Fully implemented text channel cache

Additionally, fixed a bug where user cache would quit immediately
after encountering a bot or webhook user.

EntityCache/ECModule.cs

@@ -13,8 +13,6 @@ namespace Noikoio.RegexBot.EntityCache
     /// </summary>
     class ECModule : BotModule
     {
-        private readonly DatabaseConfig _db;
-
         public ECModule(DiscordSocketClient client) : base(client)
         {
             if (RegexBot.Config.DatabaseAvailable)
@@ -26,6 +24,8 @@ namespace Noikoio.RegexBot.EntityCache
                 client.GuildMemberUpdated += Client_GuildMemberUpdated;
                 client.UserJoined += Client_UserJoined;
                 client.UserLeft += Client_UserLeft;
+                client.ChannelCreated += Client_ChannelCreated;
+                client.ChannelUpdated += Client_ChannelUpdated;
             }
             else
             {
@@ -33,6 +33,18 @@ namespace Noikoio.RegexBot.EntityCache
             }
         }
 
+        private async Task Client_ChannelUpdated(SocketChannel arg1, SocketChannel arg2)
+        {
+            if (arg2 is SocketGuildChannel ch)
+                await SqlHelper.UpdateGuildChannelAsync(ch);
+        }
+
+        private async Task Client_ChannelCreated(SocketChannel arg)
+        {
+            if (arg is SocketGuildChannel ch)
+                await SqlHelper.UpdateGuildChannelAsync(ch);
+        }
+
         // Guild and guild member information has become available.
         // This is a very expensive operation, especially when joining larger guilds.
         private async Task Client_GuildAvailable(SocketGuild arg)
@@ -43,6 +55,7 @@ namespace Noikoio.RegexBot.EntityCache
                 {
                     await SqlHelper.UpdateGuildAsync(arg);
                     await SqlHelper.UpdateGuildMemberAsync(arg.Users);
+                    await SqlHelper.UpdateGuildChannelAsync(arg.Channels);
                 }
                 catch (NpgsqlException ex)
                 {

EntityCache/SqlHelper.cs

@@ -1,4 +1,5 @@
-using Discord.WebSocket;
+using Discord;
+using Discord.WebSocket;
 using NpgsqlTypes;
 using System;
 using System.Collections.Generic;
@@ -40,13 +41,20 @@ namespace Noikoio.RegexBot.EntityCache
                 using (var c = db.CreateCommand())
                 {
                     c.CommandText = "CREATE TABLE IF NOT EXISTS " + TableTextChannel + " ("
-                        + "channel_id bigint not null primary key, "
+                        + "channel_id bigint not null, "
                         + $"guild_id bigint not null references {TableGuild}, "
                         + "cache_date timestamptz not null, "
                         + "channel_name text not null"
                         + ")";
                     await c.ExecuteNonQueryAsync();
                 }
+                using (var c = db.CreateCommand())
+                {
+                    // guild_id is a foreign key, and also one half of the primary key here
+                    c.CommandText = "CREATE UNIQUE INDEX IF NOT EXISTS "
+                        + $"{TableTextChannel}_ck_idx on {TableTextChannel} (channel_id, guild_id)";
+                    await c.ExecuteNonQueryAsync();
+                }
                 // As of the time of this commit, Discord doesn't allow any uppercase characters
                 // in channel names. No lowercase name index needed.
 
@@ -66,7 +74,7 @@ namespace Noikoio.RegexBot.EntityCache
                 }
                 using (var c = db.CreateCommand())
                 {
-                    // guild_id is a foreign key, and also one half of the primary key here
+                    // compound primary key
                     c.CommandText = "CREATE UNIQUE INDEX IF NOT EXISTS "
                         + $"{TableUser}_ck_idx on {TableUser} (user_id, guild_id)";
                     await c.ExecuteNonQueryAsync();
@@ -103,10 +111,7 @@ namespace Noikoio.RegexBot.EntityCache
         }
 
         internal static Task UpdateGuildMemberAsync(SocketGuildUser user)
-        {
+            => UpdateGuildMemberAsync(new SocketGuildUser[] { user });
-            var ml = new SocketGuildUser[] { user };
-            return UpdateGuildMemberAsync(ml);
-        }
         internal static async Task UpdateGuildMemberAsync(IEnumerable<SocketGuildUser> users)
         {
             var db = await RegexBot.Config.GetOpenDatabaseConnectionAsync();
@@ -150,6 +155,41 @@ namespace Noikoio.RegexBot.EntityCache
                 }
             }
         }
+
+        internal static Task UpdateGuildChannelAsync(SocketGuildChannel channel)
+            => UpdateGuildChannelAsync(new SocketGuildChannel[] { channel });
+        internal static async Task UpdateGuildChannelAsync(IEnumerable<SocketGuildChannel> channels)
+        {
+            var db = await RegexBot.Config.GetOpenDatabaseConnectionAsync();
+            if (db == null) return;
+            using (db)
+            {
+                using (var c = db.CreateCommand())
+                {
+                    c.CommandText = "INSERT INTO " + TableTextChannel
+                        + " (channel_id, guild_id, cache_date, channel_name)"
+                        + " VALUES (@Cid, @Gid, @Date, @Name) "
+                        + "ON CONFLICT (channel_id, guild_id) DO UPDATE SET "
+                        + "cache_date = EXCLUDED.cache_date, channel_name = EXCLUDED.channel_name";
+
+                    var cid = c.Parameters.Add("@Cid", NpgsqlDbType.Bigint);
+                    var gid = c.Parameters.Add("@Gid", NpgsqlDbType.Bigint);
+                    c.Parameters.Add("@Date", NpgsqlDbType.TimestampTZ).Value = DateTime.Now;
+                    var cname = c.Parameters.Add("@Name", NpgsqlDbType.Text);
+                    c.Prepare();
+
+                    foreach (var item in channels)
+                    {
+                        if (!(item is ITextChannel ich)) continue;
+
+                        cid.Value = item.Id;
+                        gid.Value = item.Guild.Id;
+                        cname.Value = item.Name;
+                        await c.ExecuteNonQueryAsync();
+                    }
+                }
+            }
+        }
         #endregion
     }
 }

Module/ModCommands/Commands/_CommandBase.cs

@@ -142,7 +142,7 @@ namespace Noikoio.RegexBot.Module.ModCommands.Commands
 
             try
             {
-                cdata = (await EntityCache.EntityCache.QueryAsync(guild, input))
+                cdata = (await EntityCache.EntityCache.QueryUserAsync(guild, input))
                     .FirstOrDefault();
                 if (cdata != null) uid = cdata.UserId;
             }

Module/ModLogs/LogEntry.cs

@@ -11,9 +11,9 @@ namespace Noikoio.RegexBot.Module.ModLogs
     class LogEntry
     {
         readonly int _logId;
-        readonly DateTime _ts;
+        readonly DateTimeOffset _ts;
         readonly ulong _guildId;
-        readonly ulong? _invokeId;
+        readonly ulong _invokeId;
         readonly ulong _targetId;
         readonly ulong? _channelId;
         readonly LogType _type;
@@ -24,9 +24,9 @@ namespace Noikoio.RegexBot.Module.ModLogs
         /// </summary>
         public int Id => _logId;
         /// <summary>
-        /// Gets the timestamp (a <see cref="DateTime"/> with <see cref="DateTimeKind.Utc"/>) of the entry.
+        /// Gets the UTC timestamp of the entry.
         /// </summary>
-        public DateTime Timestamp => _ts;
+        public DateTimeOffset Timestamp => _ts;
         /// <summary>
         /// Gets the ID of the guild to which this log entry corresponds.
         /// </summary>
@@ -37,9 +37,10 @@ namespace Noikoio.RegexBot.Module.ModLogs
         public ulong Target => _targetId;
         /// <summary>
         /// Gets the ID of the invoking user.
-        /// This value exists only if this entry was created through action of another user that is not the target.
+        /// This value differs from <see cref="Target"/> if this entry was created through
+        /// action of another user, such as the issuer of notes and warnings.
         /// </summary>
-        public ulong? Invoker => _invokeId;
+        public ulong Invoker => _invokeId;
         /// <summary>
         /// Gets the guild channel ID to which this log entry corresponds, if any.
         /// </summary>
@@ -63,8 +64,7 @@ namespace Noikoio.RegexBot.Module.ModLogs
             {
                 _guildId = (ulong)r.GetInt64(2);
                 _targetId = (ulong)r.GetInt64(3);
-                if (r.IsDBNull(4)) _invokeId = null;
+                _invokeId = (ulong)r.GetInt64(4);
-                else _invokeId = (ulong)r.GetInt64(4);
                 if (r.IsDBNull(5)) _channelId = null;
                 else _channelId = (ulong)r.GetInt64(5);
             }
@@ -144,12 +144,14 @@ namespace Noikoio.RegexBot.Module.ModLogs
                         + "id int primary key, "
                         + "entry_ts timestamptz not null, "
                         + "guild_id bigint not null, "
-                        + "target_id bigint not null, "
+                        + "target_id bigint not null, " // No foreign constraint: some targets may not be cached
-                        + $"invoke_id bigint null references {EntityCache.SqlHelper.TableUser}.user_id, "
+                        + "invoker_id bigint not null, "
-                        + "target_channel_id bigint null, " // TODO channel cache reference?
+                        + "target_channel_id bigint null, "
                         + "entry_type integer not null, "
                         + "message text not null, "
-                        + $"FOREIGN KEY (target_id, guild_id) REFERENCES {EntityCache.SqlHelper.TableUser} (user_id, guild_id)";
+                        + $"FOREIGN KEY (invoker_id, guild_id) REFERENCES {EntityCache.SqlHelper.TableUser} (user_id, guild_id), "
+                        + $"FOREIGN KEY (target_channel_id, guild_id) REFERENCES {EntityCache.SqlHelper.TableTextChannel} (channel_id, guild_id)"
+                        + ")";
                     c.ExecuteNonQuery();
                 }
                 using (var c = db.CreateCommand())
@@ -162,7 +164,7 @@ namespace Noikoio.RegexBot.Module.ModLogs
         }
 
         // Double-check constructor if making changes to this constant
-        const string QueryColumns = "id, entry_ts, guild_id, target_id, invoke_id, target_channel_id, entry_type, message";
+        const string QueryColumns = "id, entry_ts, guild_id, target_id, invoker_id, target_channel_id, entry_type, message";
         
         /// <summary>
         /// Attempts to look up a log entry by its ID.