# ============================================================
# File:    main_system.py
# Board:   Raspberry Pi Pico (MicroPython)
# Purpose: Full integration for 3.3 - reads occupancy,
#          temperature and light level, then displays all
#          three on the 16x2 I2C LCD, updating continuously.
#          Requires lcd_api.py and pico_i2c_lcd.py (standard
#          community I2C LCD driver files) saved on the Pico.
# Wiring:  PIR OUT      -> GP16
#          LED          -> GP15 (+330ohm resistor)
#          Thermistor   -> GP26 / ADC0
#          Photoresistor-> GP27 / ADC1
#          LCD SDA      -> GP4
#          LCD SCL      -> GP5
# ============================================================

from machine import Pin, ADC, I2C
from pico_i2c_lcd import I2cLcd
import time
import math

# --- Pin setup ---
pir = Pin(16, Pin.IN)
led = Pin(15, Pin.OUT)
thermistor_adc = ADC(Pin(26))
ldr_adc = ADC(Pin(27))

# --- LCD setup (I2C0 on GP4/GP5, default PCF8574 address 0x27) ---
i2c = I2C(0, sda=Pin(4), scl=Pin(5), freq=400000)
lcd = I2cLcd(i2c, 0x27, 2, 16)

# --- Thermistor conversion constants ---
SERIES_RESISTOR = 10000.0
NOMINAL_RESISTANCE = 10000.0
NOMINAL_TEMP = 25.0
B_COEFFICIENT = 3950.0


def read_temperature():
    raw = thermistor_adc.read_u16()
    ratio = raw / 65535.0
    if ratio <= 0.0 or ratio >= 1.0:
        return 0.0
    resistance = SERIES_RESISTOR * (1.0 / ratio - 1.0)
    steinhart = math.log(resistance / NOMINAL_RESISTANCE)
    steinhart /= B_COEFFICIENT
    steinhart += 1.0 / (NOMINAL_TEMP + 273.15)
    return round((1.0 / steinhart) - 273.15, 1)


def read_light_level():
    raw = ldr_adc.read_u16()
    return round((raw / 65535.0) * 100, 1)


print("Smart Campus Monitor running...")

while True:
    occupied = pir.value() == 1
    led.value(1 if occupied else 0)

    temperature = read_temperature()
    light = read_light_level()

    # --- Update LCD: line 1 = temperature + occupancy, line 2 = light ---
    lcd.clear()
    lcd.putstr("T:{}C  {}".format(temperature, "OCC" if occupied else "EMPTY"))
    lcd.move_to(0, 1)
    lcd.putstr("Light: {}%".format(light))

    # --- Also log to the console/serial for a historical record ---
    print(time.time(), "| Temp:", temperature, "| Light:", light, "| Occupied:", occupied)

    time.sleep(2)