add sqlc, fix background img fetching

grpc-backend/sqlc/query/beatmap.sql

@@ -0,0 +1,30 @@
+-- name: InsertBeatmap :exec
+INSERT INTO Beatmap (
+    BeatmapId, Artist, ArtistUnicode, Title, TitleUnicode, Creator,
+    Difficulty, Audio, MD5Hash, File, RankedStatus, 
+    LastModifiedTime, TotalTime, AudioPreviewTime, BeatmapSetId, 
+    Source, Tags, LastPlayed, Folder
+) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);
+
+-- name: GetBeatmapByHash :one
+SELECT * FROM Beatmap WHERE MD5Hash = ?;
+
+-- name: GetBeatmapCount :one
+SELECT COUNT(*) FROM Beatmap;
+
+-- name: GetRecentBeatmaps :many
+SELECT BeatmapId, MD5Hash, Title, Artist, Creator, Folder, File, Audio, TotalTime
+FROM Beatmap GROUP BY Folder ORDER BY LastModifiedTime DESC LIMIT ? OFFSET ?;
+
+-- name: SearchBeatmaps :many
+SELECT BeatmapId, MD5Hash, Title, Artist, Creator, Folder, File, Audio, TotalTime 
+FROM Beatmap 
+WHERE Title LIKE ? OR Artist LIKE ? 
+LIMIT ? OFFSET ?;
+
+-- name: GetArtists :many
+SELECT Artist, COUNT(Artist) AS count
+FROM Beatmap 
+WHERE Artist LIKE ? OR Title LIKE ?
+GROUP BY Artist 
+LIMIT ? OFFSET ?;

grpc-backend/sqlc/query/collection.sql

@@ -0,0 +1,42 @@
+-- name: InsertCollection :exec
+INSERT INTO Collection (Name, MD5Hash) VALUES (?, ?);
+
+-- name: GetCollectionCountByName :one
+SELECT COUNT(*) FROM Collection WHERE Name = ?;
+
+-- name: GetCollections :many
+SELECT c.Name, COUNT(b.MD5Hash) AS Count, MIN(b.Folder) AS Folder, MIN(b.File) AS File
+FROM Collection c
+JOIN Beatmap b ON c.MD5Hash = b.MD5Hash
+WHERE c.Name LIKE ?
+GROUP BY c.Name
+LIMIT ? OFFSET ?;
+
+-- name: GetCollection :many
+SELECT 
+  c.Name, 
+  b.BeatmapId, 
+  b.MD5Hash, 
+  b.Title, 
+  b.Artist, 
+  b.Creator, 
+  b.Folder, 
+  b.File, 
+  b.Audio, 
+  b.TotalTime
+FROM Collection c
+JOIN Beatmap b ON c.MD5Hash = b.MD5Hash
+JOIN (
+  SELECT DISTINCT Name
+  FROM Collection
+  ORDER BY Name
+  LIMIT 1 OFFSET ?
+) selected_name ON c.Name = selected_name.Name
+LIMIT ? OFFSET ?;
+
+-- name: GetCollectionByName :many
+SELECT c.Name, b.BeatmapId, b.MD5Hash, b.Title, b.Artist, b.Creator, b.Folder, b.File, b.Audio, b.TotalTime
+FROM Collection c
+JOIN Beatmap b ON c.MD5Hash = b.MD5Hash
+WHERE c.Name = ?
+LIMIT ? OFFSET ?;