import logger from '../utils/logger';

/**
 * DMS (Document Management System) Integration Service
 * Handles integration with DMS for e-invoice and credit note generation
 * 
 * NOTE: This is a placeholder/stub implementation.
 * Replace with actual DMS API integration based on your DMS system.
 */
export class DMSIntegrationService {
  private dmsBaseUrl: string;
  private dmsApiKey?: string;
  private dmsUsername?: string;
  private dmsPassword?: string;

  constructor() {
    this.dmsBaseUrl = process.env.DMS_BASE_URL || '';
    this.dmsApiKey = process.env.DMS_API_KEY;
    this.dmsUsername = process.env.DMS_USERNAME;
    this.dmsPassword = process.env.DMS_PASSWORD;
  }

  /**
   * Check if DMS integration is configured
   */
  private isConfigured(): boolean {
    return !!this.dmsBaseUrl && (!!this.dmsApiKey || (!!this.dmsUsername && !!this.dmsPassword));
  }

  /**
   * Generate e-invoice in DMS
   * @param invoiceData - Invoice data
   * @returns E-invoice details including invoice number, DMS number, etc.
   */
  async generateEInvoice(invoiceData: {
    requestNumber: string;
    dealerCode: string;
    dealerName: string;
    amount: number;
    description: string;
    ioNumber?: string;
    taxDetails?: any;
  }): Promise<{
    success: boolean;
    eInvoiceNumber?: string;
    dmsNumber?: string;
    invoiceDate?: Date;
    invoiceUrl?: string;
    error?: string;
  }> {
    try {
      if (!this.isConfigured()) {
        logger.warn('[DMS] DMS integration not configured, generating mock e-invoice');
        // Return mock data for development/testing
        const mockInvoiceNumber = `EINV-${Date.now()}`;
        const mockDmsNumber = `DMS-${Date.now()}`;
        return {
          success: true,
          eInvoiceNumber: mockInvoiceNumber,
          dmsNumber: mockDmsNumber,
          invoiceDate: new Date(),
          invoiceUrl: `https://dms.example.com/invoices/${mockInvoiceNumber}`,
          error: 'DMS not configured - e-invoice generation simulated'
        };
      }

      // TODO: Implement actual DMS API call
      // Example:
      // const response = await axios.post(`${this.dmsBaseUrl}/api/invoices/generate`, {
      //   request_number: invoiceData.requestNumber,
      //   dealer_code: invoiceData.dealerCode,
      //   dealer_name: invoiceData.dealerName,
      //   amount: invoiceData.amount,
      //   description: invoiceData.description,
      //   io_number: invoiceData.ioNumber,
      //   tax_details: invoiceData.taxDetails
      // }, {
      //   headers: {
      //     'Authorization': `Bearer ${this.dmsApiKey}`,
      //     'Content-Type': 'application/json'
      //   }
      // });
      //
      // return {
      //   success: response.data.success,
      //   eInvoiceNumber: response.data.e_invoice_number,
      //   dmsNumber: response.data.dms_number,
      //   invoiceDate: new Date(response.data.invoice_date),
      //   invoiceUrl: response.data.invoice_url
      // };

      logger.warn('[DMS] DMS e-invoice generation not implemented, generating mock invoice');
      const mockInvoiceNumber = `EINV-${Date.now()}`;
      const mockDmsNumber = `DMS-${Date.now()}`;
      return {
        success: true,
        eInvoiceNumber: mockInvoiceNumber,
        dmsNumber: mockDmsNumber,
        invoiceDate: new Date(),
        invoiceUrl: `https://dms.example.com/invoices/${mockInvoiceNumber}`,
        error: 'DMS API not implemented - e-invoice generation simulated'
      };
    } catch (error) {
      logger.error('[DMS] Error generating e-invoice:', error);
      return {
        success: false,
        error: error instanceof Error ? error.message : 'Unknown error'
      };
    }
  }

  /**
   * Generate credit note in DMS
   * @param creditNoteData - Credit note data
   * @returns Credit note details including credit note number, amount, etc.
   */
  async generateCreditNote(creditNoteData: {
    requestNumber: string;
    eInvoiceNumber: string;
    dealerCode: string;
    dealerName: string;
    amount: number;
    reason: string;
    description?: string;
  }): Promise<{
    success: boolean;
    creditNoteNumber?: string;
    creditNoteDate?: Date;
    creditNoteAmount?: number;
    creditNoteUrl?: string;
    error?: string;
  }> {
    try {
      if (!this.isConfigured()) {
        logger.warn('[DMS] DMS integration not configured, generating mock credit note');
        // Return mock data for development/testing
        const mockCreditNoteNumber = `CN-${Date.now()}`;
        return {
          success: true,
          creditNoteNumber: mockCreditNoteNumber,
          creditNoteDate: new Date(),
          creditNoteAmount: creditNoteData.amount,
          creditNoteUrl: `https://dms.example.com/credit-notes/${mockCreditNoteNumber}`,
          error: 'DMS not configured - credit note generation simulated'
        };
      }

      // TODO: Implement actual DMS API call
      // Example:
      // const response = await axios.post(`${this.dmsBaseUrl}/api/credit-notes/generate`, {
      //   request_number: creditNoteData.requestNumber,
      //   e_invoice_number: creditNoteData.eInvoiceNumber,
      //   dealer_code: creditNoteData.dealerCode,
      //   dealer_name: creditNoteData.dealerName,
      //   amount: creditNoteData.amount,
      //   reason: creditNoteData.reason,
      //   description: creditNoteData.description
      // }, {
      //   headers: {
      //     'Authorization': `Bearer ${this.dmsApiKey}`,
      //     'Content-Type': 'application/json'
      //   }
      // });
      //
      // return {
      //   success: response.data.success,
      //   creditNoteNumber: response.data.credit_note_number,
      //   creditNoteDate: new Date(response.data.credit_note_date),
      //   creditNoteAmount: response.data.credit_note_amount,
      //   creditNoteUrl: response.data.credit_note_url
      // };

      logger.warn('[DMS] DMS credit note generation not implemented, generating mock credit note');
      const mockCreditNoteNumber = `CN-${Date.now()}`;
      return {
        success: true,
        creditNoteNumber: mockCreditNoteNumber,
        creditNoteDate: new Date(),
        creditNoteAmount: creditNoteData.amount,
        creditNoteUrl: `https://dms.example.com/credit-notes/${mockCreditNoteNumber}`,
        error: 'DMS API not implemented - credit note generation simulated'
      };
    } catch (error) {
      logger.error('[DMS] Error generating credit note:', error);
      return {
        success: false,
        error: error instanceof Error ? error.message : 'Unknown error'
      };
    }
  }

  /**
   * Get invoice status from DMS
   * @param eInvoiceNumber - E-invoice number
   * @returns Invoice status and details
   */
  async getInvoiceStatus(eInvoiceNumber: string): Promise<{
    success: boolean;
    status?: string;
    invoiceNumber?: string;
    dmsNumber?: string;
    invoiceDate?: Date;
    amount?: number;
    error?: string;
  }> {
    try {
      if (!this.isConfigured()) {
        logger.warn('[DMS] DMS integration not configured, returning mock invoice status');
        return {
          success: true,
          status: 'GENERATED',
          invoiceNumber: eInvoiceNumber,
          dmsNumber: `DMS-${Date.now()}`,
          invoiceDate: new Date(),
          amount: 0,
          error: 'DMS not configured - invoice status simulated'
        };
      }

      // TODO: Implement actual DMS API call
      // Example:
      // const response = await axios.get(`${this.dmsBaseUrl}/api/invoices/${eInvoiceNumber}/status`, {
      //   headers: {
      //     'Authorization': `Bearer ${this.dmsApiKey}`,
      //     'Content-Type': 'application/json'
      //   }
      // });
      //
      // return {
      //   success: true,
      //   status: response.data.status,
      //   invoiceNumber: response.data.invoice_number,
      //   dmsNumber: response.data.dms_number,
      //   invoiceDate: new Date(response.data.invoice_date),
      //   amount: response.data.amount
      // };

      logger.warn('[DMS] DMS invoice status check not implemented, returning mock status');
      return {
        success: true,
        status: 'GENERATED',
        invoiceNumber: eInvoiceNumber,
        dmsNumber: `DMS-${Date.now()}`,
        invoiceDate: new Date(),
        amount: 0,
        error: 'DMS API not implemented - invoice status simulated'
      };
    } catch (error) {
      logger.error('[DMS] Error getting invoice status:', error);
      return {
        success: false,
        error: error instanceof Error ? error.message : 'Unknown error'
      };
    }
  }

  /**
   * Download invoice document from DMS
   * @param eInvoiceNumber - E-invoice number
   * @returns Invoice document URL or file buffer
   */
  async downloadInvoice(eInvoiceNumber: string): Promise<{
    success: boolean;
    documentUrl?: string;
    documentBuffer?: Buffer;
    mimeType?: string;
    error?: string;
  }> {
    try {
      if (!this.isConfigured()) {
        logger.warn('[DMS] DMS integration not configured, returning mock download URL');
        return {
          success: true,
          documentUrl: `https://dms.example.com/invoices/${eInvoiceNumber}/download`,
          mimeType: 'application/pdf',
          error: 'DMS not configured - download URL simulated'
        };
      }

      // TODO: Implement actual DMS API call
      // Example:
      // const response = await axios.get(`${this.dmsBaseUrl}/api/invoices/${eInvoiceNumber}/download`, {
      //   headers: {
      //     'Authorization': `Bearer ${this.dmsApiKey}`
      //   },
      //   responseType: 'arraybuffer'
      // });
      //
      // return {
      //   success: true,
      //   documentBuffer: Buffer.from(response.data),
      //   mimeType: response.headers['content-type'] || 'application/pdf'
      // };

      logger.warn('[DMS] DMS invoice download not implemented, returning mock URL');
      return {
        success: true,
        documentUrl: `https://dms.example.com/invoices/${eInvoiceNumber}/download`,
        mimeType: 'application/pdf',
        error: 'DMS API not implemented - download URL simulated'
      };
    } catch (error) {
      logger.error('[DMS] Error downloading invoice:', error);
      return {
        success: false,
        error: error instanceof Error ? error.message : 'Unknown error'
      };
    }
  }
}

export const dmsIntegrationService = new DMSIntegrationService();