import { CloudWatchLogsClient, DescribeLogGroupsCommand } from '@aws-sdk/client-cloudwatch-logs';
import { loadEnvConfig, getAwsCredentialStatus } from '../config/env';
import { AwsConnectionResult } from '../types/client';
import { logger } from '../utils/logger';
import { AwsServiceError, toBaseError } from '../utils/error-utils';

/**
 * Service for interacting with AWS services
 */
export class AwsService {
  private cloudWatchLogsClient: CloudWatchLogsClient;
  
  /**
   * Initialize the AWS service
   */
  constructor() {
    const config = loadEnvConfig();
    this.cloudWatchLogsClient = new CloudWatchLogsClient({ region: config.awsRegion });
  }

  /**
   * Log AWS credential information
   */
  private logCredentialInfo(): void {
    logger.info('Testing AWS CloudWatch Logs connection...');
    logger.info('AWS SDK will use credentials from environment variables or ~/.aws/credentials');
    
    // Log credential status
    const credStatus = getAwsCredentialStatus();
    logger.info('Environment variables check:', credStatus);
  }
  
  /**
   * Create a successful connection result
   * @param logGroupName Optional log group name if found
   * @returns Successful connection result
   */
  private createSuccessResult(logGroupName?: string): AwsConnectionResult {
    if (logGroupName) {
      return {
        success: true,
        message: 'AWS connection successful!',
        logGroupName
      };
    } else {
      return {
        success: true,
        message: 'AWS connection successful! No log groups found in this account/region.'
      };
    }
  }
  
  /**
   * Create a failed connection result
   * @param error Error that occurred
   * @returns Failed connection result
   */
  private createFailureResult(error: unknown): AwsConnectionResult {
    const awsError = new AwsServiceError(
      'AWS connection failed!',
      'AWS_CONNECTION_ERROR',
      error
    );
    
    logger.error('AWS connection failed!', awsError.toJSON());
    
    return {
      success: false,
      message: 'AWS connection failed!',
      error: awsError
    };
  }

  /**
   * Test connection to AWS CloudWatch Logs
   * @returns Result of the connection test
   */
  async testConnection(): Promise<AwsConnectionResult> {
    try {
      // Log credential information
      this.logCredentialInfo();
      
      // Create a simple command to test connectivity
      const command = new DescribeLogGroupsCommand({
        limit: 1
      });
      
      // Send request to AWS
      logger.info('Sending DescribeLogGroupsCommand to AWS...');
      const response = await this.cloudWatchLogsClient.send(command);
      
      // Log success and check for log groups
      logger.info('AWS connection successful!');
      
      // Extract log group name if available
      const logGroupName = response.logGroups && response.logGroups.length > 0
        ? response.logGroups[0].logGroupName
        : undefined;
      
      if (logGroupName) {
        logger.info(`Found log group: ${logGroupName}`);
      }
      
      // Return success result
      return this.createSuccessResult(logGroupName);
      
    } catch (error) {
      // Handle and return failure
      return this.createFailureResult(error);
    }
  }
}