import board                 # Import board pin definitions (GP pins)
import digitalio             # Import GPIO control module
import time                  # Import time module for delays

# ------------------------
# Keypad setup (4x4)
# ------------------------

# Define row pins (outputs)
rows = [board.GP13, board.GP12, board.GP11, board.GP10]

# Define column pins (inputs)
cols = [board.GP9, board.GP8, board.GP7, board.GP6]

row_pins = []   # List to store configured row pins
col_pins = []   # List to store configured column pins

# Initialize row pins as OUTPUT
for r in rows:
    pin = digitalio.DigitalInOut(r)          # Create pin object
    pin.direction = digitalio.Direction.OUTPUT  # Set as output
    pin.value = True                         # Default HIGH (inactive)
    row_pins.append(pin)                     # Store in list

# Initialize column pins as INPUT with pull-up resistor
for c in cols:
    pin = digitalio.DigitalInOut(c)          # Create pin object
    pin.direction = digitalio.Direction.INPUT   # Set as input
    pin.pull = digitalio.Pull.UP             # Enable pull-up resistor
    col_pins.append(pin)                     # Store in list

# ------------------------
# Key map (button layout)
# ------------------------

keys = [
    ['1','2','3','A'],   # Row 1
    ['4','5','6','B'],   # Row 2
    ['7','8','9','C'],   # Row 3
    ['*','0','#','D']    # Row 4
]

# ------------------------
# 7-Segment Character Map
# Format: a,b,c,d,e,f,g
# ------------------------

segments = {
    '0':[1,1,1,1,1,1,0],  # Display 0
    '1':[0,1,1,0,0,0,0],  # Display 1
    '2':[1,1,0,1,1,0,1],  # Display 2
    '3':[1,1,1,1,0,0,1],  # Display 3
    '4':[0,1,1,0,0,1,1],  # Display 4
    '5':[1,0,1,1,0,1,1],  # Display 5
    '6':[1,0,1,1,1,1,1],  # Display 6
    '7':[1,1,1,0,0,0,0],  # Display 7
    '8':[1,1,1,1,1,1,1],  # Display 8
    '9':[1,1,1,1,0,1,1],  # Display 9

    'A':[1,1,1,0,1,1,1],  # Display A
    'B':[0,0,1,1,1,1,1],  # Display b
    'C':[0,0,0,1,1,0,1],  # Display c
    'D':[0,1,1,1,1,0,1],  # Display d

    '-':[0,0,0,0,0,0,1],  # Display dash "-"
    'h':[0,1,1,0,1,1,1],  # Display h

    ' ':[0,0,0,0,0,0,0]   # Blank (all OFF)
}

# ------------------------
# Segment pins (a-g)
# ------------------------

seg_pins = [
    board.GP16,  # Segment a
    board.GP17,  # Segment b
    board.GP18,  # Segment c
    board.GP19,  # Segment d
    board.GP20,  # Segment e
    board.GP21,  # Segment f
    board.GP22   # Segment g
]

seg_outputs = []   # Store segment output pins

# Initialize segment pins as OUTPUT
for p in seg_pins:
    pin = digitalio.DigitalInOut(p)        # Create pin object
    pin.direction = digitalio.Direction.OUTPUT  # Set as output
    seg_outputs.append(pin)                # Store in list

# ------------------------
# Function: Display character
# ------------------------

def display(char):
    pattern = segments.get(char, segments[' '])  # Get segment pattern
    for i in range(7):                           # Loop through 7 segments
        seg_outputs[i].value = pattern[i]        # Set ON/OFF

# ------------------------
# Function: Scan keypad
# ------------------------

def scan_keypad():
    for i, row in enumerate(row_pins):   # Loop through each row
        row.value = False                # Activate current row (LOW)

        for j, col in enumerate(col_pins):  # Check each column
            if not col.value:              # If column reads LOW → key pressed
                row.value = True           # Deactivate row
                return keys[i][j]          # Return key value

        row.value = True   # Deactivate row after checking

    return None            # No key pressed

# ------------------------
# Main loop
# ------------------------

last_key = None   # Store previous key (for debounce)

while True:
    key = scan_keypad()   # Read keypad

    if key and key != last_key:   # If new key detected
        time.sleep(0.15)          # Debounce delay
        key = scan_keypad()       # Confirm key again

        print("Key:", key)        # Print key to console

        # ---- Numeric keys ----
        if key in ['0','1','2','3','4','5','6','7','8','9']:
            display(key)

        # ---- Letters A-D ----
        elif key in ['A','B','C','D']:
            display(key)

        # ---- Special keys ----
        elif key == '*':
            display('-')   # Show dash

        elif key == '#':
            display('h')   # Show h

        last_key = key     # Save last key

    # If no key pressed → clear display
    if not key:
        display(' ')
        last_key = None

    time.sleep(0.05)   # Small delay for stability