"""
Type Helpers

Utilities for type introspection and resolution.
Used by generators and loaders.
"""

import dataclasses as dc
from enum import Enum
from typing import Any, Union, get_args, get_origin


def unwrap_optional(type_hint: Any) -> tuple[Any, bool]:
    """Unwrap Optional[T] -> (T, True) or (T, False) if not optional."""
    origin = get_origin(type_hint)
    if origin is Union:
        args = [a for a in get_args(type_hint) if a is not type(None)]
        return (args[0] if args else str, True)
    return (type_hint, False)


def get_origin_name(type_hint: Any) -> str | None:
    """Get origin type name: 'dict', 'list', or None."""
    origin = get_origin(type_hint)
    if origin is dict:
        return "dict"
    if origin is list:
        return "list"
    return None


def get_type_name(type_hint: Any) -> str | None:
    """Get type name for special types like UUID, datetime."""
    if hasattr(type_hint, "__name__"):
        return type_hint.__name__
    return None


def get_list_inner(type_hint: Any) -> str:
    """Get inner type of List[T]."""
    args = get_args(type_hint)
    if args and args[0] in (str, int, float, bool):
        return {str: "str", int: "int", float: "float", bool: "bool"}[args[0]]
    return "str"


def get_field_default(field: dc.Field) -> Any:
    """Get default value from dataclass field."""
    if field.default is not dc.MISSING:
        return field.default
    return dc.MISSING


def format_opts(optional: bool, extra: list[str] | None = None) -> str:
    """Format field options string for Django."""
    parts = []
    if optional:
        parts.append("null=True, blank=True")
    if extra:
        parts.extend(extra)
    return ", ".join(parts)


def is_enum(type_hint: Any) -> bool:
    """Check if type is an Enum."""
    base, _ = unwrap_optional(type_hint)
    return isinstance(base, type) and issubclass(base, Enum)


def get_enum_values(enum_class: type) -> list[tuple[str, str]]:
    """Get list of (name, value) pairs from an Enum."""
    return [(m.name, m.value) for m in enum_class]