""" Purpose: provide weather forecast by accessing US Weather Service 
    Usage:   user provides a zipcode
    Output:  current forecast for that zipcode
"""

# get access to web-based data support
import url 

# set base weather.gov query
WEATHER_GOV_QUERY = "https://forecast.weather.gov/zipcity.php?inputstring="
# base query is going to be the root of every link that we create, modified by different zip codes

# get zipcode of interest
reply = input( "Enter zipcode: " )
zipcode = reply.strip() # clean it up so it doesn't get mad at us if we try to put spaces in the link

# set complete query link
link = WEATHER_GOV_QUERY + zipcode # builds a link out of query base and relevant zip code
# this is not a folder/file system, it's a website that runs specific programs
# when you log into collab you can see something=True, this also uses a function to see if you're logged in

# query weather.gov
page = url.get_contents( link )
# we got the contents, but we don't want that huge awful string, we only want some

# need to find the forecast within the page

# forecast delimiters
FRONT_DELIMITER = "<div class=\"col-sm-10 forecast-text\">"   # text preceding forecast
REAR_DELIMITER  = "</div>"                                    # text following forecast
# delimiters tell us where we can find our forecast. delimeters surround the text of interest

# will we ask you to find the pattern? no, the pattern will be given and you'll use string methods to find()
# the occurrences

# delimiter lengths
LENGTH_FRONT_DELIMITER = len( FRONT_DELIMITER )
LENGTH_REAR_DELIMITER  = len( REAR_DELIMITER ) # we don't use this in this program!

# start by finding the forecast delimiters
front_index = page.find( FRONT_DELIMITER ) # this tells us when the pattern starts, not where it ends
rear_index  = page.find( REAR_DELIMITER, front_index )
# there are a bunch of </div> comments in html code, so we have to look for the first one after the start
# of the front delimiter to get the forecast. the second input gives the starting index for the search
forecast = page[ front_index : rear_index ] # [i:j] slicing/substrings - start at i and go to j-1
print( forecast )

# account for length of front delimiter, as the forecast starts directly after it
forecast_start = front_index + LENGTH_FRONT_DELIMITER
# get rid of that yucky front delimiter and only give us our forecast

print( "front_index:", front_index )
print( "forecast_start:", forecast_start )
print( "rear_index:",  rear_index )

# get and print the forecast
forecast = page[ forecast_start : rear_index ] # [i:j] slicing/substrings - start at i and go to j-1

print( zipcode, "forecast:", forecast )