import { Router } from 'express';
import { sql } from 'drizzle-orm';
import multer from 'multer';
import { db } from '../db/client';
import { rabbits } from '../db/schema';
import { isPedigreeScanEnabled, PedigreeScanError, scanPedigreeImage } from '../lib/pedigreeScan';

const router = Router();

const MEDIA_TYPES = new Set(['image/jpeg', 'image/png', 'image/webp'] as const);
type MediaType = 'image/jpeg' | 'image/png' | 'image/webp';

// In memory: the image is forwarded to the API and discarded, never written to
// disk. The client downsizes to ~2400px JPEG first, so real uploads are well
// under the limit.
const upload = multer({
  storage: multer.memoryStorage(),
  limits: { fileSize: 10 * 1024 * 1024 },
}).single('image');

// Lets the client decide whether to show the "Scan a pedigree" button.
router.get('/', (req, res) => {
  res.json({ enabled: isPedigreeScanEnabled() });
});

// Confident herd match for a scanned sire/dam (FEATURE_OCR_Pedigree_Scan.md
// Q6): an exact ear number wins; otherwise exactly one exact-name match.
// Anything looser stays a manual entry the user can link by hand.
function findHerdMatch(name: string | null, earNumber: string | null) {
  const columns = { id: rabbits.id, name: rabbits.name };
  if (earNumber) {
    const byEar = db
      .select(columns)
      .from(rabbits)
      .where(sql`upper(${rabbits.earNumber}) = ${earNumber.toUpperCase()}`)
      .limit(2)
      .all();
    if (byEar.length === 1) return byEar[0];
  }
  if (name) {
    const byName = db
      .select(columns)
      .from(rabbits)
      .where(sql`lower(${rabbits.name}) = ${name.toLowerCase()}`)
      .limit(2)
      .all();
    if (byName.length === 1) return byName[0];
  }
  return null;
}

router.post('/', (req, res, next) => {
  if (!isPedigreeScanEnabled()) {
    res.status(503).json({ error: 'Pedigree scanning isn’t set up on this server.' });
    return;
  }

  upload(req, res, async (uploadErr) => {
    if (uploadErr) {
      res.status(400).json({ error: uploadErr.message });
      return;
    }
    const file = req.file;
    if (!file || !MEDIA_TYPES.has(file.mimetype as MediaType)) {
      res.status(400).json({ error: 'Upload a JPEG, PNG, or WebP photo of the pedigree.' });
      return;
    }

    try {
      const result = await scanPedigreeImage(file.buffer, file.mimetype as MediaType);
      const matches = {
        sire: findHerdMatch(result.ancestors.sire.name, result.ancestors.sire.ear_number),
        dam: findHerdMatch(result.ancestors.dam.name, result.ancestors.dam.ear_number),
      };
      res.json({ ...result, matches });
    } catch (err) {
      if (err instanceof PedigreeScanError) {
        res.status(err.status).json({ error: err.message });
        return;
      }
      next(err);
    }
  });
});

export default router;