"""策略实例 JSON 存储（配置数据，几行；无需 DB 迁移）。

实例 = 代码文件的参数变体（spec §12 三层模型中层）。
运行态字段 status/last_return 给默认占位，由后续运行关联回填。
"""
from __future__ import annotations
import json
import os
import time

_DEFAULT_STATUS = {"backtest": "-", "replay": "-", "paper_live": "-", "live": "-"}

# 路径：env 覆盖 > 仓库根 data/strategy_instances.json。测试用 monkeypatch 改 _STORE_PATH。
_STORE_PATH: str = os.environ.get(
    "SANGUO_INSTANCE_STORE",
    os.path.join(
        os.path.dirname(os.path.dirname(os.path.abspath(__file__))),
        "data", "strategy_instances.json",
    ),
)


def _load() -> list[dict]:
    if not os.path.exists(_STORE_PATH):
        return []
    with open(_STORE_PATH, encoding="utf-8") as f:
        try:
            return json.load(f)
        except json.JSONDecodeError:
            return []


def _save(rows: list[dict]) -> None:
    os.makedirs(os.path.dirname(_STORE_PATH), exist_ok=True)
    with open(_STORE_PATH, "w", encoding="utf-8") as f:
        json.dump(rows, f, ensure_ascii=False, indent=2)


def list_instances() -> dict:
    return {"instances": _load()}


def get_instance(inst_id: int) -> dict:
    for r in _load():
        if r.get("id") == inst_id:
            return {"instance": r}
    return {"instance": None}


def create_instance(payload: dict) -> int:
    rows = _load()
    new_id = (max((r.get("id", 0) for r in rows), default=0) + 1) if rows else 1
    row = {
        "id": new_id,
        "code_file": payload.get("code_file", ""),
        "name": payload.get("name", ""),
        "type": payload.get("type", "cta"),
        "params": payload.get("params", {}),
        "symbol_or_pool": payload.get("symbol_or_pool", ""),
        "interval": payload.get("interval", "d"),
        "match_session": payload.get("match_session", "next_open"),
        "status": dict(_DEFAULT_STATUS),
        "last_return": None,
        "updated_at": time.strftime("%Y-%m-%d"),
    }
    rows.append(row)
    _save(rows)
    return new_id


def update_instance(inst_id: int, payload: dict) -> None:
    rows = _load()
    for r in rows:
        if r.get("id") == inst_id:
            for k in ("code_file", "name", "type", "params", "symbol_or_pool", "interval", "match_session"):
                if k in payload:
                    r[k] = payload[k]
            r["updated_at"] = time.strftime("%Y-%m-%d")
            _save(rows)
            return


def delete_instance(inst_id: int) -> bool:
    rows = _load()
    new_rows = [r for r in rows if r.get("id") != inst_id]
    if len(new_rows) == len(rows):
        return False
    _save(new_rows)
    return True