# -*- Mode: Python; tab-width: 4 -*-

# python weight_chart.py [-o {png|ps}] mm/dd <data-file>

import os
import string
import sys
import time

if '-o' in sys.argv:
    i = sys.argv.index ('-o')
    oo = sys.argv[i+1]
    if oo not in ('ps','png'):
        raise ValueError, "supported output is <ps> or <png>"
    fileout = 1
    del sys.argv[i:i+2]
else:
    fileout = 0

# get the start date
now = list(time.localtime (time.time()))
[m,d] = map (int, string.split (sys.argv[1], '/'))
now[1] = m
now[2] = d
secs = time.mktime (now)

data = []
# first, read the data
f = open (sys.argv[2])
while 1:
    line = f.readline()
    if not line:
        break
    if line[0] == '#':
        continue
    else:
        w = string.atof (line)
        data.append (w)

f.close()
if not fileout:
    sys.stderr.write ('%d data points\n' % (len(data)))

# exponentially-weighted moving average,
# recreating/checking the pencil-and-paper 1/10 algorithm.

def ewma (values, trend=None, f=10):
    trends = []
    if trend is None:
        trend = values[0]
    for v in values:
        delta = trend - v
        delta = delta/f
        delta = round (delta, 1)
        trend = trend - delta
        trends.append (trend)
    return trends

trends = ewma (data, f=10)

# write the data to a tempfile
import tempfile
fn = tempfile.mktemp()
f = open (fn, 'w')

w0 = trends[0]
w1 = trends[-1]

tw0 = data[0]
tw1 = data[-1]

for i in range(len(data)):
    w = data[i]
    t = trends[i]
    # convert secs to mm/dd
    [mm, dd] = time.localtime (secs)[1:3]
    f.write ('%d/%d %f %f\n' % (mm,dd,w,t))
    secs = secs + 86400

f.close()

loss = (w0-w1)
tloss = (tw0-tw1)
deficit = (loss/len(data)) * 3500
tdeficit = (tloss/len(data)) * 3500

# get a pipe to gnuplot

p = os.popen ('/usr/local/bin/gnuplot', 'w')

commands = """
set ytics 1
set title "Loss: %.1f/%.1f pounds. \\nDaily Deficit: %d/%d kCal"
set grid
set timefmt "%%m/%%d"
set xdata time
set format x "%%m/%%d"
plot '%s' using 1:2:2:3 notitle with yerrorbars,\
 '%s' using 1:3 title "Trend" with lines, \
 '%s' using 1:2 title "Weight" with lines
"""

if fileout:
    if oo == 'ps':
        p.write ('set terminal postscript landscape color\n')
    elif oo == 'png':
        p.write ('set size 1.25, 1.25\n')
        p.write ('set terminal png color\n')

p.write (commands % (tloss,loss,int(tdeficit),int(deficit),fn,fn,fn))

if not fileout:
    p.write ('pause -1 "[hit return]"\n')
    p.flush()
    raw_input()
    p.write ('\n')

p.close()
os.unlink (fn)