// GRU Settlement Pipeline Service
// Implements Classical → Quantum → Ω-Layer settlement flow
// GRU → FX/SSU → GAS Atomic Network → Ω-Layer Merge → DBIS Prime Ledger

import prisma from '@/shared/database/prisma';
import { Decimal } from '@prisma/client/runtime/library';
import { v4 as uuidv4 } from 'uuid';
import { logger } from '@/infrastructure/monitoring/logger';
import { atomicSettlementService } from '@/core/settlement/isn/atomic-settlement.service';


export type PipelineStage = 'classical' | 'quantum' | 'omega_layer' | 'completed';
export type PipelineStatus = 'pending' | 'classical_initiated' | 'quantum_initiated' | 'omega_initiated' | 'completed' | 'failed';

export interface SettlementPipelineRequest {
  issuanceId: string;
  amount: string;
  currencyCode: string;
  sourceBankId: string;
  destinationBankId?: string;
}

export interface SettlementPipelineResult {
  pipelineId: string;
  stage: PipelineStage;
  status: PipelineStatus;
  gasSettlementId?: string;
  omegaFinalityId?: string;
}

export class GruSettlementPipelineService {
  /**
   * Initiate settlement pipeline
   * Flow: Classical → Quantum → Ω-Layer
   */
  async initiatePipeline(
    request: SettlementPipelineRequest
  ): Promise<SettlementPipelineResult> {
    logger.info('GRU Settlement Pipeline: Initiating pipeline', { request });

    // Create pipeline record
    const pipeline = await prisma.gru_settlement_pipelines.create({
      data: {
        pipelineId: `GRU-PIPE-${uuidv4()}`,
        issuanceId: request.issuanceId,
        pipelineStage: 'classical',
        status: 'pending',
        classicalState: {
          amount: request.amount,
          currencyCode: request.currencyCode,
          sourceBankId: request.sourceBankId,
          destinationBankId: request.destinationBankId,
        },
      },
    });

    // Proceed to classical settlement
    await this.proceedToClassical(pipeline.pipelineId, request);

    return {
      pipelineId: pipeline.pipelineId,
      stage: pipeline.pipelineStage as PipelineStage,
      status: pipeline.status as PipelineStatus,
    };
  }

  /**
   * Get pipeline status
   */
  async getPipelineStatus(pipelineId: string): Promise<any> {
    return await prisma.gru_settlement_pipelines.findUnique({
      where: { pipelineId },
      include: {
        gasSettlement: true,
        omegaFinality: true,
      },
    });
  }

  /**
   * Proceed to classical settlement
   */
  private async proceedToClassical(
    pipelineId: string,
    request: SettlementPipelineRequest
  ): Promise<void> {
    logger.info('GRU Settlement Pipeline: Proceeding to classical settlement', {
      pipelineId,
    });

    // Update pipeline status
    await prisma.gru_settlement_pipelines.update({
      where: { pipelineId },
      data: {
        status: 'classical_initiated',
        classicalState: {
          ...request,
          initiatedAt: new Date().toISOString(),
        },
      },
    });

    // Proceed to quantum (GAS) settlement
    await this.proceedToQuantum(pipelineId, request);
  }

  /**
   * Proceed to quantum (GAS) settlement
   */
  private async proceedToQuantum(
    pipelineId: string,
    request: SettlementPipelineRequest
  ): Promise<void> {
    logger.info('GRU Settlement Pipeline: Proceeding to quantum (GAS) settlement', {
      pipelineId,
    });

    try {
      // Execute GAS atomic settlement
      const gasResult = await atomicSettlementService.executeAtomicSettlement({
        sourceBankId: request.sourceBankId,
        destinationBankId: request.destinationBankId || request.sourceBankId,
        amount: parseFloat(request.amount),
        currencyCode: request.currencyCode,
        assetType: 'gru',
        transactionId: pipelineId,
      });

      // Create GAS settlement record
      const gasSettlement = await prisma.gru_gas_settlements.create({
        data: {
          settlementId: `GRU-GAS-${uuidv4()}`,
          pipelineId,
          gasTransactionId: gasResult.settlementId,
          atomicNetwork: 'GAS',
          settlementAmount: new Decimal(request.amount),
          currencyCode: request.currencyCode,
          atomicConfirmation: gasResult.dbisLedgerHash,
          status: 'atomic_confirmed',
          confirmedAt: new Date(),
        },
      });

      // Update pipeline
      await prisma.gru_settlement_pipelines.update({
        where: { pipelineId },
        data: {
          pipelineStage: 'quantum',
          status: 'quantum_initiated',
          quantumState: {
            gasSettlementId: gasSettlement.settlementId,
            atomicConfirmation: gasResult.dbisLedgerHash,
            quantumInitiatedAt: new Date().toISOString(),
          },
          gasSettlementId: gasSettlement.settlementId,
        },
      });

      // Proceed to Ω-Layer finality
      await this.proceedToOmegaLayer(pipelineId, gasSettlement.settlementId);

      logger.info('GRU Settlement Pipeline: GAS settlement completed', {
        pipelineId,
        gasSettlementId: gasSettlement.settlementId,
      });
    } catch (error) {
      logger.error('GRU Settlement Pipeline: GAS settlement failed', {
        pipelineId,
        error,
      });

      await prisma.gru_settlement_pipelines.update({
        where: { pipelineId },
        data: {
          status: 'failed',
        },
      });

      throw error;
    }
  }

  /**
   * Proceed to Ω-Layer finality
   */
  private async proceedToOmegaLayer(
    pipelineId: string,
    gasSettlementId: string
  ): Promise<void> {
    logger.info('GRU Settlement Pipeline: Proceeding to Ω-Layer finality', {
      pipelineId,
      gasSettlementId,
    });

    try {
      // Get GAS settlement details
      const gasSettlement = await prisma.gru_gas_settlements.findUnique({
        where: { settlementId: gasSettlementId },
      });

      if (!gasSettlement) {
        throw new Error(`GAS settlement not found: ${gasSettlementId}`);
      }

      // Perform Ω-Layer merge operation
      const mergeOperationId = `GRU-OMEGA-MERGE-${uuidv4()}`;
      const finalityProof = await this.performOmegaLayerMerge(
        pipelineId,
        gasSettlement,
        mergeOperationId
      );

      // Verify causality stability
      const causalityStable = await this.verifyCausalityStability(pipelineId);

      // Verify multi-reality reconciliation
      const multiRealityReconciled = await this.verifyMultiRealityReconciliation(
        pipelineId
      );

      // Create Ω-Layer finality record
      const omegaFinality = await prisma.gru_omega_layer_finalities.create({
        data: {
          finalityId: `GRU-OMEGA-${uuidv4()}`,
          pipelineId,
          omegaLayerId: 'OMEGA-LAYER-0',
          mergeOperationId,
          finalityProof,
          causalityStable,
          multiRealityReconciled,
          status: 'finalized',
          mergedAt: new Date(),
          finalizedAt: new Date(),
        },
      });

      // Update pipeline
      await prisma.gru_settlement_pipelines.update({
        where: { pipelineId },
        data: {
          pipelineStage: 'omega_layer',
          status: 'omega_initiated',
          omegaLayerState: {
            finalityId: omegaFinality.finalityId,
            mergeOperationId,
            finalityProof,
            causalityStable,
            multiRealityReconciled,
            finalizedAt: new Date().toISOString(),
          },
          omegaFinalityId: omegaFinality.finalityId,
        },
      });

      // Complete pipeline
      await this.completePipeline(pipelineId);

      logger.info('GRU Settlement Pipeline: Ω-Layer finality completed', {
        pipelineId,
        finalityId: omegaFinality.finalityId,
      });
    } catch (error) {
      logger.error('GRU Settlement Pipeline: Ω-Layer finality failed', {
        pipelineId,
        error,
      });

      await prisma.gru_settlement_pipelines.update({
        where: { pipelineId },
        data: {
          status: 'failed',
        },
      });

      throw error;
    }
  }

  /**
   * Perform Ω-Layer merge operation
   */
  private async performOmegaLayerMerge(
    pipelineId: string,
    gasSettlement: any,
    mergeOperationId: string
  ): Promise<string> {
    // Ω-Layer merge: MERGE(classical_state, quantum_state, omega_state)
    // This integrates with the existing Ω-Layer Settlement Fabric from Volume XII

    const pipeline = await prisma.gru_settlement_pipelines.findUnique({
      where: { pipelineId },
    });

    if (!pipeline) {
      throw new Error(`Pipeline not found: ${pipelineId}`);
    }

    // Create merge hash from all states
    const mergeData = {
      classicalState: pipeline.classicalState,
      quantumState: pipeline.quantumState,
      gasSettlement: {
        settlementId: gasSettlement.settlementId,
        atomicConfirmation: gasSettlement.atomicConfirmation,
      },
      mergeOperationId,
      timestamp: new Date().toISOString(),
    };

    // Generate finality proof (simplified - should use actual Ω-Layer merge logic)
    const finalityProof = this.generateFinalityProof(mergeData);

    return finalityProof;
  }

  /**
   * Verify causality stability
   */
  private async verifyCausalityStability(pipelineId: string): Promise<boolean> {
    // Causality stability verification
    // Ensures that the settlement doesn't violate causality constraints
    // This integrates with temporal settlement logic

    // For now, return true if pipeline exists
    const pipeline = await prisma.gru_settlement_pipelines.findUnique({
      where: { pipelineId },
    });

    return pipeline !== null;
  }

  /**
   * Verify multi-reality reconciliation
   */
  private async verifyMultiRealityReconciliation(
    pipelineId: string
  ): Promise<boolean> {
    // Multi-reality reconciliation verification
    // Ensures consistency across classical, quantum, and Ω-Layer states

    const pipeline = await prisma.gru_settlement_pipelines.findUnique({
      where: { pipelineId },
      include: {
        gasSettlement: true,
        omegaFinality: true,
      },
    });

    if (!pipeline) {
      return false;
    }

    // Verify all states are consistent
    const hasClassical = pipeline.classicalState !== null;
    const hasQuantum = pipeline.quantumState !== null;
    const hasGas = pipeline.gas_settlements !== null;
    const hasOmega = pipeline.omegaFinality !== null;

    return hasClassical && hasQuantum && hasGas && hasOmega;
  }

  /**
   * Generate finality proof
   */
  private generateFinalityProof(mergeData: any): string {
    // Generate a proof hash from merge data
    // In production, this would use actual Ω-Layer merge logic
    const crypto = require('crypto');
    const hash = crypto
      .createHash('sha256')
      .update(JSON.stringify(mergeData))
      .digest('hex');

    return `OMEGA-PROOF-${hash}`;
  }

  /**
   * Complete pipeline
   */
  private async completePipeline(pipelineId: string): Promise<void> {
    await prisma.gru_settlement_pipelines.update({
      where: { pipelineId },
      data: {
        pipelineStage: 'completed',
        status: 'completed',
        completedAt: new Date(),
      },
    });

    logger.info('GRU Settlement Pipeline: Pipeline completed', { pipelineId });
  }

  /**
   * Execute GAS atomic settlement (wrapper)
   */
  async executeGasSettlement(
    pipelineId: string,
    request: SettlementPipelineRequest
  ): Promise<string> {
    const gasResult = await atomicSettlementService.executeAtomicSettlement({
      sourceBankId: request.sourceBankId,
      destinationBankId: request.destinationBankId || request.sourceBankId,
      amount: parseFloat(request.amount),
      currencyCode: request.currencyCode,
      assetType: 'gru',
      transactionId: pipelineId,
    });

    // Create or update GAS settlement record
    const gasSettlement = await prisma.gru_gas_settlements.upsert({
      where: { pipelineId },
      update: {
        gasTransactionId: gasResult.settlementId,
        atomicConfirmation: gasResult.dbisLedgerHash,
        status: 'atomic_confirmed',
        confirmedAt: new Date(),
      },
      create: {
        settlementId: `GRU-GAS-${uuidv4()}`,
        pipelineId,
        gasTransactionId: gasResult.settlementId,
        atomicNetwork: 'GAS',
        settlementAmount: new Decimal(request.amount),
        currencyCode: request.currencyCode,
        atomicConfirmation: gasResult.dbisLedgerHash,
        status: 'atomic_confirmed',
        confirmedAt: new Date(),
      },
    });

    return gasSettlement.settlementId;
  }

  /**
   * Execute Ω-Layer finality (wrapper)
   */
  async executeOmegaFinality(
    pipelineId: string
  ): Promise<string> {
    const pipeline = await prisma.gru_settlement_pipelines.findUnique({
      where: { pipelineId },
      include: {
        gasSettlement: true,
      },
    });

    if (!pipeline || !pipeline.gas_settlements) {
      throw new Error(
        `Pipeline or GAS settlement not found: ${pipelineId}`
      );
    }

    await this.proceedToOmegaLayer(pipelineId, pipeline.gas_settlements.settlementId);

    const omegaFinality = await prisma.gru_omega_layer_finalities.findUnique({
      where: { pipelineId },
    });

    if (!omegaFinality) {
      throw new Error(`Ω-Layer finality not found for pipeline: ${pipelineId}`);
    }

    return omegaFinality.finalityId;
  }
}

export const gruSettlementPipelineService = new GruSettlementPipelineService();

