/**
 * logger.js — persistent JSONL log to ~/.logs/token-monitor/YYYY-MM-DD.jsonl
 */

import { appendFileSync, mkdirSync, existsSync, readFileSync } from 'fs';
import { homedir } from 'os';
import { join } from 'path';

export function logRun(data) {
  const dir = join(homedir(), '.logs', 'token-monitor');
  mkdirSync(dir, { recursive: true });
  const file = join(dir, `${new Date().toISOString().slice(0, 10)}.jsonl`);
  appendFileSync(file, JSON.stringify({ ts: new Date().toISOString(), ...data }) + '\n');
}

export function getLogPath() {
  const today = new Date().toISOString().slice(0, 10);
  return join(homedir(), '.logs', 'token-monitor', `${today}.jsonl`);
}

/**
 * Returns the last logged run if it was within maxAgeMinutes, otherwise null.
 * Skips test/empty entries (entries where providers has no typed providers).
 */
export function getCachedRun(maxAgeMinutes = 20) {
  const dir = join(homedir(), '.logs', 'token-monitor');
  const today = new Date().toISOString().slice(0, 10);
  const file = join(dir, `${today}.jsonl`);
  if (!existsSync(file)) return null;

  const lines = readFileSync(file, 'utf-8').trim().split('\n').filter(Boolean);

  for (let i = lines.length - 1; i >= 0; i--) {
    try {
      const entry = JSON.parse(lines[i]);
      const providers = entry.providers || {};
      // Skip test/empty entries — real entries have at least one provider with a type
      const hasRealData = Object.values(providers).some(p => p && p.type);
      if (!hasRealData) continue;

      const ageMinutes = (Date.now() - new Date(entry.ts).getTime()) / 60000;
      if (ageMinutes <= maxAgeMinutes) return entry;
      return null; // last real entry is too old
    } catch { continue; }
  }
  return null;
}