"""
Privacy-focused, anonymous telemetry system for MCP for Unity
Inspired by Onyx's telemetry implementation with Unity-specific adaptations

Fire-and-forget telemetry sender with a single background worker.
- No context/thread-local propagation to avoid re-entrancy into tool resolution.
- Small network timeouts to prevent stalls.
"""

import contextlib
from dataclasses import dataclass
from enum import Enum
from importlib import import_module, metadata
import json
import logging
import os
from pathlib import Path
import platform
import queue
import sys
import threading
import time
from typing import Any
from urllib.parse import urlparse
import uuid

import tomli

try:
    import httpx
    HAS_HTTPX = True
except ImportError:
    httpx = None  # type: ignore
    HAS_HTTPX = False

logger = logging.getLogger("unity-mcp-telemetry")


def get_package_version() -> str:
    """
    Get package version in different ways:
    1. First we try the installed metadata - this is because uvx is used on the asset store
    2. If that fails, we try to read from pyproject.toml - this is available for users who download via Git
    Default is "unknown", but that should never happen
    """
    try:
        return metadata.version("MCPForUnityServer")
    except Exception:
        # Fallback for development: read from pyproject.toml
        try:
            pyproject_path = Path(__file__).parent / "pyproject.toml"
            with open(pyproject_path, "rb") as f:
                data = tomli.load(f)
            return data["project"]["version"]
        except Exception:
            return "unknown"


MCP_VERSION = get_package_version()


class RecordType(str, Enum):
    """Types of telemetry records we collect"""
    VERSION = "version"
    STARTUP = "startup"
    USAGE = "usage"
    LATENCY = "latency"
    FAILURE = "failure"
    RESOURCE_RETRIEVAL = "resource_retrieval"
    TOOL_EXECUTION = "tool_execution"
    UNITY_CONNECTION = "unity_connection"
    CLIENT_CONNECTION = "client_connection"


class MilestoneType(str, Enum):
    """Major user journey milestones"""
    FIRST_STARTUP = "first_startup"
    FIRST_TOOL_USAGE = "first_tool_usage"
    FIRST_SCRIPT_CREATION = "first_script_creation"
    FIRST_SCENE_MODIFICATION = "first_scene_modification"
    MULTIPLE_SESSIONS = "multiple_sessions"
    DAILY_ACTIVE_USER = "daily_active_user"
    WEEKLY_ACTIVE_USER = "weekly_active_user"


@dataclass
class TelemetryRecord:
    """Structure for telemetry data"""
    record_type: RecordType
    timestamp: float
    customer_uuid: str
    session_id: str
    data: dict[str, Any]
    milestone: MilestoneType | None = None


class TelemetryConfig:
    """Telemetry configuration"""

    def __init__(self):
        """
        Prefer config file, then allow env overrides
        """
        server_config = None
        for modname in (
            # Prefer plain module to respect test-time overrides and sys.path injection
            "src.core.config",
            "config",
            "src.config",
            "Server.config",
        ):
            try:
                mod = import_module(modname)
                server_config = getattr(mod, "config", None)
                if server_config is not None:
                    break
            except Exception:
                continue

        # Determine enabled flag: config -> env DISABLE_* opt-out
        cfg_enabled = True if server_config is None else bool(
            getattr(server_config, "telemetry_enabled", True))
        self.enabled = cfg_enabled and not self._is_disabled()

        # Telemetry endpoint (Cloud Run default; override via env)
        cfg_default = None if server_config is None else getattr(
            server_config, "telemetry_endpoint", None)
        default_ep = cfg_default or "https://api-prod.coplay.dev/telemetry/events"
        self.default_endpoint = default_ep
        # Prefer config default; allow explicit env override only when set
        env_ep = os.environ.get("UNITY_MCP_TELEMETRY_ENDPOINT")
        if env_ep is not None and env_ep != "":
            self.endpoint = self._validated_endpoint(env_ep, default_ep)
        else:
            # Validate config-provided default as well to enforce scheme/host rules
            self.endpoint = self._validated_endpoint(default_ep, default_ep)
        try:
            logger.info(
                f"Telemetry configured: endpoint={self.endpoint} (default={default_ep}), timeout_env={os.environ.get('UNITY_MCP_TELEMETRY_TIMEOUT') or '<unset>'}")
        except Exception:
            pass

        # Local storage for UUID and milestones
        self.data_dir = self._get_data_directory()
        self.uuid_file = self.data_dir / "customer_uuid.txt"
        self.milestones_file = self.data_dir / "milestones.json"

        # Request timeout (small, fail fast). Override with UNITY_MCP_TELEMETRY_TIMEOUT
        try:
            self.timeout = float(os.environ.get(
                "UNITY_MCP_TELEMETRY_TIMEOUT", "1.5"))
        except Exception:
            self.timeout = 1.5
        try:
            logger.info(f"Telemetry timeout={self.timeout:.2f}s")
        except Exception:
            pass

        # Session tracking
        self.session_id = str(uuid.uuid4())

    def _is_disabled(self) -> bool:
        """Check if telemetry is disabled via environment variables"""
        disable_vars = [
            "DISABLE_TELEMETRY",
            "UNITY_MCP_DISABLE_TELEMETRY",
            "MCP_DISABLE_TELEMETRY"
        ]

        for var in disable_vars:
            if os.environ.get(var, "").lower() in ("true", "1", "yes", "on"):
                return True
        return False

    def _get_data_directory(self) -> Path:
        """Get directory for storing telemetry data"""
        if os.name == 'nt':  # Windows
            base_dir = Path(os.environ.get(
                'APPDATA', Path.home() / 'AppData' / 'Roaming'))
        elif os.name == 'posix':  # macOS/Linux
            if 'darwin' in os.uname().sysname.lower():  # macOS
                base_dir = Path.home() / 'Library' / 'Application Support'
            else:  # Linux
                base_dir = Path(os.environ.get('XDG_DATA_HOME',
                                Path.home() / '.local' / 'share'))
        else:
            base_dir = Path.home() / '.unity-mcp'

        data_dir = base_dir / 'UnityMCP'
        data_dir.mkdir(parents=True, exist_ok=True)
        return data_dir

    def _validated_endpoint(self, candidate: str, fallback: str) -> str:
        """Validate telemetry endpoint URL scheme; allow only http/https.
        Falls back to the provided default on error.
        """
        try:
            parsed = urlparse(candidate)
            if parsed.scheme not in ("https", "http"):
                raise ValueError(f"Unsupported scheme: {parsed.scheme}")
            # Basic sanity: require network location and path
            if not parsed.netloc:
                raise ValueError("Missing netloc in endpoint")
            # Reject localhost/loopback endpoints in production to avoid accidental local overrides
            host = parsed.hostname or ""
            if host in ("localhost", "127.0.0.1", "::1"):
                raise ValueError(
                    "Localhost endpoints are not allowed for telemetry")
            return candidate
        except Exception as e:
            logger.debug(
                f"Invalid telemetry endpoint '{candidate}', using default. Error: {e}",
                exc_info=True,
            )
            return fallback


class TelemetryCollector:
    """Main telemetry collection class"""

    def __init__(self):
        self.config = TelemetryConfig()
        self._customer_uuid: str | None = None
        self._milestones: dict[str, dict[str, Any]] = {}
        self._lock: threading.Lock = threading.Lock()
        # Bounded queue with single background worker (records only; no context propagation)
        self._queue: "queue.Queue[TelemetryRecord]" = queue.Queue(maxsize=1000)
        # Load persistent data before starting worker so first events have UUID
        self._load_persistent_data()
        self._worker: threading.Thread = threading.Thread(
            target=self._worker_loop, daemon=True)
        self._worker.start()

    def _load_persistent_data(self):
        """Load UUID and milestones from disk"""
        # Load customer UUID
        try:
            if self.config.uuid_file.exists():
                self._customer_uuid = self.config.uuid_file.read_text(
                    encoding="utf-8").strip() or str(uuid.uuid4())
            else:
                self._customer_uuid = str(uuid.uuid4())
                try:
                    self.config.uuid_file.write_text(
                        self._customer_uuid, encoding="utf-8")
                    if os.name == "posix":
                        os.chmod(self.config.uuid_file, 0o600)
                except OSError as e:
                    logger.debug(
                        f"Failed to persist customer UUID: {e}", exc_info=True)
        except OSError as e:
            logger.debug(f"Failed to load customer UUID: {e}", exc_info=True)
            self._customer_uuid = str(uuid.uuid4())

        # Load milestones (failure here must not affect UUID)
        try:
            if self.config.milestones_file.exists():
                content = self.config.milestones_file.read_text(
                    encoding="utf-8")
                self._milestones = json.loads(content) or {}
                if not isinstance(self._milestones, dict):
                    self._milestones = {}
        except (OSError, json.JSONDecodeError, ValueError) as e:
            logger.debug(f"Failed to load milestones: {e}", exc_info=True)
            self._milestones = {}

    def _save_milestones(self):
        """Save milestones to disk. Caller must hold self._lock."""
        try:
            self.config.milestones_file.write_text(
                json.dumps(self._milestones, indent=2),
                encoding="utf-8",
            )
        except OSError as e:
            logger.warning(f"Failed to save milestones: {e}", exc_info=True)

    def record_milestone(self, milestone: MilestoneType, data: dict[str, Any] | None = None) -> bool:
        """Record a milestone event, returns True if this is the first occurrence"""
        if not self.config.enabled:
            return False
        milestone_key = milestone.value
        with self._lock:
            if milestone_key in self._milestones:
                return False  # Already recorded
            milestone_data = {
                "timestamp": time.time(),
                "data": data or {},
            }
            self._milestones[milestone_key] = milestone_data
            self._save_milestones()

        # Also send as telemetry record
        self.record(
            record_type=RecordType.USAGE,
            data={"milestone": milestone_key, **(data or {})},
            milestone=milestone
        )

        return True

    def record(self,
               record_type: RecordType,
               data: dict[str, Any],
               milestone: MilestoneType | None = None):
        """Record a telemetry event (async, non-blocking)"""
        if not self.config.enabled:
            return

        # Allow fallback sender when httpx is unavailable (no early return)

        record = TelemetryRecord(
            record_type=record_type,
            timestamp=time.time(),
            customer_uuid=self._customer_uuid or "unknown",
            session_id=self.config.session_id,
            data=data,
            milestone=milestone
        )
        # Enqueue for background worker (non-blocking). Drop on backpressure.
        try:
            self._queue.put_nowait(record)
        except queue.Full:
            logger.debug(
                f"Telemetry queue full; dropping {record.record_type}")

    def _worker_loop(self):
        """Background worker that serializes telemetry sends."""
        while True:
            rec = self._queue.get()
            try:
                # Run sender directly; do not reuse caller context/thread-locals
                self._send_telemetry(rec)
            except Exception:
                logger.debug("Telemetry worker send failed", exc_info=True)
            finally:
                with contextlib.suppress(Exception):
                    self._queue.task_done()

    def _send_telemetry(self, record: TelemetryRecord):
        """Send telemetry data to endpoint"""
        try:
            # System fingerprint (top-level remains concise; details stored in data JSON)
            _platform = platform.system()          # 'Darwin' | 'Linux' | 'Windows'
            _source = sys.platform                 # 'darwin' | 'linux' | 'win32'
            _platform_detail = f"{_platform} {platform.release()} ({platform.machine()})"
            _python_version = platform.python_version()

            # Enrich data JSON so BigQuery stores detailed fields without schema change
            enriched_data = dict(record.data or {})
            enriched_data.setdefault("platform_detail", _platform_detail)
            enriched_data.setdefault("python_version", _python_version)

            payload = {
                "record": record.record_type.value,
                "timestamp": record.timestamp,
                "customer_uuid": record.customer_uuid,
                "session_id": record.session_id,
                "data": enriched_data,
                "version": MCP_VERSION,
                "platform": _platform,
                "source": _source,
            }

            if record.milestone:
                payload["milestone"] = record.milestone.value

            # Prefer httpx when available; otherwise fall back to urllib
            if httpx:
                with httpx.Client(timeout=self.config.timeout) as client:
                    # Re-validate endpoint at send time to handle dynamic changes
                    endpoint = self.config._validated_endpoint(
                        self.config.endpoint, self.config.default_endpoint)
                    response = client.post(endpoint, json=payload)
                    if 200 <= response.status_code < 300:
                        logger.debug(f"Telemetry sent: {record.record_type}")
                    else:
                        logger.warning(
                            f"Telemetry failed: HTTP {response.status_code}")
            else:
                import urllib.request
                import urllib.error
                data_bytes = json.dumps(payload).encode("utf-8")
                endpoint = self.config._validated_endpoint(
                    self.config.endpoint, self.config.default_endpoint)
                req = urllib.request.Request(
                    endpoint,
                    data=data_bytes,
                    headers={"Content-Type": "application/json"},
                    method="POST",
                )
                try:
                    with urllib.request.urlopen(req, timeout=self.config.timeout) as resp:
                        if 200 <= resp.getcode() < 300:
                            logger.debug(
                                f"Telemetry sent (urllib): {record.record_type}")
                        else:
                            logger.warning(
                                f"Telemetry failed (urllib): HTTP {resp.getcode()}")
                except urllib.error.URLError as ue:
                    logger.warning(f"Telemetry send failed (urllib): {ue}")

        except Exception as e:
            # Never let telemetry errors interfere with app functionality
            logger.debug(f"Telemetry send failed: {e}")


# Global telemetry instance
_telemetry_collector: TelemetryCollector | None = None


def get_telemetry() -> TelemetryCollector:
    """Get the global telemetry collector instance"""
    global _telemetry_collector
    if _telemetry_collector is None:
        _telemetry_collector = TelemetryCollector()
    return _telemetry_collector


def record_telemetry(record_type: RecordType,
                     data: dict[str, Any],
                     milestone: MilestoneType | None = None):
    """Convenience function to record telemetry"""
    get_telemetry().record(record_type, data, milestone)


def record_milestone(milestone: MilestoneType, data: dict[str, Any] | None = None) -> bool:
    """Convenience function to record a milestone"""
    return get_telemetry().record_milestone(milestone, data)


def record_tool_usage(tool_name: str, success: bool, duration_ms: float, error: str | None = None, sub_action: str | None = None):
    """Record tool usage telemetry

    Args:
        tool_name: Name of the tool invoked (e.g., 'manage_scene').
        success: Whether the tool completed successfully.
        duration_ms: Execution duration in milliseconds.
        error: Optional error message (truncated if present).
        sub_action: Optional sub-action/operation within the tool (e.g., 'get_hierarchy').
    """
    data = {
        "tool_name": tool_name,
        "success": success,
        "duration_ms": round(duration_ms, 2)
    }

    if sub_action is not None:
        try:
            data["sub_action"] = str(sub_action)
        except Exception:
            # Ensure telemetry is never disruptive
            data["sub_action"] = "unknown"

    if error:
        data["error"] = str(error)[:200]  # Limit error message length

    record_telemetry(RecordType.TOOL_EXECUTION, data)


def record_resource_usage(resource_name: str, success: bool, duration_ms: float, error: str | None = None):
    """Record resource usage telemetry

    Args:
        resource_name: Name of the resource invoked (e.g., 'get_tests').
        success: Whether the resource completed successfully.
        duration_ms: Execution duration in milliseconds.
        error: Optional error message (truncated if present).
    """
    data = {
        "resource_name": resource_name,
        "success": success,
        "duration_ms": round(duration_ms, 2)
    }

    if error:
        data["error"] = str(error)[:200]  # Limit error message length

    record_telemetry(RecordType.RESOURCE_RETRIEVAL, data)


def record_latency(operation: str, duration_ms: float, metadata: dict[str, Any] | None = None):
    """Record latency telemetry"""
    data = {
        "operation": operation,
        "duration_ms": round(duration_ms, 2)
    }

    if metadata:
        data.update(metadata)

    record_telemetry(RecordType.LATENCY, data)


def record_failure(component: str, error: str, metadata: dict[str, Any] | None = None):
    """Record failure telemetry"""
    data = {
        "component": component,
        "error": str(error)[:500]  # Limit error message length
    }

    if metadata:
        data.update(metadata)

    record_telemetry(RecordType.FAILURE, data)


def is_telemetry_enabled() -> bool:
    """Check if telemetry is enabled"""
    return get_telemetry().config.enabled
