#!/usr/bin/env python
#------------------------------------------------------------------------------
# Title     : maxeff.py
# Purpose   : plot efficiency targets for a given battery pack
# Author    : Synthetic Transport (synthetictransport.com)
# Date      : Oct 2, 2007
#------------------------------------------------------------------------------
import os, sys, getopt, Gnuplot

def plotpowerpoints(output, watthours, startspeed, endspeed, startdist, enddist,
        disttics):

    g = Gnuplot.Gnuplot(debug=1)
    g.title('Efficient Power Targets using %0.0f Watthours' %watthours)

    g('set data style linespoints')
    g('set key top left')
    g('set grid')
    g('set ytics 25')
    g('set xtics 1')
    g.xlabel('Speed (MPH)')
    g.ylabel('Power (Watts)')

    for i in range(startdist, enddist+1, disttics):

        curve =[]
        # calculate efficiency targets for each speed at this distance
        for x in range(startspeed, endspeed+1):
            curve.append((x, watthours / (i/float(x))))

        g.replot(Gnuplot.Data(curve, title="%d miles (%0.0f Wh/m)" \
            %(i, watthours/i)))

    if output:
        g.hardcopy(output, enhanced=1, color=1)

    raw_input('Press return to exit...\n')

def usage(msg):
    sys.stdout = sys.stderr
    if msg: print msg
    print 'usage: %s -o(utputfile -w(atthours -s(tartspeed -e(ndspeed -S(tartdist E(nddist' \
        %os.path.basename(sys.argv[0])
    sys.exit(2)

if __name__ == '__main__':

    try:
        opts, args = getopt.getopt(sys.argv[1:], 'o:w:s:e:S:E:?')
    except getopt.error, msg:
        usage('Incorrect arguments')

    output = ''
    watthours = 1440.

    startspeed = 15.
    endspeed = 30.

    startdist = 60.
    enddist = 100.
    disttics = 10

    for o, a in opts:
        if o in ['-?', '-h']:
            usage('')
        if o == '-o':
            output = a
        if o == '-w':
            watthours = float(a)
        if o == '-s':
            startspeed = float(a)
        if o == '-e':
            endspeed = float(a)
        if o == '-E':
            enddist = float(a)
        if o == '-S':
            startdist = float(a)

    if enddist - startdist <= 20:
        disttics = 5
    if enddist - startdist <= 10:
        disttics = 2

    plotpowerpoints(output, watthours, startspeed, endspeed,
        startdist, enddist, disttics)