large refactor

src/sqlite/migrations.ts

@@ -0,0 +1,94 @@
+import { unixNow } from "applesauce-core/helpers";
+import { Database } from "better-sqlite3";
+
+type ScriptFunction = (database: Database, log: (message: string) => void) => Promise<void>;
+type MigrationScript = { version: number; migrate: ScriptFunction };
+
+export class MigrationSet {
+  scripts: MigrationScript[] = [];
+
+  name: string;
+  database?: Database;
+  setupMigrationTables = true;
+
+  constructor(name: string, database?: Database) {
+    this.database = database;
+    this.name = name;
+  }
+
+  private ensureMigrations(database: Database | undefined = this.database) {
+    if (!database) throw new Error("database required");
+
+    database
+      .prepare(
+        `
+			CREATE TABLE IF NOT EXISTS "migrations" (
+				"id"	INTEGER NOT NULL,
+				"name"	TEXT NOT NULL,
+				"version"	INTEGER NOT NULL,
+				"date"	INTEGER NOT NULL,
+				PRIMARY KEY("id" AUTOINCREMENT)
+			);
+			`,
+      )
+      .run();
+    database
+      .prepare(
+        `
+			CREATE TABLE IF NOT EXISTS "migration_logs" (
+				"id"	INTEGER NOT NULL,
+				"migration"	INTEGER NOT NULL,
+				"message"	TEXT NOT NULL,
+				FOREIGN KEY("migration") REFERENCES "migrations",
+				PRIMARY KEY("id" AUTOINCREMENT)
+			);
+			`,
+      )
+      .run();
+  }
+
+  addScript(version: number, migrate: ScriptFunction) {
+    this.scripts.push({ version, migrate });
+  }
+
+  async run(database: Database | undefined = this.database) {
+    if (!database) throw new Error("database required");
+
+    // ensure migration tables are setup
+    await this.ensureMigrations(database);
+
+    const prev = database
+      .prepare<[string], { name: string; version: number }>(`SELECT * FROM migrations WHERE name=?`)
+      .all(this.name);
+    const lastVersion = prev.reduce((v, m) => Math.max(m.version, v), 0);
+
+    const sorted = Array.from(this.scripts).sort((a, b) => a.version - b.version);
+
+    let version = lastVersion;
+    for (const script of sorted) {
+      if (version < script.version) {
+        let logs: string[] = [];
+        await database.transaction(() => {
+          return script.migrate(database, (message) => logs.push(message));
+        })();
+
+        version = script.version;
+
+        // save the migration
+        database.transaction(() => {
+          const result = database
+            .prepare<[string, number, number]>(`INSERT INTO migrations (name, version, date) VALUES (?1, ?2, ?3)`)
+            .run(this.name, script.version, unixNow());
+
+          const insertLog = database.prepare<[number | bigint, string]>(
+            `INSERT INTO migration_logs (migration, message) VALUES (?, ?)`,
+          );
+
+          for (const message of logs) {
+            insertLog.run(result.lastInsertRowid, message);
+          }
+        })();
+      }
+    }
+  }
+}