// API: Single Offer Management
// GET /api/marketplace/offers/[id] - Get an offer
// PUT /api/marketplace/offers/[id] - Update offer (accept/reject/withdraw)

import type { NextApiRequest, NextApiResponse } from 'next';
import { offerService, listingService } from '@/lib/marketplace';

export default async function handler(
  req: NextApiRequest,
  res: NextApiResponse
) {
  const { id: offerId } = req.query;

  if (!offerId || typeof offerId !== 'string') {
    return res.status(400).json({ error: 'Offer ID is required' });
  }

  try {
    switch (req.method) {
      case 'GET':
        return handleGet(offerId, req, res);
      case 'PUT':
        return handlePut(offerId, req, res);
      default:
        res.setHeader('Allow', ['GET', 'PUT']);
        return res.status(405).json({ error: `Method ${req.method} Not Allowed` });
    }
  } catch (error) {
    console.error('Offer API error:', error);
    return res.status(500).json({
      error: 'Internal server error',
      message: error instanceof Error ? error.message : 'Unknown error',
    });
  }
}

async function handleGet(offerId: string, req: NextApiRequest, res: NextApiResponse) {
  const userId = req.headers['x-user-id'] as string;

  const offer = await offerService.getOfferById(offerId);

  if (!offer) {
    return res.status(404).json({ error: 'Offer not found' });
  }

  // Get listing to check authorization
  const listing = await listingService.getListingById(offer.listingId);

  // Only buyer or seller can view the offer
  if (userId !== offer.buyerId && userId !== listing?.sellerId) {
    return res.status(403).json({ error: 'Not authorized to view this offer' });
  }

  return res.status(200).json({
    ...offer,
    listing,
  });
}

async function handlePut(offerId: string, req: NextApiRequest, res: NextApiResponse) {
  const userId = req.headers['x-user-id'] as string;

  if (!userId) {
    return res.status(401).json({ error: 'Authentication required' });
  }

  const { action, amount } = req.body;

  if (!action) {
    return res.status(400).json({ error: 'Action is required (accept, reject, withdraw, update)' });
  }

  try {
    let result;

    switch (action) {
      case 'accept':
        result = await offerService.acceptOffer(offerId, userId);
        break;

      case 'reject':
        result = await offerService.rejectOffer(offerId, userId);
        break;

      case 'withdraw':
        result = await offerService.withdrawOffer(offerId, userId);
        break;

      case 'update':
        if (!amount || typeof amount !== 'number') {
          return res.status(400).json({ error: 'New amount is required for update action' });
        }
        result = await offerService.updateOfferAmount(offerId, userId, amount);
        break;

      default:
        return res.status(400).json({
          error: 'Invalid action',
          validActions: ['accept', 'reject', 'withdraw', 'update'],
        });
    }

    return res.status(200).json({
      success: true,
      action,
      offer: result,
    });
  } catch (error) {
    if (error instanceof Error) {
      if (error.message.includes('Unauthorized') || error.message.includes('not your')) {
        return res.status(403).json({ error: error.message });
      }
      return res.status(400).json({ error: error.message });
    }
    throw error;
  }
}