add(conversationSerivice):后端新增消息会话服务add(main)：完善主面板

backend/IM_API/Services/ConversationService.cs

@@ -0,0 +1,44 @@
+using IM_API.Dtos;
+using IM_API.Exceptions;
+using IM_API.Interface.Services;
+using IM_API.Models;
+using IM_API.Tools;
+using Microsoft.EntityFrameworkCore;
+
+namespace IM_API.Services
+{
+    public class ConversationService : IConversationService
+    {
+        private readonly ImContext _context;
+        public ConversationService(ImContext context)
+        {
+            _context = context;
+        }
+        #region 删除用户会话
+        public async Task<bool> ClearConversationsAsync(int userId)
+        {
+           await _context.Conversations.Where(x => x.UserId == userId).ExecuteDeleteAsync();
+            return true;
+        }
+
+        
+        #endregion
+        #region 获取用户会话列表
+        public async Task<List<Conversation>> GetConversationsAsync(int userId)
+        {
+            return await _context.Conversations.Where(x => x.UserId == userId)
+                .ToListAsync();
+        }
+        #endregion
+        #region 删除单个会话
+        public async Task<bool> DeleteConversationAsync(int conversationId)
+        {
+            var conversation = await _context.Conversations.FirstOrDefaultAsync(x => x.Id == conversationId);
+            if (conversation == null) throw new BaseException(CodeDefine.CONVERSATION_NOT_FOUND);
+            _context.Conversations.Remove(conversation);
+            await _context.SaveChangesAsync();
+            return true;
+        }
+        #endregion
+    }
+}

backend/IM_API/Services/FriendService.cs

@@ -68,7 +68,7 @@ namespace IM_API.Services
             {
                 query = query.OrderByDescending(x => x.UserId);
             }
-            var friendList = await query.Skip((page - 1 * limit)).Take(limit).ToListAsync();
+            var friendList = await query.Skip(((page - 1) * limit)).Take(limit).ToListAsync();
             return _mapper.Map<List<FriendInfoDto>>(friendList);
         }
         #endregion

backend/IM_API/Services/MessageService.cs

@@ -54,12 +54,24 @@ namespace IM_API.Services
         {
             throw new NotImplementedException();
         }
-
-        public Task<bool> SendGroupMessageAsync(int senderId, int groupId, MessageBaseDto dto)
+        #region 发送群消息
+        public async Task<bool> SendGroupMessageAsync(int senderId, int groupId, MessageBaseDto dto)
         {
-            throw new NotImplementedException();
-        }
+            //判断群存在
+            var isExist = await _context.Groups.AnyAsync(x => x.Id == groupId);
+            if (!isExist) throw new BaseException(CodeDefine.GROUP_NOT_FOUND);
+            //判断是否是群成员
+            var isMember = await _context.GroupMembers.AnyAsync(x => x.GroupId == groupId && x.UserId == senderId);
+            if (!isMember) throw new BaseException(CodeDefine.NO_GROUP_PERMISSION);
+            var message = _mapper.Map<Message>(dto);
+            message.Sender = senderId;
+            _context.Messages.Add(message);
+            await _context.SaveChangesAsync();
+            return true;
 
+        }
+        #endregion
+        #region 发送私聊消息
         public async Task<bool> SendPrivateMessageAsync(int senderId, int receiverId, MessageBaseDto dto)
         {
             bool isExist = await _context.Friends.AnyAsync(x => x.FriendId == receiverId);
@@ -70,5 +82,6 @@ namespace IM_API.Services
             await _context.SaveChangesAsync();
             return true;
         }
+        #endregion
     }
 }