from __future__ import annotations

import sys
from collections.abc import Iterator
from http import HTTPStatus
from pathlib import Path
from typing import Any
from unittest.mock import patch

import pytest
from arcade_core.errors import (
    ErrorKind,
    NetworkTransportError,
    UpstreamError,
    UpstreamRateLimitError,
)

LIBS_DIR = Path(__file__).resolve().parents[2]
TDK_SRC = LIBS_DIR / "arcade-tdk"
if str(TDK_SRC) not in sys.path:
    sys.path.insert(0, str(TDK_SRC))

import arcade_tdk.providers.graphql.error_adapter as gql_adapter  # noqa: E402

# --- Dummy exception classes for testing ---


class DummyTransportError(Exception):
    def __init__(self, message: str, code: int | None = None) -> None:
        super().__init__(message)
        self.code = code


class DummyTransportQueryError(Exception):
    def __init__(self, errors: list[dict[str, Any]] | None = None) -> None:
        super().__init__("query error")
        self.errors = errors


class DummyResponse:
    def __init__(self, headers: dict[str, str] | None = None) -> None:
        self.headers = headers or {}


class DummyTransportServerError(Exception):
    def __init__(
        self, message: str, code: int | None = None, headers: dict[str, str] | None = None
    ):
        super().__init__(message)
        self.code = code
        if headers is not None:
            self.response = DummyResponse(headers)


class DummyTransportConnectionFailed(DummyTransportError):
    pass


class DummyTransportProtocolError(DummyTransportError):
    pass


@pytest.fixture(autouse=True)
def reset_cache() -> Iterator[None]:
    """Clear cached gql import state between tests."""
    gql_adapter._load_gql_transport_errors.cache_clear()
    yield
    gql_adapter._load_gql_transport_errors.cache_clear()


def _patch_loader() -> Any:
    """Patch the loader to return our dummy classes."""
    return patch.object(
        gql_adapter,
        "_load_gql_transport_errors",
        return_value=(
            DummyTransportError,
            DummyTransportQueryError,
            DummyTransportServerError,
            DummyTransportConnectionFailed,
            DummyTransportProtocolError,
        ),
    )


class TestGraphQLErrorAdapter:
    # --- Import/caching tests ---

    def test_skips_when_gql_not_installed(self, monkeypatch: pytest.MonkeyPatch) -> None:
        """Should return None and cache the import failure."""
        call_count = {"n": 0}

        def fake_import(name: str) -> None:
            call_count["n"] += 1
            raise ImportError("no gql")

        monkeypatch.setattr(gql_adapter.importlib, "import_module", fake_import)
        adapter = gql_adapter.GraphQLErrorAdapter()

        assert adapter.from_exception(Exception("x")) is None
        assert adapter.from_exception(Exception("y")) is None
        assert call_count["n"] == 1  # Only tried once

    def test_ignores_non_gql_exceptions(self) -> None:
        """Non-gql exceptions should return None."""
        with _patch_loader():
            adapter = gql_adapter.GraphQLErrorAdapter()
            assert adapter.from_exception(RuntimeError("not gql")) is None

    # --- TransportQueryError tests ---

    def test_query_error_extracts_messages_and_codes(self) -> None:
        """Should extract messages and map error codes to status."""
        errors = [
            {"message": "Not authorized", "extensions": {"code": "FORBIDDEN"}},
            {"message": "Server error", "extensions": {"code": "INTERNAL_SERVER_ERROR"}},
        ]
        exc = DummyTransportQueryError(errors=errors)

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert isinstance(result, UpstreamError)
        assert result.status_code == HTTPStatus.INTERNAL_SERVER_ERROR  # Highest mapped status
        assert "Not authorized" in result.message
        assert "Server error" in result.message
        assert result.extra["gql_error_codes"] == ["FORBIDDEN", "INTERNAL_SERVER_ERROR"]

    def test_query_error_defaults_when_empty(self) -> None:
        """Should handle empty/missing errors gracefully."""
        exc = DummyTransportQueryError(errors=None)

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert isinstance(result, UpstreamError)
        assert result.status_code == HTTPStatus.UNPROCESSABLE_ENTITY
        assert "Unknown GraphQL error" in result.message

    def test_query_error_deduplicates_codes(self) -> None:
        """Duplicate error codes should be deduplicated."""
        errors = [
            {"message": "A", "extensions": {"code": "FORBIDDEN"}},
            {"message": "B", "extensions": {"code": "FORBIDDEN"}},
        ]
        exc = DummyTransportQueryError(errors=errors)

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert result.extra["gql_error_codes"] == ["FORBIDDEN"]

    # --- TransportServerError tests ---

    def test_server_error_detects_rate_limit(self) -> None:
        """Should detect rate limits from status + headers."""
        exc = DummyTransportServerError(
            message="Too many requests",
            code=429,
            headers={"retry-after": "5"},
        )

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert isinstance(result, UpstreamRateLimitError)
        assert result.retry_after_ms == 5000

    def test_server_error_defaults_to_500(self) -> None:
        """Should default to 500 when no status code."""
        exc = DummyTransportServerError("Server error", code=None)

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert isinstance(result, UpstreamError)
        assert result.status_code == HTTPStatus.INTERNAL_SERVER_ERROR
        assert result.message == "Upstream GraphQL request failed with status code 500."
        assert result.developer_message == "Server error"

    def test_server_error_extracts_headers_from_cause(self) -> None:
        """Should extract headers from __cause__ if not on exception."""
        exc = DummyTransportServerError("Error", code=429)
        # No headers on exc, but on __cause__
        cause = Exception("inner")
        cause.response = DummyResponse({"retry-after": "10"})  # type: ignore
        exc.__cause__ = cause

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert isinstance(result, UpstreamRateLimitError)
        assert result.retry_after_ms == 10000

    def test_server_error_extracts_url_from_cause_aiohttp(self) -> None:
        """Should extract URL from __cause__ (aiohttp pattern)."""
        exc = DummyTransportServerError("Error", code=500)

        # aiohttp style: request_info.url
        class FakeRequestInfo:
            url = "https://api.github.com/graphql"
            method = "POST"

        cause = Exception("inner")
        cause.request_info = FakeRequestInfo()  # type: ignore
        exc.__cause__ = cause

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert isinstance(result, UpstreamError)
        assert result.extra is not None
        assert result.extra.get("endpoint") == "https://api.github.com/graphql"
        assert result.extra.get("http_method") == "POST"

    def test_server_error_extracts_url_from_cause_httpx(self) -> None:
        """Should extract URL from __cause__ (httpx/requests pattern)."""
        exc = DummyTransportServerError("Error", code=500)

        # httpx style: response.request.url
        class FakeRequest:
            url = "https://api.stripe.com/graphql"
            method = "POST"

        class FakeResponse:
            request = FakeRequest()

        cause = Exception("inner")
        cause.response = FakeResponse()  # type: ignore
        exc.__cause__ = cause

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert isinstance(result, UpstreamError)
        assert result.extra is not None
        assert result.extra.get("endpoint") == "https://api.stripe.com/graphql"
        assert result.extra.get("http_method") == "POST"

    # --- Connection/Protocol error tests ---

    def test_connection_failed_maps_to_network_transport_unreachable(self) -> None:
        """Connection failures never reached upstream — NetworkTransportError."""
        exc = DummyTransportConnectionFailed("Connection refused")

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert isinstance(result, NetworkTransportError)
        assert result.kind == ErrorKind.NETWORK_TRANSPORT_RUNTIME_UNREACHABLE
        assert result.can_retry is True
        assert result.status_code is None
        assert result.extra["error_type"] == "DummyTransportConnectionFailed"

    def test_protocol_error_maps_to_network_transport_unreachable(self) -> None:
        """Protocol errors (incomplete / malformed exchange) → NetworkTransportError."""
        exc = DummyTransportProtocolError("Invalid response")

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert isinstance(result, NetworkTransportError)
        assert result.kind == ErrorKind.NETWORK_TRANSPORT_RUNTIME_UNREACHABLE
        assert result.can_retry is True
        assert result.status_code is None
        assert result.extra["error_type"] == "DummyTransportProtocolError"

    # --- Generic TransportError catch-all ---

    def test_generic_transport_error_handled(self) -> None:
        """Unknown TransportError subclasses should be caught."""
        exc = DummyTransportError("Unknown error", code=503)

        with _patch_loader():
            result = gql_adapter.GraphQLErrorAdapter().from_exception(exc)

        assert isinstance(result, UpstreamError)
        assert result.status_code == 503
        assert result.message == "Upstream GraphQL request failed with status code 503."
        assert result.developer_message == "Unknown error"

    # --- Edge cases ---

    def test_extract_message_handles_bad_str(self) -> None:
        """Should handle objects that fail str()."""

        class BadStr:
            def __str__(self) -> str:
                raise ValueError("nope")

        assert gql_adapter._extract_error_message(BadStr()) == "Unknown GraphQL error"

    def test_extract_message_handles_empty(self) -> None:
        """Should handle empty/None messages."""
        assert gql_adapter._extract_error_message(None) == "Unknown GraphQL error"
        assert gql_adapter._extract_error_message("") == "Unknown GraphQL error"