''' Purpose: provide weather forecast by accessing US Weather Service web
             service

    Usage:   user provides a zipcode

    Output:  municipality and state combo along with its current forecast
'''

# get url access capabilities from cs 1112 module
import url

# define weather.gov base query
WEATHER_GOV_QUERY = 'https://forecast.weather.gov/zipcity.php?inputstring='

# forecast delimiters
FRONT_DELIMITER = '<div class="col-sm-10 forecast-text">'   # this precedes forecast

REAR_DELIMITER  = '</div>'                                  # this follows forecast 

# delimiter lengths
LENGTH_FRONT_DELIMITER = len( FRONT_DELIMITER )
LENGTH_REAR_DELIMITER  = len( REAR_DELIMITER )

# get zipcode of interest
reply = input( 'Enter zipcode: ' )
zipcode = reply.strip()                                     # clean-up response

# specify complete query
query_link = WEATHER_GOV_QUERY + zipcode        

# get response from weather.gov
text = url.get_text( query_link )

# to get the forecast, itself, we need to find the forecast

# start by finding the forecast delimiters
front_index = text.find( FRONT_DELIMITER )                  # find starting index of
                                                            # FRONT_DELIMITER

rear_index  = text.find( REAR_DELIMITER, front_index )      # find starting index of
                                                            # READ_DELIMITER. However,
                                                            # want the occurrence that
                                                            # follows the FRONT_DELIMITER

forecast = text[ front_index : rear_index ]                 # print what we got for region
                                                            # of interest
print( forecast )

print()

# get the indices for the front and rear of the forecast
forecast_start = front_index + LENGTH_FRONT_DELIMITER       # forecast starts right beyond the
                                                            # front delimiter

forecast_rear  = rear_index - 1                             # end of the forecast is immediately
                                                            # before rear delimiter

# ready to get and print the forecast
forecast = text[ forecast_start : forecast_rear + 1 ]       # remember when slicing -- the end is
                                                            # 1 index after what you want up to

# print the forecast
print( forecast )