import { NextRequest, NextResponse } from 'next/server';
import { requireAdminAuth, getClientIP } from '@/lib/admin/session';
import { auditLog } from '@/lib/admin/audit';
import { logger } from '@/lib/logger';
import { getEntitlementState, setSeatTotal, revokeSeat, readMeteringLedger } from '@/lib/ai/entitlement';

export const runtime = 'nodejs';

/**
 * Admin-only data endpoints for the `server` AI class's real entitlement
 * enforcement (lib/ai/entitlement.ts). This is the data plumbing only — the
 * visual admin console (docs/AI-ASSISTANT-CONCEPT.md §6) is a separate,
 * not-yet-built UI on top of these same endpoints.
 */
export async function GET(request: NextRequest) {
  const result = await requireAdminAuth(request);
  if ('error' in result) return result.error;

  try {
    const [state, ledger] = await Promise.all([getEntitlementState(), readMeteringLedger()]);
    return NextResponse.json({ ...state, recentUsage: ledger }, { headers: { 'Cache-Control': 'no-store' } });
  } catch (error) {
    logger.error('ai entitlement read error', { error: error instanceof Error ? error.message : String(error) });
    return NextResponse.json({ error: 'Internal server error' }, { status: 500 });
  }
}

export async function PUT(request: NextRequest) {
  const result = await requireAdminAuth(request);
  if ('error' in result) return result.error;
  const ip = getClientIP(request);

  let body: { seatsTotal?: unknown; revokeUsername?: unknown };
  try {
    body = await request.json();
  } catch {
    return NextResponse.json({ error: 'invalid JSON body' }, { status: 400 });
  }

  try {
    if (typeof body.seatsTotal === 'number') {
      const state = await setSeatTotal(body.seatsTotal);
      await auditLog('ai.entitlement.seats_total', { seatsTotal: state.seatsTotal }, ip);
      return NextResponse.json(state);
    }
    if (typeof body.revokeUsername === 'string' && body.revokeUsername) {
      const state = await revokeSeat(body.revokeUsername);
      await auditLog('ai.entitlement.revoke_seat', { username: body.revokeUsername }, ip);
      return NextResponse.json(state);
    }
    return NextResponse.json({ error: 'seatsTotal or revokeUsername is required' }, { status: 400 });
  } catch (error) {
    logger.error('ai entitlement update error', { error: error instanceof Error ? error.message : String(error) });
    return NextResponse.json({ error: 'Internal server error' }, { status: 500 });
  }
}