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

export interface DecisionFactor {
  name: string;
  value: any;
  weight: number;
  impact: 'POSITIVE' | 'NEGATIVE' | 'NEUTRAL';
}

/**
 * [UX_XAI_01] AGI 决策可解释性引擎 (Explainable AI / XAI)
 * @description 核心逻辑：记录 AGI 决策的因果链 (Causal Chain)，支持流式叙述生成与证据链溯源。
 */
export class DecisionExplainabilityEngine {
  private static readonly TABLE_NAME = 'cf_decision_logs';

  /**
   * 初始化数据库表
   */
  static async initTable() {
    const hasTable = await db.schema.hasTable(this.TABLE_NAME);
    if (!hasTable) {
      logger.info(`📦 Creating ${this.TABLE_NAME} table...`);
      await db.schema.createTable(this.TABLE_NAME, (table) => {
        table.increments('id').primary();
        table.string('tenant_id', 64).index();
        table.string('module', 32).index(); // e.g., PRICING, SOURCING, ADS
        table.string('resource_id', 64).index();
        table.string('decision_type', 64);
        table.text('causal_chain'); // 因果叙述
        table.json('factors'); // 影响因子 [{name, value, weight, impact}]
        table.string('trace_id', 64);
        table.timestamp('created_at').defaultTo(db.fn.now());
      });
    }
  }

  /**
   * 记录决策证据链
   */
  static async logDecision(params: {
    tenantId: string;
    module: string;
    resourceId: string;
    decisionType: string;
    causalChain: string;
    factors: DecisionFactor[];
    traceId: string;
  }) {
    try {
      await db(this.TABLE_NAME).insert({
        tenant_id: params.tenantId,
        module: params.module,
        resource_id: params.resourceId,
        decision_type: params.decisionType,
        causal_chain: params.causalChain,
        factors: JSON.stringify(params.factors),
        trace_id: params.traceId,
        created_at: new Date()
      });
      
      logger.debug(`[XAI] Decision logged for ${params.module}:${params.resourceId}`);
    } catch (err: any) {
      // [CORE_DIAG_01] Agent 异常自省
      logger.error(`[XAI][WARN] Failed to log decision: ${err.message}`);
    }
  }

  /**
   * 获取决策证据链 (用于 Sandbox ROI 评估)
   */
  static async getDecisionByResourceId(resourceId: string) {
    const record = await db(this.TABLE_NAME)
      .where({ resource_id: resourceId })
      .orderBy('created_at', 'desc')
      .first();

    if (!record) return null;

    return {
      ...record,
      factors: record.factors ? JSON.parse(record.factors) : []
    };
  }

  /**
   * 获取决策叙述 (用于前端 Console 展示)
   */
  static async getDecisionNarrative(tenantId: string, resourceId: string) {
    return await db(this.TABLE_NAME)
      .where({ tenant_id: tenantId, resource_id: resourceId })
      .orderBy('created_at', 'desc')
      .first();
  }

  /**
   * [BIZ_GOV_05] 获取建议采纳 ROI 统计
   */
  static async getRoiStats(tenantId: string) {
    logger.info(`[XAI] Calculating ROI stats for tenant: ${tenantId}`);

    // 1. 调价建议 ROI (基于已执行的 cf_pricing_audit)
    const pricingRoi = await db('cf_pricing_audit')
      .join('cf_product', 'cf_pricing_audit.product_id', 'cf_product.id')
      .where('cf_pricing_audit.status', 'EXECUTED')
      .where('cf_product.tenant_id', tenantId)
      .select(db.raw('SUM((new_price - old_price) * 100) as total_profit_delta')); // 假设估算 100 销量

    // 2. 采购建议 ROI (基于已执行的 cf_sourcing_audit)
    const sourcingRoi = await db('cf_sourcing_audit')
      .where('status', 'EXECUTED')
      .where('tenant_id', tenantId)
      .select(db.raw('SUM(price * 0.1) as total_savings')); // 假设估算节省 10% (示例)

    return {
      pricing: {
        estimatedProfitDelta: Number(pricingRoi[0]?.total_profit_delta || 0),
        executedCount: await db('cf_pricing_audit').where({ status: 'EXECUTED' }).count('id as count')
      },
      sourcing: {
        estimatedSavings: Number(sourcingRoi[0]?.total_savings || 0),
        executedCount: await db('cf_sourcing_audit').where({ status: 'EXECUTED', tenant_id: tenantId }).count('id as count')
      },
      totalRoi: Number(pricingRoi[0]?.total_profit_delta || 0) + Number(sourcingRoi[0]?.total_savings || 0)
    };
  }
}