import express from 'express';
import { pool, withTransaction } from '../db.js';
import { hasRole } from '../middleware/auth.js';
import { visibleUserIds } from '../lib/access.js';
import { getSettings } from '../lib/settings.js';
import { loadEntries } from '../lib/entries.js';
import { parseDate } from '../lib/dates.js';
import { BookingError, isBillable, loadProjects, resolvePot } from '../lib/projects.js';

const router = express.Router();

function publicEntry(entry, showAmounts) {
  return {
    id: entry.id,
    user_id: entry.user_id,
    user_name: entry.user_name,
    project_id: entry.project_id,
    project_name: entry.project_name,
    project_code: entry.project_code,
    project_display: entry.project_display,
    project_type: entry.project_type,
    customer_id: entry.customer_id,
    customer_name: entry.customer_name,
    customer_color: entry.customer_color,
    task_id: entry.task_id,
    task_name: entry.task_name,
    pot_id: entry.pot_id,
    pot_label: entry.pot_label,
    entry_date: entry.entry_date,
    minutes: entry.minutes,
    note: entry.note,
    billable: entry.billable,
    amount: showAmounts ? entry.amount : null,
    created_at: entry.created_at,
    updated_at: entry.updated_at,
  };
}

router.get('/', async (req, res, next) => {
  try {
    const { from, to } = req.query;
    if (!parseDate(from) || !parseDate(to)) return res.status(400).json({ error: 'Zeitraum von/bis fehlt.' });
    let userIds = [req.user.id];
    if (req.query.user_id && Number(req.query.user_id) !== req.user.id) {
      const visible = await visibleUserIds(req.user);
      const wanted = Number(req.query.user_id);
      if (visible !== null && !visible.includes(wanted)) return res.status(403).json({ error: 'Keine Einsicht in diese Zeiten.' });
      userIds = [wanted];
    }
    const settings = await getSettings();
    // Optionaler Kundenfilter, damit die Listenansicht im Report den dort
    // gesetzten Filter uebernehmen kann.
    const customerId = req.query.customer_id ? Number(req.query.customer_id) : undefined;
    const entries = await loadEntries(settings, { from, to, userIds, customerId });
    res.json(entries.map((e) => publicEntry(e, hasRole(req.user, 'lead'))));
  } catch (err) {
    next(err);
  }
});

async function validate(conn, user, body, existing) {
  const projectId = Number(body.project_id ?? existing?.project_id);
  const date = body.entry_date ?? existing?.entry_date;
  const minutes = Number(body.minutes ?? existing?.minutes);
  const taskId = body.task_id !== undefined ? (body.task_id ? Number(body.task_id) : null) : existing?.task_id ?? null;
  const note = body.note !== undefined ? String(body.note || '').trim().slice(0, 1000) || null : existing?.note ?? null;

  if (user.role === 'admin' && !existing) throw new BookingError('Administratoren buchen keine Zeiten.');
  if (!parseDate(date)) throw new BookingError('Datum fehlt.');
  if (!Number.isInteger(minutes) || minutes < 1) throw new BookingError('Bitte eine Zeit größer 0:00 eingeben.');
  if (minutes > 24 * 60) throw new BookingError('Mehr als 24 Stunden an einem Tag gehen nicht.');

  const [projects] = await conn.query('SELECT * FROM pulse_projects WHERE id = ? LIMIT 1', [projectId]);
  const project = projects[0];
  if (!project) throw new BookingError('Projekt nicht gefunden.');
  if (!project.is_active) throw new BookingError('Das Projekt ist archiviert und nicht mehr buchbar.');

  // Gebucht wird nur auf zugewiesene Projekte - fuer jede Rolle.
  const [member] = await conn.query('SELECT 1 FROM pulse_project_members WHERE project_id = ? AND user_id = ?', [
    project.id,
    existing?.user_id ?? user.id,
  ]);
  if (!member.length) throw new BookingError('Dieses Projekt ist dir nicht zugewiesen.');

  let task = null;
  if (taskId) {
    const [tasks] = await conn.query('SELECT * FROM pulse_tasks WHERE id = ? AND project_id = ?', [taskId, project.id]);
    task = tasks[0];
    if (!task) throw new BookingError('Der Task gehört nicht zu diesem Projekt.');
    if (!task.is_active && task.id !== existing?.task_id) throw new BookingError('Der Task ist nicht mehr aktiv.');
  }

  const [[day]] = await conn.query(
    'SELECT COALESCE(SUM(minutes), 0) AS total FROM pulse_time_entries WHERE user_id = ? AND entry_date = ? AND id <> ?',
    [existing?.user_id ?? user.id, date, existing?.id || 0]
  );
  if (Number(day.total) + minutes > 24 * 60) throw new BookingError('An diesem Tag wären es mehr als 24 Stunden.');

  const billable = isBillable(project, task);
  const pot = await resolvePot(conn, project, date, minutes, existing?.id, billable);
  return { project, task, pot, date, minutes, note, billable: billable ? 1 : 0 };
}

async function respond(req, res, id, status) {
  const settings = await getSettings();
  const [[row]] = await pool.query('SELECT entry_date, user_id, project_id, pot_id FROM pulse_time_entries WHERE id = ?', [id]);
  const entries = await loadEntries(settings, { from: row.entry_date, to: row.entry_date, userIds: [row.user_id] });
  const entry = entries.find((e) => e.id === id);
  // Hinweis zum Topf gleich mitliefern, damit der Dialog warnen kann.
  let warning = null;
  if (row.pot_id) {
    const [project] = await loadProjects(settings, { where: 'p.id = ?', params: [row.project_id] });
    warning = project?.pots.find((p) => p.id === row.pot_id)?.warning ?? null;
  }
  res.status(status).json({ entry: publicEntry(entry, hasRole(req.user, 'lead')), warning });
}

router.post('/', async (req, res, next) => {
  try {
    const id = await withTransaction(async (conn) => {
      const v = await validate(conn, req.user, req.body || {}, null);
      const [result] = await conn.query(
        `INSERT INTO pulse_time_entries (user_id, project_id, task_id, pot_id, entry_date, minutes, note, billable)
         VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
        [req.user.id, v.project.id, v.task?.id ?? null, v.pot?.id ?? null, v.date, v.minutes, v.note, v.billable]
      );
      return result.insertId;
    });
    await respond(req, res, id, 201);
  } catch (err) {
    if (err instanceof BookingError) return res.status(422).json({ error: err.message });
    next(err);
  }
});

async function loadOwned(req) {
  const [rows] = await pool.query('SELECT * FROM pulse_time_entries WHERE id = ? LIMIT 1', [Number(req.params.id)]);
  const entry = rows[0];
  if (!entry) return { error: [404, 'Buchung nicht gefunden.'] };
  // Eigene Buchungen; Administratoren duerfen korrigieren.
  if (entry.user_id !== req.user.id && req.user.role !== 'admin') {
    return { error: [403, 'Nur eigene Buchungen können geändert werden.'] };
  }
  return { entry };
}

router.put('/:id', async (req, res, next) => {
  try {
    const { entry, error } = await loadOwned(req);
    if (error) return res.status(error[0]).json({ error: error[1] });
    await withTransaction(async (conn) => {
      const v = await validate(conn, req.user, req.body || {}, entry);
      await conn.query(
        `UPDATE pulse_time_entries SET project_id = ?, task_id = ?, pot_id = ?, entry_date = ?, minutes = ?, note = ?, billable = ?
          WHERE id = ?`,
        [v.project.id, v.task?.id ?? null, v.pot?.id ?? null, v.date, v.minutes, v.note, v.billable, entry.id]
      );
    });
    await respond(req, res, entry.id, 200);
  } catch (err) {
    if (err instanceof BookingError) return res.status(422).json({ error: err.message });
    next(err);
  }
});

router.delete('/:id', async (req, res, next) => {
  try {
    const { entry, error } = await loadOwned(req);
    if (error) return res.status(error[0]).json({ error: error[1] });
    await pool.query('DELETE FROM pulse_time_entries WHERE id = ?', [entry.id]);
    res.json({ ok: true });
  } catch (err) {
    next(err);
  }
});

export default router;