# Copyright (c) Microsoft. All rights reserved.
"""
Pytest configuration for Azure Functions integration tests.

This module provides fixtures, configuration, and test utilities for pytest.
"""

import os
import shutil
import socket
import subprocess
import sys
import time
import uuid
from collections.abc import Iterator, Mapping
from contextlib import suppress
from pathlib import Path
from typing import Any

import pytest
import requests

# =============================================================================
# Configuration Constants
# =============================================================================

TIMEOUT = 30  # seconds
ORCHESTRATION_TIMEOUT = 180  # seconds for orchestrations
_DEFAULT_HOST = "localhost"

# Emulator ports (match CI workflow configuration)
_AZURITE_BLOB_PORT = 10000
_DTS_EMULATOR_PORT = 8080


# =============================================================================
# Exceptions
# =============================================================================


class FunctionAppStartupError(RuntimeError):
    """Raised when the Azure Functions host fails to start reliably."""

    pass


# =============================================================================
# Environment and Service Checks
# =============================================================================


def _load_env_file_if_present() -> None:
    """Load environment variables from the local .env file when available."""
    env_file = Path(__file__).parent / ".env"
    if not env_file.exists():
        return

    try:
        from dotenv import load_dotenv

        load_dotenv(env_file)
    except ImportError:
        # python-dotenv not available; rely on existing environment
        pass


def _check_func_cli_available() -> bool:
    """Check if Azure Functions Core Tools (func) is installed and available."""
    return shutil.which("func") is not None


def _check_port_listening(port: int, host: str = _DEFAULT_HOST) -> bool:
    """Check if a service is listening on the given port."""
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
        sock.settimeout(1)
        return sock.connect_ex((host, port)) == 0


def _check_azurite_available() -> bool:
    """Check if Azurite (Azure Storage emulator) is available on the expected port."""
    return _check_port_listening(_AZURITE_BLOB_PORT)


def _check_dts_emulator_available() -> bool:
    """Check if Durable Task Scheduler emulator is available on the expected port."""
    return _check_port_listening(_DTS_EMULATOR_PORT)


def _should_skip_azure_functions_integration_tests() -> tuple[bool, str]:
    """Determine whether Azure Functions integration tests should be skipped."""
    _load_env_file_if_present()

    # Check for Azure Functions Core Tools
    if not _check_func_cli_available():
        return (
            True,
            "Azure Functions Core Tools (func) not installed. Install with: npm install -g azure-functions-core-tools@4",  # noqa: E501
        )

    # Check for Azurite (Azure Storage emulator)
    if not _check_azurite_available():
        return (
            True,
            f"Azurite not running on port {_AZURITE_BLOB_PORT}. Start with: docker run -d -p 10000:10000 -p 10001:10001 -p 10002:10002 mcr.microsoft.com/azure-storage/azurite",  # noqa: E501
        )

    # Check for Durable Task Scheduler emulator
    if not _check_dts_emulator_available():
        return (
            True,
            f"Durable Task Scheduler emulator not running on port {_DTS_EMULATOR_PORT}. Start with: docker run -d -p 8080:8080 -p 8082:8082 mcr.microsoft.com/dts/dts-emulator:latest",  # noqa: E501
        )

    has_foundry_config = bool(os.getenv("FOUNDRY_PROJECT_ENDPOINT", "").strip()) and bool(
        os.getenv("FOUNDRY_MODEL", "").strip()
    )
    has_azure_openai_config = bool(os.getenv("AZURE_OPENAI_ENDPOINT", "").strip()) and bool(
        os.getenv("AZURE_OPENAI_MODEL", "").strip()
    )
    if not has_foundry_config and not has_azure_openai_config:
        return (
            True,
            "No real FOUNDRY_* or AZURE_OPENAI_* configuration provided; skipping integration tests.",
        )

    return False, "Integration tests enabled."


_SKIP_AZURE_FUNCTIONS_INTEGRATION_TESTS, _AZURE_FUNCTIONS_SKIP_REASON = _should_skip_azure_functions_integration_tests()

skip_if_azure_functions_integration_tests_disabled = pytest.mark.skipif(
    _SKIP_AZURE_FUNCTIONS_INTEGRATION_TESTS,
    reason=_AZURE_FUNCTIONS_SKIP_REASON,
)


# =============================================================================
# Test Helper Class
# =============================================================================


class SampleTestHelper:
    """Helper class for testing samples."""

    @staticmethod
    def post_json(url: str, data: dict[str, Any], timeout: int = TIMEOUT) -> requests.Response:
        """POST JSON data to a URL."""
        return requests.post(url, json=data, headers={"Content-Type": "application/json"}, timeout=timeout)

    @staticmethod
    def post_text(url: str, text: str, timeout: int = TIMEOUT) -> requests.Response:
        """POST plain text to a URL."""
        return requests.post(url, data=text, headers={"Content-Type": "text/plain"}, timeout=timeout)

    @staticmethod
    def get(url: str, timeout: int = TIMEOUT) -> requests.Response:
        """GET request to a URL."""
        return requests.get(url, timeout=timeout)

    @staticmethod
    def wait_for_orchestration(
        status_url: str, max_wait: int = ORCHESTRATION_TIMEOUT, poll_interval: int = 2
    ) -> dict[str, Any]:
        """Wait for an orchestration to complete.

        Args:
            status_url: URL to poll for orchestration status
            max_wait: Maximum seconds to wait
            poll_interval: Seconds between polls

        Returns:
            Final orchestration status

        Raises:
            TimeoutError: If orchestration doesn't complete in time
        """
        start_time = time.time()
        while time.time() - start_time < max_wait:
            response = requests.get(status_url, timeout=TIMEOUT)
            response.raise_for_status()
            status = response.json()

            runtime_status = status.get("runtimeStatus", "")
            if runtime_status in ["Completed", "Failed", "Terminated"]:
                return status

            time.sleep(poll_interval)

        raise TimeoutError(f"Orchestration did not complete within {max_wait} seconds")

    @staticmethod
    def wait_for_orchestration_with_output(
        status_url: str, max_wait: int = ORCHESTRATION_TIMEOUT, poll_interval: int = 2
    ) -> dict[str, Any]:
        """Wait for an orchestration to complete and have output available.

        This is a specialized version of wait_for_orchestration that also
        ensures the output field is present, handling timing race conditions.

        Args:
            status_url: URL to poll for orchestration status
            max_wait: Maximum seconds to wait
            poll_interval: Seconds between polls

        Returns:
            Final orchestration status with output

        Raises:
            TimeoutError: If orchestration doesn't complete with output in time
        """
        start_time = time.time()
        while time.time() - start_time < max_wait:
            response = requests.get(status_url, timeout=TIMEOUT)
            response.raise_for_status()
            status = response.json()

            runtime_status = status.get("runtimeStatus", "")
            if runtime_status in ["Failed", "Terminated"]:
                return status
            if runtime_status == "Completed" and status.get("output"):
                return status
            # If completed but no output, continue polling for a bit more to
            # handle the race condition where output has not been persisted yet.

            time.sleep(poll_interval)

        # Provide detailed error message based on final status
        final_response = requests.get(status_url, timeout=TIMEOUT)
        final_response.raise_for_status()
        final_status = final_response.json()
        final_runtime_status = final_status.get("runtimeStatus", "Unknown")

        if final_runtime_status == "Completed":
            if "output" not in final_status:
                raise TimeoutError(
                    "Orchestration completed but 'output' field is missing after "
                    f"{max_wait} seconds. Final status: {final_status}"
                )
            if not final_status["output"]:
                raise TimeoutError(
                    "Orchestration completed but output is empty after "
                    f"{max_wait} seconds. Final status: {final_status}"
                )
            raise TimeoutError(
                "Orchestration completed with output but validation failed after "
                f"{max_wait} seconds. Final status: {final_status}"
            )
        raise TimeoutError(
            "Orchestration did not complete within "
            f"{max_wait} seconds. Final status: {final_runtime_status}, "
            f"Full status: {final_status}"
        )


# =============================================================================
# Function App Lifecycle Management
# =============================================================================


def _resolve_repo_root() -> Path:
    """Resolve the repository root, preferring GITHUB_WORKSPACE when available."""
    workspace = os.getenv("GITHUB_WORKSPACE")
    if workspace:
        candidate = Path(workspace).expanduser()
        if not (candidate / "samples").exists() and (candidate / "python" / "samples").exists():
            return (candidate / "python").resolve()
        return candidate.resolve()

    # If `GITHUB_WORKSPACE` is not set,
    # go up from conftest.py -> integration_tests -> tests -> azurefunctions -> packages -> python
    return Path(__file__).resolve().parents[4]


def _get_sample_path_from_marker(request: pytest.FixtureRequest) -> tuple[Path | None, str | None]:
    """Get sample path from @pytest.mark.sample() marker.

    Returns a tuple of (sample_path, error_message).
    If successful, error_message is None.
    If failed, sample_path is None and error_message contains the reason.
    """
    marker = request.node.get_closest_marker("sample")

    if not marker:
        return (
            None,
            (
                "No @pytest.mark.sample() marker found on test. Add pytestmark with "
                "@pytest.mark.sample('sample_name') to the test module."
            ),
        )

    if not marker.args:
        return (
            None,
            "@pytest.mark.sample() marker found but no sample name provided. Use @pytest.mark.sample('sample_name').",
        )

    sample_name = marker.args[0]
    repo_root = _resolve_repo_root()
    sample_path = repo_root / "samples" / "04-hosting" / "azure_functions" / sample_name

    if not sample_path.exists():
        return None, f"Sample directory does not exist: {sample_path}"

    return sample_path, None


def _find_available_port(host: str = _DEFAULT_HOST) -> int:
    """Find an available TCP port on the given host."""
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
        sock.bind((host, 0))
        return sock.getsockname()[1]


def _build_base_url(port: int, host: str = _DEFAULT_HOST) -> str:
    """Construct a base URL for the Azure Functions host."""
    return f"http://{host}:{port}"


def _is_port_in_use(port: int, host: str = _DEFAULT_HOST) -> bool:
    """Check if a port is already in use.

    Returns True if the port is in use, False otherwise.
    """
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
        return sock.connect_ex((host, port)) == 0


def _load_and_validate_env(sample_path: Path) -> None:
    """Load .env file from current directory if it exists, then validate required environment variables.

    Raises pytest.fail if required environment variables are missing.
    """
    _load_env_file_if_present()
    # Required environment variables for Azure Functions samples
    required_env_vars = [
        "AzureWebJobsStorage",
        "DURABLE_TASK_SCHEDULER_CONNECTION_STRING",
        "FUNCTIONS_WORKER_RUNTIME",
    ]
    # Samples that host no AI agents need no model credentials (only the DTS emulator
    # and Azurite). The suite-level gate still requires *some* LLM config to be present.
    no_llm_samples = {"13_subworkflow_hitl"}
    if sample_path.name in no_llm_samples:
        pass
    elif sample_path.name == "11_workflow_parallel":
        required_env_vars.extend(["AZURE_OPENAI_ENDPOINT", "AZURE_OPENAI_MODEL"])
    else:
        required_env_vars.extend(["FOUNDRY_PROJECT_ENDPOINT", "FOUNDRY_MODEL"])

    # Check if required env vars are set
    missing_vars = [var for var in required_env_vars if not os.environ.get(var)]

    if missing_vars:
        pytest.fail(
            f"Missing required environment variables: {', '.join(missing_vars)}. "
            "Please create a .env file in tests/integration_tests/ based on .env.example or "
            "set these variables in your environment."
        )


def _start_function_app(sample_path: Path, port: int) -> subprocess.Popen[Any]:
    """Start a function app in the specified sample directory.

    Returns the subprocess.Popen object for the running process.
    """
    env = os.environ.copy()
    # Use a unique TASKHUB_NAME for each test run to ensure test isolation.
    # This prevents conflicts between parallel or repeated test runs, as Durable Functions
    # use the task hub name to separate orchestration state.
    env["TASKHUB_NAME"] = f"test{uuid.uuid4().hex[:8]}"

    # The Azure Functions Python worker's dependency isolation mechanism crashes
    # on Python 3.13 with a SIGSEGV in the protobuf C extension (google._upb).
    # Disabling isolation lets the worker load dependencies from the app's own
    # environment, which avoids the crash.
    # See: https://github.com/Azure/azure-functions-python-worker/issues/1797
    if sys.version_info >= (3, 13):
        env.setdefault("PYTHON_ISOLATE_WORKER_DEPENDENCIES", "0")

    # On Windows, use CREATE_NEW_PROCESS_GROUP to allow proper termination
    # shell=True only on Windows to handle PATH resolution
    if sys.platform == "win32":
        return subprocess.Popen(
            ["func", "start", "--port", str(port)],
            cwd=str(sample_path),
            creationflags=subprocess.CREATE_NEW_PROCESS_GROUP,
            shell=True,
            env=env,
        )
    # On Unix, use start_new_session=True to isolate the process group from the
    # pytest-xdist worker.  Without this, signals (e.g. from test-timeout) can
    # propagate to the func host and vice-versa, potentially killing the worker.
    return subprocess.Popen(
        ["func", "start", "--port", str(port)],
        cwd=str(sample_path),
        env=env,
        start_new_session=True,
    )


def _wait_for_function_app_ready(func_process: subprocess.Popen[Any], port: int, max_wait: int = 60) -> None:
    """Block until the Azure Functions host responds healthy or fail fast."""
    start_time = time.time()
    health_url = f"{_build_base_url(port)}/api/health"
    last_error: Exception | None = None

    while time.time() - start_time < max_wait:
        # If the process exited early, capture any previously seen error and fail fast.
        if func_process.poll() is not None:
            raise FunctionAppStartupError(
                f"Function app process exited with code {func_process.returncode} before becoming healthy"
            ) from last_error

        if _is_port_in_use(port):
            try:
                response = requests.get(health_url, timeout=5)
                if response.status_code == 200:
                    return
                last_error = RuntimeError(f"Health check returned {response.status_code}")
            except requests.RequestException as exc:
                last_error = exc

        time.sleep(1)

    raise FunctionAppStartupError(
        f"Function app did not become healthy on port {port} within {max_wait} seconds"
    ) from last_error


def _cleanup_function_app(func_process: subprocess.Popen[Any]) -> None:
    """Clean up the function app process and all its children.

    Uses psutil if available for more thorough cleanup, falls back to basic termination.
    """
    try:
        import psutil

        if func_process.poll() is None:  # Process still running
            # Get parent process
            parent = psutil.Process(func_process.pid)

            # Get all child processes recursively
            children = parent.children(recursive=True)

            # Kill children first
            for child in children:
                with suppress(psutil.NoSuchProcess, psutil.AccessDenied):
                    child.kill()

            # Kill parent
            with suppress(psutil.NoSuchProcess, psutil.AccessDenied):
                parent.kill()

            # Wait for all to terminate
            _gone, alive = psutil.wait_procs(children + [parent], timeout=3)

            # Force kill any remaining
            for proc in alive:
                with suppress(psutil.NoSuchProcess, psutil.AccessDenied):
                    proc.kill()
    except ImportError:
        # Fallback if psutil not available
        try:
            if func_process.poll() is None:
                func_process.kill()
                func_process.wait()
        except Exception:
            # Ignore all exceptions during fallback cleanup; best effort to terminate process.
            pass
    except Exception:
        pass  # Best effort cleanup

    # Give the port time to be released
    time.sleep(2)


# =============================================================================
# Pytest Configuration
# =============================================================================


def pytest_configure(config: pytest.Config) -> None:
    """Register custom markers."""
    config.addinivalue_line("markers", "orchestration: marks tests that use orchestrations (require Azurite)")
    config.addinivalue_line(
        "markers",
        "sample(path): specify the sample directory path for the test (e.g., @pytest.mark.sample('01_single_agent'))",
    )


def pytest_collection_modifyitems(config: pytest.Config, items: list[pytest.Item]) -> None:
    """Skip integration tests in this directory if prerequisites are not met."""
    should_skip, reason = _should_skip_azure_functions_integration_tests()
    if should_skip:
        skip_marker = pytest.mark.skip(reason=reason)
        for item in items:
            # Only skip items that are in this integration_tests directory
            if "integration_tests" in str(item.fspath):
                item.add_marker(skip_marker)


# =============================================================================
# Pytest Fixtures
# =============================================================================


@pytest.fixture(scope="session")
def function_app_running() -> bool:
    """Check if the function app is running on localhost:7071.

    This fixture can be used to skip tests if the function app is not available.
    """
    try:
        response = requests.get("http://localhost:7071/api/health", timeout=2)
        return response.status_code == 200
    except requests.exceptions.RequestException:
        return False


@pytest.fixture(scope="session")
def skip_if_no_function_app(function_app_running: bool) -> None:
    """Skip test if function app is not running."""
    if not function_app_running:
        pytest.skip("Function app is not running on http://localhost:7071")


@pytest.fixture(scope="module")
def function_app_for_test(request: pytest.FixtureRequest) -> Iterator[dict[str, int | str]]:
    """Start the function app for the corresponding sample based on marker.

    This fixture:
    1. Determines which sample to run from @pytest.mark.sample()
    2. Validates environment variables
    3. Starts the function app using 'func start'
    4. Waits for the app to be ready
    5. Tears down the app after tests complete

    Usage:
    @pytest.mark.sample("01_single_agent")
    @pytest.mark.usefixtures("function_app_for_test")
    class TestSample01SingleAgent:
        ...
    """
    # Get sample path from marker
    sample_path, error_message = _get_sample_path_from_marker(request)
    if error_message:
        pytest.fail(error_message)

    assert sample_path is not None, "Sample path must be resolved before starting the function app"

    # Load .env file if it exists and validate required env vars
    _load_and_validate_env(sample_path)

    max_attempts = 3
    # The overall budget MUST be shorter than the pytest-timeout value
    # (--timeout=120 by default) so that the fixture finishes cleanly instead
    # of being killed by os._exit() which crashes the xdist worker.
    overall_budget = 100  # seconds – leaves headroom below the 120 s test timeout
    last_error: Exception | None = None
    func_process: subprocess.Popen[Any] | None = None
    base_url = ""
    port = 0
    overall_start = time.monotonic()
    attempts_made = 0

    for _ in range(max_attempts):
        remaining = overall_budget - (time.monotonic() - overall_start)
        if remaining < 10:
            # Not enough time for another attempt; bail out.
            break

        attempts_made += 1
        port = _find_available_port()
        base_url = _build_base_url(port)
        func_process = _start_function_app(sample_path, port)

        try:
            # Cap each attempt's wait to the remaining budget minus a small
            # buffer for cleanup.
            per_attempt_wait = min(60, int(remaining) - 5)
            _wait_for_function_app_ready(func_process, port, max_wait=max(per_attempt_wait, 10))
            last_error = None
            break
        except FunctionAppStartupError as exc:
            last_error = exc
            _cleanup_function_app(func_process)
            func_process = None

    if func_process is None:
        elapsed = int(time.monotonic() - overall_start)
        error_message = f"Function app failed to start after {attempts_made} attempt(s) ({elapsed}s elapsed)."
        if last_error is not None:
            error_message += f" Last error: {last_error}"
        pytest.fail(error_message)

    try:
        yield {"base_url": base_url, "port": port}
    finally:
        if func_process is not None:
            _cleanup_function_app(func_process)


@pytest.fixture(scope="module")
def base_url(function_app_for_test: Mapping[str, int | str]) -> str:
    """Expose the function app's base URL to tests."""
    return str(function_app_for_test["base_url"])


@pytest.fixture(scope="session")
def sample_helper() -> type[SampleTestHelper]:
    """Provide the SampleTestHelper class for tests."""
    return SampleTestHelper
