from __future__ import annotations

from http import HTTPStatus
from typing import TYPE_CHECKING, Any

from apify_client._docs import docs_group

if TYPE_CHECKING:
    from typing import Self

    from apify_client.http_clients import HttpResponse


@docs_group('Errors')
class ApifyClientError(Exception):
    """Base class for all Apify API client errors."""


@docs_group('Errors')
class ApifyApiError(ApifyClientError):
    """Error raised when the Apify API returns an error response.

    Instantiating `ApifyApiError` dispatches to the subclass matching the HTTP status code (e.g. 404 → `NotFoundError`,
    any 5xx → `ServerError`). Unmapped statuses stay on `ApifyApiError`. Existing `except ApifyApiError` handlers keep
    working because every subclass inherits from this class.

    The `type`, `message` and `data` fields from the response body are exposed for inspection but are treated as
    non-authoritative metadata — dispatch is driven by the status code only.

    Attributes:
        message: The error message from the API response.
        type: The error type identifier from the API response (e.g. `record-not-found`).
        status_code: The HTTP status code of the error response.
        attempt: The attempt number when the error was raised.
        http_method: The HTTP method of the failed request.
        data: Additional error data from the API response.
    """

    # Subclasses in `_STATUS_TO_CLASS` must keep the `(response, attempt, *, method='GET')` constructor signature —
    # `__new__` forwards those arguments verbatim.

    def __new__(cls, response: HttpResponse, attempt: int, *, method: str = 'GET') -> Self:  # noqa: ARG004
        """Dispatch to the subclass matching the response's HTTP status code, if any."""
        instance = super().__new__(cls)
        if cls is ApifyApiError:
            status = response.status_code
            mapped = _STATUS_TO_CLASS.get(status)
            if mapped is None and status >= HTTPStatus.INTERNAL_SERVER_ERROR:
                mapped = ServerError
            if mapped is not None:
                # Retagging is runtime-equivalent to allocating `mapped` directly, but keeps the return type `Self`.
                instance.__class__ = mapped
        return instance

    def __init__(self, response: HttpResponse, attempt: int, *, method: str = 'GET') -> None:
        """Initialize the API error from a failed response.

        Args:
            response: The failed HTTP response from the Apify API.
            attempt: The attempt number when the request failed (1-indexed).
            method: The HTTP method of the failed request.
        """
        payload = self._extract_error_payload(response)

        self.message: str | None = f'Unexpected error: {response.text}'
        self.type: str | None = None
        self.data = dict[str, str]()

        if payload is not None:
            self.message = payload.get('message', self.message)
            self.type = payload.get('type')
            if 'data' in payload:
                self.data = payload['data']

        super().__init__(self.message)

        self.status_code = response.status_code
        self.attempt = attempt
        self.http_method = method

    @staticmethod
    def _extract_error_payload(response: HttpResponse) -> dict[str, Any] | None:
        """Return the `error` dict from the response body, or None if absent or unparsable."""
        try:
            data = response.json()
        except ValueError:
            return None
        if not isinstance(data, dict):
            return None
        error = data.get('error')
        return error if isinstance(error, dict) else None


@docs_group('Errors')
class InvalidRequestError(ApifyApiError):
    """Raised when the Apify API returns an HTTP 400 Bad Request response."""


@docs_group('Errors')
class UnauthorizedError(ApifyApiError):
    """Raised when the Apify API returns an HTTP 401 Unauthorized response."""


@docs_group('Errors')
class ForbiddenError(ApifyApiError):
    """Raised when the Apify API returns an HTTP 403 Forbidden response."""


@docs_group('Errors')
class NotFoundError(ApifyApiError):
    """Raised when the Apify API returns an HTTP 404 Not Found response."""


@docs_group('Errors')
class ConflictError(ApifyApiError):
    """Raised when the Apify API returns an HTTP 409 Conflict response."""


@docs_group('Errors')
class RateLimitError(ApifyApiError):
    """Raised when the Apify API returns an HTTP 429 Too Many Requests response.

    Rate-limited requests are retried automatically; this error is only raised after all retry attempts have been
    exhausted.
    """


@docs_group('Errors')
class ServerError(ApifyApiError):
    """Raised when the Apify API returns an HTTP 5xx response.

    Server errors are retried automatically; this error is only raised after all retry attempts have been exhausted.
    """


@docs_group('Errors')
class InvalidResponseBodyError(ApifyClientError):
    """Error raised when a response body cannot be parsed.

    This occurs when the API returns a body that does not match its content type, for example a malformed JSON
    document. It is raised on a response the client already accepted, so it is not retried - a transfer that breaks
    mid-body surfaces as a transport error inside the retry loop instead.
    """

    def __init__(self, response: HttpResponse) -> None:
        """Initialize the error from an unparsable response.

        Args:
            response: The HTTP response whose body could not be parsed.
        """
        super().__init__('Response body could not be parsed')

        self.code = 'invalid-response-body'
        self.response = response


_STATUS_TO_CLASS: dict[int, type[ApifyApiError]] = {
    400: InvalidRequestError,
    401: UnauthorizedError,
    403: ForbiddenError,
    404: NotFoundError,
    409: ConflictError,
    429: RateLimitError,
}


__all__ = [
    'ApifyApiError',
    'ApifyClientError',
    'ConflictError',
    'ForbiddenError',
    'InvalidRequestError',
    'InvalidResponseBodyError',
    'NotFoundError',
    'RateLimitError',
    'ServerError',
    'UnauthorizedError',
]