group import/export

PluralKit.Core/Services/DataFileService.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 
@@ -42,6 +43,23 @@ namespace PluralKit.Core
             o.Add("accounts", new JArray((await _repo.GetSystemAccounts(conn, system.Id)).ToList()));
             o.Add("members", new JArray((await _repo.GetSystemMembers(conn, system.Id).ToListAsync()).Select(m => m.ToJson(LookupContext.ByOwner))));
 
+            var groups = (await _repo.GetSystemGroups(conn, system.Id).ToListAsync());
+            var j_groups = groups.Select(x => x.ToJson(LookupContext.ByOwner, isExport: true)).ToList();
+
+            if (groups.Count > 0)
+            {
+                var q = await conn.QueryAsync<GroupMember>(@$"select groups.hid as group, members.hid as member from group_members
+                        left join groups on groups.id = group_members.group_id
+                        left join members on members.id = group_members.member_id 
+                    where group_members.group_id in ({string.Join(", ", groups.Select(x => x.Id.Value.ToString()))})
+                ");
+
+                foreach (var row in q)
+                    ((JArray)j_groups.Find(x => x.Value<string>("id") == row.Group)["members"]).Add(row.Member);
+            }
+
+            o.Add("groups", new JArray(j_groups));
+
             var switches = new JArray();
             var switchList = await _repo.GetPeriodFronters(conn, system.Id, null,
                 Instant.FromDateTimeUtc(DateTime.MinValue.ToUniversalTime()), SystemClock.Instance.GetCurrentInstant());
@@ -64,5 +82,12 @@ namespace PluralKit.Core
 
             return await BulkImporter.PerformImport(conn, tx, _repo, _logger, userId, system, importFile, confirmFunc);
         }
+
+    }
+    
+    public class GroupMember
+    {
+        public string Group { get; set; }
+        public string Member { get; set; }
     }
 }