# ============================================================
# SAP 集成桩（moduleId: integ-sap-stub, 可重生 ✅）
# MD-05 最小切片：进程内 Mock SAP，无真实 RFC/OData。
# 入站：生产订单 / 库存；出站：开完工、产量、异常（幂等键防重复）。
# ============================================================
from __future__ import annotations

import json
from datetime import datetime, timedelta
from pathlib import Path
from typing import Any

_MIRROR_PATH = Path(__file__).resolve().parents[1] / "data" / "sap_mirror.json"


def _today() -> datetime:
    return datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)


def default_mirror() -> dict[str, Any]:
    """演示用 SAP 镜像：含待同步生产订单与库存。"""
    base = _today()
    due1 = (base + timedelta(days=7)).strftime("%Y-%m-%d")
    due2 = (base + timedelta(days=5)).strftime("%Y-%m-%d")
    return {
        "system": "SAP-MOCK",
        "plant": "CNWH",
        "updatedAt": datetime.now().strftime("%Y-%m-%d %H:%M"),
        "productionOrders": [
            {"aufnr": "1000123456", "matnr": "HV-HARNESS", "maktx": "高压线束总成",
             "gamng": 120, "gstrp": due1, "priority": 3, "status": "REL",
             "kitOk": True},
            {"aufnr": "1000123457", "matnr": "PDU-UNIT", "maktx": "PDU配电单元",
             "gamng": 80, "gstrp": due2, "priority": 2, "status": "REL",
             "kitOk": False},
            {"aufnr": "1000123458", "matnr": "CHARGE-GUN", "maktx": "充电枪总成",
             "gamng": 60, "gstrp": due1, "priority": 4, "status": "REL",
             "kitOk": True},
        ],
        "stocks": [
            {"matnr": "WIRE-HV", "labst": 15000, "inTransit": 0},
            {"matnr": "TERM-HV", "labst": 8000, "inTransit": 500},
            {"matnr": "BUSBAR", "labst": 2000, "inTransit": 0},
        ],
        "receipts": [],          # APS→SAP 回写流水
        "idempotency": {},       # key → receipt id
    }


class MockSapClient:
    """进程内 Mock SAP：读写本地镜像文件，模拟外部系统。"""

    def __init__(self, path: Path | None = None):
        self.path = path or _MIRROR_PATH
        self.path.parent.mkdir(parents=True, exist_ok=True)
        if not self.path.exists():
            self._save(default_mirror())

    def _load(self) -> dict:
        try:
            return json.loads(self.path.read_text(encoding="utf-8"))
        except (OSError, json.JSONDecodeError):
            data = default_mirror()
            self._save(data)
            return data

    def _save(self, data: dict) -> None:
        data["updatedAt"] = datetime.now().strftime("%Y-%m-%d %H:%M")
        self.path.write_text(json.dumps(data, ensure_ascii=False, indent=2), encoding="utf-8")

    def status(self) -> dict:
        m = self._load()
        return {
            "connected": True,
            "mode": "stub",
            "system": m.get("system"),
            "plant": m.get("plant"),
            "updatedAt": m.get("updatedAt"),
            "openOrders": len(m.get("productionOrders") or []),
            "receiptCount": len(m.get("receipts") or []),
        }

    def pull_orders(self) -> list[dict]:
        return list(self._load().get("productionOrders") or [])

    def pull_stocks(self) -> list[dict]:
        return list(self._load().get("stocks") or [])

    def push_receipt(self, payload: dict, idem_key: str) -> dict:
        """幂等回写：相同 idem_key 返回原回执，不重复建单。"""
        m = self._load()
        existing = (m.get("idempotency") or {}).get(idem_key)
        if existing:
            receipt = next((r for r in m.get("receipts", []) if r["id"] == existing), None)
            return {"duplicate": True, "receipt": receipt or {"id": existing, "idemKey": idem_key}}
        rid = f"SAP-RCPT-{len(m.get('receipts') or []) + 1:04d}"
        receipt = {
            "id": rid, "idemKey": idem_key, "plant": m.get("plant"),
            "at": datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
            **payload,
        }
        m.setdefault("receipts", []).append(receipt)
        m.setdefault("idempotency", {})[idem_key] = rid
        self._save(m)
        return {"duplicate": False, "receipt": receipt}

    def reset(self) -> dict:
        data = default_mirror()
        self._save(data)
        return self.status()


_client: MockSapClient | None = None


def get_sap_client() -> MockSapClient:
    global _client
    if _client is None:
        _client = MockSapClient()
    return _client


def reset_sap_client(path: Path | None = None) -> MockSapClient:
    """测试/演示：重置单例（可选临时镜像路径）。"""
    global _client
    _client = MockSapClient(path)
    _client.reset()
    return _client