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

/**
 * [BIZ_OPS_132] 供应商响应时效动态分级 (Supplier SLA)
 * @description 核心逻辑：基于响应速度 (avg_response_hours) 与交期 (avg_delivery_days) 自动标记低效方，并提供切换建议。
 */
export class SLAScoringService {
  private static readonly AUDIT_TABLE = 'cf_sourcing_audit';

  /**
   * 审计供应商 SLA 并生成警告/建议 (BIZ_OPS_132)
   */
  static async auditSupplierSLA(tenantId: string, supplierId: string): Promise<any> {
    logger.info(`[SLAScoring] Auditing SLA for Supplier: ${supplierId}, Tenant: ${tenantId}`);

    try {
      // 1. 获取供应商最新绩效报告
      const supplierReport = await SupplierService.getSupplierTrustReport(supplierId);
      const metrics = supplierReport.metrics;
      const score = supplierReport.trustScore;

      // 2. SLA 阈值校验 (务实点)
      // 响应速度 > 24h 或 交期 > 10d 触发预警
      let slaBreached = false;
      let breachReason = '';

      if (metrics.responseHours > 24) {
        slaBreached = true;
        breachReason += `Response time (${metrics.responseHours}h) exceeds 24h limit. `;
      }

      if (metrics.deliveryDays > 10) {
        slaBreached = true;
        breachReason += `Delivery time (${metrics.deliveryDays}d) exceeds 10d limit. `;
      }

      if (score < 50) {
        slaBreached = true;
        breachReason += `Overall TrustScore (${score.toFixed(1)}) is dangerously low. `;
      }

      if (slaBreached) {
        logger.warn(`[SLAScoring] SLA Breach detected for ${supplierId}: ${breachReason}`);

        // 3. 寻找同租户下同类目更好的备选供应商 (模拟逻辑)
        const alternatives = await db('cf_suppliers')
          .where({ tenant_id: tenantId })
          .where('rating_score', '>', score + 10)
          .orderBy('rating_score', 'desc')
          .limit(1);

        const bestAlt = alternatives[0];
        const reason = `SLA BREACH: ${breachReason} ` + 
          (bestAlt ? `Recommended to switch to ${bestAlt.name} (Score: ${bestAlt.rating_score.toFixed(1)}).` : 'Immediate review required.');

        // 4. 生成建议 (Suggestion-First) -> 统一至 AdviceService
        const suggestionId = await AdviceService.recordAdvice({
          tenantId,
          shopId: 'GLOBAL', // 供应商审核通常是全局的
          traceId: 'sla-audit-' + Date.now(),
          insight: {
            type: 'SUPPLIER',
            title: `SLA Breach: ${supplierReport.name}`,
            description: reason,
            impact: 'high',
            confidence: 0.95,
            suggestedAction: bestAlt ? `SWITCH_TO_${bestAlt.id}` : 'MANUAL_REVIEW',
            metadata: { 
              supplierId, 
              bestAlternativeId: bestAlt?.id,
              metrics 
            }
          }
        });

        // 5. [UX_XAI_01] 记录决策证据链
        await DecisionExplainabilityEngine.logDecision({
          tenantId,
          module: 'SUPPLIER_SLA',
          resourceId: String(suggestionId),
          decisionType: 'SLA_BREACH_WARNING',
          causalChain: reason,
          factors: [
            { name: 'ResponseHours', value: metrics.responseHours, weight: 0.4, impact: 'NEGATIVE' },
            { name: 'DeliveryDays', value: metrics.deliveryDays, weight: 0.4, impact: 'NEGATIVE' },
            { name: 'TrustScore', value: score, weight: 0.2, impact: 'NEGATIVE' }
          ],
          traceId: 'sla-audit-' + Date.now()
        });

        return { 
          success: true, 
          suggestionId, 
          slaBreached, 
          reason, 
          bestAlternative: bestAlt?.name,
          status: 'PENDING_REVIEW' 
        };
      }

      return { success: true, slaBreached: false, message: 'SLA compliant' };
    } catch (err: any) {
      logger.error(`[SLAScoring][WARN] SLA audit failed: ${err.message}`);
      return { success: false, error: err.message };
    }
  }
}