import { requireSession } from '@/lib/session'
import { restoreAgent } from '@/lib/oauth'
import { getBlockEvent } from '@/lib/lexicon'
import { fetchEngagementByAtUri } from '@/lib/engagement'

// GET /api/blocks/refresh?rkey=...
// Re-fetches engagement for the original post and returns accounts that have
// engaged since the block was created (i.e. not already in blockedDids or failedDids).

export async function GET(request: Request) {
  const { searchParams } = new URL(request.url)
  const rkey = searchParams.get('rkey')

  if (!rkey) return Response.json({ error: 'rkey is required' }, { status: 400 })

  let session: { did: string }
  try {
    session = await requireSession()
  } catch {
    return Response.json({ error: 'Not authenticated' }, { status: 401 })
  }

  try {
    const agent = await restoreAgent(session.did)
    const { record } = await getBlockEvent(agent, session.did, rkey)

    if (!record.sourcePostUri) {
      return Response.json(
        { error: 'Source post URI not recorded for this event' },
        { status: 400 }
      )
    }

    if (record.undoneAt) {
      return Response.json(
        { error: 'Cannot refresh an undone block event' },
        { status: 400 }
      )
    }

    // Build the exclusion set — accounts already processed
    const alreadyProcessed = new Set([
      ...(record.blockedDids ?? []),
      ...(record.failedDids ?? []),
      ...(record.pendingDids ?? []),
    ])

    // Re-fetch engagement using the stored AT URI and original criteria
    const { post, accounts } = await fetchEngagementByAtUri(
      record.sourcePostUri,
      session.did,
      record.criteria
    )

    // Filter to only accounts not yet processed
    const newAccounts = accounts.filter((a) => !alreadyProcessed.has(a.profile.did))

    return Response.json({
      post,
      newAccounts,
      checkedAt: new Date().toISOString(),
      totalFound: accounts.length,
      alreadyProcessed: alreadyProcessed.size,
    })
  } catch (err) {
    console.error('[api/blocks/refresh]', err)
    return Response.json({ error: 'Failed to refresh engagement' }, { status: 500 })
  }
}