import db from '../config/database';
import { logger } from '../utils/logger';
import { DecisionExplainabilityEngine } from '../core/ai/DecisionExplainabilityEngine';

/**
 * [BIZ_OPS_145] 供应商节假日发货延迟预警 (Holiday)
 * @description 核心逻辑：基于各国节假日日历（如中国春节、斋月、圣诞节），自动识别供应商所在地的假期风险，提前 15 天提示备货建议。
 */
export class HolidayRiskService {
  /**
   * 预测节假日延迟风险 (BIZ_OPS_145)
   */
  static async predictHolidayDelays(tenantId: string, supplierId: string): Promise<any> {
    logger.info(`[HolidayRisk] Analyzing holiday risks for Supplier: ${supplierId}, Tenant: ${tenantId}`);

    try {
      // 1. 模拟获取供应商所在地及假期日历
      const upcomingHolidays = [
        { name: 'Spring Festival', start: '2026-02-10', end: '2026-02-20', location: 'CN' }
      ];

      const today = new Date();
      const holiday = upcomingHolidays[0];
      const holidayStart = new Date(holiday.start);
      const daysUntilHoliday = (holidayStart.getTime() - today.getTime()) / (1000 * 3600 * 24);

      // 2. 预警逻辑：如果假期在 15 天内
      if (daysUntilHoliday > 0 && daysUntilHoliday < 15) {
        const advice = `UPCOMING HOLIDAY RISK: ${holiday.name} starts in ${daysUntilHoliday.toFixed(0)} days. ` +
          `Supplier fulfillment will likely stop. Suggesting immediate bulk stock order for high-velocity SKUs.`;

        // 3. [UX_XAI_01] 记录决策证据链
        await DecisionExplainabilityEngine.logDecision({
          tenantId,
          module: 'SUPPLY_CHAIN_RISK',
          resourceId: supplierId,
          decisionType: 'HOLIDAY_DELAY_WARNING',
          causalChain: advice,
          factors: [
            { name: 'DaysToHoliday', value: daysUntilHoliday, weight: 0.9, impact: 'NEGATIVE' },
            { name: 'HolidayDuration', value: 10, weight: 0.1, impact: 'NEGATIVE' }
          ],
          traceId: 'holiday-risk-' + Date.now()
        });

        return { success: true, riskLevel: 'HIGH', holiday: holiday.name, advice, status: 'PENDING_REVIEW' };
      }

      return { success: true, riskLevel: 'LOW', message: 'No major holiday risk detected in next 15 days' };
    } catch (err: any) {
      logger.error(`[HolidayRisk][WARN] Prediction failed: ${err.message}`);
      return { success: false, error: err.message };
    }
  }
}
