"""风控事件引擎（B4 · 架构 §3.1 ④ / PRD FR-3）。

编排（网关 B5 在 core_trade 落库后**同步调用**，不用消息队列）：
当日流水上下文（core_ro）→ RISK-001~005 纯函数 → AML 姓名匹配 → 预警落库
（alert_service：聚合/去重/审计/推送）→ L3 upsert（profile_l3）。
审计 pass（未命中）与命中审计均由 alert_service 完成，本层不重复落审计。

RISK-004 窗口以 trade["traded_at"] 为事件时点（非墙钟 now）：rebuild_alerts
幂等重放可复现窗口判定，演示脚本不受执行时刻影响。

客户事件钩子 on_customer_created/on_customer_updated 为 FR-5 预留（本期 no-op，
模拟环境无开户流程）。
"""

from __future__ import annotations

from datetime import datetime
from typing import Any

from app.repository.core_ro import CoreReadOnlyRepository
from app.repository.risk_repository import RiskRepository
from app.service.risk.alert_service import record_aml_alert, record_trade_alerts
from app.service.risk.aml_service import match_customer
from app.service.risk.profile_l3 import upsert_profile_l3
from app.service.risk.rules import RiskThresholds, run_rules


def _as_datetime(value: Any) -> datetime:
    if isinstance(value, datetime):
        return value
    if isinstance(value, str):
        return datetime.fromisoformat(value)
    raise TypeError(f"traded_at must be datetime/str, got {type(value)!r}")


def _normalize_trades(trades: list[dict[str, Any]]) -> list[dict[str, Any]]:
    """驱动差异防御：sqlite text 查询返回 str 时间，统一转 datetime（MySQL 驱动本就返回 datetime）。"""
    for t in trades:
        if isinstance(t.get("traded_at"), str):
            t["traded_at"] = datetime.fromisoformat(t["traded_at"])
    return trades


def process_trade_event(
    trade: dict[str, Any],
    core_ro: CoreReadOnlyRepository | None = None,
    risk_repo: RiskRepository | None = None,
    thresholds: RiskThresholds | None = None,
) -> dict[str, Any]:
    """处理一笔已落库交易（PRD FR-1 ②③b 之后）。

    返回 {"triggered_rules": [...], "alert_ids": [...], "aml_hit": bool}，
    网关据此拼装响应（FR-1 ⑤：blocked=false + trade_id + 触发规则列表）。
    """
    core = core_ro or CoreReadOnlyRepository()
    repo = risk_repo or RiskRepository()
    th = thresholds or RiskThresholds.from_settings()

    event_at = _as_datetime(trade["traded_at"])
    day_start = event_at.replace(hour=0, minute=0, second=0, microsecond=0)
    trades = _normalize_trades(core.list_trades(trade["customer_id"], since=day_start, limit=1000))

    result: dict[str, Any] = {"triggered_rules": [], "alert_ids": [], "aml_hit": False}

    hits = run_rules(trades, th, now=event_at)
    # 无条件走预警编排：空 hits 由 alert_service 落 pass 审计（架构 §3.1 ④ 未命中分支）
    alert = record_trade_alerts(trade, hits, risk_repo=repo)
    if hits:
        result["triggered_rules"] = sorted({h.rule_id for h in hits})
        if alert:
            result["alert_ids"].append(alert["alert_id"])
        best = max(hits, key=lambda h: h.risk_score)
        upsert_profile_l3(
            trade["customer_id"],
            best.alert_type,
            last_alert_id=alert["alert_id"] if alert else None,
            risk_repo=repo,
        )

    aml_hits = match_customer(trade["customer_id"], core_ro=core, risk_repo=repo)
    if aml_hits:
        result["aml_hit"] = True
        alert = record_aml_alert(
            trade["customer_id"],
            {"trigger": "trade", "trade_id": trade.get("trade_id"), "matches": aml_hits},
            risk_repo=repo,
        )
        result["alert_ids"].append(alert["alert_id"])
        upsert_profile_l3(
            trade["customer_id"], "aml", last_alert_id=alert["alert_id"], risk_repo=repo
        )

    return result


def on_customer_created(customer_id: str) -> None:
    """AML 开户触发预留（本期 no-op；模拟环境无开户流程，PRD FR-5）。"""

def on_customer_updated(customer_id: str) -> None:
    """客户信息变更触发预留（本期 no-op；PRD FR-5）。"""