#!/usr/bin/python3
"""Parse status data from the Sunpower PVS6 and turn it into Influx format, for use with Telegraf.
PVS6 data comes from its endpoint /cgi-bin/dl_cgi?Command=DeviceList'
The PVS6 itself can be the server for this, or a Raspberry Pi or something running as a proxy.
Output contains lots of data from the Sunpower mointors.
Computer status, production and consumption wattages etc (as measured by CT sensors),
also power data from each individual inverter.
Also produces some summary statistics rolling up info about all the inverters.

By Nelson Minar <nelson@monkey.org>.
I have no intent to support this or turn it into a resuable product.
"""
import json, sys, os.path, re, statistics, urllib.request, time

_PVS6_URL = 'http://192.168.3.140/cgi-bin/dl_cgi?Command=DeviceList'

output = []


def extract_fields_tags(record, field_keys, tag_keys, ignore_keys):
	"""Given a JSON blob, return three dicts.
        One containing all keys in field_keys, one for tag_keys, and one for things not in fields, tags, or ignore."""
	field_keys = field_keys.split(',')
	tag_keys = tag_keys.split(',')
	ignore_keys = ignore_keys.split(',')
	fields = {k: v for k, v in record.items() if k in field_keys}
	tags = {k: v for k, v in record.items() if k in tag_keys}
	others = {k: v for k, v in record.items() if not (k in (field_keys + tag_keys + ignore_keys))}

	return fields, tags, others


_strip_whitespace = re.compile(r'\s+')


def _s(s):
	"Remove all whitespace from string"
	return _strip_whitespace.sub("_", s)


def _v(v):
	"Turn the input into a string for influx format. Quotes strings, converts numbers"
	try:
		return float(v)
	except ValueError:
		pass
	return f'"{v}"'


# Some rollup data populated by the parsing system
summary = {}
inverter_kws = []
inverter_temps = []


def init_summary():
	global inverter_kws, inverter_temps, summary
	inverter_kws = []
	inverter_temps = []
	summary = {
		'count_not_working': 0,
		'count_not_working_inverters': 0,
		'avg_inverter_kw': 0,
		'sd_inverter_kw': 0,
		'count_inverter_low_kw': 0,
		'avg_inverter_temp': 0,
		'sd_inverter_temp': 0,
	}


def create_summary():
	summary['avg_inverter_kw'] = statistics.fmean(inverter_kws)
	summary['sd_inverter_kw'] = statistics.pstdev(inverter_kws)
	summary['avg_inverter_temp'] = statistics.fmean(inverter_temps)
	summary['sd_inverter_temp'] = statistics.pstdev(inverter_temps)

	# Count "low" inverters
	mean_kw = summary['avg_inverter_kw']
	if mean_kw < 0.02:  # if no power is being generated then skip this check
		low = 0
	else:
		# low means less than 80% of average
		low_factor = 0.8
		low = sum([1 for x in inverter_kws if x < low_factor * summary['avg_inverter_kw']])
	summary['count_inverter_low_kw'] = low

	return "pvs6_summary", summary, {}, {}


def parse(data, timestamp):
	output = []
	skipped = 0
	init_summary()

	# Parse every record in the JSON input
	for record in data['devices']:
		device_type = record.get("DEVICE_TYPE")
		if device_type == 'Power Meter' and record.get('TYPE') == 'PVS5-METER-P':
			output.append(parse_production(record))
		elif device_type == 'Power Meter' and record.get('TYPE') == 'PVS5-METER-C':
			output.append(parse_consumption(record))
		elif device_type == 'Inverter':
			output.append(parse_inverter(record))
		elif device_type == 'PVS':
			output.append(parse_pvs(record))
		else:
			skipped += 1
	if skipped > 0:
		sys.stderr.write(f'Skipped {skipped} records of unknown type.\n')

	# Make a rollup from the collected data
	output.append(create_summary())

	# Emit the records in Influx format

	for measurement, fields, tags, others in output:
		if len(others) != 0:
			sys.stderr.write(f'Ignoring {len(others)} unknown data items in {measurement}: {others}\n')

		# Strip whitespace from tag names and values and format as k=v,k=v lists for Influx
		tag_set = ','.join(f"{_s(k)}={_s(v)}" for k, v in tags.items())
		field_set = ','.join(f"{_s(k)}={_v(v)}" for k, v in fields.items())

		# Format timestamp into nanoseconds
		ts = int(1_000_000_000 * timestamp)

		# Only print this delimeter if there are tags
		d = ',' if len(tag_set) > 0 else ''

		# Emit the Influx record
		print(f'{measurement}{d}{tag_set} {field_set} {ts}')


def parse_pvs(record):
	fields, tags, others = extract_fields_tags(
		record,
		"STATE,SWVER,dl_comm_err,dl_cpu_load,dl_err_count,dl_flash_avail,dl_mem_used,dl_scan_time,dl_skipped_scans,dl_untransmitted,dl_uptime",
		"SERIAL", "CURTIME,DATATIME,DETAIL,DEVICE_TYPE,HWVER,MODEL,STATEDESCR,panid")
	if fields['STATE'] != 'working':
		summary['count_not_working'] += 1
	return "pvs6_computer", fields, tags, others


def parse_production(record):
	fields, tags, others = extract_fields_tags(
		record, "STATE,freq_hz,net_ltea_3phsum_kwh,p_3phsum_kw,q_3phsum_kvar,s_3phsum_kva,tot_pf_rto", "SERIAL",
		"CAL0,CURTIME,DATATIME,DESCR,DEVICE_TYPE,ISDETAIL,MODEL,OPERATION,PORT,STATEDESCR,SWVER,TYPE,ct_scl_fctr,interface,origin,subtype"
	)
	if fields['STATE'] != 'working':
		summary['count_not_working'] += 1
	return "pvs6_production", fields, tags, others


def parse_consumption(record):
	fields, tags, others = extract_fields_tags(
		record,
		"STATE,freq_hz,i1_a,i2_a,neg_ltea_3phsum_kwh,net_ltea_3phsum_kwh,p1_kw,p2_kw,p_3phsum_kw,pos_ltea_3phsum_kwh,q_3phsum_kvar,s_3phsum_kva,tot_pf_rto,v12_v,v1n_v,v2n_v",
		"SERIAL",
		"CAL0,CURTIME,DATATIME,DESCR,DEVICE_TYPE,ISDETAIL,MODEL,OPERATION,PORT,STATEDESCR,SWVER,TYPE,ct_scl_fctr,interface,origin,subtype"
	)
	if fields['STATE'] != 'working':
		summary['count_not_working'] += 1
	return "pvs6_consumption", fields, tags, others


def parse_inverter(record):
	fields, tags, others = extract_fields_tags(
		record,
		"STATE,freq_hz,i_3phsum_a,i_mppt1_a,ltea_3phsum_kwh,p_3phsum_kw,p_mppt1_kw,stat_ind,t_htsnk_degc,v_mppt1_v,vln_3phavg_v",
		"SERIAL",
		"CURTIME,DATATIME,DESCR,DEVICE_TYPE,ISDETAIL,MODEL,MOD_SN,NMPLT_SKU,OPERATION,PANEL,PORT,STATEDESCR,SWVER,TYPE,hw_version,interface,origin"
	)
	if fields['STATE'] != 'working':
		summary['count_not_working'] += 1
		summary['count_not_working_inverters'] += 1
	inverter_kws.append(float(fields['p_3phsum_kw']))
	inverter_temps.append(float(fields['t_htsnk_degc']))
	return "pvs6_inverter", fields, tags, others


def load_from_file(fn):
	ts = os.path.getmtime(fn)
	try:
		data = json.load(open(fn))
	except:
		sys.stderr.write(f'Error parsing JSON file {fn}, skipping.\n')
		return
	parse(data, ts)


def load_from_url(url):
	# PVS6 often takes 10-15 seconds to respond
	fp = urllib.request.urlopen(url, timeout=50)
	data = json.load(fp)
	parse(data, time.time())


if __name__ == '__main__':
	if len(sys.argv) > 1:
		for fn in sys.argv[1:]:
			load_from_file(fn)
	else:
		load_from_url(_PVS6_URL)