#!/usr/bin/perl

use strict;
use warnings;
use Encode;


for my $file (@ARGV) {
    open my $fh, '<:encoding(UTF-8)', $file;
    my $input = join q{}, <$fh>; 
    close $fh;
    while ( $input =~ /(^>.*?\w?)$([^>]*)/smxg ) {
        my $name = $1;
        my $seq = $2;
        $seq =~ s/\n//smxg;
        my $mass = calc_mass($seq);
        print "$name, Molecular weight: $mass\n";
    }
}

sub calc_mass {
    my $a = shift;
    my @a = ();
    my $x = length $a;
    @a = split q{}, $a;
    my $b = 0;
    my %data = (
        A=>88,  R=>173,  D=>132,  N=>131,
        C=>120,  E=>146,  Q=>145,  G=>74,
        H=>154,  I=>130,  L=>130,  K=>145,
        M=>198,  F=>164,  P=>114,  S=>104,
        T=>118,  W=>203,  Y=>180,  V=>116,
        X=>0,U=>0,Z=>0
    );
    for my $i( @a ) {
        $b += $data{$i};
    }
    my $c = sprintf("%0.2f",$b - (18.01528 * ($x - 1)));
    return $c;
}