#!/usr/bin/perl

use strict;
use warnings;
#use Data::Dumper;

my $Port = 8080;
my $Highlight = 1;

#----------------------------------------------------------

my $Pre = $Highlight?
    '<span style="background: #ffffcc; color: #800000">' : '';
my $Post = $Highlight?
    '</span>' : '';

my @Typos = ();

open(TYPO, "$ENV{HOME}/.typo") and do
{
    @Typos = ();
    while (<TYPO>)
    {
        chomp;
        my ($wrong, $right) = split /\t+/;
        next if not $right;
        next if length($wrong) < 2;
        push(@Typos,
             [ $wrong, $right ]);
        push(@Typos,
             [ ucfirst($wrong), ucfirst($right) ])
            if ucfirst($wrong) ne $wrong;
    }
    close(TYPO);
};

die "No typos loaded from ~/.typo.\n" if not @Typos;
print STDERR "$0: ", scalar @Typos, " typos filtered on port $Port.\n";

# Longer corrections first.
@Typos =
    map { $_->[1] }
    sort { $b->[0] <=> $a->[0] }
    map { [ length($_->[0]), $_ ] }
    @Typos;

# Spaces are lenient.
$_->[0] =~ s/ \s+ /\\s+/gx
    foreach @Typos;

# Precompile the correction patterns.
$_->[0] = qr/ (?<! [<>] ) \b ( $_->[0] ) \b/x
    foreach @Typos;

#print Dumper $Typos[0], $Typos[-1];

#----------------------------------------------------------

use HTTP::Proxy;
my $proxy = HTTP::Proxy->new(port => $Port);
$proxy->push_body_filter( response => \&typo_filter );
$proxy->start();

#----------------------------------------------------------

sub typo_filter
{
    foreach (@Typos)
    {
        ${$_[0]} =~ s|$_->[0]|$Pre$_->[1]$Post|g;
    }
}