From 443ad63f21f79eb48f840894828e29a9d8285dc4 Mon Sep 17 00:00:00 2001
From: zkldi <ktchidev@gmail.com>
Date: Sat, 10 Dec 2022 14:44:33 +0000
Subject: [PATCH] feat: handle bms table removals

---
 server/src/lib/jobs/bms-table-sync.ts | 77 +++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/server/src/lib/jobs/bms-table-sync.ts b/server/src/lib/jobs/bms-table-sync.ts
index 2bb36c377..014742592 100644
--- a/server/src/lib/jobs/bms-table-sync.ts
+++ b/server/src/lib/jobs/bms-table-sync.ts
@@ -11,6 +11,69 @@ import type { BMSTableInfo, ChartDocument } from "tachi-common";
 
 const logger = CreateLogCtx(__filename);
 
+/**
+ * Tables might have updates that remove charts from their table.
+ *
+ * We need to handle this -- infact, it's quite common for something
+ * to go from the sl12 folder to st0 -- which is a cross-table
+ * change.
+ */
+async function HandleTableRemovals(tableJSON: Array<BMSTableEntry>, prefix: string) {
+	// There are two ways to approach this, we could wipe the table
+	// and then just apply the update. That is easy enough, but
+	// leaves us in a temporary* invalid state for a while.
+
+	// *unless this script  crashes, in which case it's
+	// no longer temporary
+
+	// garbage cast:
+	// @todo, make these collections actually return the type they
+	// should.
+	const existingMD5s = (await db.charts.bms.find(
+		{
+			"data.tableFolders.table": prefix,
+		},
+		{
+			projection: {
+				"data.hashMD5": 1,
+			},
+		}
+	)) as unknown as Array<ChartDocument<"bms:7K" | "bms:14K">>;
+
+	// As such, the easiest way to handle this is to disjoint
+	// the current md5s in the table against the md5s in the new
+	// table. If the existing md5set doesn't exist in the new
+	// table, we need to pull it.
+
+	const newTableMD5s = new Set(...tableJSON.map((e) => e.md5));
+
+	const toRemove: Array<string> = [];
+
+	for (const md5 of existingMD5s.map((e) => e.data.hashMD5)) {
+		if (!newTableMD5s.has(md5)) {
+			toRemove.push(md5);
+		}
+	}
+
+	if (toRemove.length === 0) {
+		return;
+	}
+
+	logger.info(`Removing ${toRemove} chart(s) from ${prefix}.`);
+
+	// pull this md5's table info
+	await db.charts.bms.update(
+		{
+			"data.hashMD5": { $in: toRemove },
+		},
+		{
+			$pull: {
+				"data.tableFolders.table": prefix,
+			},
+		}
+	);
+}
+
 async function ImportTableLevels(
 	tableJSON: Array<BMSTableEntry>,
 	prefix: string,
@@ -20,6 +83,20 @@ async function ImportTableLevels(
 	let success = 0;
 	const total = tableJSON.length;
 
+	logger.info(`Handling removals for ${prefix}...`);
+	await HandleTableRemovals(tableJSON, prefix);
+
+	await db.charts.bms.update(
+		{
+			"data.hashMD5": { $in: tableJSON.map((e) => e.md5) },
+		},
+		{
+			$pull: {
+				"tableFolders.table": prefix,
+			},
+		}
+	);
+
 	for (const td of tableJSON) {
 		let chart = (await db.charts.bms.findOne({ "data.hashMD5": td.md5 })) as ChartDocument<
 			"bms:7K" | "bms:14K"