// CSSE Pre-Commit Service
// Pre-commit: t_precommit = HASH(predicted_state + sovereign_signature)

import prisma from '@/shared/database/prisma';
import { createHash } from 'crypto';
import { v4 as uuidv4 } from 'uuid';
import { quantumCryptoService } from '@/infrastructure/quantum/quantum-crypto.service';


export interface CreatePreCommitRequest {
  predictedState: Record<string, unknown>;
  sovereignSignature?: string;
}

export class CssePrecommitService {
  /**
   * Create pre-commit
   * Formula: t_precommit = HASH(predicted_state + sovereign_signature)
   */
  async createPreCommit(settlementId: string, request: CreatePreCommitRequest) {
    const settlement = await prisma.chronoSettlement.findUnique({
      where: { settlementId },
    });

    if (!settlement) {
      throw new Error(`Settlement not found: ${settlementId}`);
    }

    // Get or generate sovereign signature
    let sovereignSignature = request.sovereignSignature;
    if (!sovereignSignature) {
      // In production, would get actual signature from sovereign bank
      // For now, generate mock signature
      const message = JSON.stringify({
        settlementId,
        predictedState: request.predictedState,
        timestamp: new Date().toISOString(),
      });
      sovereignSignature = createHash('sha256').update(message).digest('hex');
    }

    // Calculate pre-commit hash: HASH(predicted_state + sovereign_signature)
    const predictedStateStr = JSON.stringify(request.predictedState);
    const combined = predictedStateStr + sovereignSignature;
    const preCommitHash = createHash('sha256').update(combined).digest('hex');

    const preCommitId = `CSSE-PC-${uuidv4()}`;

    const preCommit = await prisma.temporalPreCommit.create({
      data: {
        preCommitId,
        settlementId,
        predictedState: request.predictedState,
        sovereignSignature,
        preCommitHash,
        status: 'pending',
      },
    });

    return preCommit;
  }

  /**
   * Verify pre-commit
   */
  async verifyPreCommit(preCommitId: string) {
    const preCommit = await prisma.temporalPreCommit.findUnique({
      where: { preCommitId },
    });

    if (!preCommit) {
      throw new Error(`Pre-commit not found: ${preCommitId}`);
    }

    // Recalculate hash to verify
    const predictedStateStr = JSON.stringify(preCommit.predictedState);
    const combined = predictedStateStr + preCommit.sovereignSignature;
    const calculatedHash = createHash('sha256').update(combined).digest('hex');

    if (calculatedHash !== preCommit.preCommitHash) {
      throw new Error('Pre-commit hash verification failed');
    }

    // Update status
    return prisma.temporalPreCommit.update({
      where: { preCommitId },
      data: {
        status: 'verified',
        verifiedAt: new Date(),
      },
    });
  }

  /**
   * Commit pre-commit
   */
  async commitPreCommit(preCommitId: string) {
    const preCommit = await prisma.temporalPreCommit.findUnique({
      where: { preCommitId },
    });

    if (!preCommit) {
      throw new Error(`Pre-commit not found: ${preCommitId}`);
    }

    if (preCommit.status !== 'verified') {
      throw new Error('Pre-commit must be verified before commit');
    }

    return prisma.temporalPreCommit.update({
      where: { preCommitId },
      data: {
        status: 'committed',
        committedAt: new Date(),
      },
    });
  }

  /**
   * Get pre-commit by ID
   */
  async getPreCommit(preCommitId: string) {
    const preCommit = await prisma.temporalPreCommit.findUnique({
      where: { preCommitId },
      include: {
        settlement: true,
      },
    });

    if (!preCommit) {
      throw new Error(`Pre-commit not found: ${preCommitId}`);
    }

    return preCommit;
  }
}

export const cssePrecommitService = new CssePrecommitService();

