// GRU Temporal Settlement Service
// Multi-timeline settlement (t0, t-n, t+n, tΩ states)

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 { createHash } from 'crypto';


export interface TemporalSettlementRequest {
  sourceBankId: string;
  destinationBankId: string;
  amount: string;
  currencyCode: string;
  gruUnitId?: string;
  temporalState?: 'classical' | 'retro' | 'future' | 'omega';
  temporalOffset?: number; // For retro/future: negative for retro, positive for future
}

export interface TemporalSettlementResult {
  settlementId: string;
  temporalState: string;
  mergedState: Record<string, unknown>;
  status: string;
  settledAt?: Date;
}

export class GruTemporalSettlementService {
  /**
   * Execute temporal settlement
   * Formula: GRU_temp_settle = MERGE(classical_state, retro_state, future_projection, Ω_truth_state)
   */
  async executeTemporalSettlement(
    request: TemporalSettlementRequest
  ): Promise<TemporalSettlementResult> {
    logger.info('GRU Temporal Settlement: Executing temporal settlement', {
      request,
    });

    const settlementId = `GRU-TEMP-SETTLE-${uuidv4()}`;
    const temporalState = request.temporalState || 'classical';

    // Get classical state (t0)
    const classicalState = await this.getClassicalState(
      request.sourceBankId,
      request.destinationBankId,
      request.amount,
      request.currencyCode
    );

    // Get retrospective state (t-n) if temporal offset is negative
    let retroState: Record<string, unknown> | null = null;
    if (
      request.temporalOffset !== undefined &&
      request.temporalOffset < 0
    ) {
      retroState = await this.getRetrospectiveState(
        request.sourceBankId,
        request.destinationBankId,
        request.amount,
        request.currencyCode,
        Math.abs(request.temporalOffset)
      );
    }

    // Get future projection (t+n) if temporal offset is positive
    let futureState: Record<string, unknown> | null = null;
    if (
      request.temporalOffset !== undefined &&
      request.temporalOffset > 0
    ) {
      futureState = await this.getFutureProjection(
        request.sourceBankId,
        request.destinationBankId,
        request.amount,
        request.currencyCode,
        request.temporalOffset
      );
    }

    // Get Ω-Layer truth state (tΩ)
    const omegaState = await this.getOmegaTruthState(
      classicalState,
      retroState,
      futureState
    );

    // Merge all states
    const mergedState = this.mergeStates(
      classicalState,
      retroState,
      futureState,
      omegaState
    );

    // Create settlement record
    const settlement = await prisma.gru_temporal_settlements.create({
      data: {
        settlementId,
        sourceBankId: request.sourceBankId,
        destinationBankId: request.destinationBankId,
        amount: new Decimal(request.amount),
        currencyCode: request.currencyCode,
        gruUnitId: request.gruUnitId || null,
        settlementType: temporalState,
        temporalState: this.getTemporalStateString(
          request.temporalOffset || 0
        ),
        temporalOffset: request.temporalOffset || null,
        classicalState,
        retroState,
        futureState,
        omegaState,
        mergedState,
        status: 'merged',
      },
    });

    // Create temporal states
    if (classicalState) {
      await this.createTemporalState(
        settlementId,
        't0',
        0,
        classicalState
      );
    }

    if (retroState) {
      await this.createTemporalState(
        settlementId,
        `t-${Math.abs(request.temporalOffset || 0)}`,
        request.temporalOffset || 0,
        retroState
      );
    }

    if (futureState) {
      await this.createTemporalState(
        settlementId,
        `t+${request.temporalOffset || 0}`,
        request.temporalOffset || 0,
        futureState
      );
    }

    if (omegaState) {
      await this.createTemporalState(settlementId, 'tΩ', null, omegaState);
    }

    // Finalize settlement
    await this.finalizeSettlement(settlementId, mergedState);

    logger.info('GRU Temporal Settlement: Temporal settlement completed', {
      settlementId,
      temporalState,
    });

    return {
      settlementId,
      temporalState,
      mergedState,
      status: 'settled',
      settledAt: new Date(),
    };
  }

  /**
   * Get classical state (t0)
   */
  private async getClassicalState(
    sourceBankId: string,
    destinationBankId: string,
    amount: string,
    currencyCode: string
  ): Promise<Record<string, unknown>> {
    // Classical timeline represents current state
    return {
      sourceBankId,
      destinationBankId,
      amount,
      currencyCode,
      timestamp: new Date().toISOString(),
      stateType: 'classical',
    };
  }

  /**
   * Get retrospective state (t-n)
   */
  private async getRetrospectiveState(
    sourceBankId: string,
    destinationBankId: string,
    amount: string,
    currencyCode: string,
    offset: number
  ): Promise<Record<string, unknown>> {
    // Retrospective timeline represents historical state
    const retroTimestamp = new Date();
    retroTimestamp.setDate(retroTimestamp.getDate() - offset);

    return {
      sourceBankId,
      destinationBankId,
      amount,
      currencyCode,
      timestamp: retroTimestamp.toISOString(),
      stateType: 'retrospective',
      temporalOffset: -offset,
    };
  }

  /**
   * Get future projection (t+n)
   */
  private async getFutureProjection(
    sourceBankId: string,
    destinationBankId: string,
    amount: string,
    currencyCode: string,
    offset: number
  ): Promise<Record<string, unknown>> {
    // Future projection represents predicted state
    const futureTimestamp = new Date();
    futureTimestamp.setDate(futureTimestamp.getDate() + offset);

    // Apply predictive adjustments
    // In production, would use predictive models
    const adjustedAmount = new Decimal(amount).times(
      new Decimal(1).plus(offset * 0.001)
    ); // Slight adjustment for time value

    return {
      sourceBankId,
      destinationBankId,
      amount: adjustedAmount.toString(),
      currencyCode,
      timestamp: futureTimestamp.toISOString(),
      stateType: 'future',
      temporalOffset: offset,
      adjustedAmount: adjustedAmount.toString(),
    };
  }

  /**
   * Get Ω-Layer truth state (tΩ)
   * Merges all realities into single truth state
   */
  private async getOmegaTruthState(
    classicalState: Record<string, unknown>,
    retroState: Record<string, unknown> | null,
    futureState: Record<string, unknown> | null
  ): Promise<Record<string, unknown>> {
    // Ω-Layer represents merged truth across all timelines
    const omegaState: Record<string, unknown> = {
      stateType: 'omega',
      timestamp: new Date().toISOString(),
      classicalState,
    };

    if (retroState) {
      omegaState.retroState = retroState;
    }

    if (futureState) {
      omegaState.futureState = futureState;
    }

    // Calculate truth merge
    omegaState.merged = true;
    omegaState.consistency = this.checkConsistency(
      classicalState,
      retroState,
      futureState
    );

    return omegaState;
  }

  /**
   * Merge states using temporal settlement algorithm
   * Formula: MERGE(classical_state, retro_state, future_projection, Ω_truth_state)
   */
  private mergeStates(
    classicalState: Record<string, unknown>,
    retroState: Record<string, unknown> | null,
    futureState: Record<string, unknown> | null,
    omegaState: Record<string, unknown>
  ): Record<string, unknown> {
    const merged: Record<string, unknown> = {
      ...classicalState,
      omegaState,
    };

    // Incorporate retrospective adjustments if available
    if (retroState) {
      merged.retroAdjustments = retroState;
      merged.hasRetroState = true;
    }

    // Incorporate future projections if available
    if (futureState) {
      merged.futureProjections = futureState;
      merged.hasFutureState = true;
    }

    // Final merged state uses Ω-Layer as authority
    merged.finalState = omegaState;
    merged.mergeTimestamp = new Date().toISOString();

    return merged;
  }

  /**
   * Check consistency across timelines
   */
  private checkConsistency(
    classicalState: Record<string, unknown>,
    retroState: Record<string, unknown> | null,
    futureState: Record<string, unknown> | null
  ): boolean {
    // Basic consistency check
    // In production, would perform more sophisticated checks

    if (!retroState && !futureState) {
      return true; // Only classical state, consistent by definition
    }

    // Check amount consistency
    const classicalAmount = new Decimal(classicalState.amount as string);
    let consistent = true;

    if (retroState) {
      const retroAmount = new Decimal(retroState.amount as string);
      const variance = classicalAmount.minus(retroAmount).abs().dividedBy(classicalAmount);
      if (variance.greaterThan(new Decimal(0.1))) {
        // More than 10% variance
        consistent = false;
      }
    }

    if (futureState) {
      const futureAmount = new Decimal(futureState.adjustedAmount as string);
      const variance = classicalAmount.minus(futureAmount).abs().dividedBy(classicalAmount);
      if (variance.greaterThan(new Decimal(0.2))) {
        // More than 20% variance
        consistent = false;
      }
    }

    return consistent;
  }

  /**
   * Create temporal state record
   */
  private async createTemporalState(
    settlementId: string,
    temporalState: string,
    temporalOffset: number | null,
    stateData: Record<string, unknown>
  ): Promise<void> {
    const stateId = `GRU-STATE-${uuidv4()}`;
    const stateHash = createHash('sha256')
      .update(JSON.stringify(stateData))
      .digest('hex');

    await prisma.gruTemporalState.create({
      data: {
        stateId,
        settlementId,
        temporalState,
        temporalOffset,
        stateData,
        stateHash,
        verified: true,
        verifiedAt: new Date(),
      },
    });
  }

  /**
   * Finalize settlement
   */
  private async finalizeSettlement(
    settlementId: string,
    mergedState: Record<string, unknown>
  ): Promise<void> {
    await prisma.gru_temporal_settlements.update({
      where: { settlementId },
      data: {
        status: 'settled',
        settledAt: new Date(),
        mergedState,
      },
    });
  }

  /**
   * Get temporal state string
   */
  private getTemporalStateString(offset: number): string {
    if (offset === 0) {
      return 't0';
    } else if (offset < 0) {
      return `t${offset}`;
    } else {
      return `t+${offset}`;
    }
  }

  /**
   * Get temporal settlement by ID
   */
  async getTemporalSettlement(settlementId: string) {
    return await prisma.gru_temporal_settlements.findUnique({
      where: { settlementId },
      include: {
        states: {
          orderBy: { temporalOffset: 'asc' },
        },
        chronoFx: true,
      },
    });
  }

  /**
   * Get temporal settlements for a bank
   */
  async getTemporalSettlementsForBank(
    sovereignBankId: string,
    temporalState?: string,
    status?: string
  ) {
    const where: any = {
      OR: [{ sourceBankId: sovereignBankId }, { destinationBankId: sovereignBankId }],
    };

    if (temporalState) {
      where.temporalState = temporalState;
    }

    if (status) {
      where.status = status;
    }

    return await prisma.gru_temporal_settlements.findMany({
      where,
      include: {
        states: true,
        chronoFx: true,
      },
      orderBy: { createdAt: 'desc' },
    });
  }
}

export const gruTemporalSettlementService = new GruTemporalSettlementService();

