"""输入验证 — JSON Schema 校验 + 参数白名单 + 类型强制"""
import json
import re
from typing import Any, Optional

from oss.logger.logger import Log


class ValidationError(Exception):
    def __init__(self, message: str, field: str = None):
        self.field = field
        super().__init__(message)


class InputValidator:
    """输入验证器"""

    # ── 内置类型校验器 ──

    @staticmethod
    def is_string(val: Any, min_len: int = 0, max_len: int = None) -> bool:
        if not isinstance(val, str):
            return False
        if len(val) < min_len:
            return False
        if max_len and len(val) > max_len:
            return False
        return True

    @staticmethod
    def is_integer(val: Any, min_val: int = None, max_val: int = None) -> bool:
        if not isinstance(val, int) or isinstance(val, bool):
            return False
        if min_val is not None and val < min_val:
            return False
        if max_val is not None and val > max_val:
            return False
        return True

    @staticmethod
    def is_float(val: Any, min_val: float = None, max_val: float = None) -> bool:
        if not isinstance(val, (int, float)) or isinstance(val, bool):
            return False
        if min_val is not None and val < min_val:
            return False
        if max_val is not None and val > max_val:
            return False
        return True

    @staticmethod
    def is_boolean(val: Any) -> bool:
        return isinstance(val, bool)

    @staticmethod
    def is_list(val: Any, item_type: type = None) -> bool:
        if not isinstance(val, list):
            return False
        if item_type:
            return all(isinstance(v, item_type) for v in val)
        return True

    @staticmethod
    def is_dict(val: Any) -> bool:
        return isinstance(val, dict)

    @staticmethod
    def is_email(val: str) -> bool:
        return bool(re.match(r"^[^\s@]+@[^\s@]+\.[^\s@]+$", val))

    @staticmethod
    def is_ip_address(val: str) -> bool:
        return bool(re.match(r"^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$", val))

    @staticmethod
    def is_alphanumeric(val: str) -> bool:
        return bool(re.match(r"^[a-zA-Z0-9_\-]+$", val))

    # ── JSON Schema 校验 ──

    def validate_schema(self, data: dict, schema: dict) -> list[str]:
        """根据 JSON Schema 校验数据，返回错误列表

        Schema 格式：
        {
            "field_name": {
                "type": "string|int|float|bool|list|dict|email|ip",
                "required": True/False,
                "min_len": 1,       # 仅 string
                "max_len": 100,     # 仅 string
                "min_val": 0,       # 仅 int/float
                "max_val": 100,     # 仅 int/float
                "pattern": "^...$", # 正则（仅 string）
                "default": "val",   # 默认值（可选字段）
                "items": "string",  # list 元素类型
                "fields": {...},    # 嵌套 dict schema
            }
        }
        """
        errors = []
        type_map = {
            "string": lambda v, r: self.is_string(v, r.get("min_len", 0), r.get("max_len")),
            "int": lambda v, r: self.is_integer(v, r.get("min_val"), r.get("max_val")),
            "float": lambda v, r: self.is_float(v, r.get("min_val"), r.get("max_val")),
            "bool": lambda v, _: self.is_boolean(v),
            "list": lambda v, r: self.is_list(v),
            "dict": lambda v, _: self.is_dict(v),
            "email": lambda v, _: self.is_email(v),
            "ip": lambda v, _: self.is_ip_address(v),
        }

        for field, rules in schema.items():
            value = data.get(field)

            # 必填检查
            if rules.get("required", False):
                if value is None:
                    errors.append(f"缺少必填字段: {field}")
                    continue
            elif value is None:
                continue

            # 类型检查
            expected_type = rules.get("type", "string")
            checker = type_map.get(expected_type)
            if checker:
                if not checker(value, rules):
                    errors.append(f"字段 '{field}' 类型错误，期望 {expected_type}")

            # 正则匹配（string 类型）
            pattern = rules.get("pattern")
            if pattern and isinstance(value, str):
                if not re.match(pattern, value):
                    errors.append(f"字段 '{field}' 格式不匹配: {pattern}")

            # 嵌套 dict 校验
            nested = rules.get("fields")
            if nested and isinstance(value, dict):
                errors.extend(self.validate_schema(value, nested))

        return errors

    # ── 快捷校验 ──

    def validate_or_raise(self, data: dict, schema: dict):
        """校验失败抛出 ValidationError"""
        errors = self.validate_schema(data, schema)
        if errors:
            raise ValidationError(errors[0])


_validator_instance: Optional[InputValidator] = None


def get_validator() -> InputValidator:
    global _validator_instance
    if _validator_instance is None:
        _validator_instance = InputValidator()
    return _validator_instance