Added channel cache to EntityCache

EntityCache/CacheChannel.cs

@@ -0,0 +1,154 @@
+using Discord.WebSocket;
+using Npgsql;
+using System;
+using System.Collections.Generic;
+using System.Data.Common;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Noikoio.RegexBot.EntityCache
+{
+    class CacheChannel
+    {
+        readonly ulong _channelId;
+        readonly ulong _guildId;
+        readonly DateTimeOffset _cacheDate;
+        readonly string _channelName;
+
+        private CacheChannel(SocketGuildChannel c)
+        {
+            _channelId = c.Id;
+            _guildId = c.Guild.Id;
+            _cacheDate = DateTimeOffset.UtcNow;
+            _channelName = c.Name;
+        }
+
+        // Double-check SqlHelper if making changes to this constant
+        const string QueryColumns = "channel_id, guild_id, cache_date, channel_name";
+        private CacheChannel(DbDataReader r)
+        {
+            // Double-check ordinals if making changes to QueryColumns
+            unchecked
+            {
+                _channelId = (ulong)r.GetInt64(0);
+                _guildId = (ulong)r.GetInt64(1);
+            }
+            _cacheDate = r.GetDateTime(2).ToUniversalTime();
+            _channelName = r.GetString(3);
+        }
+
+        #region Queries
+        // Accessible by EntityCache. Documentation is there.
+        internal static async Task<CacheChannel> QueryAsync(DiscordSocketClient c, ulong guild, ulong channel)
+        {
+            // Local cache search
+            var lresult = LocalQueryAsync(c, guild, channel);
+            if (lresult != null) return lresult;
+
+            // Database cache search
+            var db = await RegexBot.Config.GetOpenDatabaseConnectionAsync();
+            if (db == null) return null; // Database not available for query.
+            return await DbQueryAsync(db, guild, channel);
+        }
+
+        private static CacheChannel LocalQueryAsync(DiscordSocketClient c, ulong guild, ulong channel)
+        {
+            var ch = c.GetGuild(guild)?.GetChannel(channel);
+            if (ch == null) return null;
+            return new CacheChannel(ch);
+        }
+        private static async Task<CacheChannel> DbQueryAsync(NpgsqlConnection db, ulong guild, ulong channel)
+        {
+            using (db)
+            {
+                using (var c = db.CreateCommand())
+                {
+                    c.CommandText = $"SELECT {QueryColumns} from {SqlHelper.TableTextChannel} WHERE "
+                        + "channel_id = @Cid AND guild_id = @Gid";
+                    c.Parameters.Add("@Cid", NpgsqlTypes.NpgsqlDbType.Bigint).Value = channel;
+                    c.Parameters.Add("@Gid", NpgsqlTypes.NpgsqlDbType.Bigint).Value = guild;
+                    c.Prepare();
+                    using (var r = await c.ExecuteReaderAsync())
+                    {
+                        if (await r.ReadAsync())
+                        {
+                            return new CacheChannel(r);
+                        }
+                        else
+                        {
+                            return null;
+                        }
+                    }
+                }
+            }
+        }
+
+        // -----
+
+        // Accessible by EntityCache. Documentation is there.
+        internal static async Task<IEnumerable<CacheChannel>> QueryAsync(DiscordSocketClient c, ulong guild, string search)
+        {
+            // Is search just a number? Assume ID, pass it on to the correct place.
+            if (ulong.TryParse(search, out var presult))
+            {
+                var r = await QueryAsync(c, guild, presult);
+                if (r == null) return new CacheChannel[0];
+                else return new CacheChannel[] { r };
+            }
+
+            // Split leading # from name, if exists
+            if (search.Length > 0 && search[0] == '#') search = search.Substring(1);
+
+            // Local cache search
+            var lresult = LocalQueryAsync(c, guild, search);
+            if (lresult.Count() != 0) return lresult;
+
+            // Database cache search
+            var db = await RegexBot.Config.GetOpenDatabaseConnectionAsync();
+            if (db == null) return new CacheChannel[0];
+            return await DbQueryAsync(db, guild, search);
+        }
+
+        private static IEnumerable<CacheChannel> LocalQueryAsync(DiscordSocketClient c, ulong guild, string search)
+        {
+            var g = c.GetGuild(guild);
+            if (g == null) return new CacheChannel[0];
+
+            var qresult = g.Channels
+                .Where(i => string.Equals(i.Name, search, StringComparison.InvariantCultureIgnoreCase));
+            var result = new List<CacheChannel>();
+            foreach (var item in qresult)
+            {
+                result.Add(new CacheChannel(item));
+            }
+            return result;
+        }
+
+        private static async Task<IEnumerable<CacheChannel>> DbQueryAsync(NpgsqlConnection db, ulong guild, string search)
+        {
+            var result = new List<CacheChannel>();
+
+            using (db)
+            {
+                using (var c = db.CreateCommand())
+                {
+                    c.CommandText = $"SELECT {QueryColumns} FROM {SqlHelper.TableTextChannel} WHERE"
+                        + " name = lower(@NameSearch)" // all channel names presumed to be lowercase already
+                        + " ORDER BY cache_date desc, name";
+                    c.Parameters.Add("@NameSearch", NpgsqlTypes.NpgsqlDbType.Text).Value = search;
+                    c.Prepare();
+
+                    using (var r = await c.ExecuteReaderAsync())
+                    {
+                        while (await r.ReadAsync())
+                        {
+                            result.Add(new CacheChannel(r));
+                        }
+                    }
+                }
+            }
+            return result;
+        }
+        #endregion
+    }
+}

EntityCache/CacheUser.cs

@@ -102,7 +102,7 @@ namespace Noikoio.RegexBot.EntityCache
             // Database cache search
             var db = await RegexBot.Config.GetOpenDatabaseConnectionAsync();
             if (db == null) return null; // Database not available for query.
-            using (db) return await DbQueryAsync(db, guild, user);
+            return await DbQueryAsync(db, guild, user);
         }
 
         private static CacheUser LocalQueryAsync(DiscordSocketClient c, ulong guild, ulong user)
@@ -175,8 +175,8 @@ namespace Noikoio.RegexBot.EntityCache
 
             // Database cache search
             var db = await RegexBot.Config.GetOpenDatabaseConnectionAsync();
-            if (db == null) return null; // Database not available for query.
-            using (db) return await DbQueryAsync(db, guild, name, disc);
+            if (db == null) return new CacheUser[0]; // Database not available for query.
+            return await DbQueryAsync(db, guild, name, disc);
         }
 
         private static IEnumerable<CacheUser> LocalQueryAsync(DiscordSocketClient c, ulong guild, string name, string disc)
@@ -210,7 +210,7 @@ namespace Noikoio.RegexBot.EntityCache
         {
             var result = new List<CacheUser>();
 
-            using (db = await RegexBot.Config.GetOpenDatabaseConnectionAsync())
+            using (db)
             {
                 using (var c = db.CreateCommand())
                 {

EntityCache/ECModule.cs

@@ -11,11 +11,11 @@ namespace Noikoio.RegexBot.EntityCache
     /// The function of this module should be transparent to the user, and thus no configuration is needed.
     /// This module should be initialized BEFORE any other modules that make use of the entity cache.
     /// </summary>
-    class Module : BotModule
+    class ECModule : BotModule
     {
         private readonly DatabaseConfig _db;
 
-        public Module(DiscordSocketClient client) : base(client)
+        public ECModule(DiscordSocketClient client) : base(client)
         {
             if (RegexBot.Config.DatabaseAvailable)
             {

EntityCache/EntityCache.cs

@@ -24,15 +24,37 @@ namespace Noikoio.RegexBot.EntityCache
         /// Does not handle exceptions that may occur.
         /// </summary>
         /// <returns>Null on no result.</returns>
-        internal static Task<CacheUser> QueryAsync(ulong guild, ulong user)
+        internal static Task<CacheUser> QueryUserAsync(ulong guild, ulong user)
             => CacheUser.QueryAsync(_client, guild, user);
 
         /// <summary>
         /// Attempts to look up the user given a search string.
         /// This string looks up case-insensitive, exact matches of nicknames and usernames.
         /// </summary>
-        /// <returns>An <see cref="IEnumerable{T}"/> containing zero or more query results, sorted by cache date.</returns>
-        internal static Task<IEnumerable<CacheUser>> QueryAsync(ulong guild, string search)
+        /// <returns>
+        /// An <see cref="IEnumerable{T}"/> containing zero or more query results,
+        /// sorted by cache date from most to least recent.
+        /// </returns>
+        internal static Task<IEnumerable<CacheUser>> QueryUserAsync(ulong guild, string search)
             => CacheUser.QueryAsync(_client, guild, search);
+
+        /// <summary>
+        /// Attempts to query for an exact result with the given parameters.
+        /// Does not handle exceptions that may occur.
+        /// </summary>
+        /// <returns>Null on no result.</returns>
+        internal static Task<CacheChannel> QueryChannelAsync(ulong guild, ulong channel)
+            => CacheChannel.QueryAsync(_client, guild, channel);
+
+        /// <summary>
+        /// Attempts to look up the channel given a search string.
+        /// This string looks up exact matches of the given name, regardless of if the channel has been deleted.
+        /// </summary>
+        /// <returns>
+        /// An <see cref="IEnumerable{T}"/> containing zero or more query results,
+        /// sorted by cache date from most to least recent.
+        /// </returns>
+        internal static Task<IEnumerable<CacheChannel>> QueryChannelAsync(ulong guild, string search)
+            => CacheChannel.QueryAsync(_client, guild, search);
     }
 }

RegexBot.cs

@@ -61,7 +61,7 @@ namespace Noikoio.RegexBot
                 new Module.EntryAutoRole.EntryAutoRole(_client),
 
                 // EntityCache loads before anything using it
-                new EntityCache.Module(_client),
+                new EntityCache.ECModule(_client),
                 new Module.ModLogs.ModLogs(_client)
             };