from dataclasses import dataclass

from mypy.nodes import OpExpr

from refurb.checks.common import get_common_expr_in_comparison_chain
from refurb.error import Error


@dataclass
class ErrorInfo(Error):
    """
    When checking that multiple objects are equal to each other, don't use
    an `and` expression. Use a comparison chain instead, for example:

    Bad:

    ```
    if x == y and x == z:
        pass

    # and

    if x is None and y is None
        pass
    ```

    Good:

    ```
    if x == y == z:
        pass

    # and

    if x is y is None:
        pass
    ```

    Note: if `x` depends on side-effects, then this check should be ignored.
    """

    name = "use-comparison-chain"
    code = 124
    categories = ("logical", "readability")


def create_message(indices: tuple[int, int], oper: str = "==") -> str:
    names = ["x", "y", "z"]
    names.insert(indices[1], names[indices[0]])

    expr = f"{names[0]} {oper} {names[1]} and {names[2]} {oper} {names[3]}"

    return f"Replace `{expr}` with `x {oper} y {oper} z`"


def check(node: OpExpr, errors: list[Error]) -> None:
    for cmp_oper in ("==", "is"):
        if data := get_common_expr_in_comparison_chain(node, "and", cmp_oper):
            expr, indices = data

            errors.append(ErrorInfo.from_node(expr, create_message(indices, cmp_oper)))
