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

const router = express.Router();

// Get vote history with filtering and pagination
router.get('/', (req, res) => {
  try {
    let { session_id, game_id, username, vote_type, page, limit } = req.query;

    page = parseInt(page) || 1;
    limit = Math.min(parseInt(limit) || 50, 100);
    if (page < 1) page = 1;
    if (limit < 1) limit = 50;
    const offset = (page - 1) * limit;

    const where = [];
    const params = [];

    if (session_id !== undefined) {
      const sid = parseInt(session_id);
      if (isNaN(sid)) {
        return res.status(400).json({ error: 'session_id must be an integer' });
      }
      where.push('lv.session_id = ?');
      params.push(sid);
    }

    if (game_id !== undefined) {
      const gid = parseInt(game_id);
      if (isNaN(gid)) {
        return res.status(400).json({ error: 'game_id must be an integer' });
      }
      where.push('lv.game_id = ?');
      params.push(gid);
    }

    if (username) {
      where.push('lv.username = ?');
      params.push(username);
    }

    if (vote_type !== undefined) {
      if (vote_type !== 'up' && vote_type !== 'down') {
        return res.status(400).json({ error: 'vote_type must be "up" or "down"' });
      }
      where.push('lv.vote_type = ?');
      params.push(vote_type === 'up' ? 1 : -1);
    }

    const whereClause = where.length > 0 ? 'WHERE ' + where.join(' AND ') : '';

    const countResult = db.prepare(
      `SELECT COUNT(*) as total FROM live_votes lv ${whereClause}`
    ).get(...params);

    const total = countResult.total;
    const total_pages = Math.ceil(total / limit) || 0;

    const votes = db.prepare(`
      SELECT
        lv.id,
        lv.session_id,
        lv.game_id,
        g.title AS game_title,
        g.pack_name,
        lv.username,
        CASE WHEN lv.vote_type = 1 THEN 'up' ELSE 'down' END AS vote_type,
        lv.timestamp,
        lv.created_at
      FROM live_votes lv
      JOIN games g ON lv.game_id = g.id
      ${whereClause}
      ORDER BY lv.timestamp DESC
      LIMIT ? OFFSET ?
    `).all(...params, limit, offset);

    res.json({
      votes,
      pagination: { page, limit, total, total_pages },
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Live vote endpoint - receives real-time votes from bot
router.post('/live', authenticateToken, (req, res) => {
  try {
    const { username, vote, timestamp } = req.body;

    // Validate payload
    if (!username || !vote || !timestamp) {
      return res.status(400).json({ 
        error: 'Missing required fields: username, vote, timestamp' 
      });
    }

    if (vote !== 'up' && vote !== 'down') {
      return res.status(400).json({ 
        error: 'vote must be either "up" or "down"' 
      });
    }

    // Validate timestamp format
    const voteTimestamp = new Date(timestamp);
    if (isNaN(voteTimestamp.getTime())) {
      return res.status(400).json({ 
        error: 'Invalid timestamp format. Use ISO 8601 format (e.g., 2025-11-01T20:30:00Z)' 
      });
    }

    // Check for active session
    const activeSession = db.prepare(`
      SELECT * FROM sessions WHERE is_active = 1 LIMIT 1
    `).get();

    if (!activeSession) {
      return res.status(404).json({ 
        error: 'No active session found' 
      });
    }

    // Get all games played in this session with timestamps
    const sessionGames = db.prepare(`
      SELECT sg.game_id, sg.played_at, g.title, g.upvotes, g.downvotes, 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(activeSession.id);

    if (sessionGames.length === 0) {
      return res.status(404).json({ 
        error: 'No games have been played in the active session yet' 
      });
    }

    // Match vote timestamp to the correct game using interval logic
    const voteTime = voteTimestamp.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 (voteTime >= currentGameTime && voteTime < nextGameTime) {
          matchedGame = currentGame;
          break;
        }
      } else {
        // Last game in session - vote belongs here if timestamp is after this game started
        if (voteTime >= currentGameTime) {
          matchedGame = currentGame;
          break;
        }
      }
    }

    if (!matchedGame) {
      return res.status(404).json({ 
        error: 'Vote timestamp does not match any game in the active session',
        debug: {
          voteTimestamp: timestamp,
          sessionGames: sessionGames.map(g => ({
            title: g.title,
            played_at: g.played_at
          }))
        }
      });
    }

    // Check for duplicate vote (within 1 second window)
    // Get the most recent vote from this user
    const lastVote = db.prepare(`
      SELECT timestamp FROM live_votes 
      WHERE username = ? 
      ORDER BY created_at DESC
      LIMIT 1
    `).get(username);

    if (lastVote) {
      const lastVoteTime = new Date(lastVote.timestamp).getTime();
      const currentVoteTime = new Date(timestamp).getTime();
      const timeDiffSeconds = Math.abs(currentVoteTime - lastVoteTime) / 1000;
      
      if (timeDiffSeconds <= 1) {
        return res.status(409).json({ 
          error: 'Duplicate vote detected (within 1 second of previous vote)',
          message: 'Please wait at least 1 second between votes',
          timeSinceLastVote: timeDiffSeconds
        });
      }
    }

    // Process the vote in a transaction
    const voteType = vote === 'up' ? 1 : -1;

    const insertVote = db.prepare(`
      INSERT INTO live_votes (session_id, game_id, username, vote_type, timestamp)
      VALUES (?, ?, ?, ?, ?)
    `);

    const updateUpvote = db.prepare(`
      UPDATE games 
      SET upvotes = upvotes + 1, popularity_score = popularity_score + 1 
      WHERE id = ?
    `);

    const updateDownvote = db.prepare(`
      UPDATE games 
      SET downvotes = downvotes + 1, popularity_score = popularity_score - 1 
      WHERE id = ?
    `);

    const processVote = db.transaction(() => {
      insertVote.run(activeSession.id, matchedGame.game_id, username, voteType, timestamp);
      
      if (voteType === 1) {
        updateUpvote.run(matchedGame.game_id);
      } else {
        updateDownvote.run(matchedGame.game_id);
      }
    });

    processVote();

    // Get updated game stats
    const updatedGame = db.prepare(`
      SELECT id, title, upvotes, downvotes, popularity_score
      FROM games
      WHERE id = ?
    `).get(matchedGame.game_id);

    // Get session stats
    const sessionStats = 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(activeSession.id);

    res.json({
      success: true,
      message: 'Vote recorded successfully',
      session: {
        id: sessionStats.id,
        games_played: sessionStats.games_played
      },
      game: {
        id: updatedGame.id,
        title: updatedGame.title,
        upvotes: updatedGame.upvotes,
        downvotes: updatedGame.downvotes,
        popularity_score: updatedGame.popularity_score
      },
      vote: {
        username: username,
        type: vote,
        timestamp: timestamp
      }
    });

  } catch (error) {
    console.error('Error processing live vote:', error);
    res.status(500).json({ error: error.message });
  }
});

module.exports = router;