/**
 * ai.js — AI draft reply via Anthropic SDK
 */
const Anthropic = require('@anthropic-ai/sdk').default;
const fs = require('fs');
const path = require('path');

let client = null;

function initAI(apiKey) {
  if (!apiKey) {
    // Try .env file
    try {
      const envPath = path.join(__dirname, '.env');
      const content = fs.readFileSync(envPath, 'utf-8');
      for (const line of content.split('\n')) {
        const m = line.match(/^ANTHROPIC_API_KEY=(.+)/);
        if (m) { apiKey = m[1].trim(); break; }
      }
    } catch {}
  }
  if (!apiKey) return false;
  client = new Anthropic({ apiKey });
  return true;
}

function isReady() { return client !== null; }

const SYSTEM = `You are a professional GitHub project maintainer for "GeneralNoCodeDP".
Draft replies to GitHub issues and pull requests.
- Be professional, helpful, concise
- Reply in English
- Bug reports: acknowledge, ask for repro steps if missing
- Feature requests: thank reporter, explain consideration
- PRs: review description, constructive feedback
- Keep under 200 words unless complexity demands more
- Use markdown where appropriate`;

async function draftReply({ type, title, body, comments, repoName }) {
  if (!client) throw new Error('AI not initialized');

  const commentText = comments?.length
    ? '\n### Comments:\n' + comments.map(c => `**${c.author}**: ${c.body}`).join('\n\n---\n')
    : '';

  const response = await client.messages.create({
    model: 'claude-sonnet-4-5-20241022',
    max_tokens: 1024,
    system: SYSTEM,
    messages: [{ role: 'user', content: `Repo: ${repoName}\n## ${type} — ${title}\n\n${body || '(empty)'}\n${commentText}\n\nDraft a reply:` }],
  });

  const draft = response.content[0].text;
  const confidence = (comments?.length || 0) > 5 ? 'low' : (body?.length || 0) > 2000 ? 'medium' : 'high';
  return { draft, confidence };
}

module.exports = { initAI, isReady, draftReply };