# -*- coding: utf-8 -*-
"""
规则引擎
"""

from datetime import datetime
from decimal import Decimal
from pathlib import Path
from typing import Any, Dict, Union

from zen import ZenDecision, ZenEngine


class RulesEngine:
    """
    规则引擎，支持：
    evaluate：调用并返回评估结果
    """

    def __init__(self, decisions_folder_path: Path):
        """
        初始化规则引擎
        :param decisions_folder_path: 决策文件夹路径
        """
        decisions_folder_path.mkdir(exist_ok=True)  # 若规则文件夹不存在则创建

        # 初始化决策缓存
        self.decisions = {}
        for decision_path in decisions_folder_path.glob("*.json"):
            # 打开并读取决策文件并实例化 ZenDecision
            self.decisions[decision_path.stem] = self._get_decision(decision_path)

    @staticmethod
    def _get_decision(decision_path: Path) -> ZenDecision:
        """
        打开并读取决策文件并实例化 ZenDecision
        :param decision_path: 决策文件路径
        :return: 实例化 ZenDecision
        """

        def loader(path):
            with open(path, "r", encoding="utf-8") as file:
                return file.read()

        return ZenEngine({"loader": loader}).get_decision(decision_path.as_posix())

    def evaluate(self, decision: str, inputs: Dict[str, Any]) -> Dict[str, Any]:
        """
        调用决策并返回评估结果
        :param decision: 决策名称
        :param inputs: 待评估对象
        :return: 评估结果
        """
        return self.decisions[decision].evaluate(self._formatter(inputs))["result"]

    def _formatter(
        self, inputs: Union[str, int, Decimal, datetime, list, dict, Any]
    ) -> Any:
        """
        格式化器
        :param inputs: 待评估对象
        :return: 格式化后待评估对象
        """
        match inputs:
            case int():
                return str(inputs)
            case Decimal():
                return format(inputs, ".2f")
            case datetime():
                return inputs.strftime("%Y-%m-%d %H:%M:%S")
            case list():
                return [self._formatter(i) for i in inputs]
            case dict():
                return {
                    key: self._formatter(value) for key, value in inputs.items()
                }  # 递归格式化
            case _:
                return inputs