#!/usr/bin/env python3
"""Fusion Plating IoT — DS18B20 poller.

Polls every DS18B20 probe the kernel exposes under /sys/bus/w1/devices/28-*
and POSTs each reading to the configured Odoo instance. Runs forever under
systemd; reads a config file at /etc/fp-iot/poller.conf.

Config file format:
    ODOO_URL=https://erp.enplating.ca
    INGEST_TOKEN=fp-iot-XXXXXXXXXXXXX
    INTERVAL_SECONDS=30

Use the customer-facing public URL (whatever their browser uses to
log into Odoo) — not an internal LAN IP. This way the Pi is site-
portable: same image/config works at office, client, or anywhere
with internet.
"""
import glob
import json
import logging
import os
import sys
import time
import urllib.error
import urllib.request
from datetime import datetime, timezone

CONFIG_PATH = '/etc/fp-iot/poller.conf'
LOG = logging.getLogger('fp-iot-poller')
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s %(levelname)s %(message)s',
    datefmt='%Y-%m-%d %H:%M:%S',
)


def load_config(path: str) -> dict:
    cfg = {}
    try:
        with open(path) as f:
            for line in f:
                line = line.strip()
                if not line or line.startswith('#') or '=' not in line:
                    continue
                key, _, val = line.partition('=')
                cfg[key.strip()] = val.strip()
    except FileNotFoundError:
        LOG.error('Config file not found: %s', path)
        sys.exit(1)
    for required in ('ODOO_URL', 'INGEST_TOKEN'):
        if not cfg.get(required):
            LOG.error('Missing required config key: %s', required)
            sys.exit(1)
    cfg.setdefault('INTERVAL_SECONDS', '30')
    return cfg


def read_probe(path: str) -> float | None:
    """Read one DS18B20 sysfs file. Returns Celsius or None on failure."""
    try:
        with open(os.path.join(path, 'w1_slave')) as f:
            data = f.read()
        # First line ends in "YES" for CRC-valid reads
        lines = data.strip().split('\n')
        if len(lines) < 2 or not lines[0].rstrip().endswith('YES'):
            LOG.warning('Probe %s bad CRC: %r', path, data)
            return None
        # Second line has "t=<millicelsius>"
        _, _, raw = lines[1].partition('t=')
        return float(raw) / 1000.0
    except Exception as e:
        LOG.warning('Probe read failed (%s): %s', path, e)
        return None


def post_readings(odoo_url: str, token: str, readings: list[dict]) -> bool:
    """POST batch to /fp/iot/ingest. Returns True on 2xx."""
    payload = json.dumps({'readings': readings}).encode()
    req = urllib.request.Request(
        odoo_url.rstrip('/') + '/fp/iot/ingest',
        data=payload,
        method='POST',
        headers={
            'Content-Type': 'application/json',
            'X-FP-IOT-Token': token,
        },
    )
    try:
        with urllib.request.urlopen(req, timeout=10) as resp:
            body = resp.read().decode()
            if 200 <= resp.status < 300:
                LOG.info('Ingest OK (%d): %s', resp.status, body.strip())
                return True
            LOG.warning('Ingest %d: %s', resp.status, body.strip())
            return False
    except urllib.error.HTTPError as e:
        LOG.warning('Ingest HTTP %d: %s', e.code, e.read().decode()[:200])
        return False
    except Exception as e:
        LOG.warning('Ingest failed: %s', e)
        return False


def main():
    cfg = load_config(CONFIG_PATH)
    odoo_url = cfg['ODOO_URL']
    token = cfg['INGEST_TOKEN']
    interval = int(cfg['INTERVAL_SECONDS'])
    LOG.info('Starting — polling every %ds, posting to %s', interval, odoo_url)

    while True:
        probes = glob.glob('/sys/bus/w1/devices/28-*')
        if not probes:
            LOG.warning('No DS18B20 probes detected under /sys/bus/w1/devices/28-*')
        readings = []
        now = datetime.now(timezone.utc).isoformat(timespec='seconds')
        for probe_path in probes:
            serial = os.path.basename(probe_path)
            temp_c = read_probe(probe_path)
            if temp_c is None:
                continue
            readings.append({
                'device_serial': serial,
                'value': round(temp_c, 3),
                'read_at': now,
            })
            LOG.info('Probe %s = %.3f°C', serial, temp_c)
        if readings:
            post_readings(odoo_url, token, readings)
        time.sleep(interval)


if __name__ == '__main__':
    main()