feat: format sql (#19)

Co-authored-by: SuLe <sule@SuLedeMacBook-Air.local>

src/lib/sqlFormatter.ts

@@ -0,0 +1,25 @@
+export type SqlFormatDialect = "mysql" | "postgres" | "sqlite" | "sqlserver" | "generic";
+
+function formatterLanguage(dialect: SqlFormatDialect) {
+  switch (dialect) {
+    case "mysql":
+      return "mysql";
+    case "postgres":
+      return "postgresql";
+    case "sqlite":
+      return "sqlite";
+    case "sqlserver":
+      return "transactsql";
+    default:
+      return "sql";
+  }
+}
+
+export async function formatSqlText(sql: string, dialect: SqlFormatDialect = "generic"): Promise<string> {
+  if (!sql.trim()) return sql;
+  const { format } = await import("sql-formatter");
+  return format(sql, {
+    language: formatterLanguage(dialect),
+    keywordCase: "upper",
+  });
+}