#!/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 = 50000

#### start of config

# If you change this you also need to change the create and graph lists below.
# Also note that samples have to be in the same order every time (the key is currently ignored).
samples_per_line=2

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

# The 4th field of the DS lines is the heartbeat. If you sample at an
# interval < that value you will not see a graph. Simply adjust if necessary.
create = [
	# 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,

	'DS:temp1:GAUGE:50:U:U',
	'DS:temp2:GAUGE:50:U:U',
	#'DS:hum1:GAUGE:50:U:U',
	'DS:abshum1:GAUGE:50:U:U',

	'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','10','-u','35', '--rigid',
	'--left-axis-format', '%4.2lf',
	'--right-axis-format', '%4.2lf',

	'DEF:temp1='+rrd_file+':temp1:AVERAGE',
	'LINE1:temp1#339966:temp 1\l',
	'DEF:temp2='+rrd_file+':temp2:AVERAGE',
	'LINE1:temp2#663399:temp 2\l',
	#'DEF:hum1='+rrd_file+':hum1:AVERAGE',
	#'CDEF:hum11=hum1,2,/',
	#'LINE1:hum11#996633:hum 1\l',
	'DEF:abshum1='+rrd_file+':abshum1:AVERAGE',
	'CDEF:abshum11=abshum1,2,*',
	'LINE1:abshum11#996633:abshum 1\l',
]

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

		elem = line.split(' ')
		values = []
		# timestamp
		values.append(int(elem[0]))
		# values
		for i in range(1, samples_per_line + 1):
			values.append(float(elem[i].split("=")[1]))

		# absolute humidity
		hum=float(elem[3].split("=")[1])
		temp=values[2]
		# 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)

		samples.append(values)

# 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: