import { readFileSync, readdirSync } from "fs";
import { join } from "path";
import { Pool } from "pg";
import { config } from "dotenv";

config();

const pool = new Pool({
  host: process.env.POSTGRES_HOST || "localhost",
  port: parseInt(process.env.POSTGRES_PORT || "5432"),
  database: process.env.POSTGRES_DB || "transceiver_db",
  user: process.env.POSTGRES_USER || "tip",
  password: process.env.POSTGRES_PASSWORD || "tip_dev_2026",
});

async function migrate(): Promise<void> {
  const sqlDir = join(__dirname, "..", "sql");
  const files = readdirSync(sqlDir)
    .filter((f) => f.endsWith(".sql"))
    .sort();

  const client = await pool.connect();
  try {
    // Create migration tracker if it doesn't exist
    await client.query(`
      CREATE TABLE IF NOT EXISTS _migrations (
        filename    TEXT PRIMARY KEY,
        applied_at  TIMESTAMPTZ NOT NULL DEFAULT NOW()
      )
    `);

    // Get already-applied migrations
    const { rows } = await client.query(
      "SELECT filename FROM _migrations ORDER BY filename"
    );
    const applied = new Set(rows.map((r: { filename: string }) => r.filename));

    const pending = files.filter((f) => !applied.has(f));
    if (pending.length === 0) {
      console.log("All migrations already applied. Nothing to do.");
      return;
    }

    console.log(
      `${applied.size} already applied, running ${pending.length} pending migrations`
    );

    for (const file of pending) {
      const sql = readFileSync(join(sqlDir, file), "utf-8");
      console.log(`Running: ${file}...`);
      await client.query("BEGIN");
      try {
        await client.query(sql);
        await client.query(
          "INSERT INTO _migrations (filename) VALUES ($1)",
          [file]
        );
        await client.query("COMMIT");
        console.log(`  Done: ${file}`);
      } catch (err) {
        await client.query("ROLLBACK");
        throw err;
      }
    }

    console.log("\nAll migrations completed successfully.");
  } catch (err) {
    console.error("Migration failed:", err);
    process.exit(1);
  } finally {
    client.release();
    await pool.end();
  }
}

migrate();