# BASE STATION (Board 2, LoRa address 2) - Phase 1
# ESP32 + RYLR998 + LCD 16x2 (I2C) + 4 status LEDs + active buzzer
# MicroPython. Matches the "Phase 1 Block Diagram".
#
# Wiring (ESP32 GPIO):
#   RYLR998 : VDD-3V3 (never 5 V), GND, TXD-16, RXD-17
#   LCD I2C : VCC-5V (VIN), GND, SDA-21, SCL-22  (backpack address 0x27)
#   Buzzer  : GPIO25 (+), GND (-)
#   LEDs    : each GPIO -> 220 ohm -> LED -> GND
#     Green  GPIO33  slow blink    = base running
#     Blue   GPIO32  quick flash   = message received
#     Yellow GPIO26  ON            = no signal 30 min, or field battery low
#     Red    GPIO27  ON + buzzer   = EARTHQUAKE
#
# Receives:  HB,1,battV,noise_g,tempC,hum%    EVT,1,peak_g,ratio
# Answers:   ACK,n   (n = number of messages received)

from machine import Pin, I2C, UART, PWM
import time

# ---------- settings ----------
MY_ADDR = 2
FIELD_ADDR = 1
NO_SIGNAL_S = 60          # real station: 1800 (30 min). 60 s for testing.
LOW_BATT_V = 3.40         # field battery warning level
ALARM_S = 10              # how long red LED + buzzer stay on after a quake

# ---------- LEDs and buzzer ----------
green = Pin(33, Pin.OUT, value=0)
blue = Pin(32, Pin.OUT, value=0)
yellow = Pin(26, Pin.OUT, value=0)
red = Pin(27, Pin.OUT, value=0)
buzzer = PWM(Pin(25), freq=2000, duty_u16=0)   # PWM works for active and passive buzzers


# ---------- LCD 16x2 with PCF8574 I2C backpack ----------
class LCD:
    def __init__(self, i2c, addr=0x27):
        self.i2c, self.addr, self.bl = i2c, addr, 0x08     # 0x08 = backlight on
        time.sleep_ms(50)
        for v in (0x30, 0x30, 0x30, 0x20):                 # wake up, 4-bit mode
            self._write4(v)
            time.sleep_ms(5)
        for c in (0x28, 0x0C, 0x06, 0x01):                 # 2 lines, display on, clear
            self._send(c, 0)
        time.sleep_ms(2)

    def _write4(self, v):
        b = v | self.bl
        self.i2c.writeto(self.addr, bytes([b | 0x04, b]))  # pulse the E pin

    def _send(self, v, rs):
        self._write4((v & 0xF0) | rs)
        self._write4(((v << 4) & 0xF0) | rs)

    def line(self, row, text):
        self._send(0x80 | (0x40 if row else 0x00), 0)      # move to start of row
        for ch in (text + " " * 16)[:16]:
            self._send(ord(ch), 1)


i2c = I2C(0, scl=Pin(22), sda=Pin(21), freq=100000)
lcd = LCD(i2c)
lcd.line(0, "Base station")
lcd.line(1, "Starting...")

# ---------- LoRa radio ----------
lora = UART(2, baudrate=115200, tx=17, rx=16, timeout=50)


def send_at(cmd, wait_ms=300):
    lora.write(cmd + "\r\n")
    time.sleep_ms(wait_ms)
    r = lora.read()
    text = r.decode().strip() if r else ""
    print(cmd, "->", text or "(no reply)")
    return text


def parse_rcv(line):
    """'+RCV=sender,length,data,RSSI,SNR' - data may contain commas."""
    sender, length, rest = line[5:].split(",", 2)
    n = int(length)
    rssi, snr = rest[n + 1:].split(",")
    return int(sender), rest[:n], int(rssi), int(snr)


def stamp():
    """Time since the base started, as hh:mm:ss (GPS/clock time comes later)."""
    s = time.ticks_ms() // 1000
    return "%02d:%02d:%02d" % (s // 3600, s // 60 % 60, s % 60)


send_at("AT")
send_at("AT+ADDRESS=%d" % MY_ADDR)
send_at("AT+NETWORKID=18")
send_at("AT+BAND=915000000")
send_at("AT+PARAMETER=9,7,1,12")

# ---------- state ----------
msg_count = 0
last_heard = time.ticks_ms()
field_batt = None
temp = hum = None
rssi = 0
blue_off = 0
alarm_until = time.ticks_ms()
next_lcd = 0

print(stamp(), "Base station ready, listening...")

while True:
    now = time.ticks_ms()

    # 1) Messages from the field station
    while lora.any():
        raw = lora.readline()
        try:
            line = raw.decode().strip()
        except Exception:
            continue
        if not line.startswith("+RCV="):
            continue                                   # +OK etc.
        sender, data, rssi, snr = parse_rcv(line)
        msg_count += 1
        last_heard = now
        blue_off = time.ticks_add(now, 150)            # quick blue flash
        lora.write("AT+SEND=%d,%d,%s\r\n" % (sender, len("ACK,%d" % msg_count), "ACK,%d" % msg_count))
        print("%s  From %d: %s  (RSSI %d dBm, SNR %d dB)" % (stamp(), sender, data, rssi, snr))

        parts = data.split(",")
        if parts[0] == "HB" and len(parts) >= 6:
            field_batt = float(parts[2])
            temp, hum = float(parts[4]), float(parts[5])
        elif parts[0] == "EVT" and len(parts) >= 4:
            alarm_until = time.ticks_add(now, ALARM_S * 1000)
            print("%s  *** EARTHQUAKE at station %s: peak %s g, STA/LTA %s ***"
                  % (stamp(), parts[1], parts[2], parts[3]))
        next_lcd = now                                 # refresh LCD right away

    # 2) Work out the status
    alarm = time.ticks_diff(alarm_until, now) > 0
    no_signal = time.ticks_diff(now, last_heard) > NO_SIGNAL_S * 1000
    low_batt = field_batt is not None and field_batt < LOW_BATT_V

    # 3) LEDs and buzzer
    green.value((now // 1000) % 2)                     # slow blink: 1 s on, 1 s off
    blue.value(time.ticks_diff(blue_off, now) > 0)
    yellow.value(no_signal or low_batt)
    red.value(alarm)
    buzzer.duty_u16(32768 if alarm and (now // 250) % 2 else 0)   # beep-beep

    # 4) LCD, once a second
    if time.ticks_diff(now, next_lcd) >= 0:
        next_lcd = time.ticks_add(now, 1000)
        status = "QUAKE!" if alarm else "NO SIG" if no_signal else "LOWBAT" if low_batt else "OK"
        if temp is None:
            lcd.line(0, "Waiting... " + status)
            lcd.line(1, "No data yet")
        else:
            lcd.line(0, "T%.1fC H%d%% %s" % (temp, hum, status))
            lcd.line(1, "Bat%.2fV %ddBm" % (field_batt, rssi))

    time.sleep_ms(10)