// Author: Dr Hamid MADANI <drmdh@msn.com>
//
// GET /api/record/audio/<sessionId>?ext=webm — stream the saved audio file.

import { NextRequest, NextResponse } from 'next/server'
import { createReadStream, statSync } from 'fs'
import path from 'path'
import { Readable } from 'stream'

export const runtime = 'nodejs'
export const dynamic = 'force-dynamic'

const ROOT = path.join(process.cwd(), 'data', 'records')
const SAFE = /^[a-zA-Z0-9_-]{1,128}$/

export async function GET(
  req: NextRequest,
  { params }: { params: Promise<{ sessionId: string }> },
) {
  const { sessionId } = await params
  if (!SAFE.test(sessionId)) {
    return NextResponse.json({ error: 'invalid sessionId' }, { status: 400 })
  }
  const ext = (req.nextUrl.searchParams.get('ext') === 'ogg' ? 'ogg' : 'webm')
  const fp = path.join(ROOT, `${sessionId}.${ext}`)
  let size: number
  try { size = statSync(fp).size }
  catch { return NextResponse.json({ error: 'not found' }, { status: 404 }) }

  const node = createReadStream(fp)
  // Convert Node Readable → Web ReadableStream for Next.js Response
  const web = Readable.toWeb(node) as unknown as ReadableStream
  return new NextResponse(web, {
    status: 200,
    headers: {
      'Content-Type': ext === 'ogg' ? 'audio/ogg' : 'audio/webm',
      'Content-Length': String(size),
      'Cache-Control': 'no-store',
    },
  })
}