// BluetoothScanner.js
import React, { useState, useEffect } from 'react';
import { BleManager } from 'react-native-ble-plx';
import { View, Text, FlatList, Button } from 'react-native';

const BluetoothScanner = () => {
  const [devices, setDevices] = useState([]);
  const [scanning, setScanning] = useState(false);

  const manager = new BleManager();

  useEffect(() => {
    return () => {
      manager.destroy();
    };
  }, []);

  const startScan = async () => {
    try {
      setScanning(true);
      const subscription = manager.onStateChange((state) => {
        if (state === 'PoweredOn') {
          manager.startDeviceScan(null, null, (error, device) => {
            if (error) {
              console.error(error);
              return;
            }
            if (!devices.some((dev) => dev.id === device.id)) {
              setDevices((prevDevices) => [...prevDevices, device]);
            }
          });
        }
      }, true);

      setTimeout(() => {
        manager.stopDeviceScan();
        setScanning(false);
        subscription.remove();
      }, 10000); // Stop scanning after 10 seconds
    } catch (error) {
      console.error(error);
    }
  };

  return (
    <View>
      <Button title={scanning ? 'Scanning...' : 'Start Scan'} onPress={startScan} disabled={scanning} />
      <FlatList
        data={devices}
        keyExtractor={(item) => item.id}
        renderItem={({ item }) => (
          <View>
            <Text>{item.name || 'Unknown'}</Text>
            <Text>{item.id}</Text>
          </View>
        )}
      />
    </View>
  );
};

export default BluetoothScanner;

export function calculateSignalStrengthPercentage(rssi) {
  // Define the minimum and maximum RSSI values in your range
  const minRssi = -95; // Replace with your desired minimum RSSI
  const maxRssi = -50; // Replace with your desired maximum RSSI

  // Ensure that RSSI values below the minimum are considered 0% signal strength
  if (rssi <= minRssi) {
    return 0;
  }

  // Ensure that RSSI values above the maximum are considered 100% signal strength
  if (rssi >= maxRssi) {
    return 100;
  }

  // Calculate the signal strength percentage within the range
  const percentage = ((rssi - minRssi) / (maxRssi - minRssi)) * 100;

  return Math.round(percentage); // Round to the nearest whole number
}

export function estimateDistanceFromRSSI(rssi, unit = 'meter') {
  // RSSI at 1 meter (adjust this value based on your measurements)
  const rssiAt1Meter = -50; // Example value, replace with your measured value

  // Path loss exponent (depends on the environment, typically between 2 and 4)
  const pathLossExponent = 3; // Example value, adjust as needed

  // Calculate estimated distance using the Friis free-space path loss equation
  const distance = Math.pow(
    10,
    (rssiAt1Meter - rssi) / (10 * pathLossExponent),
  );

  // Convert the distance to the desired unit (meter or foot)
  let resultDistance;
  if (unit === 'foot') {
    // Convert meters to feet (1 meter = 3.28084 feet)
    resultDistance = Math.round(distance * 3.28084);
  } else {
    // Default to meters
    resultDistance = Math.round(distance);
  }

  return resultDistance;
}