import csv

# 1. Load the raw edges from the CSV
edges = []
with open('capture.csv', 'r') as f:
    reader = csv.reader(f)
    next(reader)  # Skip the header row
    for row in reader:
        # row[0] is time in seconds, row[1] is logic state (0 or 1)
        edges.append((float(row[0]), int(row[1])))

# 2. Reconstruct the physical bitstream (1 Mbps = 1 microsecond per bit)
bit_time = 1e-6 
bits = []

for i in range(len(edges)-1):
    duration = edges[i+1][0] - edges[i][0]
    num_bits = int(round(duration / bit_time))
    bits.extend([edges[i][1]] * num_bits)

# 3. Parse the CAN frames directly (Ignoring Bit Stuffing Rules)
idx = 0
print("Hunting for payloads...\n")

while idx < len(bits) - 50:
    # Look for Start of Frame (0) after an idle bus (1)
    if bits[idx] == 0 and (idx == 0 or bits[idx-1] == 1):
        idx += 1  # Skip SOF
        
        id_bits = bits[idx : idx+11] # 11-bit ID
        idx += 11
        
        idx += 3  # Skip RTR, IDE, and r0 control bits
        
        dlc_bits = bits[idx : idx+4] # 4-bit Data Length Code
        dlc = int("".join(map(str, dlc_bits)), 2)
        idx += 4
        
        # If payload exists, decode it into ASCII
        if 0 < dlc <= 8:
            payload = []
            for _ in range(dlc):
                byte_bits = bits[idx : idx+8]
                byte_val = int("".join(map(str, byte_bits)), 2)
                payload.append(chr(byte_val))
                idx += 8
            print(f"Decoded Payload: {''.join(payload)}")
        else:
            idx += 1 # Step forward if it was a false start
    else:
        idx += 1