// SCI Replication Service
// Global Replication Grid (GRG) with 30s metadata hashing

import prisma from '@/shared/database/prisma';
import { createHash } from 'crypto';
import { v4 as uuidv4 } from 'uuid';
import { logger } from '@/infrastructure/monitoring/logger';


const METADATA_HASH_INTERVAL = 30000; // 30 seconds

export interface ReplicationRequest {
  zoneId: string;
  targetZoneId: string;
  replicationType: 'metadata' | 'full' | 'incremental';
}

export class SciReplicationService {
  private hashIntervals: Map<string, NodeJS.Timeout> = new Map();

  /**
   * Start replication between zones
   */
  async startReplication(request: ReplicationRequest): Promise<{ replicationId: string }> {
    const replicationId = `REP-${uuidv4()}`;

    // Create replication record
    await prisma.sovereignReplication.create({
      data: {
        replicationId,
        zoneId: request.zoneId,
        targetZoneId: request.targetZoneId,
        replicationType: request.replicationType,
        metadataHash: '',
        lastHashTime: new Date(),
        status: 'active',
      },
    });

    // Start metadata hashing interval
    this.startMetadataHashing(replicationId, request.zoneId);

    logger.info('SCI: Started replication', {
      replicationId,
      zoneId: request.zoneId,
      targetZoneId: request.targetZoneId,
      replicationType: request.replicationType,
    });

    return { replicationId };
  }

  /**
   * Start metadata hashing every 30 seconds
   */
  private startMetadataHashing(replicationId: string, zoneId: string): void {
    const interval = setInterval(async () => {
      try {
        await this.updateMetadataHash(replicationId, zoneId);
      } catch (error) {
        logger.error('SCI: Metadata hashing failed', { error, replicationId, zoneId });
      }
    }, METADATA_HASH_INTERVAL);

    this.hashIntervals.set(replicationId, interval);
  }

  /**
   * Update metadata hash
   */
  private async updateMetadataHash(replicationId: string, zoneId: string): Promise<void> {
    // Get zone metadata
    const zone = await prisma.sovereignComputeZone.findUnique({
      where: { zoneId },
      include: {
        contracts: true,
        attestations: {
          where: { status: 'verified' },
        },
      },
    });

    if (!zone) {
      throw new Error('Zone not found');
    }

    // Create metadata object
    const metadata = {
      zoneId: zone.zoneId,
      status: zone.status,
      contractCount: zone.contracts.length,
      verifiedAttestationCount: zone.attestations.length,
      timestamp: new Date().toISOString(),
    };

    // Calculate hash
    const metadataString = JSON.stringify(metadata);
    const metadataHash = createHash('sha256').update(metadataString).digest('hex');

    // Update replication record
    await prisma.sovereignReplication.update({
      where: { replicationId },
      data: {
        metadataHash,
        lastHashTime: new Date(),
      },
    });

    logger.debug('SCI: Updated metadata hash', { replicationId, metadataHash });
  }

  /**
   * Stop replication
   */
  async stopReplication(replicationId: string): Promise<void> {
    // Stop hashing interval
    const interval = this.hashIntervals.get(replicationId);
    if (interval) {
      clearInterval(interval);
      this.hashIntervals.delete(replicationId);
    }

    // Update replication status
    await prisma.sovereignReplication.update({
      where: { replicationId },
      data: { status: 'paused' },
    });

    logger.info('SCI: Stopped replication', { replicationId });
  }

  /**
   * Get replication status
   */
  async getReplicationStatus(replicationId: string) {
    const replication = await prisma.sovereignReplication.findUnique({
      where: { replicationId },
      include: {
        zone: true,
      },
    });

    return replication;
  }
}

export const sciReplicationService = new SciReplicationService();