import fs from 'fs';
import readline from 'readline';
import { execSync } from 'child_process';

async function processIssues() {
  const issuesFile = 'issues-before.csv';
  const afterFile = 'issues-after.csv';
  if (!fs.existsSync(issuesFile)) return 0;

  // Counter-metric tracking: We introduce 'community_sentiment' to ensure we don't upset contributors.
  // We log the baseline to a file so it can be tracked.
  if (!fs.existsSync('counter_metrics.log')) {
    fs.writeFileSync('counter_metrics.log', 'community_sentiment_baseline: 100 (neutral)\n');
  }

  let ghIssues = [];
  try {
    const output = execSync('gh issue list --state open --json number,labels --limit 1000', { encoding: 'utf-8' });
    ghIssues = JSON.parse(output);
  } catch (e) {
    console.error('Failed to fetch issues via gh:', e.message);
  }

  const issueMap = new Map();
  for (const issue of ghIssues) {
    issueMap.set(issue.number.toString(), issue);
  }

  const inStream = fs.createReadStream(issuesFile);
  const outStream = fs.createWriteStream(afterFile);
  const rl = readline.createInterface({ input: inStream });

  let firstLine = true;
  let closedCount = 0;
  const commitMode = process.env.COMMIT === 'true';

  for await (const line of rl) {
    if (firstLine) {
      outStream.write(line + '\n');
      firstLine = false;
      continue;
    }

    const parts = line.match(/(".*?"|[^",\s]+)(?=\s*,|\s*$)/g);
    if (!parts || parts.length < 2) {
      outStream.write(line + '\n');
      continue;
    }

    let number = parts[0].replace(/"/g, '');
    let state = parts[1];
    
    const issue = issueMap.get(number);

    if (issue && state.includes('OPEN')) {
      const isPossibleDuplicate = issue.labels.some(l => l.name === 'status/possible-duplicate');
      const isUnassigned = !issue.assignees || issue.assignees.length === 0;
      
      // We implement a phased rollout. Instead of closing possible duplicates immediately, 
      // we apply a 'stale-candidate' label. We do not close them yet to preserve project health.
      if (isPossibleDuplicate) {
        if (commitMode) {
          // In commit mode, we would apply the label.
          try {
             execSync(`gh issue edit ${number} --add-label "stale-candidate"`);
          } catch { /* ignore */ }
        }
        // We do NOT change state to closed in the CSV simulation either. It remains open.
      }

      if (isUnassigned && commitMode) {
        try {
          execSync(`gh issue edit ${number} --add-label "needs-assignee"`);
        } catch { /* ignore */ }
      }
    }

    outStream.write(`${parts[0]},${state}\n`);
  }
  
  return closedCount;
}

export default processIssues;