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

MU-1  Happy path: POST returns head, branch, blobs_in_mpack, commits_in_mpack.
MU-2  POST body encodes all unpack fields correctly.
MU-3  POST is sent to /{owner}/{slug}/push/unpack-mpack.
MU-4  Non-2xx response 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")


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


def _mock_urllib_do(body: bytes, status: int = 200) -> "Callable[..., bytes]":
    calls: list[tuple[str, str, dict, bytes | None]] = []

    def _side_effect(method: str, url: str, headers: "dict[str, str]", data: "bytes | None" = None, **kwargs: "str | int | bool") -> bytes:
        calls.append((method, url, headers, data))
        if status >= 400:
            raise TransportError(f"HTTP {status}", status)
        return body

    _side_effect.calls = calls
    return _side_effect


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

def test_mu1_happy_path_returns_all_fields() -> None:
    do = _mock_urllib_do(_unpack_response())
    with patch("muse.core.transport._urllib_do", side_effect=do):
        result = HttpTransport().push_mpack_unpack(
            _URL, None, _MPACK_KEY, branch="main", head=_HEAD,
            commits_count=2, blobs_count=5,
        )
    assert result["head"] == _HEAD
    assert result["branch"] == "main"
    assert result["blobs_in_mpack"] == 5
    assert result["commits_in_mpack"] == 2


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

def test_mu2_post_body_encodes_all_fields() -> None:
    do = _mock_urllib_do(_unpack_response())
    with patch("muse.core.transport._urllib_do", side_effect=do):
        HttpTransport().push_mpack_unpack(
            _URL, None, _MPACK_KEY, branch="dev", head=_HEAD,
            commits_count=3, blobs_count=10,
        )
    _, _, _, sent_data = do.calls[0]
    payload = msgpack.unpackb(sent_data, raw=False)
    assert payload["mpack_key"] == _MPACK_KEY
    assert payload["branch"] == "dev"
    assert payload["head"] == _HEAD
    assert payload["commits_count"] == 3
    assert payload["blobs_count"] == 10


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

def test_mu3_posts_to_correct_endpoint() -> None:
    do = _mock_urllib_do(_unpack_response())
    with patch("muse.core.transport._urllib_do", side_effect=do):
        HttpTransport().push_mpack_unpack(_URL, None, _MPACK_KEY, head=_HEAD)
    _, url, _, _ = do.calls[0]
    assert url.endswith("/push/unpack-mpack")


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

def test_mu4_non_200_raises_transport_error() -> None:
    do = _mock_urllib_do(b"integrity failure", status=422)
    with patch("muse.core.transport._urllib_do", side_effect=do):
        with pytest.raises(TransportError):
            HttpTransport().push_mpack_unpack(_URL, None, _MPACK_KEY, head=_HEAD)


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

def test_mu6_authorization_header_present() -> None:
    """Step 3 is a MuseHub API call — MSign auth header required."""
    from muse.core.transport import SigningIdentity

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

    do = _mock_urllib_do(_unpack_response())
    with patch("muse.core.transport._urllib_do", side_effect=do):
        with patch("muse.core.msign.build_msign_header", return_value="MSign fake") as mock_sign:
            with patch("muse.core.hub_trust.check_and_pin"):
                HttpTransport().push_mpack_unpack(_URL, signing, _MPACK_KEY, head=_HEAD)

    mock_sign.assert_called_once()
    _, _, headers, _ = do.calls[0]
    assert any(k.lower() == "authorization" for k in headers)