import type { TInvoice } from '../../interfaces/common.js';
import { ValidationLevel } from '../../interfaces/common.js';
import type { ValidationResult } from '../../interfaces/common.js';

/**
 * Base decoder class that defines common decoding functionality
 * for all invoice format decoders
 */
export abstract class BaseDecoder {
  protected xml: string;

  constructor(xml: string) {
    this.xml = xml;
  }

  /**
   * Decodes XML into a TInvoice object
   * @returns Promise resolving to a TInvoice object
   */
  abstract decode(): Promise<TInvoice>;

  /**
   * Gets letter data in the standard format
   * @returns Promise resolving to a TInvoice object
   */
  public async getLetterData(): Promise<TInvoice> {
    return this.decode();
  }

  /**
   * Gets the raw XML content
   * @returns XML string
   */
  public getXml(): string {
    return this.xml;
  }

  /**
   * Parses a CII date string based on format code
   * @param dateStr Date string
   * @param format Format code (e.g., '102' for YYYYMMDD)
   * @returns Timestamp in milliseconds
   */
  protected parseCIIDate(dateStr: string, format?: string): number {
    if (!dateStr) return Date.now();

    // Format 102 is YYYYMMDD
    if (format === '102' && dateStr.length === 8) {
      const year = parseInt(dateStr.substring(0, 4));
      const month = parseInt(dateStr.substring(4, 6)) - 1; // Month is 0-indexed in JS
      const day = parseInt(dateStr.substring(6, 8));
      return new Date(year, month, day).getTime();
    }
    
    // Format 610 is YYYYMM  
    if (format === '610' && dateStr.length === 6) {
      const year = parseInt(dateStr.substring(0, 4));
      const month = parseInt(dateStr.substring(4, 6)) - 1;
      return new Date(year, month, 1).getTime();
    }

    // Try to parse as ISO date or other standard formats
    const parsed = Date.parse(dateStr);
    return isNaN(parsed) ? Date.now() : parsed;
  }
}