# Copyright Google Inc. 2010 All Rights Reserved
import simplejson
import urllib

ELEVATION_BASE_URL = 'http://maps.google.com/maps/api/elevation/json'
CHART_BASE_URL = 'http://chart.googleapis.com/chart'

def getChart(chartData, chartDataScaling="-500,5000", chartType="lc",chartLabel="Elevation in Meters",chartSize="500x160", chartColor="orange", **chart_args):
    chart_args.update({
        'cht': chartType,
        'chs': chartSize,
        'chl': chartLabel,
        'chco': chartColor,
        'chds': chartDataScaling,
        'chxt': 'x,y',
        'chxr': '1,-500,5000'
    })

    dataString = 't:' + ','.join(str(x) for x in chartData)
    chart_args['chd'] = dataString.strip(',')

    chartUrl = CHART_BASE_URL + '?' + urllib.urlencode(chart_args)

    print("")
    print("Elevation Chart URL:")
    print("")
    print chartUrl

def getElevation(path="36.578581,-118.291994|36.23998,-116.83171",samples="100",sensor="false", **elvtn_args):
    elvtn_args.update({
        'path': path,
        'samples': samples,
        'sensor': sensor
    })

    url = ELEVATION_BASE_URL + '?' + urllib.urlencode(elvtn_args)
    response = simplejson.load(urllib.urlopen(url))


    # Create a dictionary for each results[] object
    elevationArray = []

    for resultset in response['results']:
      elevationArray.append(resultset['elevation'])

    # Create the chart passing the array of elevation data
    getChart(chartData=elevationArray)   

if __name__ == '__main__':
        
    print("")
    print("Elevation Chart Maker 1.0")
    print("")
    print("The following service calculates elevation data between two points")
    print("and builds an HTTP chart using Google's Elevation service and Chart API")
    print("")

    # Collect the Latitude/Longitude input string
    # from the user
    startStr = raw_input('Enter the start latitude,longitude value (default Mt. Whitney) --> ').replace(' ','')
    if not startStr:
      startStr = "36.578581,-118.291994"

    endStr = raw_input('Enter the end latitude,longitude value (default Death Valley) --> ').replace(' ','')
    if not endStr:
      endStr = "36.23998,-116.83171"

    pathStr = startStr + "|" + endStr

    getElevation(pathStr)