"""Shared test helpers: a mock ESI client backed by httpx.MockTransport."""

from __future__ import annotations

import base64
import json
from collections.abc import Callable

import httpx
import pytest

from familiar import esi


def make_jwt(claims: dict) -> str:
    """Build a fake JWT (header.payload.signature) whose payload is `claims`.

    Only the payload segment is ever decoded by familiar, so the header and
    signature can be arbitrary.
    """
    payload = base64.urlsafe_b64encode(json.dumps(claims).encode()).rstrip(b"=").decode()
    return f"header.{payload}.signature"


Handler = Callable[[httpx.Request], httpx.Response]


@pytest.fixture
def mock_esi():
    """Install a mock ESI client driven by a request handler.

    Usage::

        def test_x(mock_esi):
            def handler(request):
                return httpx.Response(200, json={...})
            mock_esi(handler)
            ...

    The shared client is reset after the test.
    """

    def _make(handler: Handler) -> esi.EsiClient:
        client = esi.EsiClient(transport=httpx.MockTransport(handler))
        esi.set_client(client)
        return client

    yield _make
    esi.set_client(None)


def route(request: httpx.Request, fixtures: dict[str, object]) -> httpx.Response:
    """Match a request against ``{substring_in_path: json_body}`` and respond.

    The special key ``"/universe/ids/"`` is matched for the name-resolution POST.
    A missing match returns 404 so tests fail loudly.
    """
    path = request.url.path
    for needle, body in fixtures.items():
        if needle in path:
            return httpx.Response(200, json=body)
    return httpx.Response(404, json={"error": f"no fixture for {path}"})