/**
 * TASKMATE - Link Routes
 * ======================
 * CRUD für Links/URLs
 */

const express = require('express');
const router = express.Router();
const { getDb } = require('../database');
const logger = require('../utils/logger');
const { validators, stripHtml } = require('../middleware/validation');

/**
 * Hilfsfunktion: Link-Icon basierend auf URL
 */
function getLinkIcon(url) {
  try {
    const hostname = new URL(url).hostname.toLowerCase();
    if (hostname.includes('youtube') || hostname.includes('youtu.be')) return 'youtube';
    if (hostname.includes('github')) return 'github';
    if (hostname.includes('gitlab')) return 'gitlab';
    if (hostname.includes('figma')) return 'figma';
    if (hostname.includes('drive.google')) return 'google-drive';
    if (hostname.includes('docs.google')) return 'google-docs';
    if (hostname.includes('notion')) return 'notion';
    if (hostname.includes('trello')) return 'trello';
    if (hostname.includes('slack')) return 'slack';
    if (hostname.includes('jira') || hostname.includes('atlassian')) return 'jira';
    return 'link';
  } catch {
    return 'link';
  }
}

/**
 * GET /api/links/:taskId
 * Alle Links einer Aufgabe
 */
router.get('/:taskId', (req, res) => {
  try {
    const db = getDb();
    const links = db.prepare(`
      SELECT l.*, u.display_name as creator_name
      FROM links l
      LEFT JOIN users u ON l.created_by = u.id
      WHERE l.task_id = ?
      ORDER BY l.created_at DESC
    `).all(req.params.taskId);

    res.json(links.map(l => ({
      id: l.id,
      taskId: l.task_id,
      title: l.title,
      url: l.url,
      icon: getLinkIcon(l.url),
      createdBy: l.created_by,
      creatorName: l.creator_name,
      createdAt: l.created_at
    })));
  } catch (error) {
    logger.error('Fehler beim Abrufen der Links:', { error: error.message });
    res.status(500).json({ error: 'Interner Serverfehler' });
  }
});

/**
 * POST /api/links
 * Neuen Link erstellen
 */
router.post('/', (req, res) => {
  try {
    const { taskId, title, url } = req.body;

    // Validierung
    const urlError = validators.required(url, 'URL') || validators.url(url, 'URL');
    if (urlError) {
      return res.status(400).json({ error: urlError });
    }

    if (title) {
      const titleError = validators.maxLength(title, 100, 'Titel');
      if (titleError) {
        return res.status(400).json({ error: titleError });
      }
    }

    const db = getDb();

    // Task prüfen
    const task = db.prepare('SELECT * FROM tasks WHERE id = ?').get(taskId);
    if (!task) {
      return res.status(404).json({ error: 'Aufgabe nicht gefunden' });
    }

    const sanitizedTitle = title ? stripHtml(title) : null;

    const result = db.prepare(`
      INSERT INTO links (task_id, title, url, created_by)
      VALUES (?, ?, ?, ?)
    `).run(taskId, sanitizedTitle, url, req.user.id);

    // Task updated_at aktualisieren
    db.prepare('UPDATE tasks SET updated_at = CURRENT_TIMESTAMP WHERE id = ?').run(taskId);

    const link = db.prepare(`
      SELECT l.*, u.display_name as creator_name
      FROM links l
      LEFT JOIN users u ON l.created_by = u.id
      WHERE l.id = ?
    `).get(result.lastInsertRowid);

    logger.info(`Link erstellt: ${url} für Task ${taskId}`);

    // WebSocket
    const io = req.app.get('io');
    io.to(`project:${task.project_id}`).emit('link:created', {
      taskId,
      link: {
        id: link.id,
        taskId: link.task_id,
        title: link.title,
        url: link.url,
        icon: getLinkIcon(link.url),
        createdBy: link.created_by,
        creatorName: link.creator_name,
        createdAt: link.created_at
      }
    });

    res.status(201).json({
      id: link.id,
      taskId: link.task_id,
      title: link.title,
      url: link.url,
      icon: getLinkIcon(link.url),
      createdBy: link.created_by,
      creatorName: link.creator_name,
      createdAt: link.created_at
    });
  } catch (error) {
    logger.error('Fehler beim Erstellen des Links:', { error: error.message });
    res.status(500).json({ error: 'Interner Serverfehler' });
  }
});

/**
 * PUT /api/links/:id
 * Link aktualisieren
 */
router.put('/:id', (req, res) => {
  try {
    const linkId = req.params.id;
    const { title, url } = req.body;

    const db = getDb();

    const existing = db.prepare('SELECT * FROM links WHERE id = ?').get(linkId);
    if (!existing) {
      return res.status(404).json({ error: 'Link nicht gefunden' });
    }

    // Validierung
    if (url) {
      const urlError = validators.url(url, 'URL');
      if (urlError) return res.status(400).json({ error: urlError });
    }
    if (title) {
      const titleError = validators.maxLength(title, 100, 'Titel');
      if (titleError) return res.status(400).json({ error: titleError });
    }

    db.prepare(`
      UPDATE links SET
        title = ?,
        url = COALESCE(?, url)
      WHERE id = ?
    `).run(title !== undefined ? stripHtml(title) : existing.title, url || null, linkId);

    const link = db.prepare(`
      SELECT l.*, u.display_name as creator_name
      FROM links l
      LEFT JOIN users u ON l.created_by = u.id
      WHERE l.id = ?
    `).get(linkId);

    const task = db.prepare('SELECT project_id FROM tasks WHERE id = ?').get(link.task_id);

    // WebSocket
    const io = req.app.get('io');
    io.to(`project:${task.project_id}`).emit('link:updated', {
      taskId: link.task_id,
      link: {
        id: link.id,
        title: link.title,
        url: link.url,
        icon: getLinkIcon(link.url)
      }
    });

    res.json({
      id: link.id,
      taskId: link.task_id,
      title: link.title,
      url: link.url,
      icon: getLinkIcon(link.url),
      createdBy: link.created_by,
      creatorName: link.creator_name,
      createdAt: link.created_at
    });
  } catch (error) {
    logger.error('Fehler beim Aktualisieren des Links:', { error: error.message });
    res.status(500).json({ error: 'Interner Serverfehler' });
  }
});

/**
 * DELETE /api/links/:id
 * Link löschen
 */
router.delete('/:id', (req, res) => {
  try {
    const linkId = req.params.id;
    const db = getDb();

    const link = db.prepare('SELECT * FROM links WHERE id = ?').get(linkId);
    if (!link) {
      return res.status(404).json({ error: 'Link nicht gefunden' });
    }

    const task = db.prepare('SELECT project_id FROM tasks WHERE id = ?').get(link.task_id);

    db.prepare('DELETE FROM links WHERE id = ?').run(linkId);

    // Task updated_at aktualisieren
    db.prepare('UPDATE tasks SET updated_at = CURRENT_TIMESTAMP WHERE id = ?').run(link.task_id);

    logger.info(`Link gelöscht: ${link.url}`);

    // WebSocket
    const io = req.app.get('io');
    io.to(`project:${task.project_id}`).emit('link:deleted', {
      taskId: link.task_id,
      linkId
    });

    res.json({ message: 'Link gelöscht' });
  } catch (error) {
    logger.error('Fehler beim Löschen des Links:', { error: error.message });
    res.status(500).json({ error: 'Interner Serverfehler' });
  }
});

module.exports = router;