import time
import network
import ssd1306

from machine import Pin, I2C
from umqtt.simple import MQTTClient

# Modify wherever the values contain <>
MQTT_BROKER = "broker.hivemq.com"
MQTT_CLIENT_ID = "keypad-<class>-<number in class>-<name>"
MQTT_TOPIC = "elsys/<class>/<number in class>/<name>"

# Keypad constants
ROW_PINS = [12, 14, 27, 26]
COL_PINS = [25, 33, 32]
KEY_MAP = [
    ['1', '2', '3'],\
    ['4', '5', '6'],\
    ['7', '8', '9'],\
    ['*', '0', '#']
]

# Display Constants
DISPLAY_SCL_PIN = 21
DISPLAY_SDA_PIN = 22
DISPLAY_WIDTH = 128
DISPLAY_HEIGHT = 64

# Connect to Wi-Fi
def connect_to_wifi():
    print("Connecting to Wi-Fi", end="")
    sta_if = network.WLAN(network.STA_IF)
    sta_if.active(True)
    sta_if.connect('Wokwi-GUEST', '')
    while not sta_if.isconnected():
        print(".", end="")
        time.sleep(0.1)
    print(" Connected!")

# Connect to MQTT Broker
def connect_to_mqtt_broker():
    connect_to_wifi()
    print("Connecting to MQTT server... ", end="")
    client.connect()
    print("Connected!")

# Read single key press
def read_key(rows, columns):
    for index, row in enumerate(rows):
        row.value(1)
        result = [columns[i].value() for i in range(len(columns))]
        row.value(0)
        if max(result) == 1:
            key = KEY_MAP[int(index)][int(result.index(1))]
            return key
    return None

# Read full code
def read_code():
    key, code = '', ""
    while key != '#':
        key = read_key(ROW_PINS, COL_PINS)
        if key != None:
            time.sleep(0.3)
            code += key
            fill_display(code)
    return code

# Publish access code
def publish_code(code):
    client.publish(MQTT_TOPIC, code)
    fill_display("Published: " + code)

# Fill display
def fill_display(text):
    display.fill(0)
    display.text(text, 0, 5)
    display.show()

# Clear display
def clear_display():
    display.fill(0)
    display.show()

# Init MQTT client
client = MQTTClient(MQTT_CLIENT_ID, MQTT_BROKER)
connect_to_mqtt_broker()

# Init keypad 
for x in range(0, 4):
    ROW_PINS[x] = Pin(ROW_PINS[x], Pin.OUT)
    ROW_PINS[x].value(0)
for x in range(0, 3):
    COL_PINS[x] = Pin(COL_PINS[x], Pin.IN, Pin.PULL_DOWN)

# Init OLED Display
i2c = I2C(0, scl=Pin(DISPLAY_SCL_PIN), sda=Pin(DISPLAY_SDA_PIN))
display = ssd1306.SSD1306_I2C(DISPLAY_WIDTH, DISPLAY_HEIGHT, i2c)

# Loop
try:
    while True:
        publish_code(read_code())
        time.sleep(5)
        clear_display()
finally:
    client.disconnect()