import os
import sys
import time
import RPi.GPIO as GPIO



# Import pin assignments and custom libraries
# Add the parent directory to the module search path
sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
from interface_board_pins import GPIO_DIGITAL_INPUTS  # Input GPIO mapping
from interface_board_pins import (  # Shift register pin assignment
    GPIO_SHIFT_REG_DATA,
    GPIO_SHIFT_REG_LATCH,
    GPIO_SHIFT_REG_CLOCK,
)
from interface_board_libs.shift_register import ShiftRegister  # Custom shift register class



# Initialize GPIO for digital inputs
GPIO.setmode(GPIO.BCM)
for pin in GPIO_DIGITAL_INPUTS.values():
    print(f"Configuring GPIO pin {pin} as input")
    GPIO.setup(pin, GPIO.IN)



# Initialize shift register
sr = ShiftRegister(GPIO_SHIFT_REG_DATA, GPIO_SHIFT_REG_LATCH, GPIO_SHIFT_REG_CLOCK)



# Main loop: Read inputs and write to shift register
print("\nStarting passthrough mode: Digital inputs → Shift register outputs")
try:
    while True:
        shift_register_value = 0  # Byte to be written to the shift register
        print("\nReading inputs and updating shift register...")

        for i, (label, pin) in enumerate(GPIO_DIGITAL_INPUTS.items()):
            state = GPIO.input(pin)  # Read GPIO state
            print(f"Input {label} (GPIO {pin}): {'HIGH' if state else 'LOW'}")

            # Set corresponding bit in shift register byte
            if state:
                shift_register_value |= (1 << i)  # Set bit at position `i`
            else:
                shift_register_value &= ~(1 << i)  # Clear bit at position `i`

        # Write the final byte to the shift register
        sr.write_byte(shift_register_value)
        print(f"Shift Register Output: {format(shift_register_value, '08b')[::-1]}") # Print binary representation (mirrored, lsb first = terminal order)

        time.sleep(0.3)  # Small delay to prevent excessive polling

except KeyboardInterrupt:
    print("\nExiting...")

finally:
    sr.clear()  # Clear shift register before exiting
    print("Shift register cleared.")
    GPIO.cleanup()  # Cleanup GPIO settings