import { logger } from '../../utils/logger';
import { FeatureGovernanceService } from '../governance/FeatureGovernanceService';
import db from '../../config/database';
import { DIDHandshakeService } from '../security/DIDHandshakeService';

export interface SettlementInstruction {
  id: string;
  sourceTenantId: string;
  targetTenantId: string;
  amount: number;
  currency: string;
  proofOfFulfillment: string; // 关联的履约证据 Hash
  status: 'PENDING' | 'EXECUTING' | 'SETTLED' | 'DISPUTED';
}

/**
 * [BIZ_SOV_10] 跨主权自治结算协议 (Autonomous Settlement)
 * @description 核心逻辑：实现基于 DID 与主权信任的跨租户自动结算。
 * 当 AGI 验证履约证据（如物流签收 Hash、质检报告签名）满足智能合约触发条件时，
 * 系统自动发起跨租户资金对冲或结算指令，支持无中介机构介入的实时贸易清算。
 */
export class AutonomousSettlementService {
  private static readonly SETTLEMENT_TABLE = 'cf_autonomous_settlements';

  /**
   * 初始化表结构
   */
  static async initTable() {
    const hasTable = await db.schema.hasTable(this.SETTLEMENT_TABLE);
    if (!hasTable) {
      console.log(`📦 Creating ${this.SETTLEMENT_TABLE} table...`);
      await db.schema.createTable(this.SETTLEMENT_TABLE, (table) => {
        table.increments('id').primary();
        table.string('settlement_id', 64).notNullable().unique();
        table.string('source_tenant_id', 64).notNullable();
        table.string('target_tenant_id', 64).notNullable();
        table.decimal('amount', 15, 2).notNullable();
        table.string('currency', 10).notNullable();
        table.string('fulfillment_hash', 128);
        table.string('status', 16).defaultTo('PENDING');
        table.timestamp('created_at').defaultTo(db.fn.now());
        table.timestamp('settled_at');
        table.index(['source_tenant_id', 'target_tenant_id', 'status']);
      });
      console.log(`✅ Table ${this.SETTLEMENT_TABLE} created`);
    }
  }

  /**
   * 触发自动结算
   */
  static async triggerSettlement(params: {
    sourceTenantId: string;
    targetTenantId: string;
    amount: number;
    currency: string;
    fulfillmentHash: string;
  }): Promise<string> {
    // 1. 验证双方 DID 握手状态
    // const isVerified = await DIDHandshakeService.isSessionValid(params.sourceTenantId, params.targetTenantId);
    // if (!isVerified) throw new Error('No valid DID handshake found between tenants.');

    const settlementId = `SET-${Date.now()}`;
    
    await db(this.SETTLEMENT_TABLE).insert({
      settlement_id: settlementId,
      source_tenant_id: params.sourceTenantId,
      target_tenant_id: params.targetTenantId,
      amount: params.amount,
      currency: params.currency,
      fulfillment_hash: params.fulfillmentHash,
      status: 'EXECUTING'
    });

    logger.info(`[Settlement] Initiated autonomous settlement ${settlementId} for ${params.amount} ${params.currency}`);

    // 2. 模拟跨银行/区块链转账逻辑
    setTimeout(async () => {
      await db(this.SETTLEMENT_TABLE)
        .where({ settlement_id: settlementId })
        .update({ status: 'SETTLED', settled_at: new Date() });
      logger.info(`[Settlement] Settlement ${settlementId} completed successfully.`);
    }, 5000);

    return settlementId;
  }

  /**
   * 获取租户待结算列表
   */
  static async getPendingSettlements(tenantId: string): Promise<any[]> {
    return await db(this.SETTLEMENT_TABLE)
      .where({ source_tenant_id: tenantId, status: 'PENDING' })
      .orWhere({ target_tenant_id: tenantId, status: 'PENDING' });
  }
}
