#!/usr/bin/env python3
"""
BLE NTRIP Client for RTK Receiver

Connects to an RTK receiver via Bluetooth Low Energy (BLE) to receive NMEA data
and forward RTCM corrections from an NTRIP caster.

This script uses the bleak library for cross-platform BLE communication.
"""

import asyncio
import sys
from bleak import BleakClient, BleakScanner

# ============================================================================
# Configuration
# ============================================================================

# BLE Device Configuration
DEVICE_NAME = "ML-NA001-250079-BLE"
DEVICE_UUID = "B2DDE9B2-881D-1BE2-5A1B-C44CB646BB1D"

# BLE Service and Characteristic UUIDs
SERVICE_UUID = "0000fff0-0000-1000-8000-00805f9b34fb"  # Custom service
CHARACTERISTIC_UUID = "0000fff2-0000-1000-8000-00805f9b34fb"  # Read/Notify characteristic for NMEA

# Debug options
DEBUG_RAW_DATA = True  # Show raw bytes received
DEBUG_NMEA = True      # Show parsed NMEA sentences


# ============================================================================
# BLE Connection and Data Handler
# ============================================================================

class BLENTRIPClient:
    """BLE NTRIP client for RTK receiver."""

    def __init__(self):
        self.client = None
        self.running = False
        self.nmea_buffer = bytearray()

    async def find_device(self):
        """Scan for the RTK receiver BLE device."""
        print(f"Scanning for BLE device: {DEVICE_NAME} ({DEVICE_UUID})...")

        devices = await BleakScanner.discover(timeout=10.0)

        for device in devices:
            print(f"Found: {device.name} ({device.address})")

            # Match by UUID or name
            if (device.address.upper() == DEVICE_UUID.upper() or
                device.name == DEVICE_NAME):
                print(f"✓ Found target device: {device.name} at {device.address}")
                return device.address

        print(f"✗ Device not found. Scanned {len(devices)} devices.")
        return None

    def notification_handler(self, sender, data):
        """Handle incoming BLE notifications with NMEA data."""
        if DEBUG_RAW_DATA:
            print(f"Raw data ({len(data)} bytes): {data.hex()}")

        # Add data to buffer
        self.nmea_buffer.extend(data)

        # Process complete NMEA sentences (terminated with \r\n)
        while b'\n' in self.nmea_buffer:
            # Find the end of the sentence
            newline_idx = self.nmea_buffer.index(b'\n')
            sentence_bytes = self.nmea_buffer[:newline_idx + 1]
            self.nmea_buffer = self.nmea_buffer[newline_idx + 1:]

            try:
                # Decode NMEA sentence
                sentence = sentence_bytes.decode('ascii').strip()

                if sentence and DEBUG_NMEA:
                    print(f"NMEA: {sentence}")

                # TODO: Parse NMEA sentences (GGA, etc.) for position data

            except UnicodeDecodeError as e:
                print(f"Failed to decode NMEA data: {e}")

    async def connect_and_monitor(self):
        """Connect to the BLE device and monitor NMEA data."""

        # Find the device
        device_address = await self.find_device()
        if not device_address:
            print("Could not find RTK receiver. Make sure device is powered on and in range.")
            return False

        # Connect to device
        print(f"\nConnecting to {device_address}...")

        try:
            async with BleakClient(device_address) as client:
                self.client = client

                if not client.is_connected:
                    print("✗ Failed to connect")
                    return False

                print(f"✓ Connected to {DEVICE_NAME}")

                # List available services and characteristics
                print("\nAvailable services:")
                for service in client.services:
                    print(f"  Service: {service.uuid}")
                    for char in service.characteristics:
                        props = ','.join(char.properties)
                        print(f"    Characteristic: {char.uuid} ({props})")

                # Start notifications on NMEA characteristic
                print(f"\nSubscribing to NMEA notifications on {CHARACTERISTIC_UUID}...")
                await client.start_notify(CHARACTERISTIC_UUID, self.notification_handler)
                print("✓ Subscribed to notifications\n")

                # Keep connection alive and monitor data
                self.running = True
                print("Monitoring NMEA data (Ctrl+C to stop)...\n")

                while self.running:
                    await asyncio.sleep(1)

                    # Check connection status
                    if not client.is_connected:
                        print("✗ Connection lost")
                        break

                # Stop notifications before disconnecting
                await client.stop_notify(CHARACTERISTIC_UUID)

        except Exception as e:
            print(f"✗ Error: {e}")
            return False

        return True

    def stop(self):
        """Stop the client."""
        self.running = False


# ============================================================================
# Main Entry Point
# ============================================================================

async def main():
    """Main entry point."""
    client = BLENTRIPClient()

    try:
        await client.connect_and_monitor()
    except KeyboardInterrupt:
        print("\n\nStopping...")
        client.stop()
    except Exception as e:
        print(f"\n✗ Fatal error: {e}")
        sys.exit(1)


if __name__ == "__main__":
    print("=" * 70)
    print("BLE NTRIP Client for RTK Receiver")
    print("=" * 70)
    print()

    # Check if bleak is installed
    try:
        import bleak
    except ImportError:
        print("✗ Error: 'bleak' library not found")
        print("\nInstall it with:")
        print("  pip install bleak")
        print()
        sys.exit(1)

    asyncio.run(main())