"""TDD — HttpTransport.push_mpack_unpack: client-side Step 3 of the mpack push protocol.

MU-1  Happy path: POST returns job_id, head, branch, objects_in_mpack, commits_in_mpack.
MU-2  POST body encodes all five unpack fields correctly.
MU-3  POST is sent to /{owner}/{slug}/push/unpack-mpack.
MU-4  Non-2xx response raises TransportError.
MU-5  Response missing job_id raises TransportError.
MU-6  MSign Authorization header is present (unlike step 2).
"""
from __future__ import annotations

from unittest.mock import MagicMock, patch

import msgpack
import pytest

from muse.core.transport import HttpTransport, TransportError
from muse.core.types import blob_id, fake_id

_Headers = dict[str, str]
_URL = "https://staging.musehub.ai/gabriel/muse"
_MPACK_KEY = blob_id(b"mpack bytes")
_HEAD = fake_id("tip-commit")
_JOB_ID = fake_id("job-id")


def _unpack_response(
    job_id: str = _JOB_ID,
    head: str = _HEAD,
    branch: str = "main",
    objects_in_mpack: int = 5,
    commits_in_mpack: int = 2,
) -> bytes:
    return msgpack.packb({
        "job_id": job_id,
        "head": head,
        "branch": branch,
        "objects_in_mpack": objects_in_mpack,
        "commits_in_mpack": commits_in_mpack,
    }, use_bin_type=True)


class _Resp:
    def __init__(self, body: bytes, status: int = 200) -> None:
        self.status_code = status
        self.content = body


def _mock_client(resp: _Resp) -> MagicMock:
    mock = MagicMock()
    mock.__enter__ = MagicMock(return_value=mock)
    mock.__exit__ = MagicMock(return_value=False)
    mock.post = MagicMock(return_value=resp)
    return mock


# ── MU-1 ──────────────────────────────────────────────────────────────────────

def test_mu1_happy_path_returns_all_fields() -> None:
    """200 response → all result fields present and correctly parsed."""
    mock_client = _mock_client(_Resp(_unpack_response()))
    transport = HttpTransport()

    with patch("muse.core.transport._httpx_mod.Client", return_value=mock_client):
        result = transport.push_mpack_unpack(
            _URL, None, _MPACK_KEY, branch="main", head=_HEAD,
            commits_count=2, objects_count=5,
        )

    assert result["job_id"] == _JOB_ID
    assert result["head"] == _HEAD
    assert result["branch"] == "main"
    assert result["objects_in_mpack"] == 5
    assert result["commits_in_mpack"] == 2


# ── MU-2 ──────────────────────────────────────────────────────────────────────

def test_mu2_post_body_encodes_all_fields() -> None:
    """POST body must contain all five unpack fields with correct values."""
    mock_client = _mock_client(_Resp(_unpack_response()))
    transport = HttpTransport()

    with patch("muse.core.transport._httpx_mod.Client", return_value=mock_client):
        transport.push_mpack_unpack(
            _URL, None, _MPACK_KEY, branch="dev", head=_HEAD,
            commits_count=3, objects_count=10,
        )

    call_kwargs = mock_client.post.call_args
    sent_body: bytes = call_kwargs[1].get("content") or call_kwargs[0][1]
    payload = msgpack.unpackb(sent_body, raw=False)

    assert payload["mpack_key"] == _MPACK_KEY
    assert payload["branch"] == "dev"
    assert payload["head"] == _HEAD
    assert payload["commits_count"] == 3
    assert payload["objects_count"] == 10


# ── MU-3 ──────────────────────────────────────────────────────────────────────

def test_mu3_posts_to_correct_endpoint() -> None:
    """POST must go to /{owner}/{slug}/push/unpack-mpack."""
    mock_client = _mock_client(_Resp(_unpack_response()))
    transport = HttpTransport()

    with patch("muse.core.transport._httpx_mod.Client", return_value=mock_client):
        transport.push_mpack_unpack(_URL, None, _MPACK_KEY, head=_HEAD)

    posted_url: str = mock_client.post.call_args[0][0]
    assert posted_url.endswith("/push/unpack-mpack")


# ── MU-4 ──────────────────────────────────────────────────────────────────────

def test_mu4_non_200_raises_transport_error() -> None:
    """4xx/5xx from server raises TransportError."""
    mock_client = _mock_client(_Resp(b"integrity failure", status=422))
    transport = HttpTransport()

    with patch("muse.core.transport._httpx_mod.Client", return_value=mock_client):
        with pytest.raises(TransportError):
            transport.push_mpack_unpack(_URL, None, _MPACK_KEY, head=_HEAD)


# ── MU-5 ──────────────────────────────────────────────────────────────────────

def test_mu5_missing_job_id_raises_transport_error() -> None:
    """Response without job_id raises TransportError."""
    bad_resp = msgpack.packb({"head": _HEAD, "branch": "main"}, use_bin_type=True)
    mock_client = _mock_client(_Resp(bad_resp))
    transport = HttpTransport()

    with patch("muse.core.transport._httpx_mod.Client", return_value=mock_client):
        with pytest.raises(TransportError, match="job_id"):
            transport.push_mpack_unpack(_URL, None, _MPACK_KEY, head=_HEAD)


# ── MU-6 ──────────────────────────────────────────────────────────────────────

def test_mu6_authorization_header_present() -> None:
    """Unlike step 2, step 3 is a MuseHub API call — MSign auth header required."""
    from muse.core.transport import SigningIdentity
    from unittest.mock import MagicMock as MM

    mock_key = MM()
    mock_key.sign = MM(return_value=b"\x00" * 64)
    mock_key.public_key = MM(return_value=MM(
        public_bytes=MM(return_value=b"\x01" * 32)
    ))
    signing = SigningIdentity(handle="gabriel", private_key=mock_key)

    mock_client = _mock_client(_Resp(_unpack_response()))

    with patch("muse.core.transport._httpx_mod.Client", return_value=mock_client):
        with patch("muse.core.msign.build_msign_header", return_value="MSign fake") as mock_sign:
            transport = HttpTransport()
            transport.push_mpack_unpack(_URL, signing, _MPACK_KEY, head=_HEAD)

    mock_sign.assert_called_once()
    call_kwargs = mock_client.post.call_args
    headers: _Headers = call_kwargs[1].get("headers") or {}
    assert any(k.lower() == "authorization" for k in headers)