import { logger } from '../../utils/logger';
import { PrivateAuditService } from '../security/PrivateAuditService';
import { FederatedNodeService } from './FederatedNodeService';
import db from '../../config/database';

/**
 * [SOV_NET_03] 节点间加密库存同步机制 (Encrypted Stock Sync)
 * @description 核心逻辑：在联邦节点间同步库存状态，但保护核心商业秘密。
 * 利用 ZKP (零知识证明) 证明库存是否满足特定阈值（如 > 100），而非泄露具体数值。
 * 联动 [PrivateAuditService] 生成与验证主权证明。
 */
export class PrivateInventorySyncService {
  /**
   * 生成库存可用性证明
   * @param tenantId 租户 ID
   * @param productId 商品 ID
   * @param threshold 最小需求阈值
   * @returns ZKP 证明对象
   */
  static async generateStockProof(tenantId: string, productId: string, threshold: number): Promise<string> {
    logger.info(`[SovNet] Generating stock proof for ${productId} (Threshold: ${threshold})`);

    // 1. 获取真实库存数据
    const product = await db('cf_product').where({ tenant_id: tenantId, product_id: productId }).first();
    const actualStock = product ? product.stock_quantity : 0;

    // 2. 调用隐私审计服务生成 Range Proof
    // 证明 actualStock >= threshold
    const proof = await PrivateAuditService.generateProof({
      value: actualStock,
      threshold,
      type: 'GEQ' // Greater than or Equal
    });

    return proof;
  }

  /**
   * 验证来自其它节点的库存证明
   * @param nodeId 来源节点 ID
   * @param productId 商品 ID
   * @param proof ZKP 证明
   * @returns 是否验证通过
   */
  static async verifyExternalStock(nodeId: string, productId: string, proof: string): Promise<boolean> {
    logger.info(`[SovNet] Verifying stock proof from node ${nodeId} for product ${productId}`);

    // 1. 获取节点公钥
    const nodes = await FederatedNodeService.getActiveNodes();
    const sourceNode = nodes.find(n => n.nodeId === nodeId);
    if (!sourceNode) {
      logger.error(`[SovNet] Source node ${nodeId} not found or offline.`);
      return false;
    }

    // 2. 验证证明真实性
    const isValid = await PrivateAuditService.verifyProof(proof, sourceNode.publicKey);
    
    if (isValid) {
      logger.info(`[SovNet] Stock proof verified. Product ${productId} is available at node ${nodeId}.`);
    } else {
      logger.warn(`[SovNet] Invalid stock proof received from node ${nodeId}.`);
    }

    return isValid;
  }
}
