import { Kysely, PostgresDialect } from "kysely";
import pg from "pg";
import type { DB } from "./types.ts";

// int8 → number(大小/序号都在 2^53 内;超出即报错而不是静默丢精度)
pg.types.setTypeParser(pg.types.builtins.INT8, (v: string) => {
  const n = Number(v);
  if (!Number.isSafeInteger(n)) throw new RangeError(`int8 超出安全整数范围: ${v}`);
  return n;
});
// date → 原样 'YYYY-MM-DD' 字符串,避免按本地时区转成 Date 造成日期漂移
pg.types.setTypeParser(pg.types.builtins.DATE, (v: string) => v);

export interface CreateDbOptions {
  /** 默认读 process.env.DATABASE_URL */
  connectionString?: string;
  max?: number;
}

/** 创建带连接池的 Kysely 实例;调用方负责在退出时 db.destroy() */
export function createDb(opts: CreateDbOptions = {}): Kysely<DB> {
  const connectionString = opts.connectionString ?? process.env.DATABASE_URL;
  if (!connectionString) throw new Error("DATABASE_URL 未设置");
  const pool = new pg.Pool({ connectionString, max: opts.max ?? 10 });
  return new Kysely<DB>({ dialect: new PostgresDialect({ pool }) });
}