bambuddy/spoolbuddy/daemon/main.py

#!/usr/bin/env python3
"""SpoolBuddy daemon — reads NFC tags and scale, pushes events to Bambuddy backend."""

import asyncio
import logging
import socket
import sys
import time
from pathlib import Path

# Add scripts/ to sys.path so hardware drivers (read_tag, scale_diag) are importable
sys.path.insert(0, str(Path(__file__).resolve().parent.parent / "scripts"))

from . import __version__
from .api_client import APIClient
from .config import Config
from .display_control import DisplayControl
from .nfc_reader import NFCReader, NFCState
from .scale_reader import ScaleReader

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(name)s] %(levelname)s: %(message)s",
    datefmt="%H:%M:%S",
)
logger = logging.getLogger("spoolbuddy")


def _get_ip() -> str:
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        s.connect(("8.8.8.8", 80))
        ip = s.getsockname()[0]
        s.close()
        return ip
    except Exception:
        return "unknown"


def _deploy_ssh_key(public_key: str) -> None:
    """Write Bambuddy's SSH public key to authorized_keys if not already present."""
    home = Path.home()
    ssh_dir = home / ".ssh"
    auth_keys = ssh_dir / "authorized_keys"

    try:
        ssh_dir.mkdir(mode=0o700, exist_ok=True)

        # Check if key already deployed
        if auth_keys.exists():
            existing = auth_keys.read_text()
            if public_key.strip() in existing:
                return

        # Append key
        with auth_keys.open("a") as f:
            f.write(public_key.strip() + "\n")
        auth_keys.chmod(0o600)
        logger.info("SSH public key deployed to %s", auth_keys)
    except Exception as e:
        logger.warning("Failed to deploy SSH key: %s", e)


async def nfc_poll_loop(config: Config, api: APIClient, shared: dict):
    """Continuous NFC polling loop — runs in asyncio with blocking reads offloaded."""
    nfc: NFCReader = shared["nfc"]
    display: DisplayControl = shared["display"]
    if not nfc.ok:
        logger.warning("NFC reader not available, skipping NFC polling")
        return

    try:
        while True:
            event_type, event_data = await asyncio.to_thread(nfc.poll)

            if event_type == "tag_detected":
                display.wake()
                await api.tag_scanned(
                    device_id=config.device_id,
                    tag_uid=event_data["tag_uid"],
                    tray_uuid=event_data.get("tray_uuid"),
                    sak=event_data.get("sak"),
                    tag_type=event_data.get("tag_type"),
                )
            elif event_type == "tag_removed":
                await api.tag_removed(
                    device_id=config.device_id,
                    tag_uid=event_data["tag_uid"],
                )

            # Check for pending write command
            pending = shared.get("pending_write")
            if pending and nfc.state == NFCState.TAG_PRESENT and nfc.current_sak == 0x00:
                logger.info("Executing pending tag write for spool %d", pending["spool_id"])
                success, msg = await asyncio.to_thread(nfc.write_ntag, pending["ndef_data"])
                await api.write_tag_result(
                    device_id=config.device_id,
                    spool_id=pending["spool_id"],
                    tag_uid=nfc.current_uid or "",
                    success=success,
                    message=msg,
                )
                shared.pop("pending_write", None)

            await asyncio.sleep(config.nfc_poll_interval)
    finally:
        nfc.close()


async def scale_poll_loop(config: Config, api: APIClient, shared: dict):
    """Continuous scale reading loop — reads at 100ms, reports at 1s intervals."""
    scale: ScaleReader = shared["scale"]
    display: DisplayControl = shared["display"]
    if not scale.ok:
        logger.warning("Scale not available, skipping scale polling")
        return

    last_report = 0.0
    last_reported_grams: float | None = None
    REPORT_THRESHOLD = 2.0  # Only report if weight changed by more than this (grams)
    try:
        while True:
            result = await asyncio.to_thread(scale.read)

            if result is not None:
                grams, stable, raw_adc = result
                now = time.monotonic()

                if now - last_report >= config.scale_report_interval:
                    # Only send when weight changed meaningfully
                    weight_changed = last_reported_grams is None or abs(grams - last_reported_grams) >= REPORT_THRESHOLD

                    if weight_changed:
                        display.wake()
                        await api.scale_reading(
                            device_id=config.device_id,
                            weight_grams=grams,
                            stable=stable,
                            raw_adc=raw_adc,
                        )
                        last_reported_grams = grams
                    last_report = now

            await asyncio.sleep(config.scale_read_interval)
    finally:
        scale.close()


async def heartbeat_loop(config: Config, api: APIClient, start_time: float, shared: dict):
    """Periodic heartbeat to keep device registered and pick up commands."""
    display: DisplayControl = shared["display"]
    ip = _get_ip()

    while True:
        await asyncio.sleep(config.heartbeat_interval)

        nfc = shared.get("nfc")
        scale = shared.get("scale")
        uptime = int(time.monotonic() - start_time)
        result = await api.heartbeat(
            device_id=config.device_id,
            nfc_ok=nfc.ok if nfc else False,
            scale_ok=scale.ok if scale else False,
            uptime_s=uptime,
            ip_address=ip,
            firmware_version=__version__,
            nfc_reader_type=nfc.reader_type if nfc else None,
            nfc_connection=nfc.connection if nfc else None,
        )

        if result:
            cmd = result.get("pending_command")
            if cmd == "tare":
                scale = shared.get("scale")
                if scale and scale.ok:
                    new_offset = await asyncio.to_thread(scale.tare)
                    logger.info("Tare executed: offset=%d", new_offset)
                    await api.update_tare(config.device_id, new_offset)
                    config.tare_offset = new_offset
                else:
                    logger.warning("Tare command received but scale not available")
                # Skip calibration sync — this heartbeat response predates the tare
                continue
            elif cmd == "write_tag":
                write_payload = result.get("pending_write_payload")
                if write_payload:
                    shared["pending_write"] = {
                        "spool_id": write_payload["spool_id"],
                        "ndef_data": bytes.fromhex(write_payload["ndef_data_hex"]),
                    }
                    logger.info("Write tag command received for spool %d", write_payload["spool_id"])

            tare = result.get("tare_offset", config.tare_offset)
            cal = result.get("calibration_factor", config.calibration_factor)
            if tare != config.tare_offset or cal != config.calibration_factor:
                config.tare_offset = tare
                config.calibration_factor = cal
                scale = shared.get("scale")
                if scale:
                    scale.update_calibration(tare, cal)
                logger.info("Calibration updated from backend: tare=%d, factor=%.6f", tare, cal)

            # Apply display settings from backend
            brightness = result.get("display_brightness")
            blank_timeout = result.get("display_blank_timeout")
            if brightness is not None:
                display.set_brightness(brightness)
            if blank_timeout is not None:
                display.set_blank_timeout(blank_timeout)

        display.tick()


async def main():
    config = Config.load()
    logger.info(
        "SpoolBuddy daemon v%s starting (device=%s, backend=%s)", __version__, config.device_id, config.backend_url
    )

    api = APIClient(config.backend_url, config.api_key)
    ip = _get_ip()
    start_time = time.monotonic()

    # Initialize hardware before registration so we can report capabilities
    nfc = NFCReader()
    scale = ScaleReader(
        tare_offset=config.tare_offset,
        calibration_factor=config.calibration_factor,
    )
    display = DisplayControl()

    # Register with backend (retries until success)
    reg = await api.register_device(
        device_id=config.device_id,
        hostname=config.hostname,
        ip_address=ip,
        firmware_version=__version__,
        has_nfc=True,
        has_scale=True,
        tare_offset=config.tare_offset,
        calibration_factor=config.calibration_factor,
        nfc_reader_type=nfc.reader_type,
        nfc_connection=nfc.connection,
        has_backlight=display.has_backlight,
    )

    # Use server-side calibration if available
    if reg:
        config.tare_offset = reg.get("tare_offset", config.tare_offset)
        config.calibration_factor = reg.get("calibration_factor", config.calibration_factor)
        scale.update_calibration(config.tare_offset, config.calibration_factor)

        # Auto-deploy Bambuddy's SSH public key for remote updates
        ssh_key = reg.get("ssh_public_key")
        if ssh_key:
            _deploy_ssh_key(ssh_key)

    logger.info("Device registered, starting poll loops")

    shared: dict = {"nfc": nfc, "scale": scale, "display": display}
    try:
        await asyncio.gather(
            nfc_poll_loop(config, api, shared),
            scale_poll_loop(config, api, shared),
            heartbeat_loop(config, api, start_time, shared),
        )
    except KeyboardInterrupt:
        logger.info("Shutting down")
    finally:
        await api.close()


if __name__ == "__main__":
    asyncio.run(main())