# -*- coding:utf-8 -*-

# Copyright (c) 2014,
# Karlsruhe Institute of Technology, Institute of Telematics
#
# This code is provided under the BSD 2-Clause License.
# Please refer to the LICENSE.txt file for further information.
#
# Author: Mario Hock


def split_proprtionally(text, weights, size=0, fill=" "):
    """
    Split a string proportional to a given weight-distribution.

    If a |size| is specified, that string is filled with |fill| at the end to match that length.
    (NOTE: len(fill) must be 1)
    """

    if ( size > 0 ):
        ## Fill text with spaces.
        if ( len(text) < size ):
            text += fill * (size-len(text))
        ## Truncate text if it's too long.
        elif ( len(text) > size ):
            text = text[size]
    else:
        size = len(text)

    # sum of all weights
    total_weights = float( sum(weights) )

    ## Calculate an int for each weight so that they sum appropriately to |size|.
    float_lengths = [ (w / total_weights)*size for w in weights ]
    weighted_lengths = [ int(round( f )) for f in float_lengths ]

    ## Compensate rounding-related inconsistencies.
        # XXX I hope this actually does what's supposed to do...
        # (Increase/decrease the fields with the biggest rounding differences in order to fit the size)
    diff = size - sum(weighted_lengths)
    while( diff != 0 ):
        sign = -1 if diff < 0 else 1

        ## Calculate index where the rounding produced the biggest difference.
        #    (On equality, the latter one wins.)
        max_diff = 0
        index_of_max_diff = None
        for i in range( len(weighted_lengths) ):
            cur_diff = ( float_lengths[i] - weighted_lengths[i] ) * sign

            if ( cur_diff >= max_diff ):
                max_diff = cur_diff
                index_of_max_diff = i

        ## Increase the just found index by 1.
        weighted_lengths[i] += sign
        diff -= sign

    assert( sum(weighted_lengths) == size )



    ## * split *
    ret = list()
    last_pos = 0
    for pos in weighted_lengths:
        ret.append( text[last_pos:last_pos + pos] )
        last_pos += pos

    return ret