#!/usr/bin/python3

# based on https://github.com/cnvogelg/ardu/blob/master/datalog/tools/plot_log.py

# This script plots a log file of the format
# "unix_timestamp key=value key2=value key3=value ..."
# using rrdtool. Keys are arbitrary values of the format "type:number"
# (e.g. t:1, t:2, h:1 for temperature and humidity) used to identify each sample.
# Note that the keys currently ignored.
#
# The whole log is plotted into one graph.

import sys
import subprocess
import os
import math
from string import Template

if len(sys.argv) != 3:
  print("Usage: plot.py <log> <png>", file=sys.stderr)
  sys.exit(1)

log_file = sys.argv[1]
png_file = sys.argv[2]
rrd_file = "tmp.rrd"
argmax = 20000

#### start of config

template_values = {
	# 0 = everything from the input
	# otherwise = only the last n
	"total_samples": 0,
}

# heartbeat. If you sample at an interval < that value you will not see a
# graph. Simply adjust if necessary.
heartbeat = 50

create_prefix = [
	# Index of the 0 after --start is used below. Adjust code if you
	# change the amount of values before it.
	'rrdtool','create',rrd_file,'--step','30','--start',0,
]

create_suffix = [
	'RRA:AVERAGE:0.5:1:$total_samples',
	'RRA:MIN:0.5:1:$total_samples',
	'RRA:MAX:0.5:1:$total_samples',
]

graph = [
	# Indices of the two Nones are used below. Adjust the code if you
	# change the amount of values before them..
	'rrdtool','graph',png_file,
	'-s',None,'-e',None,
	'--height=500','--width=1000',
	'--color=BACK#FFFFFF',
	#'--title','Temperature',
	'--vertical-label', 'Temperature °C',
	'--right-axis-label', 'Humidity g/m³',
	'--right-axis', '0.5:0',
	#'--alt-autoscale',
	'-l','-5','-u','30', '--rigid',
	'--left-axis-format', '%4.2lf',
	'--right-axis-format', '%4.2lf',
]

colors = [
		'#339966',
		'#663399',
		'#993366',
		'#336699',
		]

#### end of config

def chunker(seq, size):
	return (seq[pos:pos + size] for pos in range(0, len(seq), size))

calc_total_from_input = False
if template_values["total_samples"] == 0:
	calc_total_from_input = True

# load samples
samples = []
value_names = []
with open(log_file,"r") as f:
	first_line = True
	for line in f:
		if calc_total_from_input:
			template_values["total_samples"] += 1

		elements = line.split(' ')
		values = []
		# timestamp
		values.append(int(elements[0]))
		# values
		for i in range(1, len(elements)):
			[key, value] = elements[i].split("=")
			[elem_type, sensorID] = key.split(":")
			if first_line:
				value_names.append(key)

			if elem_type == "t":
				values.append(float(value))
			elif elem_type == "h":
				# absolute humidity
				hum=float(value)
				temp=values[i - 1]
				# Source: https://carnotcycle.wordpress.com/2012/08/04/how-to-convert-relative-humidity-to-absolute-humidity/
				abshum=(6.112 * math.e**(17.67 * temp / (temp + 243.5)) * hum * 2.1674) / (273.15+temp)
				values.append(abshum)
			else:
				raise ValueError("Unhandled element type")


		samples.append(values)
		first_line = False

create_values = []
color_counter = 0
for elem in value_names:
	[elem_type, sensorID] = elem.split(":")
	color = colors[color_counter]
	color_counter = (color_counter + 1) % len(colors)
	if elem_type == "t":
		create_values.append("DS:temp{sensorID}:GAUGE:{heartbeat}:U:U".format(sensorID=sensorID, heartbeat=heartbeat))
		graph.extend([
			# TODO change color for each value. select from a list of defined colors
			'DEF:temp{sensorID}={rrd_file}:temp{sensorID}:AVERAGE'.format(sensorID=sensorID, rrd_file=rrd_file),
			'LINE1:temp{sensorID}{color}:temp {sensorID}\l'.format(sensorID=sensorID, color=color),
			])
	elif elem_type == "h":
		create_values.append("DS:abshum{sensorID}:GAUGE:{heartbeat}:U:U".format(sensorID=sensorID, heartbeat=heartbeat))
		graph.extend([
			# TODO change color for each value. select from a list of defined colors
			'DEF:abshum{sensorID}={rrd_file}:abshum{sensorID}:AVERAGE'.format(sensorID=sensorID, rrd_file=rrd_file),
			'CDEF:abshum{sensorID}_1=abshum{sensorID},2,*'.format(sensorID=sensorID),
			'LINE1:abshum{sensorID}_1{color}:abshum {sensorID}\l'.format(sensorID=sensorID, color=color),
			])
	else:
		raise ValueError("Unhandled element type")

create = create_prefix + create_values + create_suffix

# create rrd
start_ts = samples[0][0]
end_ts = samples[-1][0]
create[6] = str(start_ts - 1)

cmd = []
for elem in create:
	cmd.append(Template(elem).substitute(template_values))
#print("creating rrdb:",create)
ret = subprocess.call(cmd)
if ret != 0:
	print("ERROR calling: {}".format(" ".join(create)))
	sys.exit(1)


# update rrd
for group in chunker(samples, argmax):
	cmd = ['rrdupdate', rrd_file, '--']
	for sample in group:
		entry = ":".join(map(str, sample))
		cmd.append(entry);

	ret = subprocess.call(cmd)
	if ret != 0:
		print("ERROR calling: {}".format(" ".join(cmd)))
		sys.exit(1)


# graph
graph[4] = str(start_ts)
graph[6] = str(end_ts)
ret = subprocess.call(graph)
if ret != 0:
	print("ERROR calling: {}".format(" ".join(graph)))
	sys.exit(1)

os.unlink(rrd_file)

# vim: set noet: