import math
import machine, time
from ssd1306 import SSD1306_I2C
import onewire, ds18x20
from machine import ADC

# === PMV Calculation ===
def calculate_pmv(Ta, Tr, RH, Va):
    Met = 1.2
    Icl = 0.5

    M = Met * 58.15
    W = 0
    Icl_m2 = Icl * 0.155

    Pa = RH * 10 * math.exp(16.6536 - 4030.183 / (Ta + 235))

    fcl = 1 + 1.29*Icl if Icl <= 0.078 else 1.05 + 0.645*Icl
    Tcla = Ta + (35.5 - Ta)/(3.5*Icl + 0.1)

    xf = Tcla
    eps = 0.00015
    for _ in range(150):
        xn = xf
        hc = 12.1 * math.sqrt(Va)
        xf = ((35.7 - 0.028*(M - W)) + Icl_m2*fcl*hc*(Ta - xn)) / (1 + Icl_m2*fcl*hc)
        if abs(xn - xf) < eps:
            break
    tcl = xf

    Ta_K = Ta + 273.0
    Tr_K = Tr + 273.0
    hl1 = 3.05 * 0.001 * (5733 - (6.99*(M - W)) - Pa)
    hl2 = 0.42 * ((M - W) - 58.15)
    hl3 = 1.7 * 0.00001 * M * (5867 - Pa)
    hl4 = 0.0014 * M * (34 - Ta)
    hl5 = 3.96e-8 * fcl * ((tcl + 273.0)**4 - Tr_K**4)
    hl6 = fcl * hc * (tcl - Ta)

    L = M - W - hl1 - hl2 - hl3 - hl4 - hl5 - hl6
    PMV = (0.303 * math.exp(-0.036*M) + 0.028) * L
    return PMV

def pmv_to_ppd(pmv):
    return 100.0 - 95.0 * math.exp(-0.03353 * pmv**4 - 0.2179 * pmv**2)

# === DS18B20 Setup ===
DS_PIN = 4
ow = onewire.OneWire(machine.Pin(DS_PIN))
ds = ds18x20.DS18X20(ow)
roms = ds.scan()
if not roms:
    raise RuntimeError("No DS18B20 sensors found on pin {}".format(DS_PIN))
sensor = roms[0]

def read_ds18b20_c():
    ds.convert_temp()
    time.sleep_ms(750)  # max conversion time at 12-bit
    return ds.read_temp(sensor)

# === OLED Setup ===
i2c = machine.I2C(0, scl=machine.Pin(22), sda=machine.Pin(21))
oled = SSD1306_I2C(128, 64, i2c)

# === Potentiometer Setup ===
pot_rh = ADC(machine.Pin(34))      # potentiometer 1 → humidity
pot_rh.atten(ADC.ATTN_11DB)

pot_va = ADC(machine.Pin(35))      # potentiometer 2 → air velocity
pot_va.atten(ADC.ATTN_11DB)

# === Main Loop ===
while True:
    Ta = read_ds18b20_c()          # air temp from DS18B20 (°C)
    Tr = Ta                        # assume mean radiant ≈ air temp

    # Humidity from potentiometer
    raw_rh = pot_rh.read()         # 0–4095
    RH = (raw_rh / 4095) * 100.0   # 0–100 %RH

    # Air velocity from potentiometer
    raw_va = pot_va.read()         # 0–4095
    Va = (raw_va / 4095)      # 0–1.0 m/s

    pmv = calculate_pmv(Ta, Tr, RH, Va)
    ppd = pmv_to_ppd(pmv)

    # Display on OLED
    oled.fill(0)
    oled.text("Thermal Comfort", 0, 0)
    oled.text("Ta: {:.1f}C".format(Ta), 0, 12)
    oled.text("RH: {:.0f}%".format(RH), 0, 24)
    oled.text("Va: {:.2f}m/s".format(Va), 0, 36)
    oled.text("PMV: {:.2f}".format(pmv), 0, 48)
    oled.show()

    time.sleep(2)