import { createClient } from '@supabase/supabase-js';

const SUPABASE_URL = process.env.SUPABASE_URL || 'https://hwithddwaapyhnfwcesj.supabase.co';
const SUPABASE_KEY = process.env.SUPABASE_SERVICE_KEY || 'sb_publishable_fGXkh0bSrAOqSk2jWKAzSg_NJD9YPCv';

const supabase = createClient(SUPABASE_URL, SUPABASE_KEY);

export default async function handler(req, res) {
  try {
    console.log('Starting migration v2...');
    
    // 1. Fetch products
    const { data: products, error: pErr } = await supabase
      .from('products')
      .select('product_id, data')
      .in('status', ['edited', 'synced', 'pending']); // Broaden to catch everything shifted
    
    if (pErr) throw new pErr;

    let pCount = 0;
    if (products && products.length > 0) {
      const updates = products.map(p => {
        const oldData = p.data;
        // Logic: if index 12 is a date/number, it's the old structure.
        // In the new structure, index 12 is "PM Classification" (string/empty).
        const valAt12 = oldData[12];
        const isOld = typeof valAt12 === 'number' || (typeof valAt12 === 'string' && /^[0-9.]+$/.test(valAt12));
        
        if (isOld && oldData.length < 110) { // Don't shift if already shifted
          const newData = [...oldData];
          newData.splice(12, 0, ''); // Shift
          pCount++;
          return supabase.from('products').update({ data: newData }).eq('product_id', p.product_id);
        }
        return null;
      }).filter(Boolean);

      // Run updates in parallel (limited) or batches if needed, but for 130 rows it's fine
      await Promise.all(updates);
    }

    // 2. History
    const { data: history, error: hErr } = await supabase.from('products_history').select('*');
    if (hErr) throw hErr;
    
    let hCount = 0;
    if (history && history.length > 0) {
      const hUpdates = history.map(h => {
        let changed = false;
        let nOld = h.old_data;
        let nNew = h.new_data;

        if (nOld && nOld.length >= 13 && (typeof nOld[12] === 'number' || (typeof nOld[12] === 'string' && /^[0-9.]+$/.test(nOld[12])))) {
          nOld = [...nOld];
          nOld.splice(12, 0, '');
          changed = true;
        }
        if (nNew && nNew.length >= 13 && (typeof nNew[12] === 'number' || (typeof nNew[12] === 'string' && /^[0-9.]+$/.test(nNew[12])))) {
          nNew = [...nNew];
          nNew.splice(12, 0, '');
          changed = true;
        }

        if (changed) {
          hCount++;
          return supabase.from('products_history').update({ old_data: nOld, new_data: nNew }).eq('id', h.id);
        }
        return null;
      }).filter(Boolean);
      await Promise.all(hUpdates);
    }

    return res.json({
      success: true,
      productsMigrated: pCount,
      historyMigrated: hCount,
      message: 'Migration v2 finished.'
    });
  } catch (err) {
    console.error('Migration error:', err);
    return res.status(500).json({ error: err.message, stack: err.stack });
  }
}