const express = require('express');
const http = require('http');
const WebSocket = require('ws');
const mysql = require('mysql2/promise');
const crypto = require('crypto');
require('dotenv').config();

const app = express();
const server = http.createServer(app);
const wss = new WebSocket.Server({ server });

// Middleware
app.use(express.json());
app.use(express.static('public'));

// UUID generator
function generateUUID() {
  return crypto.randomUUID();
}

// Database pool
const pool = mysql.createPool({
  host: process.env.DB_HOST,
  port: process.env.DB_PORT || 3306,
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  database: process.env.DB_NAME,
  waitForConnections: true,
  connectionLimit: 10,
  queueLimit: 0
});

// Initialize database tables
async function initDatabase() {
  const connection = await pool.getConnection();
  try {
    await connection.query(`
      CREATE TABLE IF NOT EXISTS users (
        id VARCHAR(36) PRIMARY KEY,
        username VARCHAR(255) UNIQUE NOT NULL,
        display_name VARCHAR(255),
        email VARCHAR(255),
        groups TEXT,
        last_login TIMESTAMP,
        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
      )
    `);

    await connection.query(`
      CREATE TABLE IF NOT EXISTS workers (
        id VARCHAR(36) PRIMARY KEY,
        name VARCHAR(255) UNIQUE NOT NULL,
        status VARCHAR(50) NOT NULL,
        last_heartbeat TIMESTAMP NULL,
        api_key VARCHAR(255),
        metadata JSON,
        INDEX idx_status (status),
        INDEX idx_heartbeat (last_heartbeat)
      )
    `);

    await connection.query(`
      CREATE TABLE IF NOT EXISTS workflows (
        id VARCHAR(36) PRIMARY KEY,
        name VARCHAR(255) NOT NULL,
        description TEXT,
        definition JSON NOT NULL,
        created_by VARCHAR(255),
        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
        updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
        INDEX idx_name (name)
      )
    `);

    await connection.query(`
      CREATE TABLE IF NOT EXISTS executions (
        id VARCHAR(36) PRIMARY KEY,
        workflow_id VARCHAR(36) NOT NULL,
        status VARCHAR(50) NOT NULL,
        started_by VARCHAR(255),
        started_at TIMESTAMP NULL,
        completed_at TIMESTAMP NULL,
        logs JSON,
        FOREIGN KEY (workflow_id) REFERENCES workflows(id) ON DELETE CASCADE,
        INDEX idx_workflow (workflow_id),
        INDEX idx_status (status),
        INDEX idx_started (started_at)
      )
    `);

    console.log('Database tables initialized successfully');
  } catch (error) {
    console.error('Database initialization error:', error);
    throw error;
  } finally {
    connection.release();
  }
}

// WebSocket connections
const clients = new Set();
wss.on('connection', (ws) => {
  clients.add(ws);
  ws.on('close', () => clients.delete(ws));
});

// Broadcast to all connected clients
function broadcast(data) {
  clients.forEach(client => {
    if (client.readyState === WebSocket.OPEN) {
      client.send(JSON.stringify(data));
    }
  });
}

// Authelia SSO Middleware
async function authenticateSSO(req, res, next) {
  // Check for Authelia headers
  const remoteUser = req.headers['remote-user'];
  const remoteName = req.headers['remote-name'];
  const remoteEmail = req.headers['remote-email'];
  const remoteGroups = req.headers['remote-groups'];

  if (!remoteUser) {
    return res.status(401).json({ 
      error: 'Not authenticated',
      message: 'Please access this service through auth.lotusguild.org'
    });
  }

  // Check if user is in allowed groups (admin or employee)
  const groups = remoteGroups ? remoteGroups.split(',').map(g => g.trim()) : [];
  const allowedGroups = ['admin', 'employee'];
  const hasAccess = groups.some(g => allowedGroups.includes(g));

  if (!hasAccess) {
    return res.status(403).json({ 
      error: 'Access denied',
      message: 'You must be in admin or employee group'
    });
  }

  // Store/update user in database
  try {
    const userId = generateUUID();
    await pool.query(
      `INSERT INTO users (id, username, display_name, email, groups, last_login)
       VALUES (?, ?, ?, ?, ?, NOW())
       ON DUPLICATE KEY UPDATE
         display_name=VALUES(display_name),
         email=VALUES(email),
         groups=VALUES(groups),
         last_login=NOW()`,
      [userId, remoteUser, remoteName, remoteEmail, remoteGroups]
    );
  } catch (error) {
    console.error('Error updating user:', error);
  }

  // Attach user info to request
  req.user = {
    username: remoteUser,
    name: remoteName || remoteUser,
    email: remoteEmail || '',
    groups: groups,
    isAdmin: groups.includes('admin')
  };

  next();
}

// Routes - All protected by SSO
app.get('/api/user', authenticateSSO, (req, res) => {
  res.json(req.user);
});

app.get('/api/workflows', authenticateSSO, async (req, res) => {
  try {
    const [rows] = await pool.query('SELECT * FROM workflows ORDER BY created_at DESC');
    res.json(rows);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

app.post('/api/workflows', authenticateSSO, async (req, res) => {
  try {
    const { name, description, definition } = req.body;
    const id = generateUUID();
    
    await pool.query(
      'INSERT INTO workflows (id, name, description, definition, created_by) VALUES (?, ?, ?, ?, ?)',
      [id, name, description, JSON.stringify(definition), req.user.username]
    );
    
    res.json({ id, name, description, definition });
    broadcast({ type: 'workflow_created', workflow_id: id });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

app.delete('/api/workflows/:id', authenticateSSO, async (req, res) => {
  try {
    // Only admins can delete workflows
    if (!req.user.isAdmin) {
      return res.status(403).json({ error: 'Admin access required' });
    }
    
    await pool.query('DELETE FROM workflows WHERE id = ?', [req.params.id]);
    res.json({ success: true });
    broadcast({ type: 'workflow_deleted', workflow_id: req.params.id });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

app.get('/api/workers', authenticateSSO, async (req, res) => {
  try {
    const [rows] = await pool.query('SELECT * FROM workers ORDER BY name');
    res.json(rows);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

app.post('/api/workers/heartbeat', async (req, res) => {
  try {
    const { worker_id, name, metadata } = req.body;
    const apiKey = req.headers['x-api-key'];
    
    // Verify API key
    if (apiKey !== process.env.WORKER_API_KEY) {
      return res.status(401).json({ error: 'Invalid API key' });
    }
    
    await pool.query(
      `INSERT INTO workers (id, name, status, last_heartbeat, api_key, metadata)
       VALUES (?, ?, 'online', NOW(), ?, ?)
       ON DUPLICATE KEY UPDATE
         status='online',
         last_heartbeat=NOW(),
         metadata=VALUES(metadata)`,
      [worker_id, name, apiKey, JSON.stringify(metadata)]
    );
    
    broadcast({ type: 'worker_update', worker_id, status: 'online' });
    res.json({ success: true });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

app.post('/api/executions', authenticateSSO, async (req, res) => {
  try {
    const { workflow_id } = req.body;
    const id = generateUUID();
    
    await pool.query(
      'INSERT INTO executions (id, workflow_id, status, started_by, started_at, logs) VALUES (?, ?, ?, ?, NOW(), ?)',
      [id, workflow_id, 'running', req.user.username, JSON.stringify([])]
    );
    
    broadcast({ type: 'execution_started', execution_id: id, workflow_id });
    res.json({ id, workflow_id, status: 'running' });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

app.get('/api/executions', authenticateSSO, async (req, res) => {
  try {
    const [rows] = await pool.query(
      'SELECT e.*, w.name as workflow_name FROM executions e LEFT JOIN workflows w ON e.workflow_id = w.id ORDER BY e.started_at DESC LIMIT 50'
    );
    res.json(rows);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

app.get('/api/executions/:id', authenticateSSO, async (req, res) => {
  try {
    const [rows] = await pool.query('SELECT * FROM executions WHERE id = ?', [req.params.id]);
    if (rows.length === 0) {
      return res.status(404).json({ error: 'Not found' });
    }
    res.json(rows[0]);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Health check (no auth required)
app.get('/health', async (req, res) => {
  try {
    await pool.query('SELECT 1');
    res.json({ 
      status: 'ok', 
      timestamp: new Date().toISOString(),
      database: 'connected',
      auth: 'authelia-sso'
    });
  } catch (error) {
    res.status(500).json({ 
      status: 'error', 
      timestamp: new Date().toISOString(),
      database: 'disconnected',
      error: error.message
    });
  }
});

// Start server
const PORT = process.env.PORT || 8080;
const HOST = process.env.HOST || '0.0.0.0';

initDatabase().then(() => {
  server.listen(PORT, HOST, () => {
    console.log(`PULSE Server running on http://${HOST}:${PORT}`);
    console.log(`Connected to MariaDB at ${process.env.DB_HOST}`);
    console.log(`Authentication: Authelia SSO`);
    console.log(`Worker API Key configured: ${process.env.WORKER_API_KEY ? 'Yes' : 'No'}`);
  });
}).catch(err => {
  console.error('Failed to start server:', err);
  process.exit(1);
});


// ============================================
// WORKFLOW EXECUTION ENGINE
// ============================================

// Store active workflow executions in memory
const activeExecutions = new Map();

// Execute workflow step by step
async function executeWorkflow(workflowId, executionId, userId, targetWorkers = 'all') {
  try {
    // Get workflow definition
    const [workflows] = await pool.query('SELECT * FROM workflows WHERE id = ?', [workflowId]);
    if (workflows.length === 0) {
      throw new Error('Workflow not found');
    }

    const workflow = workflows[0];
    const definition = JSON.parse(workflow.definition);
    
    // Initialize execution state
    const executionState = {
      id: executionId,
      workflowId: workflowId,
      currentStep: 0,
      steps: definition.steps || [],
      results: [],
      status: 'running',
      waitingForInput: false,
      targetWorkers: targetWorkers,
      userId: userId
    };

    activeExecutions.set(executionId, executionState);

    // Start executing steps
    await executeNextStep(executionId);

  } catch (error) {
    console.error('Workflow execution error:', error);
    await updateExecutionStatus(executionId, 'failed', error.message);
  }
}

// Execute the next step in a workflow
async function executeNextStep(executionId) {
  const state = activeExecutions.get(executionId);
  if (!state) return;

  // Check if we've completed all steps
  if (state.currentStep >= state.steps.length) {
    await updateExecutionStatus(executionId, 'completed');
    activeExecutions.delete(executionId);
    return;
  }

  const step = state.steps[state.currentStep];
  
  // Check if step has a condition
  if (step.condition && !evaluateCondition(step.condition, state)) {
    console.log(`[Workflow] Skipping step ${state.currentStep}: condition not met`);
    state.currentStep++;
    return executeNextStep(executionId);
  }

  console.log(`[Workflow] Executing step ${state.currentStep}: ${step.name}`);

  try {
    switch (step.type) {
      case 'execute':
        await executeCommandStep(executionId, step);
        break;
      case 'prompt':
        await executePromptStep(executionId, step);
        break;
      case 'wait':
        await executeWaitStep(executionId, step);
        break;
      default:
        throw new Error(`Unknown step type: ${step.type}`);
    }
  } catch (error) {
    await addExecutionLog(executionId, {
      step: state.currentStep,
      error: error.message,
      timestamp: new Date().toISOString()
    });
    await updateExecutionStatus(executionId, 'failed', error.message);
    activeExecutions.delete(executionId);
  }
}

// Execute a command on workers
async function executeCommandStep(executionId, step) {
  const state = activeExecutions.get(executionId);
  
  // Get target workers
  const [workers] = await pool.query(
    'SELECT * FROM workers WHERE status = "online"'
  );

  if (workers.length === 0) {
    throw new Error('No online workers available');
  }

  // Filter workers based on target
  let targetWorkers = workers;
  if (step.targets && step.targets[0] !== 'all') {
    targetWorkers = workers.filter(w => step.targets.includes(w.name));
  }

  // Send command to workers via WebSocket
  const commandMessage = {
    type: 'execute_command',
    execution_id: executionId,
    step_index: state.currentStep,
    command: step.command,
    timeout: step.timeout || 300000
  };

  // Broadcast to target workers
  clients.forEach(client => {
    if (client.readyState === WebSocket.OPEN) {
      client.send(JSON.stringify(commandMessage));
    }
  });

  await addExecutionLog(executionId, {
    step: state.currentStep,
    action: 'command_sent',
    command: step.command,
    workers: targetWorkers.map(w => w.name),
    timestamp: new Date().toISOString()
  });

  // For now, move to next step immediately
  // In production, we'd wait for worker responses
  state.currentStep++;
  
  // Small delay to allow command to execute
  setTimeout(() => executeNextStep(executionId), 1000);
}

// Execute a user prompt step
async function executePromptStep(executionId, step) {
  const state = activeExecutions.get(executionId);
  
  state.waitingForInput = true;
  state.promptData = {
    message: step.message,
    options: step.options,
    step: state.currentStep
  };

  await addExecutionLog(executionId, {
    step: state.currentStep,
    action: 'waiting_for_input',
    prompt: step.message,
    timestamp: new Date().toISOString()
  });

  // Notify frontend that input is needed
  broadcast({
    type: 'execution_prompt',
    execution_id: executionId,
    prompt: state.promptData
  });
}

// Execute a wait/delay step
async function executeWaitStep(executionId, step) {
  const state = activeExecutions.get(executionId);
  const delay = step.duration || 1000;

  await addExecutionLog(executionId, {
    step: state.currentStep,
    action: 'waiting',
    duration: delay,
    timestamp: new Date().toISOString()
  });

  state.currentStep++;
  setTimeout(() => executeNextStep(executionId), delay);
}

// Handle user input for prompts
function handleUserInput(executionId, response) {
  const state = activeExecutions.get(executionId);
  if (!state || !state.waitingForInput) {
    return false;
  }

  state.promptResponse = response;
  state.waitingForInput = false;
  state.currentStep++;

  addExecutionLog(executionId, {
    step: state.currentStep - 1,
    action: 'user_response',
    response: response,
    timestamp: new Date().toISOString()
  });

  executeNextStep(executionId);
  return true;
}

// Evaluate conditions
function evaluateCondition(condition, state) {
  try {
    // Simple condition evaluation
    // In production, use a proper expression evaluator
    const promptResponse = state.promptResponse;
    return eval(condition);
  } catch (error) {
    console.error('Condition evaluation error:', error);
    return false;
  }
}

// Helper functions
async function updateExecutionStatus(executionId, status, error = null) {
  const updates = { status };
  if (status === 'completed' || status === 'failed') {
    updates.completed_at = new Date();
  }
  if (error) {
    // Add error to logs
    await addExecutionLog(executionId, { error, timestamp: new Date().toISOString() });
  }

  await pool.query(
    'UPDATE executions SET status = ?, completed_at = ? WHERE id = ?',
    [status, updates.completed_at || null, executionId]
  );

  broadcast({
    type: 'execution_status',
    execution_id: executionId,
    status: status
  });
}

async function addExecutionLog(executionId, logEntry) {
  const [rows] = await pool.query('SELECT logs FROM executions WHERE id = ?', [executionId]);
  if (rows.length === 0) return;

  const logs = JSON.parse(rows[0].logs || '[]');
  logs.push(logEntry);

  await pool.query('UPDATE executions SET logs = ? WHERE id = ?', [
    JSON.stringify(logs),
    executionId
  ]);
}

// ============================================
// API ROUTES - Add these to your server.js
// ============================================

// Start workflow execution
app.post('/api/executions', authenticateSSO, async (req, res) => {
  try {
    const { workflow_id, target_workers } = req.body;
    const id = generateUUID();
    
    await pool.query(
      'INSERT INTO executions (id, workflow_id, status, started_by, started_at, logs) VALUES (?, ?, ?, ?, NOW(), ?)',
      [id, workflow_id, 'running', req.user.username, JSON.stringify([])]
    );
    
    // Start execution
    executeWorkflow(workflow_id, id, req.user.username, target_workers || 'all');
    
    broadcast({ type: 'execution_started', execution_id: id, workflow_id });
    res.json({ id, workflow_id, status: 'running' });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Respond to workflow prompt
app.post('/api/executions/:id/respond', authenticateSSO, async (req, res) => {
  try {
    const { response } = req.body;
    const success = handleUserInput(req.params.id, response);
    
    if (success) {
      res.json({ success: true });
    } else {
      res.status(400).json({ error: 'Execution not waiting for input' });
    }
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Get execution details with logs
app.get('/api/executions/:id', authenticateSSO, async (req, res) => {
  try {
    const [rows] = await pool.query('SELECT * FROM executions WHERE id = ?', [req.params.id]);
    if (rows.length === 0) {
      return res.status(404).json({ error: 'Not found' });
    }
    
    const execution = rows[0];
    const state = activeExecutions.get(req.params.id);
    
    res.json({
      ...execution,
      logs: JSON.parse(execution.logs || '[]'),
      waiting_for_input: state?.waitingForInput || false,
      prompt: state?.promptData || null
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Delete worker (admin only)
app.delete('/api/workers/:id', authenticateSSO, async (req, res) => {
  try {
    if (!req.user.isAdmin) {
      return res.status(403).json({ error: 'Admin access required' });
    }
    
    await pool.query('DELETE FROM workers WHERE id = ?', [req.params.id]);
    res.json({ success: true });
    broadcast({ type: 'worker_deleted', worker_id: req.params.id });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Send direct command to specific worker (for testing)
app.post('/api/workers/:id/command', authenticateSSO, async (req, res) => {
  try {
    const { command } = req.body;
    const executionId = generateUUID();
    
    // Send command via WebSocket
    const commandMessage = {
      type: 'execute_command',
      execution_id: executionId,
      command: command,
      worker_id: req.params.id,
      timeout: 60000
    };

    clients.forEach(client => {
      if (client.readyState === WebSocket.OPEN) {
        client.send(JSON.stringify(commandMessage));
      }
    });

    res.json({ success: true, execution_id: executionId });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// ============================================
// EXAMPLE WORKFLOW DEFINITIONS
// ============================================

// Example 1: Simple command execution
const simpleWorkflow = {
  name: "Update System Packages",
  description: "Update all packages on target servers",
  steps: [
    {
      name: "Update package list",
      type: "execute",
      targets: ["all"],
      command: "apt update"
    },
    {
      name: "User Approval",
      type: "prompt",
      message: "Packages updated. Proceed with upgrade?",
      options: ["Yes", "No"]
    },
    {
      name: "Upgrade packages",
      type: "execute",
      targets: ["all"],
      command: "apt upgrade -y",
      condition: "promptResponse === 'Yes'"
    }
  ]
};

// Example 2: Complex workflow with conditions
const backupWorkflow = {
  name: "Backup and Verify",
  description: "Create backup and verify integrity",
  steps: [
    {
      name: "Create backup",
      type: "execute",
      targets: ["all"],
      command: "tar -czf /tmp/backup-$(date +%Y%m%d).tar.gz /opt/pulse-worker"
    },
    {
      name: "Wait for backup",
      type: "wait",
      duration: 5000
    },
    {
      name: "Verify backup",
      type: "execute",
      targets: ["all"],
      command: "tar -tzf /tmp/backup-*.tar.gz > /dev/null && echo 'Backup OK' || echo 'Backup FAILED'"
    },
    {
      name: "Cleanup decision",
      type: "prompt",
      message: "Backup complete. Delete old backups?",
      options: ["Yes", "No", "Cancel"]
    },
    {
      name: "Cleanup old backups",
      type: "execute",
      targets: ["all"],
      command: "find /tmp -name 'backup-*.tar.gz' -mtime +7 -delete",
      condition: "promptResponse === 'Yes'"
    }
  ]
};