print("Smart Soil Moisture Monitoring System (Pico)")
print("          BY STAR BANU — IOT")

# STEP 1: IMPORTS
from machine import Pin, I2C, ADC, PWM
import time
from ssd1306 import SSD1306_I2C  # make sure ssd1306.py is in the project

# STEP 2: PIN SETUP (Pico)
BUZZER_PIN = 0            # GP0
ADC_PIN    = 26           # GP26 = ADC0
LED_YEL    = 2            # yellow  (mid/ideal)
LED_RED    = 3            # red     (dry)
LED_GRN    = 6            # green   (wet/ok)
I2C_SDA    = 4            # GP4
I2C_SCL    = 5            # GP5
OLED_ADDR  = 0x3C

buzzer = PWM(Pin(BUZZER_PIN))
buzzer.duty_u16(0)

soil = ADC(ADC_PIN)

led_yellow = Pin(LED_YEL, Pin.OUT)
led_red    = Pin(LED_RED,  Pin.OUT)
led_green  = Pin(LED_GRN,  Pin.OUT)

i2c  = I2C(0, sda=Pin(I2C_SDA), scl=Pin(I2C_SCL), freq=400_000)
oled = SSD1306_I2C(128, 64, i2c, addr=OLED_ADDR)

# STEP 2.1: CALIBRATION
# read_u16 returns 0..65535. Set these after watching the log a few seconds.
CAL_MIN = 9000    # raw value when soil is VERY DRY    (slide low)
CAL_MAX = 60000   # raw value when soil is VERY WET    (slide high)

# Thresholds for bands (percent)
TH_DRY  = 40
TH_WET  = 60

def clamp(v, lo, hi): 
    return lo if v < lo else hi if v > hi else v

def raw_to_percent(raw):
    if CAL_MAX <= CAL_MIN:
        return 0
    pct = int((raw - CAL_MIN) * 100 / (CAL_MAX - CAL_MIN))
    return clamp(pct, 0, 100)

def beep(ms=120, freq=2000, duty=30000):
    buzzer.freq(freq)
    buzzer.duty_u16(duty)
    time.sleep_ms(ms)
    buzzer.duty_u16(0)

def set_leds(state):
    # state: "DRY", "IDEAL", "WET"
    led_red.value(1 if state == "DRY" else 0)
    led_yellow.value(1 if state == "IDEAL" else 0)
    led_green.value(1 if state == "WET" else 0)

def show_oled(raw, pct, state):
    oled.fill(0)
    oled.text("Soil Moisture", 0, 0)
    oled.text("Raw: {}".format(raw), 0, 14)
    oled.text("Moist: {}%".format(pct), 0, 26)
    oled.text("State: {}".format(state), 0, 38)
    # simple bar
    bar_x, bar_y, bar_w, bar_h = 0, 50, 128, 12
    oled.rect(bar_x, bar_y, bar_w, bar_h, 1)
    fill_w = int((pct/100) * (bar_w - 2))
    if fill_w > 0:
        oled.fill_rect(bar_x + 1, bar_y + 1, fill_w, bar_h - 2, 1)
    oled.show()

print("Move the Soil Moisture slider on the custom chip. Calibrate CAL_MIN/CAL_MAX if needed.")

while True:
    raw = soil.read_u16()              # 0..65535
    pct = raw_to_percent(raw)          # 0..100 mapped by calibration

    # STEP 3: DECISION LOGIC (bands)
    if pct < TH_DRY:
        state = "DRY"
        set_leds(state)
        # alert for DRY
        beep(ms=150, freq=2200)
    elif pct > TH_WET:
        state = "WET"
        set_leds(state)
        # optional wet alert (milder chirp)
        beep(ms=60, freq=1200)
    else:
        state = "IDEAL"
        set_leds(state)
        buzzer.duty_u16(0)  # ensure buzzer off

    # Display
    show_oled(raw, pct, state)

    # Console log
    print("Raw:", raw, "Moisture:", pct, "% ->", state)

    time.sleep(0.3)