"""CircuitPython BLE UART utility.

Wraps the adafruit_ble library to advertise Nordic UART Service and scan for nearby devices.
"""

import time
from adafruit_ble import BLERadio
from adafruit_ble.services.nordic import UARTService
from adafruit_ble.advertising.standard import ProvideServicesAdvertisement

class BLEUART:
    def __init__(self, ble=None, name="ESP32-S3-RLCD"):
        self.ble = BLERadio()
        self.ble.name = name
        self.uart = UARTService()
        self.advertisement = ProvideServicesAdvertisement(self.uart)
        self.rx_callback = None
        self._is_advertising = False
        self._start_advertise()

    def _start_advertise(self):
        if not self.ble.connected and not self._is_advertising:
            try:
                self.ble.start_advertising(self.advertisement)
                self._is_advertising = True
                print(f"BLE advertising started as '{self.ble.name}'")
            except Exception as e:
                print(f"Failed to start BLE advertising: {e}")

    def on_rx(self, callback):
        self.rx_callback = callback
        return callback

    def update(self):
        """Polls the UART stream for incoming data and triggers callbacks."""
        if self.ble.connected:
            self._is_advertising = False
            try:
                if self.uart.in_waiting:
                    data = self.uart.read(self.uart.in_waiting)
                    if self.rx_callback and data:
                        try:
                            decoded = data.decode("utf-8").strip()
                            self.rx_callback(decoded)
                        except:
                            self.rx_callback(data)
            except Exception as e:
                print(f"Error reading BLE RX: {e}")
        else:
            if not self._is_advertising:
                self._start_advertise()

    def write(self, data):
        if not self.ble.connected:
            return False
        if isinstance(data, str):
            data = data.encode("utf-8")
        try:
            self.uart.write(data)
            return True
        except Exception as e:
            print(f"Error sending BLE data: {e}")
            return False

    def is_connected(self):
        return self.ble.connected

    def scan(self, duration_ms=3000):
        """Scans for nearby BLE devices."""
        duration_s = duration_ms / 1000.0
        results = {}
        was_advertising = self._is_advertising
        if was_advertising:
            try:
                self.ble.stop_advertising()
            except:
                pass
            self._is_advertising = False

        try:
            print("Starting BLE scan...")
            for adv in self.ble.start_scan(timeout=duration_s):
                # Clean up address representation (mac address)
                mac = str(adv.address).replace("Address(", "").replace(")", "").strip()
                name = adv.complete_name or ""
                results[mac] = {"rssi": adv.rssi, "name": name}
            self.ble.stop_scan()
        except Exception as e:
            print(f"BLE scan error: {e}")

        if was_advertising:
            self._start_advertise()
        return results

    def close(self):
        try:
            self.ble.stop_advertising()
        except:
            pass
        self._is_advertising = False
        print("BLE closed.")