import { Client } from "pg";
import { existsSync, readFileSync } from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

export function loadDotEnvIfPresent() {
  const envPath = path.resolve(__dirname, "../../..", ".env");
  if (!existsSync(envPath)) return;
  const raw = readFileSync(envPath, "utf8");
  for (const line of raw.split(/\r?\n/)) {
    const trimmed = line.trim();
    if (!trimmed || trimmed.startsWith("#")) continue;
    const eqIndex = trimmed.indexOf("=");
    if (eqIndex <= 0) continue;

    const key = trimmed.slice(0, eqIndex).trim();
    let value = trimmed.slice(eqIndex + 1).trim();
    if (
      (value.startsWith('"') && value.endsWith('"')) ||
      (value.startsWith("'") && value.endsWith("'"))
    ) {
      value = value.slice(1, -1);
    }
    if (process.env[key] === undefined) {
      process.env[key] = value;
    }
  }
}

export function getDatabaseUrl() {
  loadDotEnvIfPresent();
  const databaseUrl = process.env.DATABASE_URL;
  if (!databaseUrl) {
    throw new Error("DATABASE_URL is not set");
  }
  return databaseUrl;
}

export function resolveMigrationPath(inputPath: string) {
  return path.isAbsolute(inputPath)
    ? inputPath
    : path.resolve(process.cwd(), inputPath);
}

export function readMigrationSql(inputPath: string) {
  return readFileSync(resolveMigrationPath(inputPath), "utf8");
}

export async function applyMigrationFile(
  client: Client,
  migrationPath: string,
  options?: { dryRun?: boolean },
) {
  if (options?.dryRun) {
    return;
  }
  await client.query(readMigrationSql(migrationPath));
}

export async function withMigrationClient<T>(
  work: (client: Client) => Promise<T>,
) {
  const client = new Client({ connectionString: getDatabaseUrl() });
  await client.connect();
  try {
    return await work(client);
  } finally {
    await client.end();
  }
}