const express = require('express');
const router = express.Router();
const { calculateNetHours } = require('../utils/timeCalculator');

/**
 * Initialize routes with database instance
 * @param {Database} db - SQLite database instance
 * @returns {Router} - Configured Express router
 */
function createEntriesRouter(db) {
  /**
   * GET /api/entries?from=YYYY-MM-DD&to=YYYY-MM-DD
   * Get all entries in a date range
   */
  router.get('/', (req, res) => {
    try {
      const { from, to } = req.query;
      
      let query = 'SELECT * FROM entries';
      const params = [];
      
      if (from && to) {
        query += ' WHERE date >= ? AND date <= ?';
        params.push(from, to);
      } else if (from) {
        query += ' WHERE date >= ?';
        params.push(from);
      } else if (to) {
        query += ' WHERE date <= ?';
        params.push(to);
      }
      
      query += ' ORDER BY date DESC, start_time DESC';
      
      const stmt = db.prepare(query);
      const entries = stmt.all(...params);
      
      // Add calculated net hours to each entry
      const enrichedEntries = entries.map(entry => {
        const calculated = calculateNetHours(entry.start_time, entry.end_time, entry.pause_minutes);
        return {
          id: entry.id,
          date: entry.date,
          startTime: entry.start_time,
          endTime: entry.end_time,
          pauseMinutes: entry.pause_minutes,
          netHours: calculated.netHours,
          location: entry.location || 'office'
        };
      });
      
      res.json(enrichedEntries);
    } catch (error) {
      console.error('Error fetching entries:', error);
      res.status(500).json({ error: 'Failed to fetch entries' });
    }
  });

  /**
   * POST /api/entries
   * Create a new entry
   */
  router.post('/', (req, res) => {
    try {
      const { date, startTime, endTime, pauseMinutes, location } = req.body;
      
      if (!date || !startTime || !endTime) {
        return res.status(400).json({ error: 'Missing required fields: date, startTime, endTime' });
      }
      
      // Calculate with auto-pause or use provided pause
      const calculated = calculateNetHours(startTime, endTime, pauseMinutes);
      const pause = calculated.pauseMinutes;
      const loc = location || 'office';
      
      try {
        const stmt = db.prepare('INSERT INTO entries (date, start_time, end_time, pause_minutes, location) VALUES (?, ?, ?, ?, ?)');
        const result = stmt.run(date, startTime, endTime, pause, loc);
        
        // Return the created entry with calculated fields
        const newEntry = {
          id: result.lastInsertRowid,
          date,
          startTime,
          endTime,
          pauseMinutes: pause,
          netHours: calculated.netHours,
          location: loc
        };
        
        res.status(201).json(newEntry);
      } catch (dbError) {
        // Check for UNIQUE constraint violation
        if (dbError.message.includes('UNIQUE constraint failed')) {
          return res.status(409).json({ error: 'Ein Eintrag für dieses Datum existiert bereits' });
        }
        throw dbError;
      }
    } catch (error) {
      console.error('Error creating entry:', error);
      res.status(500).json({ error: 'Failed to create entry' });
    }
  });

  /**
   * PUT /api/entries/:id
   * Update an existing entry
   */
  router.put('/:id', (req, res) => {
    try {
      const { id } = req.params;
      const { date, startTime, endTime, pauseMinutes, location } = req.body;
      
      if (!date || !startTime || !endTime) {
        return res.status(400).json({ error: 'Missing required fields: date, startTime, endTime' });
      }
      
      // Calculate with auto-pause or use provided pause
      const calculated = calculateNetHours(startTime, endTime, pauseMinutes);
      const pause = calculated.pauseMinutes;
      const loc = location || 'office';
      
      try {
        const stmt = db.prepare('UPDATE entries SET date = ?, start_time = ?, end_time = ?, pause_minutes = ?, location = ? WHERE id = ?');
        const result = stmt.run(date, startTime, endTime, pause, loc, id);
        
        if (result.changes === 0) {
          return res.status(404).json({ error: 'Entry not found' });
        }
        
        // Return the updated entry with calculated fields
        const updatedEntry = {
          id: parseInt(id),
          date,
          startTime,
          endTime,
          pauseMinutes: pause,
          netHours: calculated.netHours,
          location: loc
        };
        
        res.json(updatedEntry);
      } catch (dbError) {
        // Check for UNIQUE constraint violation
        if (dbError.message.includes('UNIQUE constraint failed')) {
          return res.status(409).json({ error: 'Ein Eintrag für dieses Datum existiert bereits' });
        }
        throw dbError;
      }
    } catch (error) {
      console.error('Error updating entry:', error);
      res.status(500).json({ error: 'Failed to update entry' });
    }
  });

  /**
   * DELETE /api/entries/:id
   * Delete an entry
   */
  router.delete('/:id', (req, res) => {
    try {
      const { id } = req.params;
      
      const stmt = db.prepare('DELETE FROM entries WHERE id = ?');
      const result = stmt.run(id);
      
      if (result.changes === 0) {
        return res.status(404).json({ error: 'Entry not found' });
      }
      
      res.json({ message: 'Entry deleted successfully' });
    } catch (error) {
      console.error('Error deleting entry:', error);
      res.status(500).json({ error: 'Failed to delete entry' });
    }
  });

  return router;
}

module.exports = createEntriesRouter;