"""
Example for continuous operation: read a DS18B20 and send the temperature.

The DS18B20 is a 1-Wire sensor. MicroPython ships the drivers for it built in
(`onewire` + `ds18x20`), so nothing extra needs to be installed.

Wiring (1-Wire, ESP32-S3): DATA=GPIO4, plus a 4.7 kOhm pull-up resistor between
DATA and 3V3. Power the sensor from 3V3 and GND. Several DS18B20 can share the
one data line; this example reads the first one found.

There is no loop here. machine.deepsleep() does not return - the ESP32 restarts
and runs this file from the top again, so the restart *is* the next cycle. In
deep sleep the chip draws microamps, where an idle time.sleep() would keep it at
tens of milliamps for the whole interval.

The restart takes the serial port down with it, so this file is awkward to watch
in Thonny. Use ../lightsleep/send_ds18b20.py while trying things out.

The LA66 is a separate chip and keeps its LoRaWAN session and frame counter
across the restart, so join() returns immediately and a cycle costs no OTAA
handshake. Do not switch the LA66 off together with the ESP32.

On a development board the USB-serial chip and the voltage regulator usually
draw far more than the ESP32 in deep sleep; the saving only shows on a board
built without them.
"""

import machine
from machine import Pin

import ds18x20
import onewire
from loramint import LoRaMINT, MintValue

UPLINK_INTERVAL = 60  # seconds of deep sleep between measurements

# DS18B20 on a 1-Wire bus (ESP32-S3 pin; change to match your board)
ONEWIRE_DATA = 4

# Stop bridge: connect this pin to GND (a jumper wire is enough) to keep the
# cycle from starting. Deep sleep leaves the board reachable for only the few
# seconds it is awake, which makes it hard to interrupt from Thonny or mpremote;
# with the bridge in place the program ends right here and hands you the REPL.
#
# Pick a free pin, never a strapping pin - on the ESP32-S3 those are GPIO0, 3,
# 45 and 46. They are sampled at reset, and waking from deep sleep *is* a reset,
# so a bridge on one of them would put the board into download mode instead.
STOP_PIN = 5

LOCATION = "Raum 101"


def sleep_until_next_cycle():
    """Enter deep sleep. Never returns - the ESP32 restarts on wake-up."""
    machine.deepsleep(UPLINK_INTERVAL * 1000)


# Checked before anything else, so the bridge works even when the sensor, the
# LA66 or the wiring is at fault.
if not Pin(STOP_PIN, Pin.IN, Pin.PULL_UP).value():
    raise SystemExit("Stop bridge on GPIO{} - cycle not started.".format(STOP_PIN))

bus = ds18x20.DS18X20(onewire.OneWire(Pin(ONEWIRE_DATA)))

# Every failure has to end in deep sleep too. A node that just stops here stays
# awake at full clock until the battery is empty - more expensive than running
# normally - and never gets a second chance.
roms = bus.scan()
if not roms:
    print("No DS18B20 on the 1-Wire bus - retrying after deep sleep.")
    sleep_until_next_cycle()
rom = roms[0]  # use the first sensor on the bus

lora = LoRaMINT()

if not lora.check_connection():
    print("No UART connection to the LA66 - retrying after deep sleep.")
    sleep_until_next_cycle()

print("Joining LoRaWAN network...")
if not lora.join():
    print("Join failed - retrying after deep sleep.")
    sleep_until_next_cycle()
print("Joined.")

if machine.reset_cause() != machine.DEEPSLEEP_RESET:
    # Cold start only: after a wake-up this would be sent on every cycle. A
    # press on RST counts as a cold start, which is intended - it makes an
    # unplanned restart visible in the backend.
    #
    # The first measurement follows in the next cycle: sending it right after
    # the log entry would make it fail on the LA66's receive windows.
    if lora.sendLog("ESP32 gestartet"):
        print("Log entry sent.")
    sleep_until_next_cycle()

# Trigger a conversion, then wait for it (>=750 ms at 12-bit resolution). The
# sensor converts on its own, so the ESP32 can spend the wait in light sleep.
bus.convert_temp()
machine.lightsleep(750)
temperature = bus.read_temp(rom)

if lora.sendValue(MintValue(temperature, "*C", LOCATION, "Temperatur", "DS18B20")):
    print("Measurement sent:", temperature)

sleep_until_next_cycle()