Core/Services/AcousticDetectionService.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using static BlockchainNetworkAnalyzer.App;

namespace BlockchainNetworkAnalyzer.Core.Services
{
    /// <summary>
    /// Advanced acoustic detection service for cryptocurrency miners
    /// Detects ultrasonic, infrasonic, and audible frequencies specific to miners
    /// </summary>
    public class AcousticDetectionService : IDisposable
    {
        private readonly ILogger<AcousticDetectionService> _logger;
        private readonly NoiseFilterService _noiseFilter;
        private readonly MinerFrequencyDatabase _frequencyDatabase;
        private CancellationTokenSource _cancellationTokenSource;
        private bool _isListening;
        private readonly List<AcousticSignal> _detectedSignals = new List<AcousticSignal>();

        public event EventHandler<AcousticSignalDetectedEventArgs> SignalDetected;
        public event EventHandler<DirectionEventArgs> DirectionUpdated;

        public AcousticDetectionService()
        {
            _logger = App.LoggerFactory.CreateLogger<AcousticDetectionService>();
            _noiseFilter = new NoiseFilterService();
            _frequencyDatabase = new MinerFrequencyDatabase();
            InitializeAudioCapture();
        }

        private void InitializeAudioCapture()
        {
            // Initialize audio capture device
            // In production, would use NAudio or similar library
            _logger.LogInformation("Audio capture initialized");
        }

        /// <summary>
        /// Start listening for miner acoustic signatures
        /// </summary>
        public async Task StartListeningAsync()
        {
            if (_isListening)
            {
                _logger.LogWarning("Already listening");
                return;
            }

            _isListening = true;
            _cancellationTokenSource = new CancellationTokenSource();
            _detectedSignals.Clear();

            try
            {
                _logger.LogInformation("Starting acoustic detection for miners...");

                // Start parallel listening for different frequency ranges
                var listeningTasks = new List<Task>
                {
                    ListenUltrasonicFrequencies(_cancellationTokenSource.Token), // 20 kHz - 100 kHz
                    ListenInfrasonicFrequencies(_cancellationTokenSource.Token), // 1 Hz - 20 Hz
                    ListenAudibleFrequencies(_cancellationTokenSource.Token), // 20 Hz - 20 kHz
                    AnalyzeAudioStream(_cancellationTokenSource.Token)
                };

                await Task.WhenAll(listeningTasks);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error during acoustic detection");
            }
            finally
            {
                _isListening = false;
            }
        }

        private async Task ListenUltrasonicFrequencies(CancellationToken cancellationToken)
        {
            await Task.Run(async () =>
            {
                try
                {
                    while (!cancellationToken.IsCancellationRequested)
                    {
                        // Capture ultrasonic frequencies (20-100 kHz)
                        var audioData = await CaptureAudioSamplesAsync(20000, 100000, cancellationToken);
                        
                        if (audioData != null && audioData.Length > 0)
                        {
                            // Apply noise filter
                            var filteredData = _noiseFilter.FilterNoise(audioData, FrequencyRange.Ultrasonic);
                            
                            // Analyze for miner signatures
                            var minerSignals = AnalyzeForMinerSignatures(filteredData, FrequencyRange.Ultrasonic);
                            
                            foreach (var signal in minerSignals)
                            {
                                if (signal.Confidence > 0.7)
                                {
                                    signal.SignalType = SignalType.Ultrasonic;
                                    ProcessDetectedSignal(signal);
                                }
                            }
                        }

                        await Task.Delay(50, cancellationToken);
                    }
                }
                catch (OperationCanceledException) { }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "Error listening to ultrasonic frequencies");
                }
            }, cancellationToken);
        }

        private async Task ListenInfrasonicFrequencies(CancellationToken cancellationToken)
        {
            await Task.Run(async () =>
            {
                try
                {
                    while (!cancellationToken.IsCancellationRequested)
                    {
                        // Capture infrasonic frequencies (1-20 Hz)
                        var audioData = await CaptureAudioSamplesAsync(1, 20, cancellationToken);
                        
                        if (_noiseFilter != null)
                        {
                            var filteredData = _noiseFilter.FilterNoise(audioData, FrequencyRange.Infrasonic);
                            var minerSignals = AnalyzeForMinerSignatures(filteredData, FrequencyRange.Infrasonic);
                            
                            foreach (var signal in minerSignals.Where(s => s.Confidence > 0.7))
                            {
                                signal.SignalType = SignalType.Ultrasonic;
                                ProcessDetectedSignal(signal);
                            }
                        }

                        await Task.Delay(100, cancellationToken);
                    }
                }
                catch (OperationCanceledException) { }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "Error listening to infrasonic frequencies");
                }
            }, cancellationToken);
        }

        private async Task ListenAudibleFrequencies(CancellationToken cancellationToken)
        {
            await Task.Run(async () =>
            {
                try
                {
                    while (!cancellationToken.IsCancellationRequested)
                    {
                        // Capture audible frequencies (20 Hz - 20 kHz)
                        var audioData = await CaptureAudioSamplesAsync(20, 20000, cancellationToken);
                        
                        if (audioData != null && audioData.Length > 0)
                        {
                            // Aggressive noise filtering for audible range
                            var filteredData = _noiseFilter.FilterNoise(audioData, FrequencyRange.Audible);
                            filteredData = _noiseFilter.RemoveEnvironmentalNoise(filteredData);
                            
                            var minerSignals = AnalyzeForMinerSignatures(filteredData, FrequencyRange.Audible);
                            
                            foreach (var signal in minerSignals.Where(s => s.Confidence > 0.8))
                            {
                                signal.SignalType = SignalType.Acoustic;
                                ProcessDetectedSignal(signal);
                            }
                        }

                        await Task.Delay(25, cancellationToken);
                    }
                }
                catch (OperationCanceledException) { }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "Error listening to audible frequencies");
                }
            }, cancellationToken);
        }

        private async Task AnalyzeAudioStream(CancellationToken cancellationToken)
        {
            await Task.Run(async () =>
            {
                try
                {
                    while (!cancellationToken.IsCancellationRequested)
                    {
                        // Continuous audio stream analysis
                        // Detect patterns and direction changes
                        await AnalyzeSignalDirection(cancellationToken);
                        await Task.Delay(100, cancellationToken);
                    }
                }
                catch (OperationCanceledException) { }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "Error analyzing audio stream");
                }
            }, cancellationToken);
        }

        private async Task<short[]> CaptureAudioSamplesAsync(double minFreq, double maxFreq, CancellationToken cancellationToken)
        {
            // In production, would use actual audio capture APIs (NAudio, etc.)
            // This simulates audio capture
            
            await Task.Delay(10, cancellationToken);

            // Simulate capturing audio samples
            // Would normally capture from microphone/audio device
            var random = new Random();
            var samples = new short[1024];
            
            for (int i = 0; i < samples.Length; i++)
            {
                samples[i] = (short)(random.Next(-32768, 32767));
            }

            return samples;
        }

        private List<AcousticSignal> AnalyzeForMinerSignatures(short[] audioData, FrequencyRange range)
        {
            var detectedSignals = new List<AcousticSignal>();

            // Perform FFT analysis
            var fftResult = PerformFFT(audioData);
            
            // Get known miner frequencies in this range
            var knownFrequencies = _frequencyDatabase.GetKnownAcousticFrequencies(range);
            
            // Match detected frequencies with known miner signatures
            foreach (var knownFreq in knownFrequencies)
            {
                var match = FindFrequencyMatch(fftResult, knownFreq);
                
                if (match != null && match.Confidence > 0.6)
                {
                    detectedSignals.Add(match);
                }
            }

            return detectedSignals;
        }

        private FFTResult PerformFFT(short[] samples)
        {
            // Perform Fast Fourier Transform
            // In production, would use optimized FFT library (MathNet, etc.)
            
            var fftResult = new FFTResult
            {
                FrequencyBins = new double[512],
                Magnitudes = new double[512],
                Phases = new double[512]
            };

            // Simplified FFT simulation
            var random = new Random();
            for (int i = 0; i < 512; i++)
            {
                fftResult.FrequencyBins[i] = i * 100; // Hz
                fftResult.Magnitudes[i] = random.NextDouble() * 100;
                fftResult.Phases[i] = random.NextDouble() * 2 * Math.PI;
            }

            return fftResult;
        }

        private AcousticSignal FindFrequencyMatch(FFTResult fftResult, KnownFrequency knownFreq)
        {
            // Find matching frequency bin
            var binIndex = Array.FindIndex(fftResult.FrequencyBins, 
                f => Math.Abs(f - knownFreq.Frequency) < knownFreq.Tolerance);
            
            if (binIndex >= 0)
            {
                var magnitude = fftResult.Magnitudes[binIndex];
                
                // Check if magnitude exceeds threshold
                if (magnitude > knownFreq.Threshold)
                {
                    var confidence = CalculateConfidence(magnitude, knownFreq);
                    
                    return new AcousticSignal
                    {
                        Frequency = knownFreq.Frequency,
                        Amplitude = magnitude,
                        Confidence = confidence,
                        MinerType = knownFreq.MinerType,
                        Timestamp = DateTime.Now
                    };
                }
            }

            return null;
        }

        private double CalculateConfidence(double magnitude, KnownFrequency knownFreq)
        {
            // Higher magnitude = higher confidence
            // Also consider how close to expected frequency
            var magnitudeConfidence = Math.Min(1.0, magnitude / 100.0);
            var frequencyMatchConfidence = 0.9; // Assuming good match if found
            
            return (magnitudeConfidence + frequencyMatchConfidence) / 2.0;
        }

        private void ProcessDetectedSignal(AcousticSignal signal)
        {
            // Estimate distance based on amplitude
            signal.EstimatedDistance = EstimateAcousticDistance(signal.Amplitude, signal.Frequency);
            
            // Calculate direction using triangulation (if multiple sensors)
            signal.Bearing = CalculateDirection(signal);
            
            lock (_detectedSignals)
            {
                _detectedSignals.Add(signal);
            }

            OnSignalDetected(new AcousticSignalDetectedEventArgs(signal));
            
            // Update direction
            if (signal.Bearing.HasValue)
            {
                OnDirectionUpdated(new DirectionEventArgs
                {
                    Bearing = signal.Bearing.Value,
                    Distance = signal.EstimatedDistance,
                    Confidence = signal.Confidence
                });
            }
        }

        private async Task AnalyzeSignalDirection(CancellationToken cancellationToken)
        {
            // Analyze signal direction using multiple audio sensors
            // Time Difference of Arrival (TDOA) method
            
            lock (_detectedSignals)
            {
                var recentSignals = _detectedSignals
                    .Where(s => (DateTime.Now - s.Timestamp).TotalSeconds < 1.0)
                    .ToList();

                if (recentSignals.Count >= 2)
                {
                    // Calculate bearing from signal differences
                    var bearing = CalculateBearingFromSignals(recentSignals);
                    var distance = recentSignals.Average(s => s.EstimatedDistance);
                    
                    OnDirectionUpdated(new DirectionEventArgs
                    {
                        Bearing = bearing,
                        Distance = distance,
                        Confidence = recentSignals.Average(s => s.Confidence)
                    });
                }
            }

            await Task.CompletedTask;
        }

        private double EstimateAcousticDistance(double amplitude, double frequency)
        {
            // Inverse square law for sound: I = P / (4πr²)
            // distance ≈ sqrt(P / (4πI))
            
            var power = amplitude * amplitude; // Approximate power
            var intensity = 1.0; // Reference intensity
            var distance = Math.Sqrt(power / (4 * Math.PI * intensity));
            
            // Convert to meters and clamp
            return Math.Max(0.5, Math.Min(100, distance));
        }

        private double? CalculateDirection(AcousticSignal signal)
        {
            // Calculate direction using signal properties
            // In production, would use multiple microphones for triangulation
            
            // Simplified: use signal phase differences
            var random = new Random();
            return random.NextDouble() * 360; // 0-360 degrees
        }

        private double CalculateBearingFromSignals(List<AcousticSignal> signals)
        {
            // Triangulation: calculate bearing from multiple signal measurements
            if (signals.Count < 2) return 0;

            // Use average bearing or calculate from signal differences
            var averageBearing = signals
                .Where(s => s.Bearing.HasValue)
                .Average(s => s.Bearing.Value);

            return averageBearing;
        }

        public void StopListening()
        {
            _cancellationTokenSource?.Cancel();
            _isListening = false;
        }

        public List<AcousticSignal> GetDetectedSignals()
        {
            lock (_detectedSignals)
            {
                return new List<AcousticSignal>(_detectedSignals);
            }
        }

        protected virtual void OnSignalDetected(AcousticSignalDetectedEventArgs e)
        {
            SignalDetected?.Invoke(this, e);
        }

        protected virtual void OnDirectionUpdated(DirectionEventArgs e)
        {
            DirectionUpdated?.Invoke(this, e);
        }

        public void Dispose()
        {
            StopListening();
            _cancellationTokenSource?.Dispose();
        }
    }

    public class AcousticSignal
    {
        public SignalType SignalType { get; set; }
        public double Frequency { get; set; } // Hz
        public double Amplitude { get; set; }
        public double Confidence { get; set; }
        public double EstimatedDistance { get; set; } // meters
        public DateTime Timestamp { get; set; }
        public string MinerType { get; set; }
        public double? Bearing { get; set; } // degrees
        public double? Elevation { get; set; }
    }

    public class AcousticSignalDetectedEventArgs : EventArgs
    {
        public AcousticSignal Signal { get; }

        public AcousticSignalDetectedEventArgs(AcousticSignal signal)
        {
            Signal = signal;
        }
    }

    public class DirectionEventArgs : EventArgs
    {
        public double Bearing { get; set; } // degrees (0-360, 0 = North)
        public double Distance { get; set; } // meters
        public double Confidence { get; set; }
    }

    public class FFTResult
    {
        public double[] FrequencyBins { get; set; }
        public double[] Magnitudes { get; set; }
        public double[] Phases { get; set; }
    }
}