import machine
import utime

# Pin Definitions
SEGMENT_PINS = [0, 1, 2, 3, 4, 5, 6, 7]  # a-g, dp segments
DIGIT_PINS = [11, 10, 9, 8]              # Digit select pins
BUTTON_PIN = 16                           # Push button
POT_PIN = 26                              # Potentiometer ADC input

# 7-segment patterns for digits 0-9 (common cathode)
DIGIT_PATTERNS = [
    [0,0,0,0,0,0,1,1],  # 0
    [1,0,0,1,1,1,1,1],  # 1
    [0,0,1,0,0,1,0,1],  # 2
    [0,0,0,0,1,1,0,1],  # 3
    [1,0,0,1,1,0,0,1],  # 4
    [0,1,0,0,1,0,0,1],  # 5
    [0,1,0,0,0,0,0,1],  # 6
    [0,0,0,1,1,1,1,1],  # 7
    [0,0,0,0,0,0,0,1],  # 8
    [0,0,0,0,1,0,0,1]   # 9
]

class SevenSegmentDisplay:
    def __init__(self):
        self.segments = [machine.Pin(p, machine.Pin.OUT) for p in SEGMENT_PINS]
        self.digits = [machine.Pin(p, machine.Pin.OUT) for p in DIGIT_PINS]
        self.clear()

    def clear(self):
        self.buffer = [(0, False)] * 4  # Initialize with all digits off

    def refresh(self):
        for digit in range(4):
            # Turn off all digits
            for d in self.digits:
                d.value(0)
            
            # Set segments for current digit
            num, dp = self.buffer[digit]
            for seg in range(7):
                self.segments[seg].value(DIGIT_PATTERNS[num][seg])
            self.segments[7].value(0 if dp else 1)  # Decimal point
            
            # Enable current digit
            self.digits[digit].value(1)
            utime.sleep_us(2000)  # Display each digit for 2ms
            self.digits[digit].value(0)

    def show_voltage(self, voltage):
        # Format voltage as 0.000 to 3.300
        text = "{:04.3f}".format(min(3.300, max(0.000, voltage)))
        self.buffer = []
        for i, c in enumerate(text.replace(".", "")):
            self.buffer.append((int(c), i == 3))  # 4th position is decimal point

class Voltmeter:
    def __init__(self):
        self.display = SevenSegmentDisplay()
        self.pot = machine.ADC(machine.Pin(POT_PIN))
        self.button = machine.Pin(BUTTON_PIN, machine.Pin.IN, machine.Pin.PULL_UP)
        self.last_press = 0
        self.button.irq(trigger=machine.Pin.IRQ_FALLING, handler=self._button_handler)
        self.display.clear()

    def _button_handler(self, pin):
        # Debounce with 200ms threshold
        current_time = utime.ticks_ms()
        if utime.ticks_diff(current_time, self.last_press) > 200:
            self.last_press = current_time
            self._update_display()

    def _update_display(self):
        # Read and display voltage for 2 seconds
        voltage = self.pot.read_u16() * 3.3 / 65535
        self.display.show_voltage(voltage)
        print("Voltage:", voltage, "V")
        
        # Display for 2 seconds
        start = utime.ticks_ms()
        while utime.ticks_diff(utime.ticks_ms(), start) < 2000:
            self.display.refresh()
        
        # Clear display
        self.display.clear()

    def run(self):
        print("Potentiometer Voltmeter Ready")
        while True:
            self.display.refresh()
            utime.sleep_ms(10)

# Start the application
if __name__ == "__main__":
    voltmeter = Voltmeter()
    voltmeter.run()