/*
 *
 * (c) Copyright Ascensio System Limited 2010-2018
 *
 * This program is freeware. You can redistribute it and/or modify it under the terms of the GNU 
 * General Public License (GPL) version 3 as published by the Free Software Foundation (https://www.gnu.org/copyleft/gpl.html). 
 * In accordance with Section 7(a) of the GNU GPL its Section 15 shall be amended to the effect that 
 * Ascensio System SIA expressly excludes the warranty of non-infringement of any third-party rights.
 *
 * THIS PROGRAM IS DISTRIBUTED WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY OR
 * FITNESS FOR A PARTICULAR PURPOSE. For more details, see GNU GPL at https://www.gnu.org/copyleft/gpl.html
 *
 * You can contact Ascensio System SIA by email at sales@onlyoffice.com
 *
 * The interactive user interfaces in modified source and object code versions of ONLYOFFICE must display 
 * Appropriate Legal Notices, as required under Section 5 of the GNU GPL version 3.
 *
 * Pursuant to Section 7 § 3(b) of the GNU GPL you must retain the original ONLYOFFICE logo which contains 
 * relevant author attributions when distributing the software. If the display of the logo in its graphic 
 * form is not reasonably feasible for technical reasons, you must include the words "Powered by ONLYOFFICE" 
 * in every copy of the program you distribute. 
 * Pursuant to Section 7 § 3(e) we decline to grant you any rights under trademark law for use of our trademarks.
 *
*/


using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;

using ASC.Collections;
using ASC.Common;
using ASC.Core.Caching;
using ASC.Core.Common.EF;
using ASC.Core.Tenants;
using ASC.Core.Users;

using Microsoft.AspNetCore.Http;

namespace ASC.Core
{
    public class UserManagerConstants
    {
        public IDictionary<Guid, UserInfo> SystemUsers { get; }
        public Constants Constants { get; }

        public UserManagerConstants(Constants constants)
        {
            SystemUsers = Configuration.Constants.SystemAccounts.ToDictionary(a => a.ID, a => new UserInfo { ID = a.ID, LastName = a.Name });
            SystemUsers[Constants.LostUser.ID] = Constants.LostUser;
            SystemUsers[Constants.OutsideUser.ID] = Constants.OutsideUser;
            SystemUsers[constants.NamingPoster.ID] = constants.NamingPoster;
            Constants = constants;
        }
    }

    public class UserManager
    {
        private IDictionary<Guid, UserInfo> SystemUsers { get => UserManagerConstants.SystemUsers; }

        private IHttpContextAccessor Accessor { get; }
        private IUserService UserService { get; }
        private TenantManager TenantManager { get; }
        private PermissionContext PermissionContext { get; }
        private UserManagerConstants UserManagerConstants { get; }
        private Constants Constants { get; }

        private Tenant tenant;
        private Tenant Tenant { get { return tenant ?? (tenant = TenantManager.GetCurrentTenant()); } }

        public UserManager()
        {

        }

        public UserManager(
            IUserService service,
            TenantManager tenantManager,
            PermissionContext permissionContext,
            UserManagerConstants userManagerConstants)
        {
            UserService = service;
            TenantManager = tenantManager;
            PermissionContext = permissionContext;
            UserManagerConstants = userManagerConstants;
            Constants = UserManagerConstants.Constants;
        }

        public UserManager(
            IUserService service,
            TenantManager tenantManager,
            PermissionContext permissionContext,
            UserManagerConstants userManagerConstants,
            IHttpContextAccessor httpContextAccessor)
            : this(service, tenantManager, permissionContext, userManagerConstants)
        {
            Accessor = httpContextAccessor;
        }


        public void ClearCache()
        {
            if (UserService is ICachedService service)
            {
                service.InvalidateCache();
            }
        }


        #region Users

        public UserInfo[] GetUsers()
        {
            return GetUsers(EmployeeStatus.Default);
        }

        public UserInfo[] GetUsers(EmployeeStatus status)
        {
            return GetUsers(status, EmployeeType.All);
        }

        public UserInfo[] GetUsers(EmployeeStatus status, EmployeeType type)
        {
            var users = GetUsersInternal().Where(u => (u.Status & status) == u.Status);
            switch (type)
            {
                case EmployeeType.User:
                    users = users.Where(u => !u.IsVisitor(this));
                    break;
                case EmployeeType.Visitor:
                    users = users.Where(u => u.IsVisitor(this));
                    break;
            }
            return users.ToArray();
        }

        public IQueryable<UserInfo> GetUsers(
            bool isAdmin,
            EmployeeStatus? employeeStatus,
            List<List<Guid>> includeGroups,
            List<Guid> excludeGroups,
            EmployeeActivationStatus? activationStatus,
            string text,
            string sortBy,
            bool sortOrderAsc,
            long limit,
            long offset,
            out int total,
            out int count)
        {
            return UserService.GetUsers(Tenant.TenantId, isAdmin, employeeStatus, includeGroups, excludeGroups, activationStatus, text, sortBy, sortOrderAsc, limit, offset, out total, out count);
        }

        public DateTime GetMaxUsersLastModified()
        {
            return UserService.GetUsers(Tenant.TenantId, default)
                .Values
                .Select(g => g.LastModified)
                .DefaultIfEmpty()
                .Max();
        }

        public string[] GetUserNames(EmployeeStatus status)
        {
            return GetUsers(status)
                .Select(u => u.UserName)
                .Where(s => !string.IsNullOrEmpty(s))
                .ToArray();
        }

        public UserInfo GetUserByUserName(string username)
        {
            return GetUsersInternal()
                .FirstOrDefault(u => string.Compare(u.UserName, username, StringComparison.CurrentCultureIgnoreCase) == 0) ?? Constants.LostUser;
        }

        public UserInfo GetUserBySid(string sid)
        {
            return GetUsersInternal()
                .FirstOrDefault(u => u.Sid != null && string.Compare(u.Sid, sid, StringComparison.CurrentCultureIgnoreCase) == 0) ?? Constants.LostUser;
        }

        public UserInfo GetSsoUserByNameId(string nameId)
        {
            return GetUsersInternal()
                .FirstOrDefault(u => !string.IsNullOrEmpty(u.SsoNameId) && string.Compare(u.SsoNameId, nameId, StringComparison.CurrentCultureIgnoreCase) == 0) ?? Constants.LostUser;
        }
        public bool IsUserNameExists(string username)
        {
            return GetUserNames(EmployeeStatus.All)
                .Contains(username, StringComparer.CurrentCultureIgnoreCase);
        }

        public UserInfo GetUsers(Guid id)
        {
            if (IsSystemUser(id)) return SystemUsers[id];
            var u = UserService.GetUser(Tenant.TenantId, id);
            return u != null && !u.Removed ? u : Constants.LostUser;
        }
        public UserInfo GetUser(Guid id, Expression<Func<User, UserInfo>> exp)
        {
            if (IsSystemUser(id)) return SystemUsers[id];
            var u = UserService.GetUser(Tenant.TenantId, id, exp);
            return u != null && !u.Removed ? u : Constants.LostUser;
        }

        public UserInfo GetUsers(int tenant, string login, string passwordHash)
        {
            var u = UserService.GetUser(tenant, login, passwordHash);
            return u != null && !u.Removed ? u : Constants.LostUser;
        }

        public bool UserExists(Guid id)
        {
            return UserExists(GetUsers(id));
        }

        public bool UserExists(UserInfo user)
        {
            return !user.Equals(Constants.LostUser);
        }

        public bool IsSystemUser(Guid id)
        {
            return SystemUsers.ContainsKey(id);
        }

        public UserInfo GetUserByEmail(string email)
        {
            if (string.IsNullOrEmpty(email)) return Constants.LostUser;

            return GetUsersInternal()
                .FirstOrDefault(u => string.Compare(u.Email, email, StringComparison.CurrentCultureIgnoreCase) == 0) ?? Constants.LostUser;
        }

        public UserInfo[] Search(string text, EmployeeStatus status)
        {
            return Search(text, status, Guid.Empty);
        }

        public UserInfo[] Search(string text, EmployeeStatus status, Guid groupId)
        {
            if (text == null || text.Trim() == string.Empty) return new UserInfo[0];

            var words = text.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            if (words.Length == 0) return new UserInfo[0];

            var users = groupId == Guid.Empty ?
                GetUsers(status) :
                GetUsersByGroup(groupId).Where(u => (u.Status & status) == status);

            var findUsers = new List<UserInfo>();
            foreach (var user in users)
            {
                var properties = new string[]
                {
                    user.LastName ?? string.Empty,
                    user.FirstName ?? string.Empty,
                    user.Title ?? string.Empty,
                    user.Location ?? string.Empty,
                    user.Email ?? string.Empty,
                };
                if (IsPropertiesContainsWords(properties, words))
                {
                    findUsers.Add(user);
                }
            }
            return findUsers.ToArray();
        }

        public UserInfo SaveUserInfo(UserInfo u, bool isVisitor = false)
        {
            if (IsSystemUser(u.ID)) return SystemUsers[u.ID];
            if (u.ID == Guid.Empty) PermissionContext.DemandPermissions(Constants.Action_AddRemoveUser);
            else PermissionContext.DemandPermissions(new UserSecurityProvider(u.ID), Constants.Action_EditUser);

            if (Constants.MaxEveryoneCount <= GetUsersByGroup(Constants.GroupEveryone.ID).Length)
            {
                throw new TenantQuotaException("Maximum number of users exceeded");
            }

            if (u.Status == EmployeeStatus.Active)
            {
                var q = TenantManager.GetTenantQuota(Tenant.TenantId);
                if (q.ActiveUsers < GetUsersByGroup(Constants.GroupUser.ID).Length)
                {
                    throw new TenantQuotaException(string.Format("Exceeds the maximum active users ({0})", q.ActiveUsers));
                }
            }

            if (u.Status == EmployeeStatus.Terminated && u.ID == TenantManager.GetCurrentTenant().OwnerId)
            {
                throw new InvalidOperationException("Can not disable tenant owner.");
            }

            var newUser = UserService.SaveUser(Tenant.TenantId, u);

            return newUser;
        }

        public void DeleteUser(Guid id)
        {
            if (IsSystemUser(id)) return;
            PermissionContext.DemandPermissions(Constants.Action_AddRemoveUser);
            if (id == Tenant.OwnerId)
            {
                throw new InvalidOperationException("Can not remove tenant owner.");
            }

            UserService.RemoveUser(Tenant.TenantId, id);
        }

        public void SaveUserPhoto(Guid id, byte[] photo)
        {
            if (IsSystemUser(id)) return;
            PermissionContext.DemandPermissions(new UserSecurityProvider(id), Constants.Action_EditUser);

            UserService.SetUserPhoto(Tenant.TenantId, id, photo);
        }

        public byte[] GetUserPhoto(Guid id)
        {
            if (IsSystemUser(id)) return null;
            return UserService.GetUserPhoto(Tenant.TenantId, id);
        }

        public IEnumerable<Guid> GetUserGroupsId(Guid id)
        {
            return GetUserGroupsGuids(id);
        }

        public List<GroupInfo> GetUserGroups(Guid id)
        {
            return GetUserGroups(id, IncludeType.Distinct, Guid.Empty);
        }

        public List<GroupInfo> GetUserGroups(Guid id, Guid categoryID)
        {
            return GetUserGroups(id, IncludeType.Distinct, categoryID);
        }

        public List<GroupInfo> GetUserGroups(Guid userID, IncludeType includeType)
        {
            return GetUserGroups(userID, includeType, null);
        }

        internal List<GroupInfo> GetUserGroups(Guid userID, IncludeType includeType, Guid? categoryId)
        {
            var httpRequestDictionary = new HttpRequestDictionary<List<GroupInfo>>(Accessor?.HttpContext, "GroupInfo");
            var fromCache = httpRequestDictionary.Get(userID.ToString());
            if (fromCache != null)
            {
                return fromCache;
            }

            var result = new List<GroupInfo>();
            var distinctUserGroups = new List<GroupInfo>();

            var refs = GetRefsInternal();
            IEnumerable<UserGroupRef> userRefs = null;
            if (refs is UserGroupRefStore store)
            {
                userRefs = store.GetRefsByUser(userID);
            }

            var userRefsContainsNotRemoved = userRefs?.Where(r => !r.Removed && r.RefType == UserGroupRefType.Contains).ToList();

            foreach (var g in GetGroupsInternal().Where(g => !categoryId.HasValue || g.CategoryID == categoryId))
            {
                if (((g.CategoryID == Constants.SysGroupCategoryId || userRefs == null) && IsUserInGroupInternal(userID, g.ID, refs)) ||
                    (userRefsContainsNotRemoved != null && userRefsContainsNotRemoved.Any(r => r.GroupId == g.ID)))
                {
                    distinctUserGroups.Add(g);
                }
            }

            if (IncludeType.Distinct == (includeType & IncludeType.Distinct))
            {
                result.AddRange(distinctUserGroups);
            }

            if (categoryId.HasValue)
            {
                result = result.Where(r => r.CategoryID.Equals(categoryId.Value)).ToList();
            }

            result.Sort((group1, group2) => string.Compare(group1.Name, group2.Name, StringComparison.Ordinal));

            httpRequestDictionary.Add(userID.ToString(), result);

            return result;
        }

        internal IEnumerable<Guid> GetUserGroupsGuids(Guid userID)
        {
            var httpRequestDictionary = new HttpRequestDictionary<List<Guid>>(Accessor?.HttpContext, "GroupInfoID");
            var fromCache = httpRequestDictionary.Get(userID.ToString());
            if (fromCache != null)
            {
                return fromCache;
            }

            var result = new List<Guid>();

            var refs = GetRefsInternal();

            if (refs is UserGroupRefStore store)
            {
                var userRefs = store.GetRefsByUser(userID);

                if (userRefs != null)
                {
                    var toAdd = userRefs.Where(r => !r.Removed &&
                        r.RefType == UserGroupRefType.Contains &&
                        !Constants.BuildinGroups.Any(g => g.ID.Equals(r.GroupId)))
                        .Select(r => r.GroupId);
                    result.AddRange(toAdd);
                }
            }

            httpRequestDictionary.Add(userID.ToString(), result);

            return result;
        }

        public bool IsUserInGroup(Guid userId, Guid groupId)
        {
            return IsUserInGroupInternal(userId, groupId, GetRefsInternal());
        }

        public UserInfo[] GetUsersByGroup(Guid groupId, EmployeeStatus employeeStatus = EmployeeStatus.Default)
        {
            var refs = GetRefsInternal();
            return GetUsers(employeeStatus).Where(u => IsUserInGroupInternal(u.ID, groupId, refs)).ToArray();
        }

        public void AddUserIntoGroup(Guid userId, Guid groupId)
        {
            if (Constants.LostUser.ID == userId || Constants.LostGroupInfo.ID == groupId)
            {
                return;
            }
            PermissionContext.DemandPermissions(Constants.Action_EditGroups);

            UserService.SaveUserGroupRef(Tenant.TenantId, new UserGroupRef(userId, groupId, UserGroupRefType.Contains));

            ResetGroupCache(userId);
        }

        public void RemoveUserFromGroup(Guid userId, Guid groupId)
        {
            if (Constants.LostUser.ID == userId || Constants.LostGroupInfo.ID == groupId) return;
            PermissionContext.DemandPermissions(Constants.Action_EditGroups);

            UserService.RemoveUserGroupRef(Tenant.TenantId, userId, groupId, UserGroupRefType.Contains);

            ResetGroupCache(userId);
        }

        internal void ResetGroupCache(Guid userID)
        {
            new HttpRequestDictionary<List<GroupInfo>>(Accessor?.HttpContext, "GroupInfo").Reset(userID.ToString());
            new HttpRequestDictionary<List<Guid>>(Accessor?.HttpContext, "GroupInfoID").Reset(userID.ToString());
        }

        #endregion Users


        #region Company

        public GroupInfo[] GetDepartments()
        {
            return GetGroups();
        }

        public Guid GetDepartmentManager(Guid deparmentID)
        {
            return GetRefsInternal()
                .Values
                .Where(r => r.RefType == UserGroupRefType.Manager && r.GroupId == deparmentID && !r.Removed)
                .Select(r => r.UserId)
                .SingleOrDefault();
        }

        public void SetDepartmentManager(Guid deparmentID, Guid userID)
        {
            var managerId = GetDepartmentManager(deparmentID);
            if (managerId != Guid.Empty)
            {
                UserService.RemoveUserGroupRef(
                    Tenant.TenantId,
                    managerId, deparmentID, UserGroupRefType.Manager);
            }
            if (userID != Guid.Empty)
            {
                UserService.SaveUserGroupRef(
                    Tenant.TenantId,
                    new UserGroupRef(userID, deparmentID, UserGroupRefType.Manager));
            }
        }

        public UserInfo GetCompanyCEO()
        {
            var id = GetDepartmentManager(Guid.Empty);
            return id != Guid.Empty ? GetUsers(id) : null;
        }

        public void SetCompanyCEO(Guid userId)
        {
            SetDepartmentManager(Guid.Empty, userId);
        }

        #endregion Company


        #region Groups

        public GroupInfo[] GetGroups()
        {
            return GetGroups(Guid.Empty);
        }

        public GroupInfo[] GetGroups(Guid categoryID)
        {
            return GetGroupsInternal()
                .Where(g => g.CategoryID == categoryID)
                .ToArray();
        }

        public GroupInfo GetGroupInfo(Guid groupID)
        {
            return GetGroupsInternal()
                .SingleOrDefault(g => g.ID == groupID) ?? Constants.LostGroupInfo;
        }

        public GroupInfo GetGroupInfoBySid(string sid)
        {
            return GetGroupsInternal()
                .SingleOrDefault(g => g.Sid == sid) ?? Constants.LostGroupInfo;
        }

        public DateTime GetMaxGroupsLastModified()
        {
            return UserService.GetGroups(Tenant.TenantId, default)
                .Values
                .Select(g => g.LastModified)
                .DefaultIfEmpty()
                .Max();
        }

        public GroupInfo SaveGroupInfo(GroupInfo g)
        {
            if (Constants.LostGroupInfo.Equals(g)) return Constants.LostGroupInfo;
            if (Constants.BuildinGroups.Any(b => b.ID == g.ID)) return Constants.BuildinGroups.Single(b => b.ID == g.ID);
            PermissionContext.DemandPermissions(Constants.Action_EditGroups);

            var newGroup = UserService.SaveGroup(Tenant.TenantId, ToGroup(g));
            return new GroupInfo(newGroup.CategoryId) { ID = newGroup.Id, Name = newGroup.Name, Sid = newGroup.Sid };
        }

        public void DeleteGroup(Guid id)
        {
            if (Constants.LostGroupInfo.Equals(id)) return;
            if (Constants.BuildinGroups.Any(b => b.ID == id)) return;
            PermissionContext.DemandPermissions(Constants.Action_EditGroups);

            UserService.RemoveGroup(Tenant.TenantId, id);
        }

        #endregion Groups


        private bool IsPropertiesContainsWords(IEnumerable<string> properties, IEnumerable<string> words)
        {
            foreach (var w in words)
            {
                var find = false;
                foreach (var p in properties)
                {
                    find = (2 <= w.Length) && (0 <= p.IndexOf(w, StringComparison.CurrentCultureIgnoreCase));
                    if (find) break;
                }
                if (!find) return false;
            }
            return true;
        }


        private IEnumerable<UserInfo> GetUsersInternal()
        {
            return UserService.GetUsers(Tenant.TenantId, default)
                .Values
                .Where(u => !u.Removed);
        }

        private IEnumerable<GroupInfo> GetGroupsInternal()
        {
            return UserService.GetGroups(Tenant.TenantId, default)
                .Values
                .Where(g => !g.Removed)
                .Select(g => new GroupInfo(g.CategoryId) { ID = g.Id, Name = g.Name, Sid = g.Sid })
                .Concat(Constants.BuildinGroups);
        }

        private IDictionary<string, UserGroupRef> GetRefsInternal()
        {
            return UserService.GetUserGroupRefs(Tenant.TenantId, default);
        }

        private bool IsUserInGroupInternal(Guid userId, Guid groupId, IDictionary<string, UserGroupRef> refs)
        {
            if (groupId == Constants.GroupEveryone.ID)
            {
                return true;
            }
            if (groupId == Constants.GroupAdmin.ID && (Tenant.OwnerId == userId || userId == Configuration.Constants.CoreSystem.ID || userId == Constants.NamingPoster.ID))
            {
                return true;
            }
            if (groupId == Constants.GroupVisitor.ID && userId == Constants.OutsideUser.ID)
            {
                return true;
            }

            UserGroupRef r;
            if (groupId == Constants.GroupUser.ID || groupId == Constants.GroupVisitor.ID)
            {
                var visitor = refs.TryGetValue(UserGroupRef.CreateKey(Tenant.TenantId, userId, Constants.GroupVisitor.ID, UserGroupRefType.Contains), out r) && !r.Removed;
                if (groupId == Constants.GroupVisitor.ID)
                {
                    return visitor;
                }
                if (groupId == Constants.GroupUser.ID)
                {
                    return !visitor;
                }
            }
            return refs.TryGetValue(UserGroupRef.CreateKey(Tenant.TenantId, userId, groupId, UserGroupRefType.Contains), out r) && !r.Removed;
        }

        private Group ToGroup(GroupInfo g)
        {
            if (g == null) return null;
            return new Group
            {
                Id = g.ID,
                Name = g.Name,
                ParentId = g.Parent != null ? g.Parent.ID : Guid.Empty,
                CategoryId = g.CategoryID,
                Sid = g.Sid
            };
        }
    }

    public static class UserManagerConfigExtension
    {
        public static DIHelper AddUserManagerService(this DIHelper services)
        {
            services.TryAddSingleton<UserManagerConstants>();
            services.TryAddScoped<UserManager>();

            return services
                .AddUserService()
                .AddTenantManagerService()
                .AddConstantsService()
                .AddPermissionContextService();
        }
    }
}