import mysql from 'mysql2/promise';
import dotenv from 'dotenv';
import fs from 'fs';
import path from 'path';
import { fileURLToPath } from 'url';

dotenv.config();

// Fix per __dirname in ES Modules
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

// Configurazione DB con gestione esplicita della porta e casting a numero
const dbConfig = {
  host: process.env.DB_HOST || 'db',
  port: Number(process.env.DB_PORT) || 3306,
  user: process.env.DB_USER || 'omni_user',
  password: process.env.DB_PASSWORD || 'omni_pass',
  database: process.env.DB_NAME || 'omnisupport',
  waitForConnections: true,
  connectionLimit: 10,
  queueLimit: 0,
  multipleStatements: true // Necessario per eseguire schema.sql che contiene più query
};

const pool = mysql.createPool(dbConfig);

export const query = async (sql, params) => {
  try {
    const [results] = await pool.execute(sql, params);
    return results;
  } catch (error) {
    console.error('Database query error:', error);
    throw error;
  }
};

export const checkConnection = async () => {
  try {
    const connection = await pool.getConnection();
    await connection.ping();
    connection.release();
    console.log(`✅ Connected to MySQL Database at ${dbConfig.host}:${dbConfig.port}`);
    return true;
  } catch (error) {
    console.error(`❌ Database connection failed (${dbConfig.host}:${dbConfig.port}):`, error.message);
    return false;
  }
};

export const initDb = async () => {
  try {
    console.log(`🔌 Attempting connection to database at ${dbConfig.host}:${dbConfig.port}...`);
    
    const isConnected = await checkConnection();
    if (!isConnected) {
        console.error("❌ Skipping initialization due to connection failure.");
        return;
    }

    // Check if main tables exist
    const [agentsExist] = await pool.query("SHOW TABLES LIKE 'agents'");
    const [settingsExist] = await pool.query("SHOW TABLES LIKE 'settings'");
    
    // Scenario 1: DB completely initialized
    if (agentsExist.length > 0 && settingsExist.length > 0) {
      console.log('ℹ️ Database tables already exist. Checking for migrations...');
      
      // MIGRATION: Add 'visibility' to kb_articles if not exists
      try {
        await pool.query("ALTER TABLE kb_articles ADD COLUMN visibility ENUM('public', 'internal') DEFAULT 'public'");
        console.log("✅ Added visibility column to kb_articles");
      } catch (e) { /* Column likely exists */ }

      // MIGRATION: Add 'has_been_analyzed' to tickets if not exists
      try {
        await pool.query("ALTER TABLE tickets ADD COLUMN has_been_analyzed BOOLEAN DEFAULT FALSE");
        console.log("✅ Added has_been_analyzed column to tickets");
      } catch (e) { /* Column likely exists */ }

      return;
    }

    // Scenario 2: Partial migration (Agents exist but Settings missing)
    if (agentsExist.length > 0 && settingsExist.length === 0) {
        console.log('⚠️ Settings table missing (Partial Migration). Creating...');
        const createSettingsSql = `
            CREATE TABLE IF NOT EXISTS settings (
              id INT PRIMARY KEY DEFAULT 1,
              branding JSON,
              smtp JSON,
              email_templates JSON,
              features JSON,
              ai_config JSON
            );
            INSERT INTO settings (id, branding, smtp, email_templates, features, ai_config) VALUES (
              1,
              '{"appName": "OmniSupport AI", "primaryColor": "#0284c7", "logoUrl": "https://via.placeholder.com/150"}',
              '{"host": "smtp.example.com", "port": 587, "user": "notifications@omnisupport.ai", "pass": "password", "secure": true, "fromEmail": "noreply@omnisupport.ai"}',
              '[{"id": "t1", "name": "Conferma Apertura Ticket", "trigger": "ticket_created", "audience": "client", "subject": "Ticket #{ticket_id} Creato", "body": "Grazie per averci contattato.", "isActive": true}]',
              '{"kbEnabled": true, "maxKbArticles": 50, "maxSupervisors": 2, "aiKnowledgeAgentEnabled": true, "maxAiGeneratedArticles": 10, "maxAgents": 10}',
              '{"provider": "gemini", "apiKey": "", "model": "gemini-3-flash-preview", "isActive": true, "agentName": "OmniSupport AI", "customPrompt": ""}'
            );
        `;
        await pool.query(createSettingsSql);
        console.log('✅ Settings table created successfully.');
        return;
    }

    // Scenario 3: Fresh Install
    console.log('⚠️ Database empty. Running full schema.sql...');
    const schemaPath = path.join(__dirname, 'schema.sql');
    const schemaSql = fs.readFileSync(schemaPath, 'utf8');

    await pool.query(schemaSql);

    console.log('✅ Database initialized successfully with schema and seed data.');
    console.log('👤 Superadmin created: fcarra79@gmail.com');

  } catch (error) {
    console.error('❌ Failed to initialize database:', error);
  }
};