Polls persist restarts now.

NadekoBot.Core/Modules/Games/Common/PollRunner.cs

@@ -0,0 +1,72 @@
+using System.Threading.Tasks;
+using Discord;
+using NadekoBot.Core.Services.Database.Models;
+using NadekoBot.Core.Services;
+using System;
+using System.Threading;
+
+namespace NadekoBot.Modules.Games.Common
+{
+    public class PollRunner
+    {
+        public Poll Poll { get; }
+        private readonly DbService _db;
+
+        public event Func<IUserMessage, IGuildUser, Task> OnVoted;
+
+        private readonly SemaphoreSlim _locker = new SemaphoreSlim(1, 1);
+
+        public PollRunner(DbService db, Poll poll)
+        {
+            _db = db;
+            Poll = poll;
+        }
+
+        public async Task<bool> TryVote(IUserMessage msg)
+        {
+            PollVote voteObj;
+            await _locker.WaitAsync().ConfigureAwait(false);
+            try
+            {
+                // has to be a user message
+                // channel must be the same the poll started in
+                if (msg == null || msg.Author.IsBot || msg.Channel.Id != Poll.ChannelId)
+                    return false;
+
+                // has to be an integer
+                if (!int.TryParse(msg.Content, out int vote))
+                    return false;
+                --vote;
+                if (vote < 0 || vote >= Poll.Answers.Count)
+                    return false;
+
+                var usr = msg.Author as IGuildUser;
+                if (usr == null)
+                    return false;
+
+                voteObj = new PollVote()
+                {
+                    UserId = msg.Author.Id,
+                    VoteIndex = vote,
+                };
+                if (!Poll.Votes.Add(voteObj))
+                    return false;
+
+                var _ = OnVoted?.Invoke(msg, usr);
+            }
+            finally { _locker.Release(); }
+            using (var uow = _db.UnitOfWork)
+            {
+                var trackedPoll = uow.Polls.Get(Poll.Id);
+                trackedPoll.Votes.Add(voteObj);
+                uow.Complete();
+            }
+            return true;
+        }
+
+        public void End()
+        {
+            OnVoted = null;
+        }
+    }
+}