import { Pool } from 'pg'
import type { PoolClient, QueryResult, QueryResultRow } from 'pg'

import { runtimeConfig } from '../config/runtime.js'

let poolInstance: Pool | null = null

export function getDb(): Pool {
  if (!poolInstance) {
    poolInstance = new Pool({
      connectionString: String(runtimeConfig.database?.url || '').trim(),
      ssl: runtimeConfig.database?.ssl ? { rejectUnauthorized: false } : false,
      max: Number(runtimeConfig.database?.maxConnections || 10),
      idleTimeoutMillis: Number(runtimeConfig.database?.idleTimeoutMs || 30_000),
      connectionTimeoutMillis: Number(runtimeConfig.database?.connectionTimeoutMs || 5_000),
      statement_timeout: Number(runtimeConfig.database?.statementTimeoutMs || 15_000),
    })
  }

  return poolInstance
}

export async function query(text: string, params?: unknown[]): Promise<QueryResult<any>>
export async function query<T extends QueryResultRow>(
  text: string,
  params?: unknown[],
): Promise<QueryResult<T>>
export async function query<T extends QueryResultRow>(
  text: string,
  params: unknown[] = [],
): Promise<QueryResult<T>> {
  const pool = getDb()
  return pool.query<T>(text, params)
}

export async function withTransaction<T>(fn: (client: PoolClient) => Promise<T>): Promise<T> {
  const client = await getDb().connect()

  try {
    await client.query('BEGIN')
    const result = await fn(client)
    await client.query('COMMIT')
    return result
  } catch (error) {
    await client.query('ROLLBACK')
    throw error
  } finally {
    client.release()
  }
}

export async function closeDb(): Promise<void> {
  if (!poolInstance) {
    return
  }

  const pool = poolInstance
  poolInstance = null
  await pool.end()
}