// IBIN Issuance Service
// Digital bond creation and HSM signing

import prisma from '@/shared/database/prisma';
import { Decimal } from '@prisma/client/runtime/library';
import { v4 as uuidv4 } from 'uuid';
import { createHash } from 'crypto';


export interface DigitalBondIssuanceRequest {
  issuerBankId: string;
  couponRate: string; // Percentage
  maturityDate: Date;
  principal: string;
  currencyCode: string;
  settlementMode?: string; // cbdc, fiat
  collateral?: Record<string, unknown>; // Optional commodity or SSU
}

export interface BondIssuanceResult {
  bondId: string;
  hsmSignature: string;
  status: string;
}

export class IbinIssuanceService {
  /**
   * Issue digital bond
   */
  async issueBond(
    request: DigitalBondIssuanceRequest
  ): Promise<BondIssuanceResult> {
    const bondId = `BOND-${uuidv4()}`;

    // Generate HSM signature
    const hsmSignature = await this.generateHSMSignature(bondId, request);

    // Create digital bond
    const bond = await prisma.digital_bonds.create({
      data: {
        bondId,
        issuerBankId: request.issuerBankId,
        couponRate: new Decimal(request.couponRate),
        maturityDate: request.maturityDate,
        principal: new Decimal(request.principal),
        currencyCode: request.currencyCode,
        settlementMode: request.settlementMode || 'cbdc',
        collateral: request.collateral || null,
        hsmSignature,
        status: 'issued',
      },
    });

    return {
      bondId: bond.bondId,
      hsmSignature: bond.hsmSignature,
      status: bond.status,
    };
  }

  /**
   * Generate HSM signature
   * In production, this would call actual HSM
   */
  private async generateHSMSignature(
    bondId: string,
    request: DigitalBondIssuanceRequest
  ): Promise<string> {
    // Create signature payload
    const payload = {
      bondId,
      issuerBankId: request.issuerBankId,
      couponRate: request.couponRate,
      maturityDate: request.maturityDate.toISOString(),
      principal: request.principal,
      currencyCode: request.currencyCode,
      timestamp: new Date().toISOString(),
    };

    // In production, this would use actual HSM
    // For now, generate a hash-based signature
    const payloadString = JSON.stringify(payload);
    const hash = createHash('sha3-256').update(payloadString).digest('hex');
    const signature = `HSM-SIG-${hash}`;

    return signature;
  }

  /**
   * Get bond details
   */
  async getBond(bondId: string): Promise<any> {
    const bond = await prisma.digital_bonds.findUnique({
      where: { bondId },
    });

    if (!bond) {
      throw new Error(`Bond not found: ${bondId}`);
    }

    return bond;
  }

  /**
   * Redeem bond
   */
  async redeemBond(bondId: string): Promise<void> {
    const bond = await prisma.digital_bonds.findUnique({
      where: { bondId },
    });

    if (!bond) {
      throw new Error(`Bond not found: ${bondId}`);
    }

    if (bond.status !== 'active') {
      throw new Error(`Bond cannot be redeemed: ${bond.status}`);
    }

    await prisma.digital_bonds.update({
      where: { bondId },
      data: {
        status: 'redeemed',
      },
    });
  }
}

export const ibinIssuanceService = new IbinIssuanceService();

