# WiFi DensePose Implementation - Core Neural Network Architecture
# Based on "DensePose From WiFi" by Carnegie Mellon University

import torch
import torch.nn as nn
import torch.nn.functional as F
import numpy as np
import math
from typing import Dict, List, Tuple, Optional
from collections import OrderedDict

# CSI Phase Sanitization Module
class CSIPhaseProcessor:
    """
    Processes raw CSI phase data through unwrapping, filtering, and linear fitting
    Based on the phase sanitization methodology from the paper
    """
    
    def __init__(self, num_subcarriers: int = 30):
        self.num_subcarriers = num_subcarriers
    
    def unwrap_phase(self, phase_data: np.ndarray) -> np.ndarray:
        """
        Unwrap phase values to handle discontinuities
        Args:
            phase_data: Raw phase data of shape (samples, frequencies, antennas, antennas)
        Returns:
            Unwrapped phase data
        """
        unwrapped = np.copy(phase_data)
        
        for i in range(1, phase_data.shape[1]):  # Along frequency dimension
            diff = unwrapped[:, i] - unwrapped[:, i-1]
            
            # Apply unwrapping logic
            unwrapped[:, i] = np.where(diff > np.pi, 
                                     unwrapped[:, i-1] + diff - 2*np.pi,
                                     unwrapped[:, i])
            unwrapped[:, i] = np.where(diff < -np.pi,
                                     unwrapped[:, i-1] + diff + 2*np.pi,
                                     unwrapped[:, i])
        
        return unwrapped
    
    def apply_filters(self, phase_data: np.ndarray) -> np.ndarray:
        """
        Apply median and uniform filters to eliminate outliers
        """
        from scipy.ndimage import median_filter, uniform_filter
        
        # Apply median filter in time domain
        filtered = median_filter(phase_data, size=(3, 1, 1, 1))
        
        # Apply uniform filter in frequency domain
        filtered = uniform_filter(filtered, size=(1, 3, 1, 1))
        
        return filtered
    
    def linear_fitting(self, phase_data: np.ndarray) -> np.ndarray:
        """
        Apply linear fitting to remove systematic phase drift
        """
        fitted_data = np.copy(phase_data)
        F = self.num_subcarriers
        
        for sample_idx in range(phase_data.shape[0]):
            for ant_i in range(phase_data.shape[2]):
                for ant_j in range(phase_data.shape[3]):
                    phase_seq = phase_data[sample_idx, :, ant_i, ant_j]
                    
                    # Calculate linear coefficients
                    alpha1 = (phase_seq[-1] - phase_seq[0]) / (2 * np.pi * F)
                    alpha0 = np.mean(phase_seq)
                    
                    # Apply linear fitting
                    frequencies = np.arange(1, F + 1)
                    linear_trend = alpha1 * frequencies + alpha0
                    fitted_data[sample_idx, :, ant_i, ant_j] = phase_seq - linear_trend
        
        return fitted_data
    
    def sanitize_phase(self, raw_phase: np.ndarray) -> np.ndarray:
        """
        Complete phase sanitization pipeline
        """
        # Step 1: Unwrap phase
        unwrapped = self.unwrap_phase(raw_phase)
        
        # Step 2: Apply filters
        filtered = self.apply_filters(unwrapped)
        
        # Step 3: Linear fitting
        sanitized = self.linear_fitting(filtered)
        
        return sanitized

print("CSI Phase Processor implementation completed!")