from starlette.requests import Request
from transport.unity_instance_middleware import (
    UnityInstanceMiddleware,
    get_unity_instance_middleware
)
from services.api_key_service import ApiKeyService
from transport.legacy.unity_connection import get_unity_connection_pool, UnityConnectionPool
from services.tools import register_all_tools
from core.telemetry import record_milestone, record_telemetry, MilestoneType, RecordType, get_package_version
from services.resources import register_all_resources
from transport.plugin_registry import PluginRegistry
from transport.plugin_hub import PluginHub
from services.custom_tool_service import (
    CustomToolService,
    resolve_project_id_for_unity_instance,
)
from core.config import config
from starlette.routing import WebSocketRoute
from starlette.responses import JSONResponse
import argparse
import asyncio

# Fix to IPV4 Connection Issue #853
# Will disable features in ProactorEventLoop including subprocess pipes and named pipes
import sys
if sys.platform == "win32":
    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())

import logging
from contextlib import asynccontextmanager
import os
import threading
import time
from typing import AsyncIterator, Any
from urllib.parse import urlparse

# Workaround for environments where tool signature evaluation runs with a globals
# dict that does not include common `typing` names (e.g. when annotations are strings
# and evaluated via `eval()` during schema generation).
# Making these names available in builtins avoids `NameError: Annotated/Literal/... is not defined`.
try:  # pragma: no cover - startup safety guard
    import builtins
    import typing as _typing

    _typing_names = (
        "Annotated",
        "Literal",
        "Any",
        "Union",
        "Optional",
        "Dict",
        "List",
        "Tuple",
        "Set",
        "FrozenSet",
    )
    for _name in _typing_names:
        if not hasattr(builtins, _name) and hasattr(_typing, _name):
            # type: ignore[attr-defined]
            setattr(builtins, _name, getattr(_typing, _name))
except Exception:
    pass

from fastmcp import FastMCP
from logging.handlers import RotatingFileHandler


class WindowsSafeRotatingFileHandler(RotatingFileHandler):
    """RotatingFileHandler that gracefully handles Windows file locking during rotation."""

    def doRollover(self):
        """Override to catch PermissionError on Windows when log file is locked."""
        try:
            super().doRollover()
        except PermissionError:
            # On Windows, another process may have the log file open.
            # Skip rotation this time - we'll try again on the next rollover.
            pass


# Configure logging using settings from config
logging.basicConfig(
    level=getattr(logging, config.log_level),
    format=config.log_format,
    stream=None,  # None -> defaults to sys.stderr; avoid stdout used by MCP stdio
    force=True    # Ensure our handler replaces any prior stdout handlers
)
logger = logging.getLogger("mcp-for-unity-server")

# Also write logs to a rotating file so logs are available when launched via stdio.
# Location follows OS conventions; override with UNITY_MCP_LOG_DIR.
try:
    from utils.log_paths import resolve_log_dir
    _log_dir = resolve_log_dir()
    os.makedirs(_log_dir, exist_ok=True)
    _file_path = os.path.join(_log_dir, "unity_mcp_server.log")
    _fh = WindowsSafeRotatingFileHandler(
        _file_path, maxBytes=512*1024, backupCount=2, encoding="utf-8")
    _fh.setFormatter(logging.Formatter(config.log_format))
    _fh.setLevel(getattr(logging, config.log_level))
    logger.addHandler(_fh)
    logger.propagate = False  # Prevent double logging to root logger
    # Add file handler to root logger so __name__-based loggers (e.g. utils.focus_nudge,
    # services.tools.run_tests) also write to the log file. Named loggers with
    # propagate=False won't double-log.
    logging.getLogger().addHandler(_fh)
    # Also route telemetry logger to the same rotating file and normal level
    try:
        tlog = logging.getLogger("unity-mcp-telemetry")
        tlog.setLevel(getattr(logging, config.log_level))
        tlog.addHandler(_fh)
        tlog.propagate = False  # Prevent double logging for telemetry too
    except Exception as exc:
        # Never let logging setup break startup
        logger.debug("Failed to configure telemetry logger", exc_info=exc)
except Exception as exc:
    # Never let logging setup break startup
    logger.debug("Failed to configure main logger file handler", exc_info=exc)
# Quieten noisy third-party loggers to avoid clutter during stdio handshake
for noisy in ("httpx", "urllib3", "mcp.server.lowlevel.server"):
    try:
        logging.getLogger(noisy).setLevel(
            max(logging.WARNING, getattr(logging, config.log_level)))
        logging.getLogger(noisy).propagate = False
    except Exception:
        pass

# Import telemetry only after logging is configured to ensure its logs use stderr and proper levels
# Ensure a slightly higher telemetry timeout unless explicitly overridden by env
try:

    # Ensure generous timeout unless explicitly overridden by env
    if not os.environ.get("UNITY_MCP_TELEMETRY_TIMEOUT"):
        os.environ["UNITY_MCP_TELEMETRY_TIMEOUT"] = "5.0"
except Exception:
    pass

# Global connection pool
_unity_connection_pool: UnityConnectionPool | None = None
_plugin_registry: PluginRegistry | None = None

# Cached server version (set at startup to avoid repeated I/O)
_server_version: str | None = None

# In-memory custom tool service initialized after MCP construction
custom_tool_service: CustomToolService | None = None


@asynccontextmanager
async def server_lifespan(server: FastMCP) -> AsyncIterator[dict[str, Any]]:
    """Handle server startup and shutdown."""
    global _unity_connection_pool, _server_version
    _server_version = get_package_version()
    logger.info(f"MCP for Unity Server v{_server_version} starting up")

    # Register custom tool management endpoints with FastMCP
    # Routes are declared globally below after FastMCP initialization

    # Note: When using HTTP transport, FastMCP handles the HTTP server
    # Tool registration will be handled through FastMCP endpoints
    enable_http_server = os.environ.get(
        "UNITY_MCP_ENABLE_HTTP_SERVER", "").lower() in ("1", "true", "yes", "on")
    if enable_http_server:
        http_host = os.environ.get("UNITY_MCP_HTTP_HOST", "localhost")
        http_port = int(os.environ.get("UNITY_MCP_HTTP_PORT", "8080"))
        logger.info(
            f"HTTP tool registry will be available on http://{http_host}:{http_port}")

    global _plugin_registry
    if _plugin_registry is None:
        _plugin_registry = PluginRegistry()
        loop = asyncio.get_running_loop()
        PluginHub.configure(_plugin_registry, loop, mcp=server)

    # Record server startup telemetry
    start_time = time.time()
    start_clk = time.perf_counter()
    # Defer initial telemetry by 1s to avoid stdio handshake interference

    def _emit_startup():
        try:
            record_telemetry(RecordType.STARTUP, {
                "server_version": _server_version,
                "startup_time": start_time,
            })
            record_milestone(MilestoneType.FIRST_STARTUP)
        except Exception:
            logger.debug("Deferred startup telemetry failed", exc_info=True)
    threading.Timer(1.0, _emit_startup).start()

    try:
        skip_connect = os.environ.get(
            "UNITY_MCP_SKIP_STARTUP_CONNECT", "").lower() in ("1", "true", "yes", "on")
        if skip_connect:
            logger.info(
                "Skipping Unity connection on startup (UNITY_MCP_SKIP_STARTUP_CONNECT=1)")
        else:
            # Initialize connection pool and discover instances
            _unity_connection_pool = get_unity_connection_pool()
            instances = _unity_connection_pool.discover_all_instances()

            if instances:
                logger.info(
                    f"Discovered {len(instances)} Unity instance(s): {[i.id for i in instances]}")

                # Try to connect to default instance
                try:
                    _unity_connection_pool.get_connection()
                    logger.info(
                        "Connected to default Unity instance on startup")

                    # In stdio mode, query Unity for tool enabled states and sync
                    # server-level visibility. In HTTP mode this is handled by
                    # register_tools via WebSocket in PluginHub.
                    if (config.transport_mode or "stdio").lower() != "http":
                        try:
                            from services.tools import sync_tool_visibility_from_unity
                            sync_result = await sync_tool_visibility_from_unity(notify=False)
                            if sync_result.get("synced"):
                                logger.info(
                                    "Stdio startup: synced tool visibility from Unity — "
                                    "enabled=[%s], disabled=[%s]",
                                    ", ".join(sync_result.get("enabled_groups", [])),
                                    ", ".join(sync_result.get("disabled_groups", [])),
                                )
                            else:
                                # Unsupported command = old Unity package; just debug-log
                                log_fn = logger.debug if sync_result.get("unsupported") else logger.warning
                                log_fn(
                                    "Stdio startup: could not sync tool visibility: %s",
                                    sync_result.get("error", "unknown"),
                                )
                        except Exception as sync_exc:
                            logger.debug(
                                "Stdio startup: tool visibility sync failed: %s", sync_exc)

                    # Record successful Unity connection (deferred)
                    threading.Timer(1.0, lambda: record_telemetry(
                        RecordType.UNITY_CONNECTION,
                        {
                            "status": "connected",
                            "connection_time_ms": (time.perf_counter() - start_clk) * 1000,
                            "instance_count": len(instances)
                        }
                    )).start()
                except Exception as e:
                    logger.warning(
                        f"Could not connect to default Unity instance: {e}")
            else:
                logger.warning("No Unity instances found on startup")

    except ConnectionError as e:
        logger.warning(f"Could not connect to Unity on startup: {e}")

        # Record connection failure (deferred)
        _err_msg = str(e)[:200]
        threading.Timer(1.0, lambda: record_telemetry(
            RecordType.UNITY_CONNECTION,
            {
                "status": "failed",
                "error": _err_msg,
                "connection_time_ms": (time.perf_counter() - start_clk) * 1000,
            }
        )).start()
    except Exception as e:
        logger.warning(f"Unexpected error connecting to Unity on startup: {e}")
        _err_msg = str(e)[:200]
        threading.Timer(1.0, lambda: record_telemetry(
            RecordType.UNITY_CONNECTION,
            {
                "status": "failed",
                "error": _err_msg,
                "connection_time_ms": (time.perf_counter() - start_clk) * 1000,
            }
        )).start()

    try:
        # Yield shared state for lifespan consumers (e.g., middleware)
        yield {
            "pool": _unity_connection_pool,
            "plugin_registry": _plugin_registry,
        }
    finally:
        if _unity_connection_pool:
            _unity_connection_pool.disconnect_all()
        logger.info("MCP for Unity Server shut down")


def _build_instructions(project_scoped_tools: bool) -> str:
    if project_scoped_tools:
        custom_tools_note = (
            "I have a dynamic tool system. Always check the mcpforunity://custom-tools resource first "
            "to see what special capabilities are available for the current project."
        )
    else:
        custom_tools_note = (
            "Custom tools are registered as standard tools when Unity connects. "
            "No project-scoped custom tools resource is available."
        )

    return f"""
This server provides tools to interact with the Unity Game Engine Editor.

{custom_tools_note}

Targeting Unity instances:
- Use the resource mcpforunity://instances to list active Unity sessions (Name@hash).
- When multiple instances are connected, call set_active_instance with the exact Name@hash before using tools/resources to pin routing for the whole session. The server will error if multiple are connected and no active instance is set.
- Alternatively, pass unity_instance as a parameter on any individual tool call to route just that call (e.g. unity_instance="MyGame@abc123", unity_instance="abc" for a hash prefix, or unity_instance="6401" for a port number in stdio mode). This does not change the session default.

Important Workflows:

Resources vs Tools:
- Use RESOURCES to read editor state (editor_state, project_info, project_tags, tests, etc)
- Use TOOLS to perform actions and mutations (manage_editor for play mode control, tag/layer management, etc)
- Always check related resources before modifying the engine state with tools

Script Management:
- After creating or modifying scripts (by your own tools or the `manage_script` tool) use `read_console` to check for compilation errors before proceeding
- Only after successful compilation can new components/types be used
- You can poll the `editor_state` resource's `isCompiling` field to check if the domain reload is complete

Scene Setup:
- Always include a Camera and main Light (Directional Light) in new scenes
- Create prefabs with `manage_asset` for reusable GameObjects
- Use `manage_scene` to load, save, and query scene information

Path Conventions:
- Unless specified otherwise, all paths are relative to the project's `Assets/` folder
- Use forward slashes (/) in paths for cross-platform compatibility

Console Monitoring:
- Check `read_console` regularly to catch errors, warnings, and compilation status
- Filter by log type (Error, Warning, Log) to focus on specific issues

Menu Items:
- Use `execute_menu_item` when you have read the menu items resource
- This lets you interact with Unity's menu system and third-party tools

Unity API Verification (requires 'docs' tool group):
- When the 'docs' tool group is active, use `unity_reflect` and `unity_docs` to verify Unity API details before answering questions or writing C# code. LLM training data frequently contains incorrect, outdated, or hallucinated Unity APIs.
- BEFORE answering Unity API questions: search the project's assets (`manage_asset`) and reflect the API (`unity_reflect`) to verify. Do NOT rely on training data alone.
- Common hallucination areas: shaders and materials (always search assets for actual shader names), package-specific APIs (Input System, Cinemachine, ProBuilder, NavMesh, URP/HDRP), and APIs that changed between Unity versions.
- Workflow: `unity_reflect search` → `unity_reflect get_type` → `unity_reflect get_member` → `unity_docs get_doc` (if you need examples/caveats).
- For shader/material questions: use `manage_asset(action="search", filter_type="Shader")` to find actual shaders in the project before recommending one.

Payload sizing & paging (important):
- Many Unity queries can return very large JSON. Prefer **paged + summary-first** calls.
- `manage_scene(action="get_hierarchy")`:
  - Use `page_size` + `cursor` and follow `next_cursor` until null.
  - `page_size` is **items per page**; recommended starting point: **50**.
- `manage_gameobject(action="get_components")`:
  - Start with `include_properties=false` (metadata-only) and small `page_size` (e.g. **10-25**).
  - Only request `include_properties=true` when needed; keep `page_size` small (e.g. **3-10**) to bound payloads.
- `manage_asset(action="search")`:
  - Use paging (`page_size`, `page_number`) and keep `page_size` modest (e.g. **25-50**) to avoid token-heavy responses.
  - Keep `generate_preview=false` unless you explicitly need thumbnails (previews may include large base64 payloads).
"""


def _normalize_instance_token(instance_token: str | None) -> tuple[str | None, str | None]:
    if not instance_token:
        return None, None
    if "@" in instance_token:
        name_part, _, hash_part = instance_token.partition("@")
        return (name_part or None), (hash_part or None)
    return None, instance_token


def create_mcp_server(project_scoped_tools: bool) -> FastMCP:
    mcp = FastMCP(
        name="mcp-for-unity-server",
        lifespan=server_lifespan,
        instructions=_build_instructions(project_scoped_tools),
    )

    global custom_tool_service
    custom_tool_service = CustomToolService(
        mcp, project_scoped_tools=project_scoped_tools)

    @mcp.custom_route("/health", methods=["GET"])
    async def health_http(_: Request) -> JSONResponse:
        return JSONResponse({
            "status": "healthy",
            "timestamp": time.time(),
            "version": _server_version or "unknown",
            "message": "MCP for Unity server is running"
        })

    @mcp.custom_route("/api/auth/login-url", methods=["GET"])
    async def auth_login_url(_: Request) -> JSONResponse:
        """Return the login URL for users to obtain/manage API keys."""
        if not config.api_key_login_url:
            return JSONResponse(
                {
                    "success": False,
                    "error": "API key management not configured. Contact your server administrator.",
                },
                status_code=404,
            )
        return JSONResponse({
            "success": True,
            "login_url": config.api_key_login_url,
        })

    # Only expose CLI routes if running locally (not in remote hosted mode)
    if not config.http_remote_hosted:
        @mcp.custom_route("/api/command", methods=["POST"])
        async def cli_command_route(request: Request) -> JSONResponse:
            """REST endpoint for CLI commands to Unity."""
            try:
                body = await request.json()

                command_type = body.get("type")
                params = body.get("params", {})
                unity_instance = body.get("unity_instance")

                if not command_type:
                    return JSONResponse({"success": False, "error": "Missing 'type' field"}, status_code=400)

                # Get available sessions
                sessions = await PluginHub.get_sessions()
                if not sessions.sessions:
                    return JSONResponse({
                        "success": False,
                        "error": "No Unity instances connected. Make sure Unity is running with MCP plugin."
                    }, status_code=503)

                # Find target session
                session_id = None
                session_details = None
                instance_name, instance_hash = _normalize_instance_token(
                    unity_instance)
                if unity_instance:
                    # Try to match by hash or project name
                    for sid, details in sessions.sessions.items():
                        if details.hash == instance_hash or details.project in (instance_name, unity_instance):
                            session_id = sid
                            session_details = details
                            break

                # If a specific unity_instance was requested but not found, return an error
                # (Check done here so execute_custom_tool can also validate the instance)
                if unity_instance and not session_id:
                    return JSONResponse(
                        {
                            "success": False,
                            "error": f"Unity instance '{unity_instance}' not found",
                        },
                        status_code=404,
                    )

                # If no specific unity_instance requested, use first available session
                # (Must be done before execute_custom_tool check so all command types benefit)
                if not session_id:
                    try:
                        session_id = next(iter(sessions.sessions.keys()))
                        session_details = sessions.sessions.get(session_id)
                    except StopIteration:
                        # No sessions available - sessions.sessions is empty
                        # This should not happen since we checked at line 378, but handle gracefully
                        return JSONResponse({
                            "success": False,
                            "error": "No Unity instances connected. Make sure Unity is running with MCP plugin."
                        }, status_code=503)

                # Custom tool execution - must be checked BEFORE the final PluginHub.send_command call
                # This applies to both cases: with or without explicit unity_instance
                if command_type == "execute_custom_tool":
                    # session_id and session_details are already set above
                    if not session_id or not session_details:
                        return JSONResponse(
                            {"success": False,
                                "error": "No valid Unity session available for custom tool execution"},
                            status_code=503,
                        )
                    tool_name = None
                    tool_params = {}
                    if isinstance(params, dict):
                        tool_name = params.get(
                            "tool_name") or params.get("name")
                        tool_params = params.get(
                            "parameters") or params.get("params") or {}

                    if not tool_name:
                        return JSONResponse(
                            {"success": False,
                                "error": "Missing 'tool_name' for execute_custom_tool"},
                            status_code=400,
                        )
                    if tool_params is None:
                        tool_params = {}
                    if not isinstance(tool_params, dict):
                        return JSONResponse(
                            {"success": False,
                                "error": "Tool parameters must be an object/dict"},
                            status_code=400,
                        )

                    # Prefer a concrete hash for project-scoped tools.
                    unity_instance_hint = unity_instance
                    if session_details and session_details.hash:
                        unity_instance_hint = session_details.hash

                    project_id = resolve_project_id_for_unity_instance(
                        unity_instance_hint)
                    if not project_id:
                        return JSONResponse(
                            {"success": False,
                                "error": "Could not resolve project id for custom tool"},
                            status_code=400,
                        )

                    service = CustomToolService.get_instance()
                    result = await service.execute_tool(
                        project_id, tool_name, unity_instance_hint, tool_params
                    )
                    return JSONResponse(result.model_dump())

                # Send command to Unity
                result = await PluginHub.send_command(session_id, command_type, params)
                return JSONResponse(result)

            except Exception as e:
                logger.exception("CLI command error: %s", e)
                return JSONResponse({"success": False, "error": str(e)}, status_code=500)

        @mcp.custom_route("/api/instances", methods=["GET"])
        async def cli_instances_route(_: Request) -> JSONResponse:
            """REST endpoint to list connected Unity instances."""
            try:
                sessions = await PluginHub.get_sessions()
                instances = []
                for session_id, details in sessions.sessions.items():
                    instances.append({
                        "session_id": session_id,
                        "project": details.project,
                        "hash": details.hash,
                        "unity_version": details.unity_version,
                        "connected_at": details.connected_at,
                    })
                return JSONResponse({"success": True, "instances": instances})
            except Exception as e:
                return JSONResponse({"success": False, "error": str(e)}, status_code=500)

        @mcp.custom_route("/api/custom-tools", methods=["GET"])
        async def cli_custom_tools_route(request: Request) -> JSONResponse:
            """REST endpoint to list custom tools for the active Unity project."""
            try:
                unity_instance = request.query_params.get("instance")
                instance_name, instance_hash = _normalize_instance_token(
                    unity_instance)

                sessions = await PluginHub.get_sessions()
                if not sessions.sessions:
                    return JSONResponse({
                        "success": False,
                        "error": "No Unity instances connected. Make sure Unity is running with MCP plugin."
                    }, status_code=503)

                session_details = None
                if unity_instance:
                    # Try to match by hash or project name
                    for _, details in sessions.sessions.items():
                        if details.hash == instance_hash or details.project in (instance_name, unity_instance):
                            session_details = details
                            break
                    if not session_details:
                        return JSONResponse(
                            {
                                "success": False,
                                "error": f"Unity instance '{unity_instance}' not found",
                            },
                            status_code=404,
                        )
                else:
                    # No specific unity_instance requested: use first available session
                    session_details = next(iter(sessions.sessions.values()))

                unity_instance_hint = unity_instance
                if session_details and session_details.hash:
                    unity_instance_hint = session_details.hash

                project_id = resolve_project_id_for_unity_instance(
                    unity_instance_hint)
                if not project_id:
                    return JSONResponse(
                        {"success": False,
                            "error": "Could not resolve project id for custom tools"},
                        status_code=400,
                    )

                service = CustomToolService.get_instance()
                tools = await service.list_registered_tools(project_id)
                tools_payload = [
                    tool.model_dump() if hasattr(tool, "model_dump") else tool for tool in tools
                ]

                return JSONResponse({
                    "success": True,
                    "project_id": project_id,
                    "tool_count": len(tools_payload),
                    "tools": tools_payload,
                })
            except Exception as e:
                logger.exception("CLI custom tools error: %s", e)
                return JSONResponse({"success": False, "error": str(e)}, status_code=500)

    # Initialize and register middleware for session-based Unity instance routing
    # Using the singleton getter ensures we use the same instance everywhere
    unity_middleware = get_unity_instance_middleware()
    mcp.add_middleware(unity_middleware)
    logger.info("Registered Unity instance middleware for session-based routing")

    # Initialize API key authentication if in remote-hosted mode
    if config.http_remote_hosted and config.api_key_validation_url:
        ApiKeyService(
            validation_url=config.api_key_validation_url,
            cache_ttl=config.api_key_cache_ttl,
            service_token_header=config.api_key_service_token_header,
            service_token=config.api_key_service_token,
        )
        logger.info(
            "Initialized API key authentication service (validation URL: %s, TTL: %.0fs)",
            config.api_key_validation_url,
            config.api_key_cache_ttl,
        )

    # Mount plugin websocket hub at /hub/plugin when HTTP transport is active.
    # NOTE: Uses FastMCP private API because custom_route() only supports HTTP
    # methods, not WebSocket. _additional_http_routes accepts Starlette Route
    # objects and is still present in FastMCP 3.x.
    existing_routes = [
        route for route in mcp._get_additional_http_routes()
        if isinstance(route, WebSocketRoute) and route.path == "/hub/plugin"
    ]
    if not existing_routes:
        mcp._additional_http_routes.append(
            WebSocketRoute("/hub/plugin", PluginHub))

    # Register all tools
    register_all_tools(mcp, project_scoped_tools=project_scoped_tools)

    # Register all resources
    register_all_resources(mcp, project_scoped_tools=project_scoped_tools)

    return mcp


def main():
    """Entry point for uvx and console scripts."""
    parser = argparse.ArgumentParser(
        description="MCP for Unity Server",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Environment Variables:
  UNITY_MCP_DEFAULT_INSTANCE   Default Unity instance to target (project name, hash, or 'Name@hash')
  UNITY_MCP_SKIP_STARTUP_CONNECT   Skip initial Unity connection attempt (set to 1/true/yes/on)
  UNITY_MCP_TELEMETRY_ENABLED   Enable telemetry (set to 1/true/yes/on)
  UNITY_MCP_TRANSPORT   Transport protocol: stdio or http (default: stdio)
  UNITY_MCP_HTTP_URL   HTTP server URL (default: http://127.0.0.1:8080)
  UNITY_MCP_HTTP_HOST   HTTP server host (overrides URL host)
  UNITY_MCP_HTTP_PORT   HTTP server port (overrides URL port)

Examples:
  # Use specific Unity project as default
  python -m src.server --default-instance "MyProject"

  # Start with HTTP transport
  python -m src.server --transport http --http-url http://127.0.0.1:8080

  # Start with stdio transport (default)
  python -m src.server --transport stdio

  # Use environment variable for transport
  UNITY_MCP_TRANSPORT=http UNITY_MCP_HTTP_URL=http://localhost:9000 python -m src.server
        """
    )
    parser.add_argument(
        "--default-instance",
        type=str,
        metavar="INSTANCE",
        help="Default Unity instance to target (project name, hash, or 'Name@hash'). "
             "Overrides UNITY_MCP_DEFAULT_INSTANCE environment variable."
    )
    parser.add_argument(
        "--transport",
        type=str,
        choices=["stdio", "http"],
        default="stdio",
        help="Transport protocol to use: stdio or http (default: stdio). "
             "Overrides UNITY_MCP_TRANSPORT environment variable."
    )
    parser.add_argument(
        "--http-url",
        type=str,
        default="http://127.0.0.1:8080",
        metavar="URL",
        help="HTTP server URL (default: http://127.0.0.1:8080). "
             "Can also set via UNITY_MCP_HTTP_URL environment variable."
    )
    parser.add_argument(
        "--http-host",
        type=str,
        default=None,
        metavar="HOST",
        help="HTTP server host (overrides URL host). "
             "Overrides UNITY_MCP_HTTP_HOST environment variable."
    )
    parser.add_argument(
        "--http-port",
        type=int,
        default=None,
        metavar="PORT",
        help="HTTP server port (overrides URL port). "
             "Overrides UNITY_MCP_HTTP_PORT environment variable."
    )
    parser.add_argument(
        "--http-remote-hosted",
        action="store_true",
        help="Treat HTTP transport as remotely hosted (forces explicit Unity instance selection). "
             "Can also set via UNITY_MCP_HTTP_REMOTE_HOSTED=true."
    )
    parser.add_argument(
        "--api-key-validation-url",
        type=str,
        default=None,
        metavar="URL",
        help="External URL to validate API keys (POST with {'api_key': '...'}). "
             "Required when --http-remote-hosted is set. "
             "Can also set via UNITY_MCP_API_KEY_VALIDATION_URL."
    )
    parser.add_argument(
        "--api-key-login-url",
        type=str,
        default=None,
        metavar="URL",
        help="URL where users can obtain/manage API keys. "
             "Returned by /api/auth/login-url endpoint. "
             "Can also set via UNITY_MCP_API_KEY_LOGIN_URL."
    )
    parser.add_argument(
        "--api-key-cache-ttl",
        type=float,
        default=300.0,
        metavar="SECONDS",
        help="Cache TTL for validated API keys in seconds (default: 300). "
             "Can also set via UNITY_MCP_API_KEY_CACHE_TTL."
    )
    parser.add_argument(
        "--api-key-service-token-header",
        type=str,
        default=None,
        metavar="HEADER",
        help="Header name for service token sent to validation endpoint (e.g. X-Service-Token). "
             "Can also set via UNITY_MCP_API_KEY_SERVICE_TOKEN_HEADER."
    )
    parser.add_argument(
        "--api-key-service-token",
        type=str,
        default=None,
        metavar="TOKEN",
        help="Service token value sent to validation endpoint for server authentication. "
             "WARNING: Prefer UNITY_MCP_API_KEY_SERVICE_TOKEN env var in production to avoid process listing exposure."
    )
    parser.add_argument(
        "--unity-instance-token",
        type=str,
        default=None,
        metavar="TOKEN",
        help="Optional per-launch token set by Unity for deterministic lifecycle management. "
             "Used by Unity to validate it is stopping the correct process."
    )
    parser.add_argument(
        "--pidfile",
        type=str,
        default=None,
        metavar="PATH",
        help="Optional path where the server will write its PID on startup. "
             "Used by Unity to stop the exact process it launched when running in a terminal."
    )
    parser.add_argument(
        "--project-scoped-tools",
        action="store_true",
        help="Keep custom tools scoped to the active Unity project and enable the custom tools resource. "
             "Can also set via UNITY_MCP_PROJECT_SCOPED_TOOLS=true."
    )

    args = parser.parse_args()

    # Set environment variables from command line args
    if args.default_instance:
        os.environ["UNITY_MCP_DEFAULT_INSTANCE"] = args.default_instance
        logger.info(
            f"Using default Unity instance from command-line: {args.default_instance}")

    # Set transport mode
    config.transport_mode = args.transport or os.environ.get(
        "UNITY_MCP_TRANSPORT", "stdio")
    logger.info(f"Transport mode: {config.transport_mode}")

    config.http_remote_hosted = (
        bool(args.http_remote_hosted)
        or os.environ.get("UNITY_MCP_HTTP_REMOTE_HOSTED", "").lower() in ("true", "1", "yes", "on")
    )

    # API key authentication configuration
    config.api_key_validation_url = (
        args.api_key_validation_url
        or os.environ.get("UNITY_MCP_API_KEY_VALIDATION_URL")
    )
    config.api_key_login_url = (
        args.api_key_login_url
        or os.environ.get("UNITY_MCP_API_KEY_LOGIN_URL")
    )
    try:
        cache_ttl_env = os.environ.get("UNITY_MCP_API_KEY_CACHE_TTL")
        config.api_key_cache_ttl = (
            float(cache_ttl_env) if cache_ttl_env else args.api_key_cache_ttl
        )
    except ValueError:
        logger.warning(
            "Invalid UNITY_MCP_API_KEY_CACHE_TTL value, using default 300.0"
        )
        config.api_key_cache_ttl = 300.0

    # Service token for authenticating to validation endpoint
    config.api_key_service_token_header = (
        args.api_key_service_token_header
        or os.environ.get("UNITY_MCP_API_KEY_SERVICE_TOKEN_HEADER")
    )
    config.api_key_service_token = (
        args.api_key_service_token
        or os.environ.get("UNITY_MCP_API_KEY_SERVICE_TOKEN")
    )

    # Validate: remote-hosted HTTP mode requires API key validation URL
    if config.http_remote_hosted and config.transport_mode == "http" and not config.api_key_validation_url:
        logger.error(
            "--http-remote-hosted requires --api-key-validation-url or "
            "UNITY_MCP_API_KEY_VALIDATION_URL environment variable"
        )
        raise SystemExit(1)

    http_url = os.environ.get("UNITY_MCP_HTTP_URL", args.http_url)
    parsed_url = urlparse(http_url)

    # Allow individual host/port to override URL components
    http_host = args.http_host or os.environ.get(
        "UNITY_MCP_HTTP_HOST") or parsed_url.hostname or "127.0.0.1"

    # Safely parse optional environment port (may be None or non-numeric)
    _env_port_str = os.environ.get("UNITY_MCP_HTTP_PORT")
    try:
        _env_port = int(_env_port_str) if _env_port_str is not None else None
    except ValueError:
        logger.warning(
            "Invalid UNITY_MCP_HTTP_PORT value '%s', ignoring", _env_port_str)
        _env_port = None

    http_port = args.http_port or _env_port or parsed_url.port or 8080

    os.environ["UNITY_MCP_HTTP_HOST"] = http_host
    os.environ["UNITY_MCP_HTTP_PORT"] = str(http_port)

    # Optional lifecycle handshake for Unity-managed terminal launches
    if args.unity_instance_token:
        os.environ["UNITY_MCP_INSTANCE_TOKEN"] = args.unity_instance_token
    if args.pidfile:
        try:
            pid_dir = os.path.dirname(args.pidfile)
            if pid_dir:
                os.makedirs(pid_dir, exist_ok=True)
            with open(args.pidfile, "w", encoding="ascii") as f:
                f.write(str(os.getpid()))
        except Exception as exc:
            logger.warning(
                "Failed to write pidfile '%s': %s", args.pidfile, exc)

    if args.http_url != "http://127.0.0.1:8080":
        logger.info(f"HTTP URL set to: {http_url}")
    if args.http_host:
        logger.info(f"HTTP host override: {http_host}")
    if args.http_port:
        logger.info(f"HTTP port override: {http_port}")

    # Explicit CLI/env overrides always win
    project_scoped_tools_explicit = (
        bool(args.project_scoped_tools)
        or os.environ.get("UNITY_MCP_PROJECT_SCOPED_TOOLS", "").lower() in ("true", "1", "yes", "on")
    )

    # If not explicitly set, check Unity status files for the default instance.
    # In stdio mode there is typically only one instance, so "first match wins" is fine.
    project_scoped_tools = project_scoped_tools_explicit
    if not project_scoped_tools_explicit:
        try:
            from transport.legacy.unity_connection import get_unity_connection_pool
            pool = get_unity_connection_pool()
            instances = pool.discover_all_instances()
            # If ANY discovered instance requests project-scoped tools, enable them
            for inst in instances:
                if getattr(inst, "project_scoped_tools", False):
                    project_scoped_tools = True
                    logger.info(
                        "Enabling project-scoped tools because Unity instance %s requested it",
                        inst.id,
                    )
                    break
        except Exception:
            logger.debug("Could not discover Unity instances for project-scoped tool default", exc_info=True)

    mcp = create_mcp_server(project_scoped_tools)

    # Determine transport mode
    if config.transport_mode == 'http':
        # Use HTTP transport for FastMCP
        transport = 'http'
        # Use the parsed host and port from URL/args
        http_url = os.environ.get("UNITY_MCP_HTTP_URL", args.http_url)
        parsed_url = urlparse(http_url)
        host = args.http_host or os.environ.get(
            "UNITY_MCP_HTTP_HOST") or parsed_url.hostname or "127.0.0.1"
        port = args.http_port or _env_port or parsed_url.port or 8080
        logger.info(f"Starting FastMCP with HTTP transport on {host}:{port}")
        mcp.run(transport=transport, host=host, port=port)
    else:
        # Use stdio transport for traditional MCP
        logger.info("Starting FastMCP with stdio transport")
        mcp.run(transport='stdio')


# Run the server
if __name__ == "__main__":
    main()
