const express = require('express');
const { name, version } = require('./package.json');

const app = express();
const PORT = 3000;

app.use(express.json());

let todos = [
  { id: 1, title: 'Buy groceries', done: false, tags: [] },
  { id: 2, title: 'Walk the dog', done: true, tags: [] },
  { id: 3, title: 'Read a book', done: false, tags: [] },
];

let nextId = 4;

app.get('/healthz', (req, res) => {
  res.json({ ok: true });
});

app.get('/version', (req, res) => {
  res.json({ name, version });
});

app.get('/todos', (req, res) => {
  const { tag } = req.query;
  if (tag !== undefined) {
    return res.json(todos.filter(t => t.tags.includes(tag)));
  }
  res.json(todos);
});

app.post('/todos', (req, res) => {
  const { title, tags } = req.body;
  const todo = { id: nextId++, title, done: false, tags: Array.isArray(tags) ? tags : [] };
  todos.push(todo);
  res.status(201).json(todo);
});

app.delete('/todos/:id', (req, res) => {
  const id = parseInt(req.params.id, 10);
  const index = todos.findIndex(t => t.id === id);
  if (index === -1) {
    return res.status(404).end();
  }
  todos.splice(index, 1);
  res.status(204).end();
});

app.listen(PORT, () => {
  console.log(`Server listening on http://localhost:${PORT}`);
});