import { requireSession } from '@/lib/session'
import { restoreAgent } from '@/lib/oauth'
import { requireListScopes } from '@/lib/scope-gate'
import { getListSubscriptionRkey, unsubscribeFromList, listBlockEvents, updateBlockEvent } from '@/lib/lexicon'

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

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

  const { listUri } = body
  if (!listUri) {
    return Response.json({ error: 'listUri is required' }, { status: 400 })
  }

  // Validate this list belongs to the session user
  const ownerDid = listUri.split('/')[2]
  if (ownerDid !== session.did) {
    return Response.json({ error: 'You can only delete your own lists' }, { status: 403 })
  }

  const rkey = listUri.split('/').pop()
  if (!rkey) {
    return Response.json({ error: 'Invalid list URI' }, { status: 400 })
  }

  try {
    const scopeGate = await requireListScopes(session.did)
    if (scopeGate) return scopeGate

    const agent = await restoreAgent(session.did)

    // Unsubscribe first if subscribed (best-effort)
    try {
      const subscriptionRkey = await getListSubscriptionRkey(agent, session.did, listUri)
      if (subscriptionRkey) {
        await unsubscribeFromList(agent, session.did, subscriptionRkey)
      }
    } catch {
      // Non-fatal — proceed with deletion even if unsubscribe fails
    }

    // Delete the list record itself
    await agent.com.atproto.repo.deleteRecord({
      repo: session.did,
      collection: 'app.bsky.graph.list',
      rkey,
    })

    // Listitem records are left orphaned (harmless without the list record)

    // Clear listUri from any block event that references this list, so the
    // event detail page doesn't show a broken link after deletion.
    try {
      const events = await listBlockEvents(agent, session.did)
      const matches = events.filter((e) => e.record.listUri === listUri)
      for (const match of matches) {
        await updateBlockEvent(agent, session.did, match.rkey, {
          ...match.record,
          listUri: undefined,
        })
      }
    } catch {
      // Non-fatal — list is deleted, event reference cleanup is best-effort
    }

    return Response.json({ deleted: true })
  } catch (err) {
    console.error('[api/list/delete]', err)
    return Response.json({ error: 'Failed to delete list' }, { status: 500 })
  }
}