'use strict';

const fs   = require('fs');
const path = require('path');

const DATA_FILE = path.join(__dirname, '..', 'data', 'stats.json');

const EMPTY = () => ({
  total_sent:       0,
  total_redirected: 0,
  total_errors:     0,
  total_searches:   0,
  by_provider:      Object.create(null), // null prototype — previene prototype pollution
  updated:          null,
});

function load() {
  try {
    return JSON.parse(fs.readFileSync(DATA_FILE, 'utf8'));
  } catch {
    return EMPTY();
  }
}

function save(data) {
  const dir = path.dirname(DATA_FILE);
  fs.mkdirSync(dir, { recursive: true });
  const tmp = DATA_FILE + '.tmp';
  fs.writeFileSync(tmp, JSON.stringify(data, null, 2), 'utf8');
  fs.renameSync(tmp, DATA_FILE); // atómico en mismo filesystem
}

function record({ type, provider }) {
  const s = load();

  if (type === 'sent')       s.total_sent++;
  else if (type === 'redirected') s.total_redirected++;
  else if (type === 'error') s.total_errors++;
  else if (type === 'search') s.total_searches++;

  if (provider && (type === 'sent' || type === 'redirected')) {
    if (!s.by_provider[provider]) s.by_provider[provider] = { sent: 0, redirected: 0 };
    if (type === 'sent')       s.by_provider[provider].sent++;
    if (type === 'redirected') s.by_provider[provider].redirected++;
  }

  s.updated = new Date().toISOString().slice(0, 10);
  save(s);
}

function get() {
  return load();
}

module.exports = { record, get };