"""
SLMM API Client Wrapper

Provides a clean interface for Terra-View to interact with the SLMM backend.
All SLM operations should go through this client instead of direct HTTP calls.

SLMM (Sound Level Meter Manager) is a separate service running on port 8100
that handles TCP/FTP communication with Rion NL-43/NL-53 devices.
"""

import httpx
import os
from typing import Optional, Dict, Any, List
from datetime import datetime
import json


# SLMM backend base URLs - use environment variable if set (for Docker)
SLMM_BASE_URL = os.environ.get("SLMM_BASE_URL", "http://localhost:8100")
SLMM_API_BASE = f"{SLMM_BASE_URL}/api/nl43"


class SLMMClientError(Exception):
    """Base exception for SLMM client errors."""
    pass


class SLMMConnectionError(SLMMClientError):
    """Raised when cannot connect to SLMM backend."""
    pass


class SLMMDeviceError(SLMMClientError):
    """Raised when device operation fails."""
    pass


class SLMMClient:
    """
    Client for interacting with SLMM backend.

    Usage:
        client = SLMMClient()
        units = await client.get_all_units()
        status = await client.get_unit_status("nl43-001")
        await client.start_recording("nl43-001", config={...})
    """

    def __init__(self, base_url: str = SLMM_BASE_URL, timeout: float = 30.0):
        self.base_url = base_url
        self.api_base = f"{base_url}/api/nl43"
        self.timeout = timeout

    async def _request(
        self,
        method: str,
        endpoint: str,
        data: Optional[Dict] = None,
        params: Optional[Dict] = None,
    ) -> Dict[str, Any]:
        """
        Make an HTTP request to SLMM backend.

        Args:
            method: HTTP method (GET, POST, PUT, DELETE)
            endpoint: API endpoint (e.g., "/units", "/{unit_id}/status")
            data: JSON body for POST/PUT requests
            params: Query parameters

        Returns:
            Response JSON as dict

        Raises:
            SLMMConnectionError: Cannot reach SLMM
            SLMMDeviceError: Device operation failed
        """
        url = f"{self.api_base}{endpoint}"

        try:
            async with httpx.AsyncClient(timeout=self.timeout) as client:
                response = await client.request(
                    method=method,
                    url=url,
                    json=data,
                    params=params,
                )
                response.raise_for_status()

                # Handle empty responses
                if not response.content:
                    return {}

                return response.json()

        except httpx.ConnectError as e:
            raise SLMMConnectionError(
                f"Cannot connect to SLMM backend at {self.base_url}. "
                f"Is SLMM running? Error: {str(e)}"
            )
        except httpx.HTTPStatusError as e:
            error_detail = "Unknown error"
            try:
                error_data = e.response.json()
                error_detail = error_data.get("detail", str(error_data))
            except:
                error_detail = e.response.text or str(e)

            raise SLMMDeviceError(
                f"SLMM operation failed: {error_detail}"
            )
        except Exception as e:
            raise SLMMClientError(f"Unexpected error: {str(e)}")

    # ========================================================================
    # Unit Management
    # ========================================================================

    async def get_all_units(self) -> List[Dict[str, Any]]:
        """
        Get all configured SLM units from SLMM.

        Returns:
            List of unit dicts with id, config, and status
        """
        # SLMM doesn't have a /units endpoint yet, so we'll need to add this
        # For now, return empty list or implement when SLMM endpoint is ready
        try:
            response = await self._request("GET", "/units")
            return response.get("units", [])
        except SLMMClientError:
            # Endpoint may not exist yet
            return []

    async def get_unit_config(self, unit_id: str) -> Dict[str, Any]:
        """
        Get unit configuration from SLMM cache.

        Args:
            unit_id: Unit identifier (e.g., "nl43-001")

        Returns:
            Config dict with host, tcp_port, ftp_port, etc.
        """
        return await self._request("GET", f"/{unit_id}/config")

    async def update_unit_config(
        self,
        unit_id: str,
        host: Optional[str] = None,
        tcp_port: Optional[int] = None,
        ftp_port: Optional[int] = None,
        ftp_username: Optional[str] = None,
        ftp_password: Optional[str] = None,
    ) -> Dict[str, Any]:
        """
        Update unit configuration in SLMM cache.

        Args:
            unit_id: Unit identifier
            host: Device IP address
            tcp_port: TCP control port (default: 2255)
            ftp_port: FTP data port (default: 21)
            ftp_username: FTP username
            ftp_password: FTP password

        Returns:
            Updated config
        """
        config = {}
        if host is not None:
            config["host"] = host
        if tcp_port is not None:
            config["tcp_port"] = tcp_port
        if ftp_port is not None:
            config["ftp_port"] = ftp_port
        if ftp_username is not None:
            config["ftp_username"] = ftp_username
        if ftp_password is not None:
            config["ftp_password"] = ftp_password

        return await self._request("PUT", f"/{unit_id}/config", data=config)

    # ========================================================================
    # Status & Monitoring
    # ========================================================================

    async def get_unit_status(self, unit_id: str) -> Dict[str, Any]:
        """
        Get cached status snapshot from SLMM.

        Args:
            unit_id: Unit identifier

        Returns:
            Status dict with measurement_state, lp, leq, battery, etc.
        """
        return await self._request("GET", f"/{unit_id}/status")

    async def get_live_data(self, unit_id: str) -> Dict[str, Any]:
        """
        Request fresh data from device (DOD command).

        Args:
            unit_id: Unit identifier

        Returns:
            Live data snapshot
        """
        return await self._request("GET", f"/{unit_id}/live")

    # ========================================================================
    # Recording Control
    # ========================================================================

    async def start_recording(
        self,
        unit_id: str,
        config: Optional[Dict[str, Any]] = None,
    ) -> Dict[str, Any]:
        """
        Start recording on a unit.

        Args:
            unit_id: Unit identifier
            config: Optional recording config (interval, settings, etc.)

        Returns:
            Response from SLMM with success status
        """
        return await self._request("POST", f"/{unit_id}/start", data=config or {})

    async def stop_recording(self, unit_id: str) -> Dict[str, Any]:
        """
        Stop recording on a unit.

        Args:
            unit_id: Unit identifier

        Returns:
            Response from SLMM
        """
        return await self._request("POST", f"/{unit_id}/stop")

    async def pause_recording(self, unit_id: str) -> Dict[str, Any]:
        """
        Pause recording on a unit.

        Args:
            unit_id: Unit identifier

        Returns:
            Response from SLMM
        """
        return await self._request("POST", f"/{unit_id}/pause")

    async def resume_recording(self, unit_id: str) -> Dict[str, Any]:
        """
        Resume paused recording on a unit.

        Args:
            unit_id: Unit identifier

        Returns:
            Response from SLMM
        """
        return await self._request("POST", f"/{unit_id}/resume")

    async def reset_data(self, unit_id: str) -> Dict[str, Any]:
        """
        Reset measurement data on a unit.

        Args:
            unit_id: Unit identifier

        Returns:
            Response from SLMM
        """
        return await self._request("POST", f"/{unit_id}/reset")

    # ========================================================================
    # Store/Index Management
    # ========================================================================

    async def get_index_number(self, unit_id: str) -> Dict[str, Any]:
        """
        Get current store/index number from device.

        Args:
            unit_id: Unit identifier

        Returns:
            Dict with current index_number (store name)
        """
        return await self._request("GET", f"/{unit_id}/index-number")

    async def set_index_number(
        self,
        unit_id: str,
        index_number: int,
    ) -> Dict[str, Any]:
        """
        Set store/index number on device.

        Args:
            unit_id: Unit identifier
            index_number: New index number to set

        Returns:
            Confirmation response
        """
        return await self._request(
            "PUT",
            f"/{unit_id}/index-number",
            data={"index_number": index_number},
        )

    async def check_overwrite_status(self, unit_id: str) -> Dict[str, Any]:
        """
        Check if data exists at the current store index.

        Args:
            unit_id: Unit identifier

        Returns:
            Dict with:
            - overwrite_status: "None" (safe) or "Exist" (would overwrite)
            - will_overwrite: bool
            - safe_to_store: bool
        """
        return await self._request("GET", f"/{unit_id}/overwrite-check")

    async def increment_index(self, unit_id: str, max_attempts: int = 100) -> Dict[str, Any]:
        """
        Find and set the next available (unused) store/index number.

        Checks the current index - if it would overwrite existing data,
        increments until finding an unused index number.

        Args:
            unit_id: Unit identifier
            max_attempts: Maximum number of indices to try before giving up

        Returns:
            Dict with old_index, new_index, and attempts_made
        """
        # Get current index
        current = await self.get_index_number(unit_id)
        old_index = current.get("index_number", 0)

        # Check if current index is safe
        overwrite_check = await self.check_overwrite_status(unit_id)
        if overwrite_check.get("safe_to_store", False):
            # Current index is safe, no need to increment
            return {
                "success": True,
                "old_index": old_index,
                "new_index": old_index,
                "unit_id": unit_id,
                "already_safe": True,
                "attempts_made": 0,
            }

        # Need to find an unused index
        attempts = 0
        test_index = old_index + 1

        while attempts < max_attempts:
            # Set the new index
            await self.set_index_number(unit_id, test_index)

            # Check if this index is safe
            overwrite_check = await self.check_overwrite_status(unit_id)
            attempts += 1

            if overwrite_check.get("safe_to_store", False):
                return {
                    "success": True,
                    "old_index": old_index,
                    "new_index": test_index,
                    "unit_id": unit_id,
                    "already_safe": False,
                    "attempts_made": attempts,
                }

            # Try next index (wrap around at 9999)
            test_index = (test_index + 1) % 10000

            # Avoid infinite loops if we've wrapped around
            if test_index == old_index:
                break

        # Could not find a safe index
        raise SLMMDeviceError(
            f"Could not find unused store index for {unit_id} after {attempts} attempts. "
            f"Consider downloading and clearing data from the device."
        )

    # ========================================================================
    # Device Settings
    # ========================================================================

    async def get_frequency_weighting(self, unit_id: str) -> Dict[str, Any]:
        """
        Get frequency weighting setting (A, C, or Z).

        Args:
            unit_id: Unit identifier

        Returns:
            Dict with current weighting
        """
        return await self._request("GET", f"/{unit_id}/frequency-weighting")

    async def set_frequency_weighting(
        self,
        unit_id: str,
        weighting: str,
    ) -> Dict[str, Any]:
        """
        Set frequency weighting (A, C, or Z).

        Args:
            unit_id: Unit identifier
            weighting: "A", "C", or "Z"

        Returns:
            Confirmation response
        """
        return await self._request(
            "PUT",
            f"/{unit_id}/frequency-weighting",
            data={"weighting": weighting},
        )

    async def get_time_weighting(self, unit_id: str) -> Dict[str, Any]:
        """
        Get time weighting setting (F, S, or I).

        Args:
            unit_id: Unit identifier

        Returns:
            Dict with current time weighting
        """
        return await self._request("GET", f"/{unit_id}/time-weighting")

    async def set_time_weighting(
        self,
        unit_id: str,
        weighting: str,
    ) -> Dict[str, Any]:
        """
        Set time weighting (F=Fast, S=Slow, I=Impulse).

        Args:
            unit_id: Unit identifier
            weighting: "F", "S", or "I"

        Returns:
            Confirmation response
        """
        return await self._request(
            "PUT",
            f"/{unit_id}/time-weighting",
            data={"weighting": weighting},
        )

    async def get_all_settings(self, unit_id: str) -> Dict[str, Any]:
        """
        Get all device settings.

        Args:
            unit_id: Unit identifier

        Returns:
            Dict with all settings
        """
        return await self._request("GET", f"/{unit_id}/settings")

    # ========================================================================
    # FTP Control
    # ========================================================================

    async def enable_ftp(self, unit_id: str) -> Dict[str, Any]:
        """
        Enable FTP server on device.

        Must be called before downloading files. FTP and TCP can work in tandem.

        Args:
            unit_id: Unit identifier

        Returns:
            Dict with status message
        """
        return await self._request("POST", f"/{unit_id}/ftp/enable")

    async def disable_ftp(self, unit_id: str) -> Dict[str, Any]:
        """
        Disable FTP server on device.

        Args:
            unit_id: Unit identifier

        Returns:
            Dict with status message
        """
        return await self._request("POST", f"/{unit_id}/ftp/disable")

    async def get_ftp_status(self, unit_id: str) -> Dict[str, Any]:
        """
        Get FTP server status on device.

        Args:
            unit_id: Unit identifier

        Returns:
            Dict with ftp_enabled status
        """
        return await self._request("GET", f"/{unit_id}/ftp/status")

    # ========================================================================
    # Data Download
    # ========================================================================

    async def download_file(
        self,
        unit_id: str,
        remote_path: str,
    ) -> Dict[str, Any]:
        """
        Download a single file from unit via FTP.

        Args:
            unit_id: Unit identifier
            remote_path: Path on device to download (e.g., "/NL43_DATA/measurement.wav")

        Returns:
            Binary file content (as response)
        """
        data = {"remote_path": remote_path}
        return await self._request("POST", f"/{unit_id}/ftp/download", data=data)

    async def download_folder(
        self,
        unit_id: str,
        remote_path: str,
    ) -> Dict[str, Any]:
        """
        Download an entire folder from unit via FTP as a ZIP archive.

        Useful for downloading complete measurement sessions (e.g., Auto_0000 folders).

        Args:
            unit_id: Unit identifier
            remote_path: Folder path on device to download (e.g., "/NL43_DATA/Auto_0000")

        Returns:
            Dict with local_path, folder_name, file_count, zip_size_bytes
        """
        data = {"remote_path": remote_path}
        return await self._request("POST", f"/{unit_id}/ftp/download-folder", data=data)

    async def download_current_measurement(
        self,
        unit_id: str,
    ) -> Dict[str, Any]:
        """
        Download the current measurement folder based on device's index number.

        This is the recommended method for scheduled downloads - it automatically
        determines which folder to download based on the device's current store index.

        Args:
            unit_id: Unit identifier

        Returns:
            Dict with local_path, folder_name, file_count, zip_size_bytes, index_number
        """
        # Get current index number from device
        index_info = await self.get_index_number(unit_id)
        index_number = index_info.get("index_number", 0)

        # Format as Auto_XXXX folder name
        folder_name = f"Auto_{index_number:04d}"
        remote_path = f"/NL43_DATA/{folder_name}"

        # Download the folder
        result = await self.download_folder(unit_id, remote_path)
        result["index_number"] = index_number
        return result

    async def download_files(
        self,
        unit_id: str,
        destination_path: str,
        files: Optional[List[str]] = None,
    ) -> Dict[str, Any]:
        """
        Download measurement files from unit via FTP.

        This method automatically determines the current measurement folder and downloads it.
        The destination_path parameter is logged for reference but actual download location
        is managed by SLMM (data/downloads/{unit_id}/).

        Args:
            unit_id: Unit identifier
            destination_path: Reference path (for logging/metadata, not used by SLMM)
            files: Ignored - always downloads the current measurement folder

        Returns:
            Dict with download result including local_path, folder_name, etc.
        """
        # Use the new method that automatically determines what to download
        result = await self.download_current_measurement(unit_id)
        result["requested_destination"] = destination_path
        return result

    # ========================================================================
    # Cycle Commands (for scheduled automation)
    # ========================================================================

    async def start_cycle(
        self,
        unit_id: str,
        sync_clock: bool = True,
    ) -> Dict[str, Any]:
        """
        Execute complete start cycle on device via SLMM.

        This handles the full pre-recording workflow:
        1. Sync device clock to server time
        2. Find next safe index (with overwrite protection)
        3. Start measurement

        Args:
            unit_id: Unit identifier
            sync_clock: Whether to sync device clock to server time

        Returns:
            Dict with clock_synced, old_index, new_index, started, etc.
        """
        return await self._request(
            "POST",
            f"/{unit_id}/start-cycle",
            data={"sync_clock": sync_clock},
        )

    async def stop_cycle(
        self,
        unit_id: str,
        download: bool = True,
        download_path: Optional[str] = None,
    ) -> Dict[str, Any]:
        """
        Execute complete stop cycle on device via SLMM.

        This handles the full post-recording workflow:
        1. Stop measurement
        2. Enable FTP
        3. Download measurement folder (if download=True)
        4. Verify download

        Args:
            unit_id: Unit identifier
            download: Whether to download measurement data
            download_path: Custom path for downloaded ZIP (optional)

        Returns:
            Dict with stopped, ftp_enabled, download_success, local_path, etc.
        """
        data = {"download": download}
        if download_path:
            data["download_path"] = download_path
        return await self._request(
            "POST",
            f"/{unit_id}/stop-cycle",
            data=data,
        )

    # ========================================================================
    # Polling Status (for device monitoring/alerts)
    # ========================================================================

    async def get_polling_status(self) -> Dict[str, Any]:
        """
        Get global polling status from SLMM.

        Returns device reachability information for all polled devices.
        Used by DeviceStatusMonitor to detect offline/online transitions.

        Returns:
            Dict with devices list containing:
            - unit_id
            - is_reachable
            - consecutive_failures
            - last_poll_attempt
            - last_success
            - last_error
        """
        try:
            async with httpx.AsyncClient(timeout=self.timeout) as client:
                response = await client.get(f"{self.base_url}/api/nl43/_polling/status")
                response.raise_for_status()
                return response.json()
        except httpx.ConnectError:
            raise SLMMConnectionError("Cannot connect to SLMM for polling status")
        except Exception as e:
            raise SLMMClientError(f"Failed to get polling status: {str(e)}")

    async def get_device_polling_config(self, unit_id: str) -> Dict[str, Any]:
        """
        Get polling configuration for a specific device.

        Args:
            unit_id: Unit identifier

        Returns:
            Dict with poll_enabled and poll_interval_seconds
        """
        return await self._request("GET", f"/{unit_id}/polling/config")

    async def update_device_polling_config(
        self,
        unit_id: str,
        poll_enabled: Optional[bool] = None,
        poll_interval_seconds: Optional[int] = None,
    ) -> Dict[str, Any]:
        """
        Update polling configuration for a device.

        Args:
            unit_id: Unit identifier
            poll_enabled: Enable/disable polling
            poll_interval_seconds: Polling interval (10-3600)

        Returns:
            Updated config
        """
        config = {}
        if poll_enabled is not None:
            config["poll_enabled"] = poll_enabled
        if poll_interval_seconds is not None:
            config["poll_interval_seconds"] = poll_interval_seconds

        return await self._request("PUT", f"/{unit_id}/polling/config", data=config)

    # ========================================================================
    # Health Check
    # ========================================================================

    async def health_check(self) -> bool:
        """
        Check if SLMM backend is reachable.

        Returns:
            True if SLMM is responding, False otherwise
        """
        try:
            async with httpx.AsyncClient(timeout=5.0) as client:
                response = await client.get(f"{self.base_url}/health")
                return response.status_code == 200
        except:
            return False


# Singleton instance for convenience
_default_client: Optional[SLMMClient] = None


def get_slmm_client() -> SLMMClient:
    """
    Get the default SLMM client instance.

    Returns:
        SLMMClient instance
    """
    global _default_client
    if _default_client is None:
        _default_client = SLMMClient()
    return _default_client