''' Module url: provide function(s) in support of getting web-based data
    into the needed information structures.
'''

# need help to get web data
import urllib.request

def get_contents( link ) :
    ''' returns the contents of the web resource indicated by parameter link
    '''

    stream = urllib.request.urlopen( link )     # connect to resource stream

    bytes = stream.read()                       # read stream to gets its contents

    content = bytes.decode( 'UTF-8' )           # decode contents to get text

    return content

def get_lines( link ) :
    ''' returns the lines of text stored at the web resource indicated by
        parameter link
    '''

    # get the contents of the page
    data = get_contents( link )

    # strip the data of surrounding whitespace
    data = data.strip()

    # split data into lines
    lines = data.split( '\n' )

    # return what they asked for
    return lines

def get_strings( link ) :
    ''' returns the strings stored at the web resource indicated by
        parameter link
    '''

    # get the contents of the page
    data = get_contents( link )

    # strip the data of surrounding whitespace
    data = data.strip()

    # split data into strings
    strings = data.split( )

    # return what they asked for
    return strings

def get_csv_dataset( link ) :
    ''' returns the contents of the web resource indicated by parameter
        link as a list of lists of strings
    '''

    contents = get_contents( link )

    # get contents into dataset form
    dataset = contents.strip()
    dataset = dataset.split( '\n' )

    nbr_rows = len( dataset )

    for i in range( 0, nbr_rows ) :
        row = dataset[ i ]
        row = row.strip()
        row = row.split( ',' )
        dataset[ i ] = row

    return dataset

def get_and_convert_csv_dataset( link ) :
    ''' the contents of the web resource indicated by parameter link as a
        list of lists. The elements of the lists will be converted to int,
        float, or bool as appropriate
    '''

    dataset = get_csv_dataset( link )

    # get element contents into proper form
    nbr_rows = len( dataset )

    for r in range( 0, nbr_rows ) :
        row = dataset[ r ]
        nbr_columns = len( row )
        for c in range( 0, nbr_columns) :
            cell = row[ c ]
            if ( cell.isnumeric() ) :
                cell = int( cell )
            elif ( cell.capitalize() == 'True' ) :
                cell = True
            elif ( cell.capitalize() == 'False' ) :
                cell = False
            else :
                try :
                    float( cell )
                    cell = float( cell )
                    int( cell )
                    cell = int( cell )
                except :
                    pass
            row[ c ] = cell
        dataset[ r ] = row
    return dataset

# constants

BLACK = (   0,   0,   0 )
WHITE = ( 255, 255, 255 )

from PIL import Image

# needed for web support
import urllib.request, io

# process image acquistion and display

def get_web_image( link ) :
    ''' returns the image at the web resource indicated by link
    '''

    # get access to module Image
    from PIL import Image
    ''' Returns a pil image of the image named by link '''

    # get a connection to the web resource name by link
    stream = urllib.request.urlopen( link )

    # get the conents of the web resource
    data = stream.read()

    # convert the data to bytes
    bytes = io.BytesIO( data )

    # get the image represented by the bytes
    image = Image.open( bytes )

    # convert the image to RGB format
    image = image.convert('RGB')

    # hand back the image
    return image

def get_student_image( id ) :
    ''' returns the image indicated web resource indicated by parameter
        id
    '''

    STUDENT_REPOSITORY = 'http://www.cs.virginia.edu/~cs1112/people/'

    link = STUDENT_REPOSITORY + id + '/photo.jpg'

    return get_web_image( link )

def get_image( source ) :
    ''' returns an image from online, local source, or an existing Image
    '''

    try :
        if ( str( type( source ) ) == "<class 'PIL.Image.Image'>" ) :
            # check to if source is an existing Image
            image = source
        elif ( 'http://' == source[ 0 : 7 ].lower() ) :
            # look at the initial characters of source to see if its on the web
            # initial characters indicate the image is out on the web
            image = get_web_image( source )
        else :
            # initial characters indicate the image is a local file
            image = Image.open( source )
        image = image.convert( 'RGB' )
    except :
        image = None

    return image


def get_dictionary( link ) :
    ''' return the contents of the page indicated by parameter link as
        a dictionary
    '''

    dataset = get_csv_dataset( link )

    # initialize the dictionary
    dictionary = {}

    # accumulate the dictionary entries from the sheet
    for entry in dataset :
        key, value = entry
        dictionary[ key ] = value

    # return what they asked for
    return dictionary

def scrub( drawing, bg=(255,255,255), fg=(0,0,0) ) :
    w, h = drawing.size

    for y in range( 0, h ) :
        for x in range( 0, w ) :
            spot = ( x, y )
            r, g, b = drawing.getpixel( spot )
            if ( ( r + g + b ) < 2.5 * 255 ) :
                drawing.putpixel( spot, fg )
            else :
                drawing.putpixel( spot, bg )

    return drawing