From 1fbbee14e4c000931a8b404bac13b4ce376ab5a8 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Thu, 19 Oct 2017 19:41:16 +0900
Subject: [PATCH] Allow migration from sqlite-net to EF

Bonus stage
---
 osu.Game/Database/DatabaseContextFactory.cs |  2 +-
 osu.Game/Database/OsuDbContext.cs           | 69 +++++++++++++++++++++
 osu.Game/OsuGameBase.cs                     |  3 +-
 3 files changed, 71 insertions(+), 3 deletions(-)

diff --git a/osu.Game/Database/DatabaseContextFactory.cs b/osu.Game/Database/DatabaseContextFactory.cs
index e22301adfe..359188b4e2 100644
--- a/osu.Game/Database/DatabaseContextFactory.cs
+++ b/osu.Game/Database/DatabaseContextFactory.cs
@@ -14,6 +14,6 @@ namespace osu.Game.Database
             this.host = host;
         }
 
-        public OsuDbContext GetContext() => new OsuDbContext(host.Storage.GetDatabaseConnectionString(@"client-ef"));
+        public OsuDbContext GetContext() => new OsuDbContext(host.Storage.GetDatabaseConnectionString(@"client"));
     }
 }
diff --git a/osu.Game/Database/OsuDbContext.cs b/osu.Game/Database/OsuDbContext.cs
index 2938a8e7be..3f51ac1910 100644
--- a/osu.Game/Database/OsuDbContext.cs
+++ b/osu.Game/Database/OsuDbContext.cs
@@ -156,5 +156,74 @@ namespace osu.Game.Database
                 public IDisposable BeginScope<TState>(TState state) => null;
             }
         }
+
+        public void Migrate()
+        {
+            migrateFromSqliteNet();
+            Database.Migrate();
+        }
+
+        private void migrateFromSqliteNet()
+        {
+            try
+            {
+                // will fail if EF hasn't touched the database yet.
+                Database.ExecuteSqlCommand("SELECT * FROM __EFMigrationsHistory LIMIT 1");
+            }
+            catch
+            {
+                try
+                {
+                    // will fail (intentionally) if we don't have sqlite-net data present.
+                    Database.ExecuteSqlCommand("SELECT OnlineBeatmapSetId FROM BeatmapMetadata LIMIT 1");
+
+                    // we are good to perform messy migration of data!.
+                    Database.ExecuteSqlCommand("ALTER TABLE BeatmapDifficulty RENAME TO BeatmapDifficulty_Old");
+                    Database.ExecuteSqlCommand("ALTER TABLE BeatmapMetadata RENAME TO BeatmapMetadata_Old");
+                    Database.ExecuteSqlCommand("ALTER TABLE FileInfo RENAME TO FileInfo_Old");
+                    Database.ExecuteSqlCommand("ALTER TABLE KeyBinding RENAME TO KeyBinding_Old");
+                    Database.ExecuteSqlCommand("ALTER TABLE BeatmapSetInfo RENAME TO BeatmapSetInfo_Old");
+                    Database.ExecuteSqlCommand("ALTER TABLE BeatmapInfo RENAME TO BeatmapInfo_Old");
+                    Database.ExecuteSqlCommand("ALTER TABLE BeatmapSetFileInfo RENAME TO BeatmapSetFileInfo_Old");
+                    Database.ExecuteSqlCommand("ALTER TABLE RulesetInfo RENAME TO RulesetInfo_Old");
+
+                    Database.ExecuteSqlCommand("DROP TABLE StoreVersion");
+
+                    // perform EF migrations to create sane table structure.
+                    Database.Migrate();
+
+                    // copy data table by table to new structure, dropping old tables as we go.
+                    Database.ExecuteSqlCommand("INSERT INTO FileInfo SELECT * FROM FileInfo_Old");
+                    Database.ExecuteSqlCommand("DROP TABLE FileInfo_Old");
+
+                    Database.ExecuteSqlCommand("INSERT INTO KeyBinding SELECT ID, [Action], Keys, RulesetID, Variant FROM KeyBinding_Old");
+                    Database.ExecuteSqlCommand("DROP TABLE KeyBinding_Old");
+
+                    Database.ExecuteSqlCommand(
+                        "INSERT INTO BeatmapMetadata SELECT ID, Artist, ArtistUnicode, AudioFile, Author, BackgroundFile, PreviewTime, Source, Tags, Title, TitleUnicode FROM BeatmapMetadata_Old");
+                    Database.ExecuteSqlCommand("DROP TABLE BeatmapMetadata_Old");
+
+                    Database.ExecuteSqlCommand(
+                        "INSERT INTO BeatmapDifficulty SELECT  `ID`, `ApproachRate`, `CircleSize`, `DrainRate`, `OverallDifficulty`, `SliderMultiplier`, `SliderTickRate` FROM BeatmapDifficulty_Old");
+                    Database.ExecuteSqlCommand("DROP TABLE BeatmapDifficulty_Old");
+
+                    Database.ExecuteSqlCommand("INSERT INTO BeatmapSetInfo SELECT ID, DeletePending, Hash, BeatmapMetadataID, OnlineBeatmapSetID, Protected FROM BeatmapSetInfo_Old");
+                    Database.ExecuteSqlCommand("DROP TABLE BeatmapSetInfo_Old");
+
+                    Database.ExecuteSqlCommand("INSERT INTO BeatmapSetFileInfo SELECT ID, BeatmapSetInfoID, FileInfoID, Filename FROM BeatmapSetFileInfo_Old");
+                    Database.ExecuteSqlCommand("DROP TABLE BeatmapSetFileInfo_Old");
+
+                    Database.ExecuteSqlCommand("INSERT INTO RulesetInfo SELECT ID, Available, InstantiationInfo, Name FROM RulesetInfo_Old");
+                    Database.ExecuteSqlCommand("DROP TABLE RulesetInfo_Old");
+
+                    Database.ExecuteSqlCommand(
+                        "INSERT INTO BeatmapInfo SELECT ID, AudioLeadIn, BaseDifficultyID, BeatDivisor, BeatmapSetInfoID, Countdown, DistanceSpacing, GridSize, Hash, Hidden, LetterboxInBreaks, MD5Hash, NULLIF(BeatmapMetadataID, 0), OnlineBeatmapID, Path, RulesetID, SpecialStyle, StackLeniency, StarDifficulty, StoredBookmarks, TimelineZoom, Version, WidescreenStoryboard FROM BeatmapInfo_Old");
+                    Database.ExecuteSqlCommand("DROP TABLE BeatmapInfo_Old");
+                }
+                catch
+                {
+                }
+            }
+        }
     }
 }
diff --git a/osu.Game/OsuGameBase.cs b/osu.Game/OsuGameBase.cs
index 22eb75fcea..be12f3ddbc 100644
--- a/osu.Game/OsuGameBase.cs
+++ b/osu.Game/OsuGameBase.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Diagnostics;
 using System.Reflection;
-using Microsoft.EntityFrameworkCore;
 using osu.Framework.Allocation;
 using osu.Framework.Configuration;
 using osu.Framework.Development;
@@ -92,7 +91,7 @@ namespace osu.Game
             dependencies.Cache(LocalConfig);
 
             using (var context = contextFactory.GetContext())
-                context.Database.Migrate();
+                context.Migrate();
 
             dependencies.Cache(API = new APIAccess
             {