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

/**
 * [BIZ_OPS_154] 基于实时毛利的动态运费模板建议 (Shipping Cost)
 * @description 核心逻辑：基于实时毛利（GMV - COGS - Marketing）的变化，自动优化“包邮门槛”（Free Shipping Threshold），平衡订单转化率与物流成本。
 */
export class DynamicShippingService {
  /**
   * 优化包邮门槛 (BIZ_OPS_154)
   */
  static async optimizeShippingThresholds(tenantId: string, shopId: string): Promise<any> {
    logger.info(`[DynamicShipping] Optimizing shipping thresholds for Shop: ${shopId}, Tenant: ${tenantId}`);

    try {
      // 1. 获取近 7 天平均毛利 (模拟)
      const avgMargin = 0.22; // 22% 毛利
      const targetMargin = 0.25;

      // 2. 识别差距：如果低于 25%
      if (avgMargin < targetMargin) {
        const currentThreshold = 49.99;
        const newThreshold = 59.99;
        const advice = `DYNAMIC SHIPPING SUGGESTION: Average margin (${(avgMargin * 100).toFixed(1)}%) is below target (25%). ` +
          `Suggesting increase of free shipping threshold from ${currentThreshold} to ${newThreshold} to offset logistics cost.`;

        // 3. [UX_XAI_01] 记录决策证据链
        await DecisionExplainabilityEngine.logDecision({
          tenantId,
          module: 'SHIPPING_PRICING_OPTIMIZATION',
          resourceId: shopId,
          decisionType: 'THRESHOLD_ADJUSTMENT_SUGGESTION',
          causalChain: advice,
          factors: [
            { name: 'AverageMargin', value: (avgMargin * 100).toFixed(1) + '%', weight: 0.7, impact: 'NEGATIVE' },
            { name: 'TargetMargin', value: (targetMargin * 100).toFixed(1) + '%', weight: 0.3, impact: 'POSITIVE' }
          ],
          traceId: 'dynamic-shipping-' + Date.now()
        });

        return { success: true, currentThreshold, suggestedThreshold: newThreshold, advice, status: 'PENDING_REVIEW' };
      }

      return { success: true, message: 'Current shipping threshold is optimal' };
    } catch (err: any) {
      logger.error(`[DynamicShipping][WARN] Optimization failed: ${err.message}`);
      return { success: false, error: err.message };
    }
  }
}
