import { getAdmin, getLogger } from "../../../shared/config";
import * as fs from 'fs';
import * as os from 'os';
import * as path from 'path';
import { format } from 'date-fns';
import { sendEmailWithAttachmentUtil } from "../../../utils/emailService";
import { jsPDF } from "jspdf";
import autoTable from 'jspdf-autotable';
const admin = getAdmin();
const logger = getLogger();

export interface InvoiceData {
  invoiceNumber: string;
  businessName: string;
  address: string;
  gstNumber?: string;
  customerName: string;
  phoneNumber: string;
  email: string;
  planName: string;
  amount: number;
  transactionId: string;
  paymentDate: Date;
  paymentMethod: string;
}

export interface EmailOptions {
  recipientEmail: string;
  recipientName?: string;
  subject?: string;
  customHtml?: string;
  additionalData?: {
    gymName?: string;
    planName?: string;
    amount?: number;
    transactionId?: string;
    paymentDate?: Date;
    paymentMethod?: string;
  };
}

export class InvoiceService {
  async generateInvoice(data: InvoiceData): Promise<string> {
    try {
      const tempFilePath = path.join(os.tmpdir(), `invoice_${data.invoiceNumber}.pdf`);

      const hasGst = data.gstNumber && data.gstNumber.length > 0;
      const baseAmount = hasGst ? data.amount / 1.18 : data.amount;
      const sgst = hasGst ? baseAmount * 0.09 : 0;
      const cgst = hasGst ? baseAmount * 0.09 : 0;
      
      const formattedDate = format(data.paymentDate, 'dd/MM/yyyy');
      const doc = new jsPDF();

      doc.setFontSize(20);
      doc.setFont('helvetica', 'bold');
      doc.text(data.businessName, 15, 20);

      doc.setFontSize(12);
      doc.setFont('helvetica', 'normal');

      const maxWidth = 170;
      const lineHeight = 5;

      const addressLines = doc.splitTextToSize(data.address, maxWidth);

      if (addressLines.length <= 2) {
        for (let i = 0; i < addressLines.length; i++) {
          doc.text(addressLines[i], 15, 30 + (i * lineHeight));
        }
      } else {
        doc.text(addressLines[0], 15, 30);

        let secondLine = addressLines[1];
        if (secondLine.length > 3) {
          secondLine = secondLine.substring(0, secondLine.length - 3) + '...';
        } else {
          secondLine += '...';
        }
        doc.text(secondLine, 15, 35);
      }

      const gstYPosition = 40;

      if (hasGst) {
        doc.text(`GSTIN: ${data.gstNumber}`, 20, gstYPosition);
      }

      doc.setFontSize(24);
      doc.setFont('helvetica', 'bold');
      doc.text('RECEIPT', 195, 20, { align: 'right' });

      doc.setFontSize(12);
      doc.text(`Receipt #: ${data.invoiceNumber}`, 195, 30, { align: 'right' });
      doc.text(`Date: ${formattedDate}`, 195, 40, { align: 'right' });

      doc.setLineWidth(0.5);
      doc.line(15, 45, 195, 45);

      doc.setFontSize(12);
      const receiptToBoxX = 15;
      const receiptToBoxY = 50;
      const receiptToBoxWidth = 100;
      const receiptToBoxHeight = 36;

      doc.setDrawColor(0, 0, 0);
      doc.setLineWidth(0.5);
      doc.rect(receiptToBoxX, receiptToBoxY, receiptToBoxWidth, receiptToBoxHeight);
      doc.setFont('helvetica', 'bold');
      doc.text('Receipt To:', 18, 60);

      doc.setFont('helvetica', 'normal');
      doc.text(data.customerName, 18, 70);
      doc.text(`Phone: ${data.phoneNumber}`, 18, 75);
      doc.text(`Email: ${data.email}`, 18, 80);

      autoTable(doc, {
        startY: 110,
        margin: {left: 15, right: 15},
        head: [
          [
            {content: 'No.', styles: {halign: 'center'}}, 
            {content: 'Description', styles: {halign: 'left'}}, 
            {content: 'HSN/SAC', styles: {halign: 'center'}}, 
            {content: 'Amount (INR)', styles: {halign: 'right'}}
          ]
        ],
        body: [
          ['1', `${data.planName} Subscription`, '999723', baseAmount.toFixed(2)]
        ],
        headStyles: {
          fillColor: [220, 220, 220],
          textColor: [0, 0, 0],
          fontStyle: 'bold',
          lineWidth: 0.5,
          lineColor: [0, 0, 0]
        },
        styles: {
          halign: 'center',
          lineWidth: 0.5,
          lineColor: [0, 0, 0]
        },
        columnStyles: {
          0: { halign: 'center', cellWidth: 20 },
          1: { halign: 'left' },
          2: { halign: 'center', cellWidth: 40 },
          3: { halign: 'right', cellWidth: 40 }
        },
        theme: 'grid',
        tableLineWidth: 0.5,
        tableLineColor: [0, 0, 0],

      });

      const finalY = (doc as any).lastAutoTable.finalY + 20;

      if (hasGst) {
        doc.text('Taxable Amount:', 150, finalY, { align: 'right' });
        doc.text(`${baseAmount.toFixed(2)} INR`, 195, finalY, { align: 'right' });

        doc.text('SGST (9%):', 150, finalY + 10, { align: 'right' });
        doc.text(`${sgst.toFixed(2)} INR`, 195, finalY + 10, { align: 'right' });

        doc.text('CGST (9%):', 150, finalY + 20, { align: 'right' });
        doc.text(`${cgst.toFixed(2)} INR`, 195, finalY + 20, { align: 'right' });

        doc.setLineWidth(0.5);
        doc.line(15, finalY + 25, 195, finalY + 25);
        
        doc.setFont('helvetica', 'bold');
        doc.text('Total Amount:', 150, finalY + 30, { align: 'right' });
        doc.text(`${data.amount.toFixed(2)} INR`, 195, finalY + 30, { align: 'right' });
      } else {
        doc.setLineWidth(0.5);
        doc.line(15, finalY - 5, 195, finalY - 5);
        doc.setFont('helvetica', 'bold');
        doc.text('Total Amount:', 150, finalY, { align: 'right' });
        doc.text(`${data.amount.toFixed(2)} INR`, 195, finalY, { align: 'right' });
      }

      const paymentY = hasGst ? finalY + 50 : finalY + 20;

      const boxX = 15;
      const boxY = paymentY - 10;
      const boxWidth = 100;
      const boxHeight = 36;

      doc.setDrawColor(0, 0, 0);
      doc.setLineWidth(0.5);
      doc.rect(boxX, boxY, boxWidth, boxHeight);

      doc.setFont('helvetica', 'bold');
      doc.text('Payment Information:', 18, paymentY);

      doc.setFont('helvetica', 'normal');
      doc.text(`Transaction ID: ${data.transactionId}`, 18, paymentY + 10);
      doc.text(`Payment Method: ${data.paymentMethod}`, 18, paymentY + 15);
      doc.text(`Payment Date: ${formattedDate}`, 18, paymentY + 20);

      doc.setFontSize(12);
      doc.setFont('helvetica', 'italic');
      doc.text('Thank you for your business!', 105, 270, { align: 'center' });

      doc.setFontSize(10);
      doc.setFont('helvetica', 'normal');
      doc.text('This is a computer-generated receipt and does not require a signature.', 105, 280, { align: 'center' });

      fs.writeFileSync(tempFilePath, Buffer.from(doc.output('arraybuffer')));

      const invoicePath = `invoices/${data.invoiceNumber}.pdf`;
      const bucket = admin.storage().bucket();
      await bucket.upload(tempFilePath, {
        destination: invoicePath,
        metadata: {
          contentType: 'application/pdf',
        },
      });

      fs.unlinkSync(tempFilePath);

      return invoicePath;
    } catch (error: any) {
      logger.error('Error generating invoice:', error);
      throw new Error(`Failed to generate invoice: ${error.message}`);
    }
  }

  async getInvoiceDownloadUrl(invoicePath: string): Promise<string> {
    try {
      const bucket = admin.storage().bucket();
      const file = bucket.file(invoicePath);

      const expirationMs = 7 * 24 * 60 * 60 * 1000;

      const [signedUrl] = await file.getSignedUrl({
        action: 'read',
        expires: Date.now() + expirationMs,
        responseDisposition: `attachment; filename="${path.basename(invoicePath)}"`,
      });

      return signedUrl;
    } catch (error: any) {
      logger.error('Error getting invoice download URL:', error);
      throw new Error(`Failed to get invoice download URL: ${error.message}`);
    }
  }

  async updateInvoicePath(membershipId: string, paymentId: string, invoicePath: string): Promise<boolean> {
    try {
      const membershipPaymentsRef = admin.firestore()
        .collection('membership_payments')
        .doc(membershipId);

      const docSnapshot = await membershipPaymentsRef.get();

      if (!docSnapshot.exists) {
        logger.error(`No membership payments found for membershipId: ${membershipId}`);
        return false;
      }

      const data = docSnapshot.data();
      const paymentsData = data?.payments || [];

      let found = false;
      for (let i = 0; i < paymentsData.length; i++) {
        if (paymentsData[i].referenceNumber === paymentId ||
          paymentsData[i].transactionId === paymentId) {
          paymentsData[i].invoicePath = invoicePath;
          found = true;
          break;
        }
      }

      if (!found) {
        logger.error(`No payment found with ID: ${paymentId} in membership: ${membershipId}`);
        return false;
      }

      await membershipPaymentsRef.update({
        'payments': paymentsData,
        'updatedAt': admin.firestore.FieldValue.serverTimestamp(),
      });

      logger.info(`Successfully updated invoice path for payment: ${paymentId}`);
      return true;
    } catch (error: any) {
      logger.error('Error updating payment with invoice path:', error);
      return false;
    }
  }

  async sendInvoiceEmail(invoicePath: string, emailOptions: EmailOptions): Promise<boolean> {
    try {
      const downloadUrl = await this.getInvoiceDownloadUrl(invoicePath);

      const formattedDate = emailOptions.additionalData?.paymentDate
        ? new Date(emailOptions.additionalData.paymentDate).toLocaleDateString('en-GB')
        : new Date().toLocaleDateString('en-GB');

      const emailHtml = emailOptions.customHtml || `
        <html>
          <body>
            <h2>Thank you for your payment</h2>
            <p>Dear ${emailOptions.recipientName || 'Valued Customer'},</p>
            <p>Thank you for your payment. Your membership has been successfully activated.</p>
            <p>Please find attached your invoice for the payment.</p>
            <p>Membership Details:</p>
            <ul>
              <li>Gym: ${emailOptions.additionalData?.gymName || 'Fitlien'}</li>
              <li>Plan: ${emailOptions.additionalData?.planName || 'Membership'}</li>
              <li>Amount: ₹${emailOptions.additionalData?.amount || '0'}</li>
              <li>Transaction ID: ${emailOptions.additionalData?.transactionId || 'N/A'}</li>
              <li>Date: ${formattedDate}</li>
              <li>Payment Method: ${emailOptions.additionalData?.paymentMethod || 'Online'}</li>
            </ul>
            <p>If you have any questions, please contact us.</p>
            <p>Regards,<br>Fitlien Team</p>
          </body>
        </html>
      `;

      await sendEmailWithAttachmentUtil(
        emailOptions.recipientEmail,
        emailOptions.subject || 'Your Fitlien Membership Invoice',
        emailHtml,
        downloadUrl,
        `Invoice_${path.basename(invoicePath)}`
      );

      logger.info(`Invoice email sent to ${emailOptions.recipientEmail}`);
      return true;
    } catch (error: any) {
      logger.error('Error sending invoice email:', error);
      return false;
    }
  }

  async processInvoice(
    membershipId: string,
    paymentId: string,
    invoiceData: InvoiceData,
    emailOptions?: EmailOptions
  ): Promise<{
    success: boolean;
    invoicePath?: string;
    downloadUrl?: string;
    emailSent: boolean;
    error?: string;
  }> {
    try {
      const invoicePath = await this.generateInvoice(invoiceData);

      const updateSuccess = await this.updateInvoicePath(membershipId, paymentId, invoicePath);

      if (!updateSuccess) {
        return {
          success: false,
          invoicePath,
          emailSent: false,
          error: 'Failed to update payment with invoice path'
        };
      }

      const downloadUrl = await this.getInvoiceDownloadUrl(invoicePath);

      let emailSent = false;
      if (emailOptions && emailOptions.recipientEmail) {
        emailSent = await this.sendInvoiceEmail(invoicePath, emailOptions);
      }

      return {
        success: true,
        invoicePath,
        downloadUrl,
        emailSent
      };
    } catch (error: any) {
      logger.error('Error processing invoice:', error);
      return {
        success: false,
        emailSent: false,
        error: error.message
      };
    }
  }
}