import { Router } from 'express';
import { db } from '../db.js';

export const statsRouter = Router();

// GET /api/stats/overview
// Bundles everything the "Overview" panel needs in one call, since the
// frontend renders all three columns (users / activity / general) together.
statsRouter.get('/overview', (req, res) => {
  const currentUsers = db
    .prepare(`
      SELECT u.id, u.username, s.started_at
      FROM sessions s
      JOIN users u ON u.id = s.user_id
      WHERE s.ended_at IS NULL
      ORDER BY s.started_at DESC
      LIMIT 20
    `)
    .all();

  const recentActivity = db
    .prepare('SELECT id, description, created_at FROM activity_log ORDER BY created_at DESC LIMIT 20')
    .all();

  const statRows = db.prepare('SELECT key, value FROM site_stats').all();
  const stats = Object.fromEntries(statRows.map((r) => [r.key, r.value]));

  const totalUsers = db.prepare('SELECT COUNT(*) AS count FROM users').get().count;
  const mostRecentUser = db
    .prepare('SELECT username, id FROM users ORDER BY joined_at DESC LIMIT 1')
    .get();

  res.json({
    currentUsers,
    recentActivity,
    general: {
      users: { total: totalUsers, mostRecent: mostRecentUser ?? null },
      reports: {
        named: stats.reports_named ?? '0',
        associated: stats.reports_associated ?? '0',
        logged: stats.reports_logged ?? '0',
      },
      build: {
        pipeline: stats.build_pipeline ?? 'unknown',
        buildNumber: stats.build_number ?? '0',
        version: stats.version ?? '0.0.0',
      },
    },
  });
});

// GET /api/stats/users  (just the current-users list, if you want it standalone)
statsRouter.get('/users', (req, res) => {
  const rows = db
    .prepare(`
      SELECT u.id, u.username, s.started_at
      FROM sessions s
      JOIN users u ON u.id = s.user_id
      WHERE s.ended_at IS NULL
      ORDER BY s.started_at DESC
    `)
    .all();
  res.json(rows);
});

// POST /api/stats/session/start  { username }
statsRouter.post('/session/start', (req, res) => {
  const { username } = req.body ?? {};
  if (!username) return res.status(400).json({ error: 'username is required' });

  let user = db.prepare('SELECT id FROM users WHERE username = ?').get(username);
  if (!user) {
    const result = db.prepare('INSERT INTO users (username) VALUES (?)').run(username);
    user = { id: result.lastInsertRowid };
  }
  db.prepare('UPDATE users SET last_seen_at = strftime(\'%Y-%m-%dT%H:%M:%fZ\', \'now\') WHERE id = ?').run(user.id);
  const session = db.prepare('INSERT INTO sessions (user_id) VALUES (?)').run(user.id);
  res.status(201).json({ sessionId: session.lastInsertRowid, userId: user.id });
});

// POST /api/stats/session/end  { sessionId }
statsRouter.post('/session/end', (req, res) => {
  const { sessionId } = req.body ?? {};
  if (!sessionId) return res.status(400).json({ error: 'sessionId is required' });
  const result = db
    .prepare('UPDATE sessions SET ended_at = strftime(\'%Y-%m-%dT%H:%M:%fZ\', \'now\') WHERE id = ? AND ended_at IS NULL')
    .run(sessionId);
  if (result.changes === 0) return res.status(404).json({ error: 'no active session with that id' });
  res.status(204).end();
});