"""前端组件目录：运行时只读启动时从 MongoDB 载入的进程内存缓存，没有文件回退"""

import hashlib
import json
from pathlib import Path

from app.schemas.component_resource import ComponentCatalog

# 进程内共享的组件目录，由启动流程载入；agent 与前端接口读取同一份
_cached_catalog: ComponentCatalog | None = None


def set_catalog_cache(catalog: ComponentCatalog | None) -> None:
    global _cached_catalog
    _cached_catalog = catalog


def get_catalog_cache() -> ComponentCatalog | None:
    return _cached_catalog


# 手写的物料定义目录，只供导入脚本读取后写入 MongoDB，运行时不读取
MATERIALS_DIR = Path(__file__).resolve().parent / "materials"
FIELD_GROUPS_FILE = "field_groups.json"
EVENT_GROUPS_FILE = "event_groups.json"


def load_material_definitions(
    directory: str | Path = MATERIALS_DIR,
) -> ComponentCatalog:
    """读取物料定义目录：共享字段分组、共享事件组各一个文件，每个物料一个文件；不合法直接报错

    version 为全部文件内容的摘要，定义有任何改动都会得到新版本
    """
    target = Path(directory)
    if not target.is_absolute():
        target = Path(__file__).resolve().parents[2] / target
    files = sorted(target.glob("*.json"))
    if not any(path.name == FIELD_GROUPS_FILE for path in files):
        raise FileNotFoundError(f"物料定义目录缺少 {FIELD_GROUPS_FILE}: {target}")
    digest = hashlib.sha256()
    components, field_groups, event_groups = [], [], []
    for path in files:
        # utf-8-sig 同时兼容带 BOM 和不带 BOM 的 UTF-8 文件
        text = path.read_text(encoding="utf-8-sig")
        digest.update(path.name.encode() + b"\0" + text.encode())
        if path.name == FIELD_GROUPS_FILE:
            field_groups = json.loads(text)
        elif path.name == EVENT_GROUPS_FILE:
            event_groups = json.loads(text)
        else:
            components.append(json.loads(text))
    # 文件名排序与展示顺序无关，物料按定义中的 order 排列，未写时排在最后
    components.sort(key=lambda item: item.get("order", len(files)))
    return ComponentCatalog.model_validate(
        {
            "version": f"sha256:{digest.hexdigest()}",
            "components": [
                {key: value for key, value in item.items() if key != "order"}
                for item in components
            ],
            "field_groups": field_groups,
            "event_groups": event_groups,
        }
    )