Initial split of the modules

NadekoBot.Core/Services/DbService.cs

@@ -0,0 +1,59 @@
+using Microsoft.Data.Sqlite;
+using Microsoft.EntityFrameworkCore;
+using NadekoBot.Services.Database;
+using System;
+using System.IO;
+using System.Linq;
+
+namespace NadekoBot.Services
+{
+    public class DbService
+    {
+        private readonly DbContextOptions<NadekoContext> options;
+        private readonly DbContextOptions<NadekoContext> migrateOptions;
+
+        public DbService(IBotCredentials creds)
+        {
+            var builder = new SqliteConnectionStringBuilder(creds.Db.ConnectionString);
+            builder.DataSource = Path.Combine(AppContext.BaseDirectory, builder.DataSource);
+            
+            var optionsBuilder = new DbContextOptionsBuilder<NadekoContext>();
+            optionsBuilder.UseSqlite(builder.ToString());
+            options = optionsBuilder.Options;
+
+            optionsBuilder = new DbContextOptionsBuilder<NadekoContext>();
+            optionsBuilder.UseSqlite(builder.ToString(), x => x.SuppressForeignKeyEnforcement());
+            migrateOptions = optionsBuilder.Options;
+        }
+
+        public NadekoContext GetDbContext()
+        {
+            var context = new NadekoContext(options);
+            if (context.Database.GetPendingMigrations().Any())
+            {
+                var mContext = new NadekoContext(migrateOptions);
+                mContext.Database.Migrate();
+                mContext.SaveChanges();
+                mContext.Dispose();
+            }
+            context.Database.SetCommandTimeout(60);
+            context.EnsureSeedData();
+
+            //set important sqlite stuffs
+            var conn = context.Database.GetDbConnection();
+            conn.Open();
+
+            context.Database.ExecuteSqlCommand("PRAGMA journal_mode=WAL");
+            using (var com = conn.CreateCommand())
+            {
+                com.CommandText = "PRAGMA journal_mode=WAL; PRAGMA synchronous=OFF";
+                com.ExecuteNonQuery();
+            }
+
+            return context;
+        }
+
+        public IUnitOfWork UnitOfWork =>
+            new UnitOfWork(GetDbContext());
+    }
+}