const fs = require('fs');
const path = require('path');
const { query, connectDB } = require('../database/connection');

async function migratePincodes() {
  try {
    await connectDB();
    console.log('Database connected for migration.');

    const csvFilePath = path.join(__dirname, '../../data/pincode.csv');
    const fileContent = fs.readFileSync(csvFilePath, 'utf8');
    const lines = fileContent.split('\n').filter(line => line.trim() !== '');

    if (lines.length === 0) {
      console.log('No data found in pincode.csv');
      return;
    }

    const headers = lines[0].split(',').map(header => header.trim().toLowerCase());
    const dataRows = lines.slice(1);

    console.log(`Starting migration of ${dataRows.length} pincode records.`);

    for (const row of dataRows) {
      const values = parseCsvLine(row);
      
      if (values.length !== headers.length) {
        console.warn('Skipping row due to column mismatch:', row);
        continue;
      }

      const record = {};
      headers.forEach((header, index) => {
        record[header] = values[index];
      });

      const pincode = record.pincode;
      const office_name = record.officename;
      const office_type = record.officetype;
      const district = record.district;
      const division = record.divisionname;
      const region = record.regionname;
      const state = record.statename;
      const latitude = record.latitude && record.latitude.toLowerCase() !== 'na' ? parseFloat(record.latitude) : null;
      const longitude = record.longitude && record.longitude.toLowerCase() !== 'na' ? parseFloat(record.longitude) : null;

      const insertQuery = `
        INSERT INTO pincodes (pincode, office_name, office_type, district, division, region, state, latitude, longitude)
        VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
        ON CONFLICT (pincode) DO UPDATE SET
          office_name = EXCLUDED.office_name,
          office_type = EXCLUDED.office_type,
          district = EXCLUDED.district,
          division = EXCLUDED.division,
          region = EXCLUDED.region,
          state = EXCLUDED.state,
          latitude = EXCLUDED.latitude,
          longitude = EXCLUDED.longitude,
          updated_at = NOW()
        ;
      `;
      const insertValues = [
        pincode,
        office_name,
        office_type,
        district,
        division,
        region,
        state,
        latitude,
        longitude
      ];

      await query(insertQuery, insertValues);
    }

    console.log('Pincode migration completed successfully.');
  } catch (error) {
    console.error('Error during pincode migration:', error);
    process.exit(1);
  }
}

// Basic CSV parser to handle commas within quoted strings
function parseCsvLine(line) {
  const values = [];
  let inQuote = false;
  let currentVal = '';
  for (let i = 0; i < line.length; i++) {
    const char = line[i];
    if (char === '"' && (i === 0 || line[i - 1] === ',')) {
      inQuote = !inQuote;
    } else if (char === ',' && !inQuote) {
      values.push(currentVal.trim());
      currentVal = '';
    } else {
      currentVal += char;
    }
  }
  values.push(currentVal.trim());
  return values.map(val => val.startsWith('"') && val.endsWith('"') ? val.slice(1, -1) : val);
}

migratePincodes();