import csv

def pretty_file(filename, **options):
    """
        Pretty print a CSV file
        """
    
    #function specific options
    new_delimiter           = options.pop("new_delimiter", " | ")
    border                  = options.pop("border", True)
    border_vertical_left    = options.pop("border_vertical_left", "| ")
    border_vertical_right   = options.pop("border_vertical_right", " |")
    border_horizontal       = options.pop("border_horizontal", "-")
    border_corner_tl        = options.pop("border_corner_tl", "+ ")
    border_corner_tr        = options.pop("border_corner_tr", " +")
    border_corner_bl        = options.pop("border_corner_bl", border_corner_tl)
    border_corner_br        = options.pop("border_corner_br", border_corner_tr)
    header                  = options.pop("header", True)
    border_header_separator = options.pop("border_header_separator", border_horizontal)
    border_header_left      = options.pop("border_header_left", border_corner_tl)
    border_header_right     = options.pop("border_header_right", border_corner_tr)
    new_filename            = options.pop("new_filename", "new_" + filename)
    newline                 = options.pop("newline", "\n")
    
    column_max_width = {} #key:column number, the max width of each column
    num_rows = 0 #the number of rows
    
    with open(filename, "r") as input: #parse the file and determine the width of each column
        reader=csv.reader(input, **options)
        for row in reader:
            num_rows += 1
            for col_number, column in enumerate(row):
                width = len(column)
                try:
                    if width > column_max_width[col_number]:
                        column_max_width[col_number] = width
                except KeyError:
                    column_max_width[col_number] = width

    max_columns = max(column_max_width.keys()) + 1 #the max number of columns (having rows with different number of columns is no problem)
    if max_columns > 1:
        total_length = sum(column_max_width.values()) + len(new_delimiter) * (max_columns - 1)
        left = border_vertical_left if border is True else ""
        right = border_vertical_right if border is True else ""
        left_header = border_header_left if border is True else ""
        right_header = border_header_right if border is True else ""
        
        with open(filename, "r") as input:
            reader=csv.reader(input, **options)
            with open(new_filename, "w") as output:
                for row_number, row in enumerate(reader):
                    max_index = len(row) - 1
                    for index in range(max_columns):
                        if index > max_index:
                            row.append(' ' * column_max_width[index]) #append empty columns
                        else:
                            diff = column_max_width[index] - len(row[index])
                            row[index] = row[index] + ' ' * diff #append spaces to fit the max width
                
                    if row_number==0 and border is True: #draw top border
                        output.write(border_corner_tl + border_horizontal * total_length + border_corner_tr + newline)
                        print border_corner_tl + border_horizontal * total_length + border_corner_tr + newline
                    output.write(left + new_delimiter.join(row) + right + newline) #print the new row
                    print left + new_delimiter.join(row) + right + newline
                    if row_number==0 and header is True: #draw header's separator
                        output.write(left_header + border_header_separator * total_length + right_header + newline)
                    if row_number==num_rows-1 and border is True: #draw bottom border
                        output.write(border_corner_bl + border_horizontal * total_length + border_corner_br)