using Model;
using Model.Dto.System;
using Model.Entity.System;
using Model.Mapper;
using ORM;
using Service.Interface;
using SqlSugar;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Service.Implement
{
    /// <summary>
    /// 用户管理 服务实现
    /// 数据权限：当前用户角色 DataScope=1 看全部；=2 只能看自己组织及下级组织下的用户
    /// </summary>
    public class UserService : IUserService
    {
        private readonly IOrgService _orgService;
        private readonly ICurrentUser _currentUser;

        public UserService(IOrgService orgService, ICurrentUser currentUser)
        {
            _orgService = orgService;
            _currentUser = currentUser;
        }

        public async Task<Result<List<UserDto>>> GetPagedAsync(int pageIndex, int pageSize, RefAsync<int> total, string? keyword = null, long? roleId = null, long? orgId = null)
        {
            try
            {
                // 按角色筛选时先查出该角色下的用户Id
                List<long>? userIdsInRole = null;
                if (roleId.HasValue && roleId.Value > 0)
                {
                    userIdsInRole = await SqlSugarContext.DbContext.Queryable<UserRoleEntity>()
                        .Where(x => x.RoleId == roleId!.Value)
                        .Select(x => x.UserId)
                        .ToListAsync();
                    if (userIdsInRole.Count == 0)
                        return Result<List<UserDto>>.Success(new List<UserDto>());
                }

                // 数据范围过滤：DataScope=2 时只允许看本组织及下级的用户
                List<long>? allowedOrgIds = null;
                if (_currentUser.IsAuthenticated && _currentUser.DataScope != 1)
                {
                    var me = await SqlSugarContext.DbContext.Queryable<UserEntity>()
                        .Where(x => x.Id == _currentUser.UserId).FirstAsync();
                    if (me != null && me.OrgId > 0)
                        allowedOrgIds = await _orgService.GetSubtreeIdsAsync(me.OrgId);
                    else
                        return Result<List<UserDto>>.Success(new List<UserDto>()); // 无组织归属则看不到任何用户
                }

                // 前端按组织节点筛选时叠加（同时受数据范围约束）
                List<long>? orgFilterIds = null;
                if (orgId.HasValue && orgId.Value > 0)
                {
                    orgFilterIds = await _orgService.GetSubtreeIdsAsync(orgId.Value);
                    if (allowedOrgIds != null)
                        orgFilterIds = orgFilterIds.Where(allowedOrgIds.Contains).ToList();
                }

                var list = await SqlSugarContext.DbContext.Queryable<UserEntity>()
                    .Where(x => x.IsDel == 0)
                    .WhereIF(!string.IsNullOrWhiteSpace(keyword), x => x.UserName.Contains(keyword!) || (x.RealName != null && x.RealName.Contains(keyword!)))
                    .WhereIF(userIdsInRole != null, x => userIdsInRole!.Contains(x.Id))
                    .WhereIF(allowedOrgIds != null, x => allowedOrgIds!.Contains(x.OrgId))
                    .WhereIF(orgFilterIds != null, x => orgFilterIds!.Contains(x.OrgId))
                    .OrderBy(x => x.CreateTime, OrderByType.Desc)
                    .ToPageListAsync(pageIndex, pageSize, total);

                var dtos = list.ToDtoList();
                await FillRolesAsync(dtos);
                await FillOrgNamesAsync(dtos);
                return Result<List<UserDto>>.Success(dtos);
            }
            catch (Exception ex)
            {
                return Result<List<UserDto>>.Error("查询用户列表失败", ex);
            }
        }

        public async Task<Result<UserDto>> GetByIdAsync(long id)
        {
            try
            {
                var entity = await SqlSugarContext.DbContext.Queryable<UserEntity>()
                    .Where(x => x.Id == id && x.IsDel == 0).FirstAsync();
                if (entity == null) return Result<UserDto>.Error("用户不存在或已被删除");
                var dto = entity.ToDto();
                await FillRolesAsync(new List<UserDto> { dto });
                await FillOrgNamesAsync(new List<UserDto> { dto });
                return Result<UserDto>.Success(dto);
            }
            catch (Exception ex)
            {
                return Result<UserDto>.Error("查询用户详情失败", ex);
            }
        }

        public async Task<Result<UserDto>> AddAsync(UserDto dto)
        {
            if (dto == null || string.IsNullOrWhiteSpace(dto.UserName))
                return Result<UserDto>.Error("用户名不能为空");

            try
            {
                var exists = await SqlSugarContext.DbContext.Queryable<UserEntity>()
                    .Where(x => x.UserName == dto.UserName && x.IsDel == 0).AnyAsync();
                if (exists) return Result<UserDto>.Error($"用户名「{dto.UserName}」已存在");

                var entity = dto.ToEntity();
                entity.Id = 0;
                entity.CreateTime = DateTime.Now;
                // 新增用户初始密码必填（前端通过 InitialPassword 明文传入，落库前 PBKDF2 哈希）
                var initialPassword = dto.InitialPassword;
                if (string.IsNullOrWhiteSpace(initialPassword) || initialPassword.Length < 6)
                    return Result<UserDto>.Error("初始密码不能为空且长度不少于 6 位");
                entity.PasswordHash = PasswordHelper.Hash(initialPassword);

                // 角色先解析校验再落库，避免"用户已插入但角色解析失败"留下无角色用户
                var newRoleIds = new List<long>();
                if (dto.RoleIds != null && dto.RoleIds.Count > 0)
                {
                    foreach (var r in dto.RoleIds)
                    {
                        if (!long.TryParse(r, out var rid) || rid <= 0)
                            return Result<UserDto>.Error($"角色Id无效：{r}");
                        newRoleIds.Add(rid);
                    }
                }

                var id = await SqlSugarContext.DbContext.Insertable(entity).ExecuteReturnSnowflakeIdAsync();
                entity.Id = id;

                if (newRoleIds.Count > 0)
                    await ReplaceUserRolesAsync(id, newRoleIds);

                var result = entity.ToDto();
                await FillRolesAsync(new List<UserDto> { result });
                return Result<UserDto>.Success(result);
            }
            catch (Exception ex)
            {
                return Result<UserDto>.Error("新增用户失败", ex);
            }
        }

        public async Task<Result<UserDto>> UpdateAsync(UserDto dto)
        {
            if (dto == null || !long.TryParse(dto.Id, out var id) || id <= 0)
                return Result<UserDto>.Error("用户Id无效");

            try
            {
                var entity = await SqlSugarContext.DbContext.Queryable<UserEntity>()
                    .Where(x => x.Id == id && x.IsDel == 0).FirstAsync();
                if (entity == null) return Result<UserDto>.Error("用户不存在或已被删除");

                var nameExists = await SqlSugarContext.DbContext.Queryable<UserEntity>()
                    .Where(x => x.UserName == dto.UserName && x.Id != id && x.IsDel == 0).AnyAsync();
                if (nameExists) return Result<UserDto>.Error($"用户名「{dto.UserName}」已存在");

                // 防锁死：把自己禁用不允许；禁用或改角色后必须仍存在可管理用户的管理员
                if (dto.IsEnabled == 0 && id == _currentUser.UserId)
                    return Result<UserDto>.Error("不能禁用当前登录的账号");
                if (dto.IsEnabled == 0 || dto.RoleIds != null)
                {
                    var guard = await EnsureAnotherActiveAdminAsync(id);
                    if (guard != null) return Result<UserDto>.Error(guard.Msg);
                }

                var newEntity = dto.ToEntity();
                newEntity.Id = id;
                // 密码、登录时间不允许在此接口覆盖
                await SqlSugarContext.DbContext.Updateable(newEntity)
                    .IgnoreColumns(x => new { x.CreateTime, x.IsDel, x.PasswordHash, x.LastLoginTime })
                    .ExecuteCommandAsync();

                // 角色变化时同步更新关联（传入 null 表示不改角色）
                if (dto.RoleIds != null)
                {
                    var roleIds = dto.RoleIds.Select(long.Parse).Where(r => r > 0).ToList();
                    await ReplaceUserRolesAsync(id, roleIds);
                }

                var result = newEntity.ToDto();
                await FillRolesAsync(new List<UserDto> { result });
                return Result<UserDto>.Success(result);
            }
            catch (Exception ex)
            {
                return Result<UserDto>.Error("修改用户失败", ex);
            }
        }

        public async Task<Result> DeleteAsync(long id)
        {
            if (id <= 0) return Result.Error("用户Id无效");
            if (id == _currentUser.UserId)
                return Result.Error("不能删除当前登录的账号");

            try
            {
                var exists = await SqlSugarContext.DbContext.Queryable<UserEntity>()
                    .Where(x => x.Id == id && x.IsDel == 0).AnyAsync();
                if (!exists) return Result.Error("用户不存在或已被删除");

                // 防锁死：删除后必须仍存在可管理用户的管理员
                var guard = await EnsureAnotherActiveAdminAsync(id);
                if (guard != null) return guard;

                await SqlSugarContext.DbContext.Updateable<UserEntity>()
                    .SetColumns(x => x.IsDel == 1)
                    .Where(x => x.Id == id).ExecuteCommandAsync();
                await SqlSugarContext.DbContext.Deleteable<UserRoleEntity>()
                    .Where(x => x.UserId == id).ExecuteCommandAsync();
                return Result.Success();
            }
            catch (Exception ex)
            {
                return Result.Error("删除用户失败", ex);
            }
        }

        public async Task<Result> AssignRolesAsync(long userId, List<long> roleIds)
        {
            if (userId <= 0) return Result.Error("用户Id无效");
            try
            {
                var exists = await SqlSugarContext.DbContext.Queryable<UserEntity>()
                    .Where(x => x.Id == userId && x.IsDel == 0).AnyAsync();
                if (!exists) return Result.Error("用户不存在或已被删除");

                // 防锁死：改角色后必须仍存在可管理用户的管理员
                var guard = await EnsureAnotherActiveAdminAsync(userId);
                if (guard != null) return guard;

                await ReplaceUserRolesAsync(userId, roleIds ?? new List<long>());
                return Result.Success();
            }
            catch (Exception ex)
            {
                return Result.Error("分配角色失败", ex);
            }
        }

        public async Task<Result> ResetPasswordAsync(long userId, string newPassword)
        {
            if (userId <= 0) return Result.Error("用户Id无效");
            if (string.IsNullOrWhiteSpace(newPassword) || newPassword.Length < 6)
                return Result.Error("新密码不能为空且长度不少于 6 位");
            try
            {
                var exists = await SqlSugarContext.DbContext.Queryable<UserEntity>()
                    .Where(x => x.Id == userId && x.IsDel == 0).AnyAsync();
                if (!exists) return Result.Error("用户不存在或已被删除");

                await SqlSugarContext.DbContext.Updateable<UserEntity>()
                    .SetColumns(x => x.PasswordHash == PasswordHelper.Hash(newPassword))
                    .Where(x => x.Id == userId).ExecuteCommandAsync();
                return Result.Success();
            }
            catch (Exception ex)
            {
                return Result.Error("重置密码失败", ex);
            }
        }

        public async Task<Result> SetEnabledAsync(long userId, bool enabled)
        {
            if (userId <= 0) return Result.Error("用户Id无效");
            if (!enabled && userId == _currentUser.UserId)
                return Result.Error("不能禁用当前登录的账号");
            try
            {
                // 防锁死：禁用后必须仍存在可管理用户的管理员
                if (!enabled)
                {
                    var guard = await EnsureAnotherActiveAdminAsync(userId);
                    if (guard != null) return guard;
                }

                await SqlSugarContext.DbContext.Updateable<UserEntity>()
                    .SetColumns(x => x.IsEnabled == (byte)(enabled ? 1 : 0))
                    .Where(x => x.Id == userId).ExecuteCommandAsync();
                return Result.Success();
            }
            catch (Exception ex)
            {
                return Result.Error("设置用户状态失败", ex);
            }
        }

        public async Task<Result<List<UserOptionDto>>> GetOptionsAsync()
        {
            try
            {
                var list = await SqlSugarContext.DbContext.Queryable<UserEntity>()
                    .Where(x => x.IsDel == 0 && x.IsEnabled == 1)
                    .OrderBy(x => x.UserName)
                    .ToListAsync();
                return Result<List<UserOptionDto>>.Success(list.ToOptionDtoList());
            }
            catch (Exception ex)
            {
                return Result<List<UserOptionDto>>.Error("查询用户选项失败", ex);
            }
        }

        /// <summary>全量覆盖用户-角色关联</summary>
        private static async Task ReplaceUserRolesAsync(long userId, List<long> roleIds)
        {
            var db = SqlSugarContext.DbContext;
            await db.Deleteable<UserRoleEntity>().Where(x => x.UserId == userId).ExecuteCommandAsync();
            if (roleIds.Count > 0)
            {
                var now = DateTime.Now;
                var links = roleIds.Distinct().Select(r => new UserRoleEntity { UserId = userId, RoleId = r, CreateTime = now }).ToList();
                await db.Insertable(links).ExecuteCommandAsync();
            }
        }

        /// <summary>
        /// 防锁死校验：排除 excludeUserId 后，系统必须仍存在「已启用且拥有 user:manage 权限」的用户，
        /// 否则返回 Error（保证管理员不会把所有管理员删光/禁用光导致无人可登录管理）
        /// </summary>
        private async Task<Result?> EnsureAnotherActiveAdminAsync(long excludeUserId)
        {
            var db = SqlSugarContext.DbContext;
            var permId = await db.Queryable<PermissionEntity>()
                .Where(x => x.Code == "user:manage" && x.IsDel == 0)
                .Select(x => x.Id).FirstAsync();
            if (permId == 0) return null; // 权限码不存在时不拦，避免权限体系变更后管理功能彻底锁死

            var roleIds = await db.Queryable<RolePermissionEntity>()
                .Where(x => x.PermissionId == permId)
                .Select(x => x.RoleId).ToListAsync();
            if (roleIds.Count == 0) return null;

            var userIds = await db.Queryable<UserRoleEntity>()
                .Where(x => roleIds.Contains(x.RoleId))
                .Select(x => x.UserId).ToListAsync();
            if (userIds.Count == 0)
                return Result.Error("操作被拒绝：系统将没有任何可管理用户的管理员");

            var exists = await db.Queryable<UserEntity>()
                .AnyAsync(x => userIds.Contains(x.Id) && x.IsDel == 0 && x.IsEnabled == 1 && x.Id != excludeUserId);
            return exists ? null : Result.Error("操作被拒绝：系统至少需要保留一名已启用且拥有用户管理权限的账号");
        }

        /// <summary>给用户 DTO 填充所属组织名称（组织链路径，如 公司/实验室/部门）</summary>
        private async Task FillOrgNamesAsync(List<UserDto> dtos)
        {
            if (dtos == null || dtos.Count == 0) return;
            var orgIds = dtos.Where(d => long.TryParse(d.OrgId, out var oid) && oid > 0)
                             .Select(d => long.Parse(d.OrgId)).Distinct().ToList();
            if (orgIds.Count == 0) return;

            var allOrgs = await SqlSugarContext.DbContext.Queryable<OrgEntity>()
                .Where(x => x.IsDel == 0).ToListAsync();
            var orgMap = allOrgs.ToDictionary(o => o.Id, o => o);

            foreach (var d in dtos)
            {
                if (!long.TryParse(d.OrgId, out var oid) || !orgMap.TryGetValue(oid, out var org))
                    continue;
                // 沿父级向上拼组织路径
                var path = new List<string>();
                var cursor = org;
                var guard = 0;
                while (cursor != null && guard++ < 10)
                {
                    path.Insert(0, cursor.Name);
                    cursor = cursor.ParentId > 0 && orgMap.TryGetValue(cursor.ParentId, out var parent) ? parent : null;
                }
                d.OrgName = string.Join(" / ", path);
            }
        }

        /// <summary>给用户 DTO 填充角色Id列表与角色名称</summary>
        private static async Task FillRolesAsync(List<UserDto> dtos)
        {
            if (dtos == null || dtos.Count == 0) return;
            var db = SqlSugarContext.DbContext;
            var userIds = dtos.Select(d => long.Parse(d.Id)).ToList();

            var links = await db.Queryable<UserRoleEntity>()
                .Where(x => userIds.Contains(x.UserId)).ToListAsync();
            var roleIds = links.Select(l => l.RoleId).Distinct().ToList();
            var roles = roleIds.Count > 0
                ? await db.Queryable<RoleEntity>().Where(x => roleIds.Contains(x.Id) && x.IsDel == 0).ToListAsync()
                : new List<RoleEntity>();
            var roleMap = roles.ToDictionary(r => r.Id, r => r.Name);

            foreach (var d in dtos)
            {
                var uid = long.Parse(d.Id);
                var myRoleIds = links.Where(l => l.UserId == uid).Select(l => l.RoleId).ToList();
                d.RoleIds = myRoleIds.Select(r => r.ToString()).ToList();
                d.RoleNames = string.Join(",", myRoleIds.Where(r => roleMap.ContainsKey(r)).Select(r => roleMap[r]));
            }
        }
    }
}