/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/**
 * Schema Manager Module
 * 
 * Handles metadata registration before performance testing to avoid
 * metadata creation overhead during benchmarks. Supports both tree
 * and table models.
 */

const { TSDataType } = require('./config');

/**
 * Map TSDataType code to IoTDB type string
 * @param {number} dataType - TSDataType code
 * @returns {string} IoTDB data type string
 */
function getDataTypeString(dataType) {
  const typeMap = {
    [TSDataType.BOOLEAN]: 'BOOLEAN',
    [TSDataType.INT32]: 'INT32',
    [TSDataType.INT64]: 'INT64',
    [TSDataType.FLOAT]: 'FLOAT',
    [TSDataType.DOUBLE]: 'DOUBLE',
    [TSDataType.TEXT]: 'TEXT',
    [TSDataType.TIMESTAMP]: 'TIMESTAMP',
    [TSDataType.DATE]: 'DATE',
    [TSDataType.BLOB]: 'BLOB',
    [TSDataType.STRING]: 'STRING',
  };
  return typeMap[dataType] || 'FLOAT';
}

/**
 * Create tree model schema
 * @param {Object} session - IoTDB session or pool
 * @param {Object} testData - Test data structure
 * @param {Object} config - Configuration object
 */
async function createTreeModelSchema(session, testData, config) {
  console.log('\n=== Creating Tree Model Schema (Using Device Template) ===');
  const startTime = Date.now();

  try {
    // Delete existing storage group if exists
    console.log(`Deleting existing storage group: ${config.STORAGE_GROUP_PREFIX}...`);
    try {
      await session.executeNonQueryStatement(
        `DROP DATABASE ${config.STORAGE_GROUP_PREFIX}`
      );
      console.log('  ✓ Existing storage group deleted');
    } catch (error) {
      if (error.message && (error.message.includes('does not exist') || error.message.includes('not exist'))) {
        console.log('  ℹ Storage group does not exist, will create new one');
      } else {
        console.log(`  ℹ Delete storage group: ${error.message}`);
      }
    }

    // Create storage group
    console.log(`Creating storage group: ${config.STORAGE_GROUP_PREFIX}...`);
    await session.executeNonQueryStatement(
      `CREATE DATABASE ${config.STORAGE_GROUP_PREFIX}`
    );
    console.log('  ✓ Storage group created');

    // Use device template for fast schema creation
    const templateName = 'benchmark_template';
    
    // Step 1: Drop existing template if exists
    console.log(`Dropping existing device template: ${templateName}...`);
    try {
      await session.executeNonQueryStatement(
        `DROP DEVICE TEMPLATE ${templateName}`
      );
      console.log('  ✓ Existing template dropped');
    } catch (error) {
      console.log('  ℹ Template does not exist, will create new one');
    }

    // Step 2: Create device template with measurements from first device
    // All devices have same structure in benchmark
    if (testData.devices && testData.devices.length > 0) {
      const device = testData.devices[0];
      
      // Build template creation SQL
      const measurements = [];
      for (let i = 0; i < device.measurements.length; i++) {
        const measurement = device.measurements[i];
        const dataType = device.dataTypes[i];
        const typeString = getDataTypeString(dataType);
        measurements.push(`${measurement} ${typeString}`);
      }
      
      const createTemplateSQL = `CREATE DEVICE TEMPLATE ${templateName} (${measurements.join(', ')})`;
      console.log(`Creating device template with ${device.measurements.length} measurements...`);
      console.log(`SQL: ${createTemplateSQL}`);
      
      await session.executeNonQueryStatement(createTemplateSQL);
      console.log('  ✓ Device template created');

      // Step 3: Set template to storage group
      console.log(`Setting template to storage group: ${config.STORAGE_GROUP_PREFIX}...`);
      await session.executeNonQueryStatement(
        `SET DEVICE TEMPLATE ${templateName} TO ${config.STORAGE_GROUP_PREFIX}`
      );
      console.log('  ✓ Template set to storage group');

      // Step 4: Template will be auto-activated when data is inserted
      // No need to manually activate for each device
      console.log(`Template will be auto-activated for ${testData.devices.length} devices on first insert`);

      const duration = Date.now() - startTime;
      console.log(`\n✓ Schema creation completed in ${(duration / 1000).toFixed(2)}s`);
      console.log(`  Using device template for ${testData.devices.length} devices`);
      console.log(`  Total measurements per device: ${device.measurements.length}`);
    } else {
      throw new Error('No devices in test data');
    }
    
  } catch (error) {
    console.error('✗ Schema creation failed:', error);
    throw error;
  }
}

/**
 * Create table model schema
 * @param {Object} session - IoTDB session or pool
 * @param {Object} testData - Test data structure
 * @param {Object} config - Configuration object
 */
async function createTableModelSchema(session, testData, config) {
  console.log('\n=== Creating Table Model Schema ===');
  const startTime = Date.now();

  try {
    // Delete existing database if exists
    console.log(`Deleting existing database: ${config.DATABASE_NAME}...`);
    try {
      await session.executeNonQueryStatement(
        `DROP DATABASE ${config.DATABASE_NAME}`
      );
      console.log('  ✓ Existing database deleted');
    } catch (error) {
      if (error.message && (error.message.includes('does not exist') || error.message.includes('not exist'))) {
        console.log('  ℹ Database does not exist, will create new one');
      } else {
        console.log(`  ℹ Delete database: ${error.message}`);
      }
    }

    // Create database
    console.log(`Creating database: ${config.DATABASE_NAME}...`);
    await session.executeNonQueryStatement(
      `CREATE DATABASE ${config.DATABASE_NAME}`
    );
    console.log('  ✓ Database created');

    // Use database
    await session.executeNonQueryStatement(`USE ${config.DATABASE_NAME}`);
    console.log('  ✓ Using database');

    // Drop existing table if exists
    try {
      await session.executeNonQueryStatement(`DROP TABLE ${config.TABLE_NAME}`);
      console.log('  ✓ Dropped existing table');
    } catch (error) {
      // Ignore if table doesn't exist
    }

    // Build CREATE TABLE statement from device structure
    const columns = ['device_id STRING TAG'];  // device_id is TAG for identification
    
    // Add sensor columns from first device (all devices have same structure)
    if (testData.devices && testData.devices.length > 0) {
      const device = testData.devices[0];
      for (let i = 0; i < device.measurements.length; i++) {
        const measurementName = device.measurements[i];
        const dataType = device.dataTypes[i];
        const typeString = getDataTypeString(dataType);
        // All sensors are FIELD columns (measurement values)
        columns.push(`${measurementName} ${typeString} FIELD`);
      }
    }

    const createTableSQL = `CREATE TABLE ${config.TABLE_NAME} (${columns.join(', ')})`;
    console.log(`Creating table with ${columns.length} columns...`);
    console.log(`SQL: ${createTableSQL}`);
    
    await session.executeNonQueryStatement(createTableSQL);
    console.log('  ✓ Table created');

    const duration = Date.now() - startTime;
    console.log(`\n✓ Schema creation completed in ${(duration / 1000).toFixed(2)}s`);
    
  } catch (error) {
    console.error('✗ Schema creation failed:', error);
    throw error;
  }
}

/**
 * Clean up test schema
 * @param {Object} session - IoTDB session or pool
 * @param {string} model - 'tree' or 'table'
 * @param {Object} config - Configuration object
 */
async function cleanupSchema(session, model, config) {
  console.log('\n=== Cleaning Up Schema ===');
  
  try {
    if (model === 'tree') {
      console.log(`Dropping storage group: ${config.STORAGE_GROUP_PREFIX}...`);
      try {
        await session.executeNonQueryStatement(
          `DELETE DATABASE ${config.STORAGE_GROUP_PREFIX}.*`
        );
        console.log('  ✓ Storage group deleted');
      } catch (error) {
        console.log('  ℹ Storage group does not exist or already deleted');
      }
    } else if (model === 'table') {
      console.log(`Dropping database: ${config.DATABASE_NAME}...`);
      try {
        await session.executeNonQueryStatement(
          `DROP DATABASE ${config.DATABASE_NAME}`
        );
        console.log('  ✓ Database dropped');
      } catch (error) {
        console.log('  ℹ Database does not exist or already deleted');
      }
    }
  } catch (error) {
    console.error('✗ Cleanup failed:', error.message);
    // Don't throw - cleanup is best effort
  }
}

/**
 * Verify schema creation
 * @param {Object} session - IoTDB session or pool
 * @param {string} model - 'tree' or 'table'
 * @param {Object} config - Configuration object
 * @returns {boolean} True if schema exists
 */
async function verifySchema(session, model, config) {
  console.log('\n=== Verifying Schema ===');
  
  try {
    if (model === 'tree') {
      // Check if storage group exists
      const result = await session.executeQueryStatement('SHOW DATABASES');
      const databases = [];
      
      while (await result.hasNext()) {
        const row = result.next();
        databases.push(row.getFields()[0]);
      }
      await result.close();
      
      const exists = databases.some(db => 
        db === config.STORAGE_GROUP_PREFIX || db.startsWith(config.STORAGE_GROUP_PREFIX + '.')
      );
      
      if (exists) {
        console.log(`  ✓ Storage group ${config.STORAGE_GROUP_PREFIX} exists`);
        return true;
      } else {
        console.log(`  ✗ Storage group ${config.STORAGE_GROUP_PREFIX} not found`);
        return false;
      }
    } else if (model === 'table') {
      // Check if database exists
      const result = await session.executeQueryStatement('SHOW DATABASES');
      const databases = [];
      
      while (await result.hasNext()) {
        const row = result.next();
        databases.push(row.getFields()[0]);
      }
      await result.close();
      
      const exists = databases.includes(config.DATABASE_NAME);
      
      if (exists) {
        console.log(`  ✓ Database ${config.DATABASE_NAME} exists`);
        return true;
      } else {
        console.log(`  ✗ Database ${config.DATABASE_NAME} not found`);
        return false;
      }
    }
  } catch (error) {
    console.error('✗ Verification failed:', error.message);
    return false;
  }
  
  return false;
}

module.exports = {
  createTreeModelSchema,
  createTableModelSchema,
  cleanupSchema,
  verifySchema,
  getDataTypeString,
};