import { restoreAgent } from '@/lib/oauth'
import { requireSession } from '@/lib/session'
import { createBlockEvent } from '@/lib/lexicon'
import { canStartJobForDid, MAX_ACTIVE_JOBS_PER_USER, startBlockJob } from '@/lib/queue'
import { generateId } from '@/lib/utils'
import type { BlockCriteria } from '@/types'

interface BlockRequestBody {
  postUri: string
  postUrl: string
  dids: string[]
  criteria: BlockCriteria
}

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

  let body: BlockRequestBody
  try {
    body = await request.json()
  } catch {
    return Response.json({ error: 'Invalid request body' }, { status: 400 })
  }

  const { postUri, postUrl, dids, criteria } = body

  if (!postUri || !dids?.length) {
    return Response.json({ error: 'postUri and dids are required' }, { status: 400 })
  }

  try {
    if (!canStartJobForDid(session.did)) {
      return Response.json(
        { error: `Too many active block jobs. Wait for one to finish before starting another. Limit: ${MAX_ACTIVE_JOBS_PER_USER}.` },
        { status: 429 }
      )
    }

    const agent = await restoreAgent(session.did)

    // Create the block event record in the user's PDS before starting the queue.
    // This records intent upfront — if the server restarts mid-queue, the record
    // still exists and can be used for status checking and retry.
    const { rkey: eventRkey } = await createBlockEvent(agent, session.did, {
      sourcePostUri: postUri,
      sourcePostUrl: postUrl,
      createdAt: new Date().toISOString(),
      criteria,
      stats: { total: dids.length, completed: 0, failed: 0 },
      pendingDids: dids,
      blockedDids: [],
      failedDids: [],
      blockedRkeys: [],
    })

    const jobId = generateId()
    await startBlockJob(jobId, session.did, eventRkey, dids)

    return Response.json({ jobId, eventRkey, total: dids.length })
  } catch (err) {
    console.error('[api/blocks] failed:', err)
    return Response.json({ error: 'Failed to start block job' }, { status: 500 })
  }
}