return true;
                }
            }
            return false;
        }

        /// <summary>
        /// True wenn der Benutzer über alle Permissions verfügt. Prüft gegen Claims.
        /// </summary>
        /// <param name="user">ClaimsPrincipal User</param>
        /// <param name="permissions">Gesuchte permissions</param>
        /// <returns>true wenn verfügbar, false sonst</returns>
        public static bool HasPermissions(this ClaimsPrincipal user, params Permission[] permissions)
        {
            var permissionClaim = user?.Claims.SingleOrDefault(x => x.Type == ClaimConstants.PackedPermissionClaimType);
            if (permissionClaim != null)
            {
                var permissionList = permissions.ToList();
                var permissionsGranted = permissionClaim.Value.UnpackPermissionsFromString();
                foreach (var permission in permissionList)
                {
                    if (!permissionsGranted.Contains(permission))
                        return false;
                }
            }
            return true;
        }
    }
}