using AutoMapper;
using IM_API.Dtos.User;
using IM_API.Exceptions;
using IM_API.Interface.Services;
using IM_API.Models;
using IM_API.Tools;
using Microsoft.EntityFrameworkCore;
using StackExchange.Redis;
using System.Text.Json;

namespace IM_API.Services
{
    public class UserService : IUserService
    {
        private readonly ImContext _context;
        private readonly ILogger<UserService> _logger;
        private readonly IMapper _mapper;
        private readonly ICacheService _cacheService;
        private readonly IDatabase _redis;
        public UserService(
            ImContext imContext,ILogger<UserService> logger,
            IMapper mapper, ICacheService cacheService, IConnectionMultiplexer connectionMultiplexer)
        {
            this._context = imContext;
            this._logger = logger;
            this._mapper = mapper;
            _cacheService = cacheService;
            _redis = connectionMultiplexer.GetDatabase();
        }
        #region 获取用户信息
        public async Task<UserInfoDto> GetUserInfoAsync(int userId)
        {
            //查询redis缓存，如果存在直接返回不走查库逻辑
            var key = RedisKeys.GetUserinfoKey(userId.ToString());
            var userinfoCache = await _cacheService.GetAsync<User>(key);
            if (userinfoCache != null) return _mapper.Map<UserInfoDto>(userinfoCache);
            //无缓存查库
            var user = await _context.Users
                .FirstOrDefaultAsync(x => x.Id == userId);
            if (user == null)
            {
                throw new BaseException(CodeDefine.USER_NOT_FOUND);
            }
            await _cacheService.SetUserCacheAsync(user);
            return _mapper.Map<UserInfoDto>(user);
        }
        #endregion
        #region 通过用户名获取用户信息
        public async Task<UserInfoDto> GetUserInfoByUsernameAsync(string username)
        {
            var userinfo = await _cacheService.GetUserCacheAsync(username);
            if (userinfo != null) return _mapper.Map<UserInfoDto>(userinfo);
            var user = await _context.Users.FirstOrDefaultAsync(x => x.Username == username);
            if (user == null)
            {
                throw new BaseException(CodeDefine.USER_NOT_FOUND);
            }
            await _cacheService.SetUserCacheAsync(user);
            return _mapper.Map<UserInfoDto>(user);
        }
        #endregion
        #region 重置用户密码
        public async Task<bool> ResetPasswordAsync(int userId, string oldPassword, string password)
        {
            var user = await _context.Users.FirstOrDefaultAsync(x => x.Id == userId);
            if (user is null) throw new BaseException(CodeDefine.USER_NOT_FOUND);
            //验证原密码
            if (user.Password != oldPassword) throw new BaseException(CodeDefine.PASSWORD_ERROR);
            user.Password = password;
            await _context.SaveChangesAsync();
            return true;
        }
        #endregion
        #region 更新用户在线状态
        public async Task<bool> UpdateOlineStatusAsync(int userId,UserOnlineStatus onlineStatus)
        {
            var user = await _context.Users.FirstOrDefaultAsync(x => x.Id == userId);
            if (user is null) throw new BaseException(CodeDefine.USER_NOT_FOUND);
            user.OnlineStatusEnum = onlineStatus;
            await _context.SaveChangesAsync();
            return true;
        }
        #endregion
        #region 更新用户信息
        public async Task<UserInfoDto> UpdateUserAsync(int userId,UpdateUserDto dto)
        {
            var user = await _context.Users.FirstOrDefaultAsync(x => x.Id == userId);
            if (user is null) throw new BaseException(CodeDefine.USER_NOT_FOUND);
            _mapper.Map(dto,user);
            await _context.SaveChangesAsync();
            await _cacheService.SetUserCacheAsync(user);
            return _mapper.Map<UserInfoDto>(user);
        }
        #endregion
        #region 批量获取用户信息
        public async Task<List<UserInfoDto>> GetUserInfoListAsync(List<int> ids)
        {
            //读取缓存中存在的用户，存在直接添加到结果列表
            var idKeyArr = ids.Select(s => (RedisKey)RedisKeys.GetUserinfoKey(s.ToString())).ToArray();
            var values = await _redis.StringGetAsync(idKeyArr);
            List<User> results = [];
            List<int> missingIds = [];
            for(int i = 0; i < ids.Count; i++)
            {
                if (values[i].HasValue)
                {
                    results.Add(JsonSerializer.Deserialize<User>(values[i]));
                }
                else
                {
                    missingIds.Add(ids[i]);
                }
            }
            //如果存在没有缓存的用户则进行查库
            if (missingIds.Any())
            {
                var dbUsers = await _context.Users
                    .Where(x => ids.Contains(x.Id)).ToListAsync();

                results.AddRange(dbUsers);

                var setTasks = dbUsers.Select(s => _cacheService.SetUserCacheAsync(s)).ToList();
                await Task.WhenAll(setTasks);
            }
            return _mapper.Map<List<UserInfoDto>>(results);
        }
        #endregion
    }
}