"""Tests for OAuth2 per-user Gitea authentication."""

from __future__ import annotations

import asyncio
from unittest.mock import AsyncMock, MagicMock, patch

import pytest
from fastapi.testclient import TestClient

from aegis_gitea_mcp.config import reset_settings
from aegis_gitea_mcp.oauth import GiteaOAuthValidator, get_oauth_validator, reset_oauth_validator
from aegis_gitea_mcp.request_context import (
    get_gitea_user_login,
    get_gitea_user_token,
    set_gitea_user_login,
    set_gitea_user_token,
)

# ---------------------------------------------------------------------------
# Fixtures
# ---------------------------------------------------------------------------


@pytest.fixture(autouse=True)
def reset_state():
    """Reset global state between tests."""
    reset_settings()
    reset_oauth_validator()
    yield
    reset_settings()
    reset_oauth_validator()


@pytest.fixture
def mock_env_oauth(monkeypatch):
    """Environment for OAuth mode tests."""
    monkeypatch.setenv("GITEA_URL", "https://gitea.example.com")
    monkeypatch.setenv("ENVIRONMENT", "test")
    monkeypatch.setenv("OAUTH_MODE", "true")
    monkeypatch.setenv("GITEA_OAUTH_CLIENT_ID", "test-client-id")
    monkeypatch.setenv("GITEA_OAUTH_CLIENT_SECRET", "test-client-secret")
    monkeypatch.setenv("STARTUP_VALIDATE_GITEA", "false")


@pytest.fixture
def oauth_validator(mock_env_oauth):
    """Create GiteaOAuthValidator instance in OAuth mode."""
    return GiteaOAuthValidator()


@pytest.fixture
def oauth_client(mock_env_oauth):
    """Create FastAPI test client in OAuth mode."""
    from aegis_gitea_mcp.server import app

    return TestClient(app, raise_server_exceptions=False)


# ---------------------------------------------------------------------------
# GiteaOAuthValidator unit tests
# ---------------------------------------------------------------------------


@pytest.mark.asyncio
async def test_validate_oauth_token_success(oauth_validator):
    """Valid Gitea OAuth token returns is_valid=True and user_data."""
    mock_response = MagicMock()
    mock_response.status_code = 200
    mock_response.json.return_value = {"login": "testuser", "id": 42}

    with patch("aegis_gitea_mcp.oauth.httpx.AsyncClient") as mock_client_cls:
        mock_client = AsyncMock()
        mock_client.get = AsyncMock(return_value=mock_response)
        mock_client_cls.return_value.__aenter__ = AsyncMock(return_value=mock_client)
        mock_client_cls.return_value.__aexit__ = AsyncMock(return_value=False)

        is_valid, error, user_data = await oauth_validator.validate_oauth_token(
            "valid-gitea-token", "127.0.0.1", "TestAgent/1.0"
        )

    assert is_valid is True
    assert error is None
    assert user_data is not None
    assert user_data["login"] == "testuser"


@pytest.mark.asyncio
async def test_validate_oauth_token_invalid_401(oauth_validator):
    """Gitea returning 401 results in is_valid=False."""
    mock_response = MagicMock()
    mock_response.status_code = 401

    with patch("aegis_gitea_mcp.oauth.httpx.AsyncClient") as mock_client_cls:
        mock_client = AsyncMock()
        mock_client.get = AsyncMock(return_value=mock_response)
        mock_client_cls.return_value.__aenter__ = AsyncMock(return_value=mock_client)
        mock_client_cls.return_value.__aexit__ = AsyncMock(return_value=False)

        is_valid, error, user_data = await oauth_validator.validate_oauth_token(
            "expired-token", "127.0.0.1", "TestAgent/1.0"
        )

    assert is_valid is False
    assert error is not None
    assert user_data is None


@pytest.mark.asyncio
async def test_validate_oauth_token_missing_token(oauth_validator):
    """Missing token results in is_valid=False."""
    is_valid, error, user_data = await oauth_validator.validate_oauth_token(
        None, "127.0.0.1", "TestAgent/1.0"
    )

    assert is_valid is False
    assert error is not None
    assert user_data is None


@pytest.mark.asyncio
async def test_validate_oauth_token_network_error(oauth_validator):
    """Network error results in is_valid=False with informative message."""
    import httpx

    with patch("aegis_gitea_mcp.oauth.httpx.AsyncClient") as mock_client_cls:
        mock_client = AsyncMock()
        mock_client.get = AsyncMock(
            side_effect=httpx.RequestError("Connection refused", request=MagicMock())
        )
        mock_client_cls.return_value.__aenter__ = AsyncMock(return_value=mock_client)
        mock_client_cls.return_value.__aexit__ = AsyncMock(return_value=False)

        is_valid, error, user_data = await oauth_validator.validate_oauth_token(
            "some-token", "127.0.0.1", "TestAgent/1.0"
        )

    assert is_valid is False
    assert error is not None
    assert "unable to validate oauth token" in error.lower()
    assert user_data is None


@pytest.mark.asyncio
async def test_validate_oauth_token_rate_limit(oauth_validator):
    """Exceeding failure threshold triggers rate limiting."""
    mock_response = MagicMock()
    mock_response.status_code = 401

    with patch("aegis_gitea_mcp.oauth.httpx.AsyncClient") as mock_client_cls:
        mock_client = AsyncMock()
        mock_client.get = AsyncMock(return_value=mock_response)
        mock_client_cls.return_value.__aenter__ = AsyncMock(return_value=mock_client)
        mock_client_cls.return_value.__aexit__ = AsyncMock(return_value=False)

        # Exhaust failures (default MAX_AUTH_FAILURES=5)
        for _ in range(5):
            await oauth_validator.validate_oauth_token("bad-token", "10.0.0.1", "Agent")

        # Next attempt should be rate-limited
        is_valid, error, user_data = await oauth_validator.validate_oauth_token(
            "bad-token", "10.0.0.1", "Agent"
        )

    assert is_valid is False
    assert error is not None
    assert "too many" in error.lower()


# ---------------------------------------------------------------------------
# Singleton tests
# ---------------------------------------------------------------------------


def test_get_oauth_validator_singleton(mock_env_oauth):
    """get_oauth_validator returns the same instance on repeated calls."""
    v1 = get_oauth_validator()
    v2 = get_oauth_validator()
    assert v1 is v2


def test_reset_oauth_validator(mock_env_oauth):
    """reset_oauth_validator creates a fresh instance after reset."""
    v1 = get_oauth_validator()
    reset_oauth_validator()
    v2 = get_oauth_validator()
    assert v1 is not v2


# ---------------------------------------------------------------------------
# ContextVar isolation tests
# ---------------------------------------------------------------------------


def test_context_var_token_isolation():
    """ContextVar values do not leak between coroutines."""
    results = {}

    async def task_a():
        set_gitea_user_token("token-for-a")
        await asyncio.sleep(0)
        results["a"] = get_gitea_user_token()

    async def task_b():
        # task_b never sets the token; should see None (default)
        await asyncio.sleep(0)
        results["b"] = get_gitea_user_token()

    async def run():
        await asyncio.gather(task_a(), task_b())

    asyncio.run(run())

    assert results["a"] == "token-for-a"
    assert results["b"] is None  # ContextVar isolation: task_b sees default


def test_context_var_login_set_and_get():
    """set_gitea_user_login / get_gitea_user_login work correctly."""
    set_gitea_user_login("alice")
    assert get_gitea_user_login() == "alice"


# ---------------------------------------------------------------------------
# /oauth/token proxy endpoint tests
# ---------------------------------------------------------------------------


def test_oauth_token_endpoint_available_when_oauth_mode_false(monkeypatch):
    """POST /oauth/token remains available regardless of OAUTH_MODE."""
    monkeypatch.setenv("GITEA_URL", "https://gitea.example.com")
    monkeypatch.setenv("GITEA_TOKEN", "test-token-12345")
    monkeypatch.setenv("ENVIRONMENT", "test")
    monkeypatch.setenv("MCP_API_KEYS", "a" * 64)
    monkeypatch.setenv("OAUTH_MODE", "false")
    monkeypatch.setenv("STARTUP_VALIDATE_GITEA", "false")

    mock_response = MagicMock()
    mock_response.status_code = 200
    mock_response.json.return_value = {"access_token": "token"}

    from aegis_gitea_mcp.server import app

    with patch("aegis_gitea_mcp.server.httpx.AsyncClient") as mock_client_cls:
        mock_client = AsyncMock()
        mock_client.post = AsyncMock(return_value=mock_response)
        mock_client_cls.return_value.__aenter__ = AsyncMock(return_value=mock_client)
        mock_client_cls.return_value.__aexit__ = AsyncMock(return_value=False)

        with TestClient(app, raise_server_exceptions=False) as client:
            response = client.post("/oauth/token", data={"code": "abc123"})

    assert response.status_code == 200


def test_oauth_token_endpoint_missing_code(oauth_client):
    """POST /oauth/token without a code returns 400."""
    response = oauth_client.post("/oauth/token", data={})
    assert response.status_code == 400


def test_oauth_token_endpoint_proxy_success(oauth_client):
    """POST /oauth/token proxies successfully to Gitea and returns access_token."""
    mock_response = MagicMock()
    mock_response.status_code = 200
    mock_response.json.return_value = {
        "access_token": "gitea-access-token-xyz",
        "token_type": "bearer",
    }

    with patch("aegis_gitea_mcp.server.httpx.AsyncClient") as mock_client_cls:
        mock_client = AsyncMock()
        mock_client.post = AsyncMock(return_value=mock_response)
        mock_client_cls.return_value.__aenter__ = AsyncMock(return_value=mock_client)
        mock_client_cls.return_value.__aexit__ = AsyncMock(return_value=False)

        response = oauth_client.post(
            "/oauth/token",
            data={"code": "auth-code-123", "redirect_uri": "https://chat.openai.com/callback"},
        )

    assert response.status_code == 200
    body = response.json()
    assert body["access_token"] == "gitea-access-token-xyz"


def test_oauth_token_endpoint_gitea_error(oauth_client):
    """POST /oauth/token propagates Gitea error status."""
    mock_response = MagicMock()
    mock_response.status_code = 400
    mock_response.json.return_value = {"error": "invalid_grant"}

    with patch("aegis_gitea_mcp.server.httpx.AsyncClient") as mock_client_cls:
        mock_client = AsyncMock()
        mock_client.post = AsyncMock(return_value=mock_response)
        mock_client_cls.return_value.__aenter__ = AsyncMock(return_value=mock_client)
        mock_client_cls.return_value.__aexit__ = AsyncMock(return_value=False)

        response = oauth_client.post("/oauth/token", data={"code": "bad-code"})

    assert response.status_code == 400


# ---------------------------------------------------------------------------
# Config validation tests
# ---------------------------------------------------------------------------


def test_config_oauth_mode_requires_client_id(monkeypatch):
    """OAUTH_MODE=true without client_id raises ValueError."""
    monkeypatch.setenv("GITEA_URL", "https://gitea.example.com")
    monkeypatch.setenv("OAUTH_MODE", "true")
    monkeypatch.setenv("GITEA_OAUTH_CLIENT_ID", "")
    monkeypatch.setenv("GITEA_OAUTH_CLIENT_SECRET", "some-secret")

    from aegis_gitea_mcp.config import Settings

    with pytest.raises(Exception, match="GITEA_OAUTH_CLIENT_ID"):
        Settings()  # type: ignore[call-arg]


def test_config_oauth_mode_requires_client_secret(monkeypatch):
    """OAUTH_MODE=true without client_secret raises ValueError."""
    monkeypatch.setenv("GITEA_URL", "https://gitea.example.com")
    monkeypatch.setenv("OAUTH_MODE", "true")
    monkeypatch.setenv("GITEA_OAUTH_CLIENT_ID", "some-id")
    monkeypatch.setenv("GITEA_OAUTH_CLIENT_SECRET", "")

    from aegis_gitea_mcp.config import Settings

    with pytest.raises(Exception, match="GITEA_OAUTH_CLIENT_SECRET"):
        Settings()  # type: ignore[call-arg]


def test_config_standard_mode_requires_gitea_token(monkeypatch):
    """Standard mode without GITEA_TOKEN raises ValueError."""
    monkeypatch.setenv("GITEA_URL", "https://gitea.example.com")
    monkeypatch.setenv("OAUTH_MODE", "false")
    monkeypatch.setenv("GITEA_TOKEN", "")
    monkeypatch.setenv("MCP_API_KEYS", "a" * 64)

    from aegis_gitea_mcp.config import Settings

    with pytest.raises(Exception, match="GITEA_TOKEN"):
        Settings()  # type: ignore[call-arg]


# ---------------------------------------------------------------------------
# Server middleware: OAuth mode authentication
# ---------------------------------------------------------------------------


def test_mcp_tool_call_requires_valid_gitea_token(oauth_client):
    """POST /mcp/tool/call with an invalid Gitea token returns 401."""
    mock_response = MagicMock()
    mock_response.status_code = 401

    with patch("aegis_gitea_mcp.oauth.httpx.AsyncClient") as mock_client_cls:
        mock_client = AsyncMock()
        mock_client.get = AsyncMock(return_value=mock_response)
        mock_client_cls.return_value.__aenter__ = AsyncMock(return_value=mock_client)
        mock_client_cls.return_value.__aexit__ = AsyncMock(return_value=False)

        response = oauth_client.post(
            "/mcp/tool/call",
            json={"tool": "list_repositories", "arguments": {}},
            headers={"Authorization": "Bearer invalid-token"},
        )

    assert response.status_code == 401


def test_mcp_tool_call_no_token_returns_401(oauth_client):
    """POST /mcp/tool/call without Authorization header returns 401."""
    response = oauth_client.post(
        "/mcp/tool/call",
        json={"tool": "list_repositories", "arguments": {}},
    )
    assert response.status_code == 401