# -*- coding: utf-8 -*-

"""
封装ZenEngine
"""

# 导入模块

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

from zen import ZenDecision, ZenEngine


class RuleEngine:
    """
    规则引擎，实现打开并读取规则，根据规则和输入评估并输出
    """

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

        # 初始化规则缓存
        self.decisions = {}
        for decision_path in rules_path.glob("*.json"):
            # 打开并读取规则文件并实例化规则
            self.decisions[decision_path.stem] = self._get_decision(decision_path)

    @staticmethod
    def _get_decision(decision_path: Path) -> ZenDecision:
        """
        打开并读取规则文件并实例化规则
        :param decision_path: 规则文件路径（path对象）
        :return: 实例化规则
        """

        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]:
        """
        调用规则并评估
        :param decision: 规则
        :param inputs: 输入
        :return: 输出
        """
        if decision not in self.decisions:
            raise ValueError(f"规则不存在：{decision}")

        return self.decisions[decision].evaluate(self._format_value(inputs))["result"]

    def _format_value(self, value: Any) -> Any:
        """
        格式化值为字符串
        :param value: 值
        :return: 格式化后值
        """
        match value:
            case int():
                return str(value)
            case Decimal():
                # noinspection PyTypeChecker
                return format(value, f".{abs(value.as_tuple().exponent)}f")
            case datetime():
                return value.strftime("%Y-%m-%d %H:%M:%S")
            case list():
                return [self._format_value(e) for e in value]
            case dict():
                return {k: self._format_value(v) for k, v in value.items()}
            case _:
                return value