#!/bin/python3
#
import argparse
import json
import nagios
import os
import urllib.request

CHECKS = ['wifi', 'mqtt', 'memory', 'filesystem', 'temperature']
#
WIFI_QUALITY_ERROR = -30
WIFI_QUALITY_WARNING = -50
#
RAM_ERROR = .15
RAM_WARNING = .30
#
FS_ERROR = .15
FS_WARNING = .30
#
TMP_WARNING = 50
TMP_ERROR = 57
#

if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        prog=os.path.basename(__file__),
        description='Check shelly for nagios monitorin',
        # epilog='Text at the bottom of help'
    )
    parser.add_argument('-H', '--hostname', required=True)
    parser.add_argument('-c', '--check', choices=CHECKS, required=True)
    args = parser.parse_args()
    #
    n = nagios.Nagios()
    status = n.UNKNOWN
    #
    with urllib.request.urlopen(f"http://{args.hostname}/status") as response:
        data = json.load(response)
    #
    #
    if args.check == 'wifi':
        connected = data['wifi_sta']['connected']
        quality = data['wifi_sta']['rssi']
        if not connected or quality > WIFI_QUALITY_ERROR:
            status = n.ERROR
        elif quality > WIFI_QUALITY_WARNING:
            status = n.WARNING
        else:
            status = n.OK
        n.exit(status, f"connected: {connected} - quality: {quality} < {WIFI_QUALITY_WARNING} < {WIFI_QUALITY_ERROR}")
    elif args.check == 'mqtt':
        connected = data['mqtt']['connected']
        if not connected:
            status = n.ERROR
        else:
            status = n.OK
        n.exit(status, f"connected: {connected}")
    elif args.check == 'memory':
        ram_total = data['ram_total']
        ram_free = data['ram_free']
        ram_left = ram_free / ram_total
        if ram_left < RAM_ERROR:
            status = n.ERROR
        elif ram_left < RAM_WARNING:
            status = n.WARNING
        else:
            status = n.OK
        n.exit(status, f"ram_left: {ram_left} ({ram_total}) > {RAM_WARNING} > {RAM_ERROR}")
    elif args.check == 'filesystem':
        fs_size = data['fs_size']
        fs_free = data['fs_free']
        fs_left = fs_free / fs_size
        if fs_left < FS_ERROR:
            status = n.ERROR
        elif fs_left < FS_WARNING:
            status = n.WARNING
        else:
            status = n.OK
        n.exit(status, f"fs_left: {fs_left} ({fs_size}) > {FS_WARNING} > {FS_ERROR}")
    elif args.check == 'temperature':
        temperature = data.get('tmp', {}).get('tC')
        if temperature is None:
            if args.hostname.startswith('shelly1-'):
                n.exit(n.OK, "Shelly1 has no temperature information")
            status = n.UNKNOWN
        elif temperature >= TMP_ERROR:
            status = n.ERROR
        elif temperature >= TMP_WARNING:
            status = n.WARNING
        else:
            status = n.OK
        n.exit(status, f"temperature: {temperature}°C")