/**
 * Server Routes
 * API endpoints for servers (guilds), channels, and members
 */

const express = require('express');
const router = express.Router();
const { authenticateUser } = require('../middleware/auth');
const db = require('../database/db');
const { v4: uuidv4 } = require('uuid');

/**
 * GET /api/servers
 * Get all servers the current user is a member of
 */
router.get('/', authenticateUser, async (req, res) => {
  try {
    const result = await db.query(`
      SELECT s.*, sm.role, sm.nickname, sm.joined_at as member_joined_at
      FROM servers s
      INNER JOIN server_members sm ON s.id = sm.server_id
      WHERE sm.user_id = $1
      ORDER BY sm.joined_at ASC
    `, [req.user.id]);

    res.json({
      success: true,
      servers: result.rows
    });
  } catch (error) {
    console.error('Failed to get servers:', error);
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
});

/**
 * POST /api/servers
 * Create a new server
 */
router.post('/', authenticateUser, async (req, res) => {
  try {
    const { name, description, icon_url, is_public } = req.body;

    if (!name || name.trim().length === 0) {
      return res.status(400).json({
        success: false,
        error: 'Server name is required'
      });
    }

    // Generate invite code
    const invite_code = uuidv4().substring(0, 8).toUpperCase();

    // Create server
    const serverResult = await db.query(`
      INSERT INTO servers (name, description, icon_url, owner_id, invite_code, is_public)
      VALUES ($1, $2, $3, $4, $5, $6)
      RETURNING *
    `, [name.trim(), description || null, icon_url || null, req.user.id, invite_code, is_public || false]);

    const server = serverResult.rows[0];

    // Add owner as member
    await db.query(`
      INSERT INTO server_members (server_id, user_id, role)
      VALUES ($1, $2, 'owner')
    `, [server.id, req.user.id]);

    // Create default channels
    await db.query(`
      INSERT INTO channels (server_id, name, channel_type, position) VALUES
      ($1, 'general', 'text', 0),
      ($1, 'voice', 'voice', 1)
    `, [server.id]);

    res.json({
      success: true,
      server
    });
  } catch (error) {
    console.error('Failed to create server:', error);
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
});

/**
 * GET /api/servers/:id
 * Get server details
 */
router.get('/:id', authenticateUser, async (req, res) => {
  try {
    // Check if user is a member
    const memberCheck = await db.query(`
      SELECT * FROM server_members WHERE server_id = $1 AND user_id = $2
    `, [req.params.id, req.user.id]);

    if (memberCheck.rows.length === 0) {
      return res.status(403).json({
        success: false,
        error: 'Not a member of this server'
      });
    }

    const result = await db.query(`
      SELECT * FROM servers WHERE id = $1
    `, [req.params.id]);

    if (result.rows.length === 0) {
      return res.status(404).json({
        success: false,
        error: 'Server not found'
      });
    }

    res.json({
      success: true,
      server: result.rows[0]
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
});

/**
 * POST /api/servers/join/:inviteCode
 * Join a server by invite code
 */
router.post('/join/:inviteCode', authenticateUser, async (req, res) => {
  try {
    const server = await db.query(`
      SELECT * FROM servers WHERE invite_code = $1
    `, [req.params.inviteCode.toUpperCase()]);

    if (server.rows.length === 0) {
      return res.status(404).json({
        success: false,
        error: 'Invalid invite code'
      });
    }

    // Check if already a member
    const existingMember = await db.query(`
      SELECT * FROM server_members WHERE server_id = $1 AND user_id = $2
    `, [server.rows[0].id, req.user.id]);

    if (existingMember.rows.length > 0) {
      return res.json({
        success: true,
        server: server.rows[0],
        message: 'Already a member'
      });
    }

    // Add as member
    await db.query(`
      INSERT INTO server_members (server_id, user_id, role)
      VALUES ($1, $2, 'member')
    `, [server.rows[0].id, req.user.id]);

    // Update member count
    await db.query(`
      UPDATE servers SET member_count = member_count + 1 WHERE id = $1
    `, [server.rows[0].id]);

    res.json({
      success: true,
      server: server.rows[0]
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
});

/**
 * GET /api/servers/:id/channels
 * Get channels for a server
 */
router.get('/:id/channels', authenticateUser, async (req, res) => {
  try {
    // Check membership
    const memberCheck = await db.query(`
      SELECT * FROM server_members WHERE server_id = $1 AND user_id = $2
    `, [req.params.id, req.user.id]);

    if (memberCheck.rows.length === 0) {
      return res.status(403).json({
        success: false,
        error: 'Not a member of this server'
      });
    }

    const channels = await db.query(`
      SELECT * FROM channels WHERE server_id = $1 ORDER BY position ASC
    `, [req.params.id]);

    res.json({
      success: true,
      channels: channels.rows
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
});

/**
 * POST /api/servers/:id/channels
 * Create a new channel in a server
 */
router.post('/:id/channels', authenticateUser, async (req, res) => {
  try {
    const { name, description, channel_type } = req.body;

    // Check if user is admin/owner
    const memberCheck = await db.query(`
      SELECT * FROM server_members WHERE server_id = $1 AND user_id = $2 AND role IN ('owner', 'admin')
    `, [req.params.id, req.user.id]);

    if (memberCheck.rows.length === 0) {
      return res.status(403).json({
        success: false,
        error: 'Permission denied'
      });
    }

    // Get next position
    const posResult = await db.query(`
      SELECT COALESCE(MAX(position), -1) + 1 as next_pos FROM channels WHERE server_id = $1
    `, [req.params.id]);

    const channel = await db.query(`
      INSERT INTO channels (server_id, name, description, channel_type, position)
      VALUES ($1, $2, $3, $4, $5)
      RETURNING *
    `, [req.params.id, name, description || null, channel_type || 'text', posResult.rows[0].next_pos]);

    res.json({
      success: true,
      channel: channel.rows[0]
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
});

/**
 * GET /api/servers/:id/members
 * Get members of a server
 */
router.get('/:id/members', authenticateUser, async (req, res) => {
  try {
    // Check membership
    const memberCheck = await db.query(`
      SELECT * FROM server_members WHERE server_id = $1 AND user_id = $2
    `, [req.params.id, req.user.id]);

    if (memberCheck.rows.length === 0) {
      return res.status(403).json({
        success: false,
        error: 'Not a member of this server'
      });
    }

    const members = await db.query(`
      SELECT u.id, u.username, u.display_name, u.avatar_url, u.status, u.custom_status,
             sm.role, sm.nickname, sm.joined_at
      FROM server_members sm
      INNER JOIN users u ON sm.user_id = u.id
      WHERE sm.server_id = $1
      ORDER BY 
        CASE sm.role 
          WHEN 'owner' THEN 0 
          WHEN 'admin' THEN 1 
          WHEN 'moderator' THEN 2 
          ELSE 3 
        END,
        sm.joined_at ASC
    `, [req.params.id]);

    res.json({
      success: true,
      members: members.rows
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
});

/**
 * GET /api/channels/:channelId/messages
 * Get messages from a channel
 */
router.get('/channels/:channelId/messages', authenticateUser, async (req, res) => {
  try {
    const { limit = 50, before } = req.query;

    // Get channel and check membership
    const channel = await db.query(`SELECT server_id FROM channels WHERE id = $1`, [req.params.channelId]);
    if (channel.rows.length === 0) {
      return res.status(404).json({ success: false, error: 'Channel not found' });
    }

    const memberCheck = await db.query(`
      SELECT * FROM server_members WHERE server_id = $1 AND user_id = $2
    `, [channel.rows[0].server_id, req.user.id]);

    if (memberCheck.rows.length === 0) {
      return res.status(403).json({ success: false, error: 'Not a member' });
    }

    let query = `
      SELECT m.*, u.username, u.display_name, u.avatar_url
      FROM messages m
      INNER JOIN users u ON m.user_id = u.id
      WHERE m.channel_id = $1
    `;
    const params = [req.params.channelId];

    if (before) {
      query += ` AND m.created_at < $2`;
      params.push(before);
    }

    query += ` ORDER BY m.created_at DESC LIMIT $${params.length + 1}`;
    params.push(parseInt(limit));

    const messages = await db.query(query, params);

    res.json({
      success: true,
      messages: messages.rows.reverse()
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
});

/**
 * POST /api/channels/:channelId/messages
 * Send a message to a channel
 */
router.post('/channels/:channelId/messages', authenticateUser, async (req, res) => {
  try {
    const { content } = req.body;

    if (!content || content.trim().length === 0) {
      return res.status(400).json({ success: false, error: 'Message content is required' });
    }

    // Get channel and check membership
    const channel = await db.query(`SELECT server_id FROM channels WHERE id = $1`, [req.params.channelId]);
    if (channel.rows.length === 0) {
      return res.status(404).json({ success: false, error: 'Channel not found' });
    }

    const memberCheck = await db.query(`
      SELECT * FROM server_members WHERE server_id = $1 AND user_id = $2
    `, [channel.rows[0].server_id, req.user.id]);

    if (memberCheck.rows.length === 0) {
      return res.status(403).json({ success: false, error: 'Not a member' });
    }

    const message = await db.query(`
      INSERT INTO messages (channel_id, user_id, content)
      VALUES ($1, $2, $3)
      RETURNING *
    `, [req.params.channelId, req.user.id, content.trim()]);

    // Get user info
    const user = await db.query(`SELECT username, display_name, avatar_url FROM users WHERE id = $1`, [req.user.id]);

    res.json({
      success: true,
      message: {
        ...message.rows[0],
        ...user.rows[0]
      }
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
});

module.exports = router;