const express = require('express');
const db = require('../db');
const router = express.Router();

// GET /api/notes — list all
router.get('/', (req, res) => {
  try {
    const rows = db.prepare('SELECT * FROM notes ORDER BY updated_at DESC').all();
    res.json(rows);
  } catch (err) {
    console.error('[notes] list error:', err.message);
    res.status(500).json({ error: err.message });
  }
});

// POST /api/notes — create
router.post('/', (req, res) => {
  const { title, content_markdown, tags = [] } = req.body;
  if (!title) {
    return res.status(400).json({ error: 'title is required' });
  }

  let tagsJson;
  try {
    tagsJson = JSON.stringify(Array.isArray(tags) ? tags : []);
  } catch {
    return res.status(400).json({ error: 'tags must be a valid array' });
  }

  try {
    const info = db.prepare(`
      INSERT INTO notes (title, content_markdown, tags)
      VALUES (?, ?, ?)
    `).run(title, content_markdown || '', tagsJson);

    const row = db.prepare('SELECT * FROM notes WHERE id = ?').get(info.lastInsertRowid);
    res.status(201).json(row);
  } catch (err) {
    console.error('[notes] create error:', err.message);
    res.status(500).json({ error: err.message });
  }
});

// PUT /api/notes/:id — update (updated_at auto-set)
router.put('/:id', (req, res) => {
  const id = parseInt(req.params.id, 10);
  if (Number.isNaN(id)) {
    return res.status(400).json({ error: 'Invalid note id' });
  }

  const { title, content_markdown, tags } = req.body;

  let tagsJson = undefined;
  if (tags !== undefined) {
    try {
      tagsJson = JSON.stringify(Array.isArray(tags) ? tags : []);
    } catch {
      return res.status(400).json({ error: 'tags must be a valid array' });
    }
  }

  try {
    const existing = db.prepare('SELECT * FROM notes WHERE id = ?').get(id);
    if (!existing) {
      return res.status(404).json({ error: 'Note not found' });
    }

    db.prepare(`
      UPDATE notes SET
        title = COALESCE(?, title),
        content_markdown = COALESCE(?, content_markdown),
        tags = COALESCE(?, tags),
        updated_at = datetime('now')
      WHERE id = ?
    `).run(title ?? null, content_markdown ?? null, tagsJson ?? null, id);

    const row = db.prepare('SELECT * FROM notes WHERE id = ?').get(id);
    res.json(row);
  } catch (err) {
    console.error('[notes] update error:', err.message);
    res.status(500).json({ error: err.message });
  }
});

// DELETE /api/notes/:id
router.delete('/:id', (req, res) => {
  const id = parseInt(req.params.id, 10);
  if (Number.isNaN(id)) {
    return res.status(400).json({ error: 'Invalid note id' });
  }

  try {
    const info = db.prepare('DELETE FROM notes WHERE id = ?').run(id);
    if (info.changes === 0) {
      return res.status(404).json({ error: 'Note not found' });
    }
    res.json({ deleted: true });
  } catch (err) {
    console.error('[notes] delete error:', err.message);
    res.status(500).json({ error: err.message });
  }
});

module.exports = router;