/**
 * TASKMATE - Proposals Routes
 * ===========================
 * API-Endpunkte fuer Vorschlaege und Genehmigungen
 */

const express = require('express');
const router = express.Router();
const { getDb } = require('../database');
const { authenticateToken, requireRegularUser, checkPermission } = require('../middleware/auth');
const logger = require('../utils/logger');
const notificationService = require('../services/notificationService');

// Alle Proposals-Routes erfordern Authentifizierung und regulaeren User (kein Admin)
router.use(authenticateToken);
router.use(requireRegularUser);

/**
 * GET /api/proposals - Alle Genehmigungen abrufen (projektbezogen)
 * Query-Parameter: sort = 'date' | 'alpha', archived = '0' | '1', projectId = number
 */
router.get('/', (req, res) => {
  try {
    const db = getDb();
    const sort = req.query.sort || 'date';
    const archived = req.query.archived === '1' ? 1 : 0;
    const projectId = req.query.projectId ? parseInt(req.query.projectId) : null;

    let orderBy;
    switch (sort) {
      case 'alpha':
        orderBy = 'p.title ASC';
        break;
      case 'date':
      default:
        orderBy = 'p.created_at DESC';
        break;
    }

    // Nur Genehmigungen des aktuellen Projekts laden
    let whereClause = 'p.archived = ?';
    const params = [archived];

    if (projectId) {
      whereClause += ' AND p.project_id = ?';
      params.push(projectId);
    }

    const proposals = db.prepare(`
      SELECT
        p.*,
        u.display_name as created_by_name,
        u.color as created_by_color,
        ua.display_name as approved_by_name,
        t.title as task_title,
        t.id as linked_task_id
      FROM proposals p
      LEFT JOIN users u ON p.created_by = u.id
      LEFT JOIN users ua ON p.approved_by = ua.id
      LEFT JOIN tasks t ON p.task_id = t.id
      WHERE ${whereClause}
      ORDER BY ${orderBy}
    `).all(...params);

    res.json(proposals);
  } catch (error) {
    logger.error('Fehler beim Abrufen der Genehmigungen:', error);
    res.status(500).json({ error: 'Fehler beim Abrufen der Genehmigungen' });
  }
});

/**
 * POST /api/proposals - Neue Genehmigung erstellen (projektbezogen)
 */
router.post('/', (req, res) => {
  try {
    const { title, description, taskId, projectId } = req.body;

    if (!title || title.trim().length === 0) {
      return res.status(400).json({ error: 'Titel erforderlich' });
    }

    if (!projectId) {
      return res.status(400).json({ error: 'Projekt erforderlich' });
    }

    const db = getDb();

    const result = db.prepare(`
      INSERT INTO proposals (title, description, created_by, task_id, project_id)
      VALUES (?, ?, ?, ?, ?)
    `).run(title.trim(), description?.trim() || null, req.user.id, taskId || null, projectId);

    const proposal = db.prepare(`
      SELECT
        p.*,
        u.display_name as created_by_name,
        u.color as created_by_color,
        t.title as task_title,
        t.id as linked_task_id
      FROM proposals p
      LEFT JOIN users u ON p.created_by = u.id
      LEFT JOIN tasks t ON p.task_id = t.id
      WHERE p.id = ?
    `).get(result.lastInsertRowid);

    logger.info(`Benutzer ${req.user.username} hat Genehmigung "${title}" erstellt`);

    // Benachrichtigungen an User mit 'genehmigung'-Berechtigung senden (persistent)
    const io = req.app.get('io');
    const usersWithPermission = db.prepare(`
      SELECT id FROM users
      WHERE role = 'user'
      AND permissions LIKE '%genehmigung%'
      AND id != ?
    `).all(req.user.id);

    usersWithPermission.forEach(user => {
      notificationService.create(user.id, 'approval:pending', {
        proposalId: proposal.id,
        proposalTitle: title.trim(),
        projectId: projectId,
        actorId: req.user.id,
        actorName: req.user.display_name || req.user.username
      }, io, true); // persistent = true
    });

    res.status(201).json(proposal);
  } catch (error) {
    logger.error('Fehler beim Erstellen der Genehmigung:', error);
    res.status(500).json({ error: 'Fehler beim Erstellen der Genehmigung' });
  }
});

/**
 * PUT /api/proposals/:id/approve - Genehmigung erteilen (nur mit Berechtigung)
 */
router.put('/:id/approve', checkPermission('genehmigung'), (req, res) => {
  try {
    const proposalId = parseInt(req.params.id);
    const { approved } = req.body;
    const db = getDb();

    // Genehmigung pruefen
    const proposal = db.prepare('SELECT * FROM proposals WHERE id = ?').get(proposalId);
    if (!proposal) {
      return res.status(404).json({ error: 'Genehmigung nicht gefunden' });
    }

    if (approved) {
      // Genehmigen
      db.prepare(`
        UPDATE proposals
        SET approved = 1, approved_by = ?, approved_at = CURRENT_TIMESTAMP
        WHERE id = ?
      `).run(req.user.id, proposalId);
      logger.info(`Benutzer ${req.user.username} hat Genehmigung ${proposalId} erteilt`);
    } else {
      // Genehmigung zurueckziehen
      db.prepare(`
        UPDATE proposals
        SET approved = 0, approved_by = NULL, approved_at = NULL
        WHERE id = ?
      `).run(proposalId);
      logger.info(`Benutzer ${req.user.username} hat Genehmigung ${proposalId} zurueckgezogen`);
    }

    // Aktualisierte Genehmigung zurueckgeben
    const updatedProposal = db.prepare(`
      SELECT
        p.*,
        u.display_name as created_by_name,
        u.color as created_by_color,
        ua.display_name as approved_by_name,
        t.title as task_title,
        t.id as linked_task_id
      FROM proposals p
      LEFT JOIN users u ON p.created_by = u.id
      LEFT JOIN users ua ON p.approved_by = ua.id
      LEFT JOIN tasks t ON p.task_id = t.id
      WHERE p.id = ?
    `).get(proposalId);

    // Benachrichtigungen senden
    const io = req.app.get('io');

    if (approved) {
      // Ersteller benachrichtigen dass genehmigt wurde
      if (proposal.created_by !== req.user.id) {
        notificationService.create(proposal.created_by, 'approval:granted', {
          proposalId: proposalId,
          proposalTitle: proposal.title,
          projectId: proposal.project_id,
          actorId: req.user.id,
          actorName: req.user.display_name || req.user.username
        }, io);
      }

      // Persistente Benachrichtigungen auflösen
      notificationService.resolvePersistent(proposalId);

      // Aktualisierte Zählung an alle User mit Berechtigung senden
      const usersWithPermission = db.prepare(`
        SELECT id FROM users
        WHERE role = 'user'
        AND permissions LIKE '%genehmigung%'
      `).all();

      usersWithPermission.forEach(user => {
        const count = notificationService.getUnreadCount(user.id);
        io.to(`user:${user.id}`).emit('notification:count', { count });
      });
    }

    res.json(updatedProposal);
  } catch (error) {
    logger.error('Fehler beim Genehmigen:', error);
    res.status(500).json({ error: 'Fehler beim Genehmigen' });
  }
});

/**
 * PUT /api/proposals/:id/archive - Genehmigung archivieren/wiederherstellen (nur mit Berechtigung)
 */
router.put('/:id/archive', checkPermission('genehmigung'), (req, res) => {
  try {
    const proposalId = parseInt(req.params.id);
    const { archived } = req.body;
    const db = getDb();

    // Genehmigung pruefen
    const proposal = db.prepare('SELECT * FROM proposals WHERE id = ?').get(proposalId);
    if (!proposal) {
      return res.status(404).json({ error: 'Genehmigung nicht gefunden' });
    }

    db.prepare(`
      UPDATE proposals
      SET archived = ?
      WHERE id = ?
    `).run(archived ? 1 : 0, proposalId);

    logger.info(`Benutzer ${req.user.username} hat Genehmigung ${proposalId} ${archived ? 'archiviert' : 'wiederhergestellt'}`);

    // Aktualisierte Genehmigung zurueckgeben
    const updatedProposal = db.prepare(`
      SELECT
        p.*,
        u.display_name as created_by_name,
        u.color as created_by_color,
        ua.display_name as approved_by_name,
        t.title as task_title,
        t.id as linked_task_id
      FROM proposals p
      LEFT JOIN users u ON p.created_by = u.id
      LEFT JOIN users ua ON p.approved_by = ua.id
      LEFT JOIN tasks t ON p.task_id = t.id
      WHERE p.id = ?
    `).get(proposalId);

    res.json(updatedProposal);
  } catch (error) {
    logger.error('Fehler beim Archivieren:', error);
    res.status(500).json({ error: 'Fehler beim Archivieren' });
  }
});

/**
 * DELETE /api/proposals/:id - Eigene Genehmigung loeschen
 */
router.delete('/:id', (req, res) => {
  try {
    const proposalId = parseInt(req.params.id);
    const db = getDb();

    // Genehmigung pruefen
    const proposal = db.prepare('SELECT * FROM proposals WHERE id = ?').get(proposalId);
    if (!proposal) {
      return res.status(404).json({ error: 'Genehmigung nicht gefunden' });
    }

    // Nur eigene Genehmigungen loeschen (oder mit genehmigung-Berechtigung)
    const permissions = req.user.permissions || [];
    if (proposal.created_by !== req.user.id && !permissions.includes('genehmigung')) {
      return res.status(403).json({ error: 'Nur eigene Genehmigungen koennen geloescht werden' });
    }

    db.prepare('DELETE FROM proposals WHERE id = ?').run(proposalId);

    logger.info(`Benutzer ${req.user.username} hat Genehmigung ${proposalId} geloescht`);

    res.json({ success: true });
  } catch (error) {
    logger.error('Fehler beim Loeschen der Genehmigung:', error);
    res.status(500).json({ error: 'Fehler beim Loeschen der Genehmigung' });
  }
});

module.exports = router;