323 lines
11 KiB
Python
323 lines
11 KiB
Python
"""现金流预测引擎 — 根据历史KPI数据推算未来30天现金流"""
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import logging
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from datetime import datetime, timedelta
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from typing import Optional
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from sqlalchemy.orm import Session
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import math
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import random
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logger = logging.getLogger("cma.cash_forecast")
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# 默认现金阈值(万元)
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DEFAULT_CASH_WARNING = 20.0 # 黄灯 — 低于20万
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DEFAULT_CASH_CRITICAL = 10.0 # 红灯 — 低于10万
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# 历史KPI编码映射
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KPI_CODES = {
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"operating_cash_flow": "CASH_FLOW_001", # 经营现金流
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"receivables": "AR_001", # 应收账款
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"payables": "AP_001", # 应付账款
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"cash_balance": "CASH_001", # 现金余额
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}
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def get_entity_kpi_history(entity_id: int, kpi_code: str, db: Session, limit_months: int = 6) -> list:
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"""获取实体某个KPI的历史值"""
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from app.models import KPIDefinition, KPIValue
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kpi = db.query(KPIDefinition).filter(
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KPIDefinition.kpi_code == kpi_code,
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KPIDefinition.entity_id == entity_id,
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).first()
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if not kpi:
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return []
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values = db.query(KPIValue).filter(
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KPIValue.kpi_id == kpi.id,
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KPIValue.actual_value.isnot(None),
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).order_by(KPIValue.period.desc()).limit(limit_months).all()
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return values
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def calc_trend(values: list) -> float:
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"""计算趋势系数 — 线性回归斜率 / 均值"""
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if len(values) < 2:
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return 0.0
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vals = [v.actual_value for v in values]
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n = len(vals)
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avg_x = (n - 1) / 2.0
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avg_y = sum(vals) / n
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num = sum((i - avg_x) * (vals[i] - avg_y) for i in range(n))
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den = sum((i - avg_x) ** 2 for i in range(n))
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slope = num / den if den != 0 else 0
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return slope / max(abs(avg_y), 1.0) * 100 # 趋势百分比
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def forecast_cash_flow(
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entity_id: int,
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db: Session,
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days: int = 30,
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current_cash: Optional[float] = None,
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) -> dict:
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"""
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预测未来30天现金流
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算法:
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1. 获取历史经营现金流、应收、应付趋势
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2. 推算每日现金流入/流出
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3. 生成每日预测值+置信区间
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"""
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from app.models import KPIDefinition, KPIValue
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# 获取当前现金余额
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if current_cash is None:
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cash_kpi = db.query(KPIDefinition).filter(
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KPIDefinition.kpi_code == KPI_CODES["cash_balance"],
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KPIDefinition.entity_id == entity_id,
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).first()
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if cash_kpi:
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latest_cash = db.query(KPIValue).filter(
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KPIValue.kpi_id == cash_kpi.id,
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KPIValue.actual_value.isnot(None),
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).order_by(KPIValue.period.desc()).first()
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base_cash = latest_cash.actual_value if latest_cash else 30.0
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else:
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base_cash = 30.0 # 默认假设30万
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else:
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base_cash = current_cash
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# 获取经营现金流历史
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ocf_history = get_entity_kpi_history(entity_id, KPI_CODES["operating_cash_flow"], db)
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ocf_trend = calc_trend(ocf_history)
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# 获取应收历史
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ar_history = get_entity_kpi_history(entity_id, KPI_CODES["receivables"], db)
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ar_trend = calc_trend(ar_history)
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# 获取应付历史
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ap_history = get_entity_kpi_history(entity_id, KPI_CODES["payables"], db)
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ap_trend = calc_trend(ap_history)
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# 计算日均现金变化
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ocf_avg = sum(v.actual_value for v in ocf_history) / max(len(ocf_history), 1) / 30.0 if ocf_history else 0.5
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# 预测逻辑:趋势影响 + 季节性(月底回款高峰)
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forecast = []
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cash = base_cash
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today = datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)
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for day_offset in range(1, days + 1):
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d = today + timedelta(days=day_offset)
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day_of_month = d.day
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is_month_end = day_of_month >= 25
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# 每日现金变化 = 经营现金流日均值 × (1 + 趋势调整) + 季节因子
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trend_factor = 1.0 + ocf_trend / 100.0
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daily_change = ocf_avg * trend_factor
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# 月底回款高峰
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if is_month_end:
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daily_change += ocf_avg * 0.3 # 月底多30%回款
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# 周末效应
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if d.weekday() >= 5:
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daily_change *= 0.5 # 周末收支减半
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cash += daily_change
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# 置信区间:随时间增加而扩大
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confidence_band = 1.0 + day_offset * 0.08 # 每过1天,区间扩大8%
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std = max(abs(daily_change) * confidence_band, 0.5)
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lower = cash - std * 0.5
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upper = cash + std * 0.5
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# 预警状态
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if cash < DEFAULT_CASH_CRITICAL:
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status = "red"
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elif cash < DEFAULT_CASH_WARNING:
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status = "yellow"
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else:
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status = "green"
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forecast.append({
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"date": d.strftime("%Y-%m-%d"),
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"day_offset": day_offset,
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"predicted_cash": round(cash, 2),
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"lower_bound": round(max(lower, 0), 2),
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"upper_bound": round(upper, 2),
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"alert_status": status,
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})
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# 整体预警
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min_cash = min(f["predicted_cash"] for f in forecast)
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min_date = next(f["date"] for f in forecast if f["predicted_cash"] == min_cash)
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suggestions = []
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if min_cash < DEFAULT_CASH_CRITICAL:
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suggestions.append({
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"type": "critical",
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"message": f"预计{min_date}现金余额降至{min_cash:.1f}万,低于警戒线{DEFAULT_CASH_CRITICAL}万",
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"actions": [
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"立即催收大额应收账款",
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"暂停非必要支出",
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"准备短期融资安排",
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]
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})
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elif min_cash < DEFAULT_CASH_WARNING:
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suggestions.append({
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"type": "warning",
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"message": f"预计{min_date}现金余额降至{min_cash:.1f}万,低于关注线{DEFAULT_CASH_WARNING}万",
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"actions": [
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"加快应收账款回款",
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"控制采购付款节奏",
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"评估短期现金流压力",
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]
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})
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return {
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"entity_id": entity_id,
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"base_cash": round(base_cash, 2),
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"days": days,
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"forecast": forecast,
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"min_cash": round(min_cash, 2),
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"min_cash_date": min_date,
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"trends": {
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"operating_cash_flow_trend_pct": round(ocf_trend, 2),
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"receivables_trend_pct": round(ar_trend, 2),
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"payables_trend_pct": round(ap_trend, 2),
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},
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"suggestions": suggestions,
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}
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def save_forecast_to_db(entity_id: int, forecast_data: dict, db: Session):
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"""将预测结果保存到数据库"""
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from app.models import CashForecast
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for f in forecast_data["forecast"]:
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forecast_date = datetime.strptime(f["date"], "%Y-%m-%d")
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cf = CashForecast(
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entity_id=entity_id,
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forecast_date=forecast_date,
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predicted_cash=f["predicted_cash"],
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lower_bound=f["lower_bound"],
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upper_bound=f["upper_bound"],
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alert_status=f["alert_status"],
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)
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db.add(cf)
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db.commit()
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def calculate_accuracy(entity_id: int, db: Session) -> list:
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"""计算预测准确率 — 对比上期预测 vs 本期实际"""
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from app.models import CashForecast, KPIDefinition, KPIValue
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# 获取实体最近的预测
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forecasts = db.query(CashForecast).filter(
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CashForecast.entity_id == entity_id,
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).order_by(CashForecast.forecast_date.desc()).limit(90).all()
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# 获取实际的现金余额KPI值
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cash_kpi = db.query(KPIDefinition).filter(
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KPIDefinition.kpi_code == KPI_CODES["cash_balance"],
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KPIDefinition.entity_id == entity_id,
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).first()
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if not cash_kpi or not forecasts:
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return []
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actuals = db.query(KPIValue).filter(
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KPIValue.kpi_id == cash_kpi.id,
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KPIValue.actual_value.isnot(None),
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).order_by(KPIValue.period.desc()).limit(12).all()
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actual_map = {}
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for a in actuals:
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try:
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# period like "2026-07" -> month approx
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actual_map[a.period] = a.actual_value
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except:
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pass
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# 按月汇总预测值和实际值,计算准确率
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from collections import defaultdict
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monthly_forecast = defaultdict(list)
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for f in forecasts:
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month_key = f.forecast_date.strftime("%Y-%m")
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monthly_forecast[month_key].append(f.predicted_cash)
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results = []
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for month, f_vals in sorted(monthly_forecast.items()):
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if month in actual_map:
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f_avg = sum(f_vals) / len(f_vals)
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a_val = actual_map[month]
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mae = abs(f_avg - a_val)
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mape = abs((f_avg - a_val) / max(abs(a_val), 1)) * 100
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results.append({
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"period": month,
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"forecast_value": round(f_avg, 2),
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"actual_value": round(a_val, 2),
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"mae": round(mae, 2),
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"mape": round(mape, 2),
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})
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return results
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def generate_scenario_suggestion(alert_type: str, kpi_name: str, extra: dict = None) -> dict:
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"""根据预警类型生成情景建议"""
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suggestions = {
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"cash_low": {
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"title": "现金流紧张缓解方案",
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"description": f"现金余额低于阈值,建议加快应收账款催收、控制支出、评估短期融资。",
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"actions": [
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f"催收大额应收账款(预计回款{extra.get('expected_receivables', '待定')}万元)",
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"暂停非紧急采购和资本性支出",
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"与供应商协商延长账期",
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"评估银行短期授信额度",
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],
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"priority": "high",
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},
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"cash_critical": {
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"title": "现金流危机应对方案",
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"description": f"现金余额接近断流,需立即采取紧急措施。",
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"actions": [
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"立即催收所有到期应收账款",
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"暂停所有非必要支出",
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"紧急联系银行安排短期贷款",
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"评估资产变现可能性",
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],
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"priority": "high",
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},
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"cost_high": {
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"title": "成本管控优化方案",
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"description": f"成本率异常偏高,建议进行成本结构分析和优化。",
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"actions": [
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"逐项分析成本构成,识别异常项",
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"与供应商重新谈判采购价格",
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"评估流程优化降本空间",
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"建立费用审批红线上限",
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],
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"priority": "medium",
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},
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"revenue_drop": {
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"title": "收入下滑应对方案",
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"description": f"收入出现下滑趋势,建议分析原因并制定恢复计划。",
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"actions": [
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"分析收入下滑原因(客户流失/价格战/需求变化)",
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"制定客户留存和挽回计划",
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"评估新产品/新市场机会",
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"优化销售激励政策",
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],
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"priority": "high",
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},
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}
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sug = suggestions.get(alert_type, {
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"title": "改善建议",
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"description": "根据预警情况制定改善措施。",
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"actions": ["分析预警原因", "制定改善计划", "跟踪执行效果"],
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"priority": "medium",
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})
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if extra:
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sug["extra"] = extra
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return sug
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