""""
预警规则智能化 — 任务6
后端组件: alert_rules 模型 + API + 预警引擎
"""
from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy.orm import Session
from sqlalchemy import text, Column, Integer, String, Text, Float, DateTime, JSON, Boolean, func
from typing import Optional, List
from datetime import datetime, timedelta
import json
import logging

from app.database import get_db, Base
from app.deps import get_entity_id
from app.auth_middleware import require_auth, require_role
from app.models import KPIDefinition, KPIValue, KPIAlert, OperationLog

logger = logging.getLogger("alert_rules")

# ============================================================
# AlertRule 模型
# ============================================================
class AlertRule(Base):
    """预警规则配置"""
    __tablename__ = "alert_rules"
    id = Column(Integer, primary_key=True, index=True)
    entity_id = Column(Integer, default=1, comment="企业ID (P2多租户隔离 2026-08-23)")
    kpi_id = Column(Integer, nullable=False, comment="关联KPI ID")
    rule_type = Column(String(30), nullable=False, comment="static/dynamic/trend_up/trend_down")
    trigger_on = Column(String(20), default="actual", comment="actual/forecast/both — 实际值/预测值/两者触发")
    enabled = Column(Integer, default=1, comment="1启用 0禁用")
    params = Column(JSON, nullable=True, comment="规则参数")
    # static: {"green": ">=90", "yellow": ">=80", "red": "<80"}
    # dynamic: {"sensitivity": 1.0} — 阈值 = mean ± sensitivity * stddev, period_months=3
    # trend_up: {"threshold_pct": 10} — 环比上升超过 threshold_pct% 触发
    # trend_down: {"threshold_pct": 10} — 环比下降超过 threshold_pct% 触发
    created_at = Column(DateTime, server_default=func.now())
    updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now())

class DynamicThresholdCache(Base):
    """动态阈值缓存 — 存储近3个月历史统计"""
    __tablename__ = "dynamic_threshold_cache"
    id = Column(Integer, primary_key=True, index=True)
    kpi_id = Column(Integer, nullable=False, comment="关联KPI ID")
    period = Column(String(20), nullable=False, comment="计算期间 2026-07")
    mean_value = Column(Float, nullable=True, comment="近3月均值")
    stddev_value = Column(Float, nullable=True, comment="近3月标准差")
    dynamic_green = Column(String(100), nullable=True, comment="动态绿灯阈值")
    dynamic_yellow = Column(String(100), nullable=True, comment="动态黄灯阈值")
    dynamic_red = Column(String(100), nullable=True, comment="动态红灯阈值")
    calculated_at = Column(DateTime, server_default=func.now())


router = APIRouter(prefix="/api/cma/alert-rules", tags=["预警规则"],
    dependencies=[Depends(require_role("ceo", "finance", "it"))],
)


# ============================================================
# API Endpoints
# ============================================================

@router.get("")
def list_alert_rules(
    kpi_id: Optional[int] = None,
    rule_type: Optional[str] = None,
    enabled: Optional[int] = None,
    db: Session = Depends(get_db),
    entity_id: int = Depends(get_entity_id),
):
    """列出所有预警规则（账套隔离: 按token企业, 2026-08-23 P2）"""
    query = db.query(AlertRule).filter(AlertRule.entity_id == entity_id)
    if kpi_id:
        query = query.filter(AlertRule.kpi_id == kpi_id)
    if rule_type:
        query = query.filter(AlertRule.rule_type == rule_type)
    if enabled is not None:
        query = query.filter(AlertRule.enabled == enabled)

    rules = query.order_by(AlertRule.id).all()
    result = []
    for r in rules:
        d = {c.name: getattr(r, c.name) for c in AlertRule.__table__.columns}
        # 关联KPI信息
        kpi = db.query(KPIDefinition).filter(KPIDefinition.id == r.kpi_id).first()
        if kpi:
            d["kpi_code"] = kpi.kpi_code
            d["kpi_name"] = kpi.kpi_name
        result.append(d)
    return {"data": result, "total": len(result)}


@router.get("/kpi/{kpi_id}")
def get_kpi_rules(kpi_id: int, db: Session = Depends(get_db)):
    """获取单个KPI的所有预警规则"""
    rules = db.query(AlertRule).filter(AlertRule.kpi_id == kpi_id).order_by(AlertRule.id).all()
    return {"data": [{c.name: getattr(r, c.name) for c in AlertRule.__table__.columns} for r in rules]}


@router.post("")
def create_alert_rule(data: dict, db: Session = Depends(get_db), user=Depends(require_role("ceo", "finance", "it"))):
    """创建预警规则"""
    kpi_id = data.get("kpi_id")
    rule_type = data.get("rule_type", "static")
    trigger_on = data.get("trigger_on", "actual")
    
    kpi = db.query(KPIDefinition).filter(KPIDefinition.id == kpi_id).first()
    if not kpi:
        raise HTTPException(404, "KPI不存在")
    if rule_type not in ("static", "dynamic", "trend_up", "trend_down"):
        raise HTTPException(400, f"不支持的规则类型: {rule_type}")

    rule = AlertRule(
        kpi_id=kpi_id,
        rule_type=rule_type,
        trigger_on=trigger_on,
        enabled=data.get("enabled", 1),
        params=data.get("params"),
    )
    db.add(rule)
    db.commit()
    db.refresh(rule)
    
    # 日志
    db.add(OperationLog(
        action="create_alert_rule", target_type="alert_rule",
        detail=f"KPI={kpi.kpi_code}({kpi.kpi_name}) type={rule_type}",
    ))
    db.commit()
    
    return {"data": {c.name: getattr(rule, c.name) for c in AlertRule.__table__.columns}}


@router.put("/{rule_id}")
def update_alert_rule(rule_id: int, data: dict, db: Session = Depends(get_db)):
    """更新预警规则"""
    rule = db.query(AlertRule).filter(AlertRule.id == rule_id).first()
    if not rule:
        raise HTTPException(404, "预警规则不存在")
    
    for field in ("rule_type", "trigger_on", "enabled", "params"):
        if field in data:
            setattr(rule, field, data[field])
    db.commit()
    db.refresh(rule)
    return {"data": {c.name: getattr(rule, c.name) for c in AlertRule.__table__.columns}}


@router.delete("/{rule_id}")
def delete_alert_rule(rule_id: int, db: Session = Depends(get_db)):
    """删除预警规则"""
    rule = db.query(AlertRule).filter(AlertRule.id == rule_id).first()
    if rule:
        db.delete(rule)
        db.commit()
    return {"message": "已删除"}


@router.post("/batch")
def batch_create_rules(data: dict, db: Session = Depends(get_db)):
    """批量创建预警规则
    data.rules: [{"kpi_id": id, "rule_type": "static", "params": {...}}, ...]
    """
    rules_data = data.get("rules", [])
    created = 0
    for rule_data in rules_data:
        kpi_id = rule_data.get("kpi_id")
        rule_type = rule_data.get("rule_type", "static")
        # 检查是否已存在相同类型的规则
        existing = db.query(AlertRule).filter(
            AlertRule.kpi_id == kpi_id,
            AlertRule.rule_type == rule_type,
        ).first()
        if existing:
            continue
        rule = AlertRule(
            kpi_id=kpi_id,
            rule_type=rule_type,
            enabled=rule_data.get("enabled", 1),
            params=rule_data.get("params"),
        )
        db.add(rule)
        created += 1
    db.commit()
    return {"message": f"批量创建完成: 新增{created}条", "created": created}


@router.post("/generate-defaults")
def generate_default_rules(db: Session = Depends(get_db)):
    """为所有尚未配置预警规则的KPI生成默认规则"""
    # 找到所有active KPI
    all_kpis = db.query(KPIDefinition).filter(KPIDefinition.status == "active").all()
    
    created = 0
    for kpi in all_kpis:
        # 检查是否已有任何规则
        existing = db.query(AlertRule).filter(AlertRule.kpi_id == kpi.id).first()
        if existing:
            continue
        
        kpi_id = kpi.id
        
        # 1. 静态阈值规则（基于kpi_definitions的阈值）
        if kpi.threshold_green or kpi.threshold_yellow or kpi.threshold_red:
            rule = AlertRule(
                kpi_id=kpi_id,
                rule_type="static",
                enabled=1,
                params={
                    "green": kpi.threshold_green,
                    "yellow": kpi.threshold_yellow,
                    "red": kpi.threshold_red,
                }
            )
            db.add(rule)
            created += 1
        
        # 2. 动态趋势规则（所有KPI默认加 trend_down）
        rule2 = AlertRule(
            kpi_id=kpi_id,
            rule_type="trend_down",
            enabled=1,
            params={"threshold_pct": 10},
        )
        db.add(rule2)
        created += 1
    
    db.commit()
    return {"message": f"默认规则生成完成: 共{created}条", "created": created}


@router.post("/check-all")
def run_all_alert_checks(db: Session = Depends(get_db)):
    """执行所有KPI的预警检查 — 生成新的预警记录"""
    rules = db.query(AlertRule).filter(AlertRule.enabled == 1).all()
    kpi_cache = {}
    value_cache = {}
    
    alerts_generated = 0
    
    for rule in rules:
        try:
            kpi = kpi_cache.get(rule.kpi_id)
            if kpi is None:
                kpi = db.query(KPIDefinition).filter(KPIDefinition.id == rule.kpi_id).first()
                if kpi:
                    kpi_cache[rule.kpi_id] = kpi
            
            if not kpi:
                continue
            
            # 获取最新值
            latest_value = value_cache.get(rule.kpi_id)
            if latest_value is None:
                latest_value = db.query(KPIValue).filter(
                    KPIValue.kpi_id == rule.kpi_id,
                ).order_by(KPIValue.period.desc()).first()
                if latest_value:
                    value_cache[rule.kpi_id] = latest_value
            
            if not latest_value or latest_value.actual_value is None:
                continue
            
            value = latest_value.actual_value
            period = latest_value.period
            import json; params = json.loads(rule.params) if isinstance(rule.params, str) else (rule.params or {})
            
            alert_level = None
            alert_message = None
            
            if rule.rule_type == "static":
                alert_level, alert_message = _check_static(value, params, kpi)
            elif rule.rule_type == "dynamic":
                alert_level, alert_message = _check_dynamic(kpi.id, value, params, db)
            elif rule.rule_type == "trend_up":
                alert_level, alert_message = _check_trend(kpi.id, value, "up", params, db)
            elif rule.rule_type == "trend_down":
                alert_level, alert_message = _check_trend(kpi.id, value, "down", params, db)
            
            if alert_level and alert_level != "green":
                # 检查是否已有相同预警
                existing_alert = db.query(KPIAlert).filter(
                    KPIAlert.kpi_id == rule.kpi_id,
                    KPIAlert.kpi_value_id == latest_value.id,
                    KPIAlert.alert_level == alert_level,
                    KPIAlert.alert_message == alert_message,
                    KPIAlert.status == "pending",
                ).first()
                if not existing_alert:
                    alert = KPIAlert(
                        kpi_id=rule.kpi_id,
                        kpi_value_id=latest_value.id,
                        alert_level=alert_level,
                        alert_message=alert_message,
                        status="pending",
                    )
                    db.add(alert)
                    alerts_generated += 1
                    
        except Exception as e:
            logger.error(f"预警检查失败: rule_id={rule.id}, error={e}")
            continue
    
    db.commit()
    return {"message": f"预警检查完成: 生成{alerts_generated}条", "generated": alerts_generated}


@router.get("/dynamic-thresholds")
def get_dynamic_thresholds(kpi_id: Optional[int] = None, db: Session = Depends(get_db)):
    """获取动态阈值缓存"""
    query = db.query(DynamicThresholdCache)
    if kpi_id:
        query = query.filter(DynamicThresholdCache.kpi_id == kpi_id)
    cache = query.order_by(DynamicThresholdCache.id.desc()).limit(50).all()
    return {"data": [{c.name: getattr(c, c.name) for c in DynamicThresholdCache.__table__.columns} for c in cache]}


@router.post("/calculate-dynamic")
def calculate_dynamic_thresholds(db: Session = Depends(get_db)):
    """计算所有KPI的动态阈值（基于近3个月历史均值±标准差）"""
    kpis = db.query(KPIDefinition).filter(KPIDefinition.status == "active").all()
    current_period = datetime.now().strftime("%Y-%m")
    
    computed = 0
    for kpi in kpis:
        # 取近3个月的历史值（不含当月）
        from sqlalchemy import text as sa_text, func as sa_func
        values = db.query(KPIValue).filter(
            KPIValue.kpi_id == kpi.id,
            KPIValue.actual_value.isnot(None),
            KPIValue.data_status.in_(["verified", "estimated"]),
            KPIValue.period < current_period,
        ).order_by(KPIValue.period.desc()).limit(3).all()
        
        if len(values) < 2:
            continue
        
        vals = [v.actual_value for v in values if v.actual_value is not None]
        if len(vals) < 2:
            continue
        
        mean_val = sum(vals) / len(vals)
        if len(vals) > 1:
            variance = sum((v - mean_val) ** 2 for v in vals) / len(vals)
            stddev = variance ** 0.5
        else:
            stddev = mean_val * 0.1  # 仅1个值时的合理估算
        
        # 生成动态阈值（±1标准差）
        dynamic_green = f">={mean_val + stddev:.2f}"
        dynamic_yellow = f">={mean_val:.2f}"
        dynamic_red = f"<{mean_val:.2f}"
        
        # 检查是否已有缓存
        existing = db.query(DynamicThresholdCache).filter(
            DynamicThresholdCache.kpi_id == kpi.id,
            DynamicThresholdCache.period == current_period,
        ).first()
        
        if existing:
            existing.mean_value = mean_val
            existing.stddev_value = stddev
            existing.dynamic_green = dynamic_green
            existing.dynamic_yellow = dynamic_yellow
            existing.dynamic_red = dynamic_red
        else:
            cache = DynamicThresholdCache(
                kpi_id=kpi.id,
                period=current_period,
                mean_value=mean_val,
                stddev_value=stddev,
                dynamic_green=dynamic_green,
                dynamic_yellow=dynamic_yellow,
                dynamic_red=dynamic_red,
            )
            db.add(cache)
        computed += 1
    
    db.commit()
    return {"message": f"动态阈值计算完成: {computed}个KPI", "computed": computed}


# ============================================================
# 检查引擎
# ============================================================

def _check_static(value: float, params: dict, kpi) -> tuple:
    """静态阈值检查"""
    green = params.get("green")
    yellow = params.get("yellow") 
    red = params.get("red")
    
    # 从KPI定义获取阈值
    if not green and not yellow and not red:
        green = kpi.threshold_green
        yellow = kpi.threshold_yellow
        red = kpi.threshold_red
    
    if _eval_threshold(value, green):
        return ("green", f"[静态] {kpi.kpi_name}={value}, 绿灯{green}")
    elif _eval_threshold(value, yellow):
        return ("yellow", f"[静态] {kpi.kpi_name}={value}, 黄灯{yellow}")
    elif red and _eval_threshold(value, red, invert=True):
        return ("red", f"[静态] {kpi.kpi_name}={value}, 红灯{red}")
    
    return (None, None)


def _check_dynamic(kpi_id: int, value: float, params: dict, db: Session) -> tuple:
    """动态阈值检查 — 基于历史均值±标准差"""
    current_period = datetime.now().strftime("%Y-%m")
    cache = db.query(DynamicThresholdCache).filter(
        DynamicThresholdCache.kpi_id == kpi_id,
        DynamicThresholdCache.period == current_period,
    ).first()
    
    if not cache:
        return (None, None)
    
    sensitivity = params.get("sensitivity", 1.0)
    mean_val = cache.mean_value or 0
    stddev_val = (cache.stddev_value or 0) * sensitivity
    
    kpi = db.query(KPIDefinition).filter(KPIDefinition.id == kpi_id).first()
    kpi_name = kpi.kpi_name if kpi else f"KPI#{kpi_id}"
    
    if value >= mean_val + stddev_val:
        return ("green", f"[动态] {kpi_name}={value}, 均值={mean_val:.1f}, 标准差={stddev_val:.1f}")
    elif value >= mean_val:
        return ("yellow", f"[动态] {kpi_name}={value}, 均值={mean_val:.1f}, 标准差={stddev_val:.1f}")
    else:
        return ("red", f"[动态] {kpi_name}={value}, 低于均值={mean_val:.1f}, 标准差={stddev_val:.1f}")


def _check_trend(kpi_id: int, value: float, direction: str, params: dict, db: Session) -> tuple:
    """趋势检查 — 环比变化"""
    threshold_pct = params.get("threshold_pct", 10)
    
    # 获取上月值
    prev_value = db.query(KPIValue).filter(
        KPIValue.kpi_id == kpi_id,
        KPIValue.actual_value.isnot(None),
    ).order_by(KPIValue.period.desc()).offset(1).limit(1).first()
    
    if not prev_value or not prev_value.actual_value or prev_value.actual_value == 0:
        return (None, None)
    
    change_pct = round((value - prev_value.actual_value) / abs(prev_value.actual_value) * 100, 2)
    
    kpi = db.query(KPIDefinition).filter(KPIDefinition.id == kpi_id).first()
    kpi_name = kpi.kpi_name if kpi else f"KPI#{kpi_id}"
    
    if direction == "up" and change_pct > threshold_pct:
        level = "yellow" if change_pct < threshold_pct * 2 else "red"
        return (level, f"[趋势↑] {kpi_name}环比上升{change_pct}%(阈值>{threshold_pct}%), 当前={value}, 上月={prev_value.actual_value}")
    elif direction == "down" and change_pct < -threshold_pct:
        level = "yellow" if abs(change_pct) < threshold_pct * 2 else "red"
        return (level, f"[趋势↓] {kpi_name}环比下降{abs(change_pct)}%(阈值>{threshold_pct}%), 当前={value}, 上月={prev_value.actual_value}")
    
    return (None, None)


def _eval_threshold(value: float, threshold_str: str, invert: bool = False) -> bool:
    """评估阈值: '>=90', '<80', '>5', '<=2' 等"""
    if not threshold_str:
        return False
    threshold_str = str(threshold_str).strip()
    
    try:
        if threshold_str.startswith(">="):
            limit = float(threshold_str[2:])
            return value >= limit if not invert else value >= limit
        elif threshold_str.startswith("<="):
            limit = float(threshold_str[2:])
            return value <= limit if not invert else value <= limit
        elif threshold_str.startswith(">"):
            limit = float(threshold_str[1:])
            return value > limit if not invert else value > limit
        elif threshold_str.startswith("<"):
            limit = float(threshold_str[1:])
            return value < limit if not invert else value < limit
        else:
            return False
    except (ValueError, TypeError):
        return False


# ============================================================
# 预测值检查 + 情景建议
# ============================================================

def _check_forecast_alerts(db: Session) -> int:
    """检查未来7天预测值是否超限 — 针对trigger_on='forecast'和'both'的规则"""
    from app.utils.cash_forecast_engine import forecast_cash_flow, generate_scenario_suggestion
    from app.models import CashForecast

    rules = db.query(AlertRule).filter(
        AlertRule.enabled == 1,
        AlertRule.trigger_on.in_(["forecast", "both"]),
    ).all()

    if not rules:
        return 0

    alerts_generated = 0
    rule_kpi_cache = {}

    for rule in rules:
        try:
            kpi = rule_kpi_cache.get(rule.kpi_id)
            if kpi is None:
                kpi = db.query(KPIDefinition).filter(KPIDefinition.id == rule.kpi_id).first()
                if kpi:
                    rule_kpi_cache[rule.kpi_id] = kpi
            if not kpi:
                continue

            entity_id = kpi.entity_id or 1
            # 获取最新的预测
            latest_forecasts = db.query(CashForecast).filter(
                CashForecast.entity_id == entity_id,
            ).order_by(CashForecast.forecast_date.asc()).limit(7).all()

            if not latest_forecasts:
                # 没有已有预测，执行一次实时预测
                from app.utils.cash_forecast_engine import save_forecast_to_db
                result = forecast_cash_flow(entity_id, db)
                try:
                    save_forecast_to_db(entity_id, result, db)
                except:
                    pass
                latest_forecasts = db.query(CashForecast).filter(
                    CashForecast.entity_id == entity_id,
                ).order_by(CashForecast.forecast_date.asc()).limit(7).all()

            if not latest_forecasts:
                continue

            # 检查预测值是否超限
            import json; params = json.loads(rule.params) if isinstance(rule.params, str) else (rule.params or {})
            params["kpi"] = kpi
            for forecast in latest_forecasts:
                value = forecast.predicted_cash
                if value is None:
                    continue
                alert_level, alert_message = _check_static(value, params, kpi)
                if alert_level and alert_level != "green":
                    # 生成情景建议
                    sug_type = "cash_critical" if alert_level == "red" else "cash_low"
                    sug = generate_scenario_suggestion(
                        sug_type, kpi.kpi_name,
                        {"expected_receivables": 20, "forecast_date": forecast.forecast_date.isoformat()}
                    )
                    suggestion_text = f"{sug['title']}：{sug['description']}\\n建议行动：{'；'.join(sug['actions'])}"

                    existing = db.query(KPIAlert).filter(
                        KPIAlert.kpi_id == rule.kpi_id,
                        KPIAlert.alert_type == "forecast",
                        KPIAlert.alert_level == alert_level,
                        KPIAlert.alert_message == alert_message,
                        KPIAlert.status == "pending",
                    ).first()
                    if not existing:
                        alert = KPIAlert(
                            kpi_id=rule.kpi_id,
                            alert_level=alert_level,
                            alert_message=alert_message,
                            alert_type="forecast",
                            suggestion=suggestion_text,
                            status="pending",
                        )
                        db.add(alert)
                        alerts_generated += 1
        except Exception as e:
            logger.error(f"预测值预警检查失败: rule_id={rule.id}, error={e}")
            continue

    db.commit()
    return alerts_generated


@router.post("/check-forecast")
def run_forecast_alert_check(db: Session = Depends(get_db)):
    """执行预测值预警检查 — 检查未来7天预测值是否超限"""
    generated = _check_forecast_alerts(db)
    return {"message": f"预测值预警检查完成: 生成{generated}条", "generated": generated}


@router.post("/generate-suggestions")
def generate_alert_suggestions(db: Session = Depends(get_db)):
    """为所有未处理的预警生成情景建议"""
    from app.utils.cash_forecast_engine import generate_scenario_suggestion

    pending = db.query(KPIAlert).filter(
        KPIAlert.status == "pending",
        KPIAlert.suggestion.is_(None),
    ).all()

    updated = 0
    for alert in pending:
        try:
            sug_type = "cash_critical" if alert.alert_level == "red" else "cash_low"
            if alert.alert_type == "forecast":
                sug_type = "cash_critical" if alert.alert_level == "red" else "cash_low"
            else:
                sug_type = "cash_low"

            kpi = db.query(KPIDefinition).filter(KPIDefinition.id == alert.kpi_id).first()
            kpi_name = kpi.kpi_name if kpi else "未知KPI"

            sug = generate_scenario_suggestion(sug_type, kpi_name, {
                "alert_level": alert.alert_level,
                "alert_message": alert.alert_message,
            })
            alert.suggestion = f"{sug['title']}：{sug['description']}\\n建议行动：{'；'.join(sug['actions'])}"
            updated += 1
        except Exception as e:
            logger.error(f"生成建议失败: alert_id={alert.id}, error={e}")

    db.commit()
    return {"message": f"已为{updated}条预警生成情景建议", "updated": updated}