import serial
import time
import os 

ARDUINO_PORT = '/dev/ttyACM0'
BAUD_RATE = 9600
FILE_PREFIX = 'arduino_data_package'
LISTENING_TIME = 1000 

START_PACKAGE_FLAG = "START_PACKAGE:"
END_PACKAGE_FLAG = "END_PACKAGE"
CLOSE_TRANSFERT_FLAG = "END_TRANSFERT"


def download_data():
    try:
        ser = serial.Serial(ARDUINO_PORT, BAUD_RATE)
        time.sleep(2)
    except serial.SerialException as e:
        print(f"Error : failure to open {ARDUINO_PORT}: {e}")
        return

    print(f"Connected to {ARDUINO_PORT}.")
    
    dowload_cmd = 'D\n'
    ser.write(dowload_cmd.encode())
    print(f"-> Cmd sent: {dowload_cmd.strip()}")
    print("-> Waiting for data...")

    current_file_handle = None
    start_download = time.time()
    
    while True:
        if LISTENING_TIME > 0 and time.time() - start_download > LISTENING_TIME:
            print("\nElapsed time, session closed.")
            break
            
        if ser.in_waiting > 0:
            raw_line = ser.readline()
            str_line = raw_line.decode('utf-8').strip()
            
            if str_line.startswith(START_PACKAGE_FLAG):
                if current_file_handle:
                    print(f"Unsignaled end file, closure of : {current_file_handle.name}")
                    current_file_handle.close()

                try:
                    unique_part = str_line.split(':', 1)[1] 
                    file_name = f"{FILE_PREFIX}_{unique_part}.csv"
                except IndexError:
                    file_name = f"{FILE_PREFIX}_auto_{time.strftime('%Y%m%d_%H%M%S')}.csv"
                
                print(f"\n*** New package detected, opening the new package : {file_name} ***")
                current_file_handle = open(file_name, 'w')
                continue 
                
            elif str_line == END_PACKAGE_FLAG:
                if current_file_handle:
                    print(f"-> Flag '{END_PACKAGE_FLAG}' detected. File closure : {current_file_handle.name}")
                    current_file_handle.close()
                    current_file_handle = None 
                else:
                     print(f"-> Flag '{END_PACKAGE_FLAG}' Ignored.")
                continue 

            elif str_line == CLOSE_TRANSFERT_FLAG:
                print(f"\n*** Flag '{CLOSE_TRANSFERT_FLAG}' detected. End of the download. ***")
                break 
                
            if current_file_handle:
                current_file_handle.write(str_line + '\n')
            
            # else:
            #     print(f"Ignored data : {str_line}")

    if current_file_handle:
        print(f"\nClosure of the opened file : {current_file_handle.name}")
        current_file_handle.close()
        
    ser.close()
    print("\nConnection closed. Download done.")

if __name__ == "__main__":
    download_data()