#!/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=http://10.200.1.26:8069
    INGEST_TOKEN=fp-iot-XXXXXXXXXXXXX
    INTERVAL_SECONDS=30
"""
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()