import { getLogger } from '@stock-bot/logger';

const logger = getLogger('DataIngestionService');
import { IngestionStep, ProcessingResult, DataSource } from '../types/DataPipeline';
import axios from 'axios';
import csv from 'csv-parser';
import * as fs from 'fs';

export class DataIngestionService {
  private activeConnections: Map<string, any> = new Map();

  async initialize(): Promise<void> {
    logger.info('🔄 Initializing Data Ingestion Service...');
    logger.info('✅ Data Ingestion Service initialized');
  }

  async ingestData(step: IngestionStep, parameters: Record<string, any>): Promise<ProcessingResult> {
    const startTime = Date.now();
    logger.info(`📥 Starting data ingestion from ${step.source.type}: ${step.source.connection.url || step.source.connection.host}`);

    try {
      switch (step.source.type) {
        case 'api':
          return await this.ingestFromApi(step.source, parameters);
        case 'file':
          return await this.ingestFromFile(step.source, parameters);
        case 'database':
          return await this.ingestFromDatabase(step.source, parameters);
        case 'stream':
          return await this.ingestFromStream(step.source, parameters);
        default:
          throw new Error(`Unsupported ingestion type: ${step.source.type}`);
      }
    } catch (error) {
      const processingTime = Date.now() - startTime;
      logger.error(`❌ Data ingestion failed after ${processingTime}ms:`, error);
      
      return {
        recordsProcessed: 0,
        recordsSuccessful: 0,
        recordsFailed: 0,
        errors: [{
          record: 0,
          message: error instanceof Error ? error.message : 'Unknown error',
          code: 'INGESTION_ERROR'
        }],
        metadata: { processingTimeMs: processingTime }
      };
    }
  }

  private async ingestFromApi(source: DataSource, parameters: Record<string, any>): Promise<ProcessingResult> {
    const config = {
      method: 'GET',
      url: source.connection.url,
      headers: source.connection.headers || {},
      params: { ...source.connection.params, ...parameters },
    };

    if (source.connection.apiKey) {
      config.headers['Authorization'] = `Bearer ${source.connection.apiKey}`;
    }

    const response = await axios(config);
    const data = response.data;

    // Process the data based on format
    let records: any[] = [];
    
    if (Array.isArray(data)) {
      records = data;
    } else if (data.data && Array.isArray(data.data)) {
      records = data.data;
    } else if (data.results && Array.isArray(data.results)) {
      records = data.results;
    } else {
      records = [data];
    }

    logger.info(`📊 Ingested ${records.length} records from API: ${source.connection.url}`);

    return {
      recordsProcessed: records.length,
      recordsSuccessful: records.length,
      recordsFailed: 0,
      errors: [],
      metadata: {
        source: 'api',
        url: source.connection.url,
        statusCode: response.status,
        responseSize: JSON.stringify(data).length
      }
    };
  }

  private async ingestFromFile(source: DataSource, parameters: Record<string, any>): Promise<ProcessingResult> {
    const filePath = source.connection.url || parameters.filePath;
    
    if (!filePath) {
      throw new Error('File path is required for file ingestion');
    }

    switch (source.format) {
      case 'csv':
        return await this.ingestCsvFile(filePath);
      case 'json':
        return await this.ingestJsonFile(filePath);
      default:
        throw new Error(`Unsupported file format: ${source.format}`);
    }
  }

  private async ingestCsvFile(filePath: string): Promise<ProcessingResult> {
    return new Promise((resolve, reject) => {
      const records: any[] = [];
      const errors: any[] = [];
      let recordCount = 0;      fs.createReadStream(filePath)
        .pipe(csv())
        .on('data', (data: any) => {
          recordCount++;
          try {
            records.push(data);
          } catch (error) {
            errors.push({
              record: recordCount,
              message: error instanceof Error ? error.message : 'Parse error',
              code: 'CSV_PARSE_ERROR'
            });
          }
        })
        .on('end', () => {
          logger.info(`📊 Ingested ${records.length} records from CSV: ${filePath}`);
          resolve({
            recordsProcessed: recordCount,
            recordsSuccessful: records.length,
            recordsFailed: errors.length,
            errors,
            metadata: {
              source: 'file',
              format: 'csv',
              filePath
            }
          });
        })
        .on('error', reject);
    });
  }

  private async ingestJsonFile(filePath: string): Promise<ProcessingResult> {
    const fileContent = await fs.promises.readFile(filePath, 'utf8');
    const data = JSON.parse(fileContent);
    
    let records: any[] = [];
    
    if (Array.isArray(data)) {
      records = data;
    } else {
      records = [data];
    }

    logger.info(`📊 Ingested ${records.length} records from JSON: ${filePath}`);

    return {
      recordsProcessed: records.length,
      recordsSuccessful: records.length,
      recordsFailed: 0,
      errors: [],
      metadata: {
        source: 'file',
        format: 'json',
        filePath,
        fileSize: fileContent.length
      }
    };
  }

  private async ingestFromDatabase(source: DataSource, parameters: Record<string, any>): Promise<ProcessingResult> {
    // Placeholder for database ingestion
    // In a real implementation, this would connect to various databases
    // (PostgreSQL, MySQL, MongoDB, etc.) and execute queries
    
    throw new Error('Database ingestion not yet implemented');
  }

  private async ingestFromStream(source: DataSource, parameters: Record<string, any>): Promise<ProcessingResult> {
    // Placeholder for stream ingestion
    // In a real implementation, this would connect to streaming sources
    // (Kafka, Kinesis, WebSocket, etc.)
    
    throw new Error('Stream ingestion not yet implemented');
  }

  async getIngestionMetrics(): Promise<any> {
    return {
      activeConnections: this.activeConnections.size,
      supportedSources: ['api', 'file', 'database', 'stream'],
      supportedFormats: ['json', 'csv', 'xml', 'parquet', 'avro']
    };
  }
}