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

    Usage:   user provides a zipcode

    Output:  current forecast for that zipcode
'''

# get url access capability from cs 1112 module
from url import get_contents

# define weather.gov base query
WEATHER_GOV_QUERY = "https://forecast.weather.gov/zipcity.php?inputstring="
# THIS IS THE BASE URL - WE WILL PROMPT FOR A ZIP CODE AND ADD IT TO THE
# END OF OUR WEATHER_GOV_QUERY URL to access weather webpage for a zipcode of
# interest
# forecast delimiters
FRONT_DELIMITER = "<div class=\"col-sm-10 forecast-text\">"   # text that precedes forecast
REAR_DELIMITER  = "</div>"                                    # text that follows forecast
# We are going to find the forecast between the front delimiter and
# the rear delimiter

# 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

# print ( query_link ) # This is us assembling the full link for the
# website for the weather webpage of the zip code of interset

# get response from weather.gov
page = get_contents( query_link )

# print ( page ) -> prints html of the entire webpage

# to get the forecast, we need to find it within the page

# start by finding the forecast delimiters
front_index = page.index( FRONT_DELIMITER )
# WHERE IN MY HUGE HTML CAN I FIND THE FRONT DELIMITER?? (FRONT PART)
rear_index  = page.index( REAR_DELIMITER, front_index )
# SO THIS IS KEY REMEMBER THAT GET_CONTENTS() GETS YOU
# A STRING OF WHATEVER IS ON THAT WEBPAGE SO STRING METHODS
# WORK ON WHERE WE STORE WHAT WAS RETURNED BY GET_CONTENTS()

# So FRONT_DELIMITER and REAR_DELIMITER SANDWICH THE FORECAST
# Find where in the html the front and rear delimiters are
# rear_index (first instance of REAR_DELIMITER occuring after
# front index)
print( front_index, rear_index )
# (mis)try to use those index delimiters to pick off the forecast
# This is slicing! Going into text (the string) and getting a slice
# (a smaller substring) of the larger string
forecast = page[ front_index : rear_index + 1  ]
# Get me everything from where the front index is to where the last index
# is + 1 so that we include the rear index!
# Forecast is the substring of the larger string of the forecast page
# from the front_index (where the FRONT_DELIMITER occurs) to the
# rear index (where the REAR_DELIMITER occurs)

# print( forecast )

print()

# get the indices for the front and rear of the forecast
forecast_start = front_index + LENGTH_FRONT_DELIMITER

forecast_rear  = rear_index - 1 # Rear index is where we find the <div...

# ready to get and print the forecast
forecast = page[ forecast_start : forecast_rear + 1 ]
# slicing with a string s works
# like this s[ firstcharacterindex : lastcharacterindex ] where
# it goes from firstcharacterindex to lastcharacterindex - 1
# and hands back the substring
# print the forecast
print( forecast )