const express = require('express');
const { authenticateToken } = require('../middleware/auth');
const db = require('../database');

const router = express.Router();

// Get all sessions
router.get('/', (req, res) => {
  try {
    const sessions = db.prepare(`
      SELECT 
        s.*,
        COUNT(sg.id) as games_played
      FROM sessions s
      LEFT JOIN session_games sg ON s.id = sg.session_id
      GROUP BY s.id
      ORDER BY s.created_at DESC
    `).all();

    res.json(sessions);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Get active session
router.get('/active', (req, res) => {
  try {
    const session = db.prepare(`
      SELECT 
        s.*,
        COUNT(sg.id) as games_played
      FROM sessions s
      LEFT JOIN session_games sg ON s.id = sg.session_id
      WHERE s.is_active = 1
      GROUP BY s.id
      LIMIT 1
    `).get();

    // Return null instead of 404 when no active session
    if (!session) {
      return res.json({ session: null, message: 'No active session' });
    }

    res.json(session);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Get single session by ID
router.get('/:id', (req, res) => {
  try {
    const session = db.prepare(`
      SELECT 
        s.*,
        COUNT(sg.id) as games_played
      FROM sessions s
      LEFT JOIN session_games sg ON s.id = sg.session_id
      WHERE s.id = ?
      GROUP BY s.id
    `).get(req.params.id);

    if (!session) {
      return res.status(404).json({ error: 'Session not found' });
    }

    res.json(session);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Create new session (admin only)
router.post('/', authenticateToken, (req, res) => {
  try {
    const { notes } = req.body;

    // Check if there's already an active session
    const activeSession = db.prepare('SELECT id FROM sessions WHERE is_active = 1').get();
    
    if (activeSession) {
      return res.status(400).json({ 
        error: 'An active session already exists. Please close it before creating a new one.',
        activeSessionId: activeSession.id
      });
    }

    const stmt = db.prepare(`
      INSERT INTO sessions (notes, is_active) 
      VALUES (?, 1)
    `);

    const result = stmt.run(notes || null);
    const newSession = db.prepare('SELECT * FROM sessions WHERE id = ?').get(result.lastInsertRowid);

    res.status(201).json(newSession);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Close/finalize session (admin only)
router.post('/:id/close', authenticateToken, (req, res) => {
  try {
    const { notes } = req.body;

    const session = db.prepare('SELECT * FROM sessions WHERE id = ?').get(req.params.id);
    
    if (!session) {
      return res.status(404).json({ error: 'Session not found' });
    }

    if (session.is_active === 0) {
      return res.status(400).json({ error: 'Session is already closed' });
    }

    // Set all 'playing' games to 'played' before closing
    db.prepare(`
      UPDATE session_games 
      SET status = 'played'
      WHERE session_id = ? AND status = 'playing'
    `).run(req.params.id);

    const stmt = db.prepare(`
      UPDATE sessions 
      SET is_active = 0, closed_at = CURRENT_TIMESTAMP, notes = COALESCE(?, notes)
      WHERE id = ?
    `);

    stmt.run(notes || null, req.params.id);

    const closedSession = db.prepare('SELECT * FROM sessions WHERE id = ?').get(req.params.id);
    res.json(closedSession);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Delete session (admin only)
router.delete('/:id', authenticateToken, (req, res) => {
  try {
    const session = db.prepare('SELECT * FROM sessions WHERE id = ?').get(req.params.id);
    
    if (!session) {
      return res.status(404).json({ error: 'Session not found' });
    }

    // Prevent deletion of active sessions
    if (session.is_active === 1) {
      return res.status(400).json({ error: 'Cannot delete an active session. Please close it first.' });
    }

    // Delete related data first (cascade)
    db.prepare('DELETE FROM chat_logs WHERE session_id = ?').run(req.params.id);
    db.prepare('DELETE FROM session_games WHERE session_id = ?').run(req.params.id);
    
    // Delete the session
    db.prepare('DELETE FROM sessions WHERE id = ?').run(req.params.id);

    res.json({ message: 'Session deleted successfully', sessionId: parseInt(req.params.id) });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Get games played in a session
router.get('/:id/games', (req, res) => {
  try {
    const games = db.prepare(`
      SELECT 
        sg.*,
        g.pack_name,
        g.title,
        g.game_type,
        g.min_players,
        g.max_players,
        g.popularity_score
      FROM session_games sg
      JOIN games g ON sg.game_id = g.id
      WHERE sg.session_id = ?
      ORDER BY sg.played_at ASC
    `).all(req.params.id);

    res.json(games);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Add game to session (admin only)
router.post('/:id/games', authenticateToken, (req, res) => {
  try {
    const { game_id, manually_added } = req.body;

    if (!game_id) {
      return res.status(400).json({ error: 'game_id is required' });
    }

    // Verify session exists and is active
    const session = db.prepare('SELECT * FROM sessions WHERE id = ?').get(req.params.id);
    
    if (!session) {
      return res.status(404).json({ error: 'Session not found' });
    }

    if (session.is_active === 0) {
      return res.status(400).json({ error: 'Cannot add games to a closed session' });
    }

    // Verify game exists
    const game = db.prepare('SELECT * FROM games WHERE id = ?').get(game_id);
    
    if (!game) {
      return res.status(404).json({ error: 'Game not found' });
    }

    // Set all current 'playing' games to 'played' (except skipped ones)
    db.prepare(`
      UPDATE session_games 
      SET status = CASE 
        WHEN status = 'skipped' THEN 'skipped'
        ELSE 'played'
      END
      WHERE session_id = ? AND status = 'playing'
    `).run(req.params.id);

    // Add game to session with 'playing' status
    const stmt = db.prepare(`
      INSERT INTO session_games (session_id, game_id, manually_added, status)
      VALUES (?, ?, ?, 'playing')
    `);

    const result = stmt.run(req.params.id, game_id, manually_added ? 1 : 0);

    // Increment play count for the game
    db.prepare('UPDATE games SET play_count = play_count + 1 WHERE id = ?').run(game_id);

    const sessionGame = db.prepare(`
      SELECT 
        sg.*,
        g.pack_name,
        g.title,
        g.game_type
      FROM session_games sg
      JOIN games g ON sg.game_id = g.id
      WHERE sg.id = ?
    `).get(result.lastInsertRowid);

    res.status(201).json(sessionGame);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Import chat log and process popularity (admin only)
router.post('/:id/chat-import', authenticateToken, (req, res) => {
  try {
    const { chatData } = req.body;

    if (!chatData || !Array.isArray(chatData)) {
      return res.status(400).json({ error: 'chatData must be an array' });
    }

    const session = db.prepare('SELECT * FROM sessions WHERE id = ?').get(req.params.id);
    
    if (!session) {
      return res.status(404).json({ error: 'Session not found' });
    }

    // Get all games played in this session with timestamps
    const sessionGames = db.prepare(`
      SELECT sg.game_id, sg.played_at, g.title
      FROM session_games sg
      JOIN games g ON sg.game_id = g.id
      WHERE sg.session_id = ?
      ORDER BY sg.played_at ASC
    `).all(req.params.id);

    if (sessionGames.length === 0) {
      return res.status(400).json({ error: 'No games played in this session to match votes against' });
    }

    let votesProcessed = 0;
    const votesByGame = {};

    const insertChatLog = db.prepare(`
      INSERT INTO chat_logs (session_id, chatter_name, message, timestamp, parsed_vote)
      VALUES (?, ?, ?, ?, ?)
    `);

    const updatePopularity = db.prepare(`
      UPDATE games SET popularity_score = popularity_score + ? WHERE id = ?
    `);

    const processVotes = db.transaction((messages) => {
      for (const msg of messages) {
        const { username, message, timestamp } = msg;

        if (!username || !message || !timestamp) {
          continue;
        }

        // Check for vote patterns
        let vote = null;
        if (message.includes('thisgame++')) {
          vote = 'thisgame++';
        } else if (message.includes('thisgame--')) {
          vote = 'thisgame--';
        }

        // Insert into chat logs
        insertChatLog.run(
          req.params.id,
          username,
          message,
          timestamp,
          vote
        );

        if (vote) {
          // Find which game was being played at this timestamp
          const messageTime = new Date(timestamp).getTime();
          let matchedGame = null;

          for (let i = 0; i < sessionGames.length; i++) {
            const currentGame = sessionGames[i];
            const nextGame = sessionGames[i + 1];
            
            const currentGameTime = new Date(currentGame.played_at).getTime();
            
            if (nextGame) {
              const nextGameTime = new Date(nextGame.played_at).getTime();
              if (messageTime >= currentGameTime && messageTime < nextGameTime) {
                matchedGame = currentGame;
                break;
              }
            } else {
              // Last game in session
              if (messageTime >= currentGameTime) {
                matchedGame = currentGame;
                break;
              }
            }
          }

          if (matchedGame) {
            const points = vote === 'thisgame++' ? 1 : -1;
            updatePopularity.run(points, matchedGame.game_id);
            
            if (!votesByGame[matchedGame.game_id]) {
              votesByGame[matchedGame.game_id] = {
                title: matchedGame.title,
                upvotes: 0,
                downvotes: 0
              };
            }
            
            if (points > 0) {
              votesByGame[matchedGame.game_id].upvotes++;
            } else {
              votesByGame[matchedGame.game_id].downvotes++;
            }
            
            votesProcessed++;
          }
        }
      }
    });

    processVotes(chatData);

    res.json({
      message: 'Chat log imported and processed successfully',
      messagesImported: chatData.length,
      votesProcessed,
      votesByGame
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Update session game status (admin only)
router.patch('/:sessionId/games/:gameId/status', authenticateToken, (req, res) => {
  try {
    const { status } = req.body;
    const { sessionId, gameId } = req.params;

    if (!status || !['playing', 'played', 'skipped'].includes(status)) {
      return res.status(400).json({ error: 'Invalid status. Must be playing, played, or skipped' });
    }

    // If setting to 'playing', first set all other games in session to 'played' or keep as 'skipped'
    if (status === 'playing') {
      db.prepare(`
        UPDATE session_games 
        SET status = CASE 
          WHEN status = 'skipped' THEN 'skipped'
          ELSE 'played'
        END
        WHERE session_id = ? AND status = 'playing'
      `).run(sessionId);
    }

    // Update the specific game
    const result = db.prepare(`
      UPDATE session_games 
      SET status = ? 
      WHERE session_id = ? AND id = ?
    `).run(status, sessionId, gameId);

    if (result.changes === 0) {
      return res.status(404).json({ error: 'Session game not found' });
    }

    res.json({ message: 'Status updated successfully', status });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Delete session game (admin only)
router.delete('/:sessionId/games/:gameId', authenticateToken, (req, res) => {
  try {
    const { sessionId, gameId } = req.params;

    const result = db.prepare(`
      DELETE FROM session_games 
      WHERE session_id = ? AND id = ?
    `).run(sessionId, gameId);

    if (result.changes === 0) {
      return res.status(404).json({ error: 'Session game not found' });
    }

    res.json({ message: 'Game removed from session successfully' });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

module.exports = router;