import { chromium, type Browser } from 'playwright-core'
import env from '#start/env'
import logger from '@adonisjs/core/services/logger'

const USER_AGENT =
  'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36'

let browserPromise: Promise<Browser> | null = null

/**
 * Lazily launches a single shared headless Chromium instance, reused
 * across requests instead of paying the ~1-2s browser startup cost on
 * every merchant lookup. Points at a system-installed Chromium/Chrome
 * binary via CHROMIUM_EXECUTABLE_PATH (see .env.example) rather than
 * bundling Playwright's own ~300MB download.
 */
function getBrowser(): Promise<Browser> {
  if (!browserPromise) {
    browserPromise = chromium
      .launch({
        executablePath: env.get('CHROMIUM_EXECUTABLE_PATH') || undefined,
        headless: true,
        args: ['--no-sandbox', '--disable-setuid-sandbox'],
      })
      .catch((error) => {
        browserPromise = null
        throw error
      })
  }
  return browserPromise
}

/**
 * Runs `fn` with a fresh browser page/context, always closing the context
 * afterwards (success or failure) so pages don't accumulate across many
 * lookups. The underlying browser process itself stays warm between calls.
 * Returns null (rather than throwing) if the browser fails to launch or the
 * callback throws, since merchant lookups are best-effort.
 */
async function withPage<T>(
  fn: (page: import('playwright-core').Page) => Promise<T>
): Promise<T | null> {
  try {
    const browser = await getBrowser()
    const context = await browser.newContext({ userAgent: USER_AGENT, locale: 'fr-FR' })
    try {
      const page = await context.newPage()
      return await fn(page)
    } finally {
      await context.close()
    }
  } catch (error) {
    logger.warn({ err: error }, 'Headless browser lookup failed')
    return null
  }
}

/**
 * Closes the shared browser instance, if running. Intended for graceful
 * shutdown hooks / tests, not needed during normal request handling.
 */
async function closeBrowser(): Promise<void> {
  if (!browserPromise) return
  const browser = await browserPromise.catch(() => null)
  browserPromise = null
  await browser?.close()
}

export { withPage, closeBrowser }