import { pathToFileURL } from 'node:url';
import { createMessage, textOf, configFromEnv } from './client.mjs';

const tools = [{
  name: 'get_github_repository',
  description: 'Read current public GitHub repository metadata. Returns stars, open issues (including pull requests), description, and URL. This does not modify the repository.',
  input_schema: {
    type: 'object', properties: {
      owner: { type: 'string', description: 'Repository owner, such as anthropics.' },
      repo: { type: 'string', description: 'Repository name, such as claude-code.' }
    }, required: ['owner', 'repo'], additionalProperties: false
  }
}];

export async function runTool(call, fetchImpl = fetch) {
  if (call.name !== 'get_github_repository') throw new Error('Unknown tool.');
  const { owner, repo } = call.input || {};
  const valid = (value) => typeof value === 'string' && /^[A-Za-z0-9_.-]{1,100}$/.test(value) && value !== '.' && value !== '..';
  if (!valid(owner) || !valid(repo)) throw new Error('Invalid repository coordinates.');
  // Fixed host and validated path prevent model-supplied arbitrary URL requests.
  const response = await fetchImpl(`https://api.github.com/repos/${encodeURIComponent(owner)}/${encodeURIComponent(repo)}`, {
    headers: { accept: 'application/vnd.github+json', 'user-agent': 'HowUseClaude-Tutorial', 'x-github-api-version': '2022-11-28' },
    signal: AbortSignal.timeout(10000)
  });
  if (!response.ok) {
    await response.body?.cancel();
    throw new Error(`GitHub HTTP ${response.status}.`);
  }
  const data = await response.json();
  return JSON.stringify({ name: data.full_name, description: data.description,
    stars: data.stargazers_count, open_issues_including_prs: data.open_issues_count,
    url: data.html_url, retrieved_at: new Date().toISOString() });
}

export async function answerWithTools(question, config, dependencies = {}) {
  const send = dependencies.send || createMessage;
  const execute = dependencies.execute || runTool;
  const messages = [{ role: 'user', content: question }];
  // Each round can incur model usage. Bound both rounds and calls per response.
  for (let round = 0; round < 5; round += 1) {
    const response = await send({ ...config, tools, messages });
    if (response.stop_reason === 'end_turn') return textOf(response);
    if (response.stop_reason !== 'tool_use') throw new Error(`Incomplete response: ${response.stop_reason}`);
    const calls = response.content.filter((block) => block.type === 'tool_use');
    if (!calls.length || calls.length > 4) throw new Error('Unexpected tool call count.');
    messages.push({ role: 'assistant', content: response.content });
    const results = [];
    for (const call of calls) {
      try {
        results.push({ type: 'tool_result', tool_use_id: call.id, content: await execute(call) });
      } catch (error) {
        results.push({ type: 'tool_result', tool_use_id: call.id, is_error: true, content: error.message });
      }
    }
    // All results immediately follow the assistant tool calls, in one user turn.
    messages.push({ role: 'user', content: results });
  }
  throw new Error('Tool round limit reached; inspect the task before trying again.');
}

if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
  try {
    console.log(await answerWithTools('Look up anthropics/claude-code on GitHub. Report its stars and source URL. Distinguish open issues from the combined issue/PR count.', configFromEnv()));
  } catch (error) {
    console.error(error.message);
    process.exitCode = 1;
  }
}