#!/usr/bin/perl
use constant DELAY => 15;
use strict;
use warnings;
use Storable;
use Win32::GuiTest 'SendKeys';

my $list = retrieve('word_list.db');
my $word = $ARGV[0] or die "Usage: $0 <input_word>";
my $file = "${word}_highest_score.txt";

open(my $fh, '<', $file) or die "Unable to open '$file' for reading: $!";
my $last_line;
while (<$fh>) {
    chomp;
    $last_line = $_;
}

my @guess = grep length($_) == 4, split ' ', $last_line;
my ($curr, @chain) = ($list->{$word}, ());
GUESS:
for my $want (@guess) {
    for my $have (@$curr) {
        if ($have->{word} eq $want) {
            push @chain, $have;
            $curr = $list->{$have->{word}};
            next GUESS;
        }
    }
}


my $score = calculate_score(\@chain);
print "Ready to get $score points (excludes time bonus)\n";
<STDIN>;
sleep 5;

my ($last_pos, $last_word) = (0, $word);
for (@chain) {
    my ($word, $pos, $let) = @{$_}{qw/word position letter/};
    move_position($last_pos, $pos) if $last_pos != $pos;
    $last_pos = $pos;
    print "Changing '$last_word' into '$word' by using $let at $pos\n";
    $last_word = $word;
    SendKeys($let, DELAY);
}

sub calculate_score {
    my ($chain) = @_;
    my ($total, $multiplier, %bonus) = (0, 1, ());
    for (@$chain) {
        my ($pos, $score) = @{$_}{qw/position score/};
        if ($bonus{$pos}) {
            %bonus = ($pos => 1);
        }
        else {
            $bonus{$pos} = 1;
        }
        if (keys %bonus == 4) {
            $multiplier++;
            %bonus = ();
        }
        $total += ($score * $multiplier);
    }
    return $total;
}

sub move_position {
    my ($src, $tgt) = @_;
    if ($src > $tgt) {
        SendKeys("{LEFT}",  DELAY) for 1 .. $src - $tgt;
    }
    else {
        SendKeys("{RIGHT}", DELAY) for 1 .. $tgt - $src;
    }
}

sub get_next_word {
    my ($list, $used, $chain, $bonus, $rule) = @_;
    my $curr = @$chain ? $chain->[-1]{word} : $ARGV[0];
    die "Usage: $0 <word>" if ! $curr;
    my ($best, $max) = ('', 0);
    {
        my %avail = map {$_ => 1} 0 .. 3;
        delete $avail{$_} for keys %$bonus;
        for my $neighbor (@{$list->{$curr}}) {
            my ($word, $pos, $let) = @{$neighbor}{qw/word position letter/};
            next if $used->{$word} || ! $avail{$pos} || fails_rule($chain, $rule, $pos, $let);
            my $count = @{$list->{$word}};
            ($best, $max) = ($neighbor, $count) if $count > $max;
        }
        if (! $best) {
            return if ! %$bonus;
            %$bonus = ();
            redo;
        }
    }
    return $best;
}

sub fails_rule {
    my ($chain, $rule, $let, $pos) = @_;
    return if ! @$rule;
    my $ord = @$chain % 10;
    if ($rule->[$ord]) {
        for ( @{$rule->[$ord]{letter}}   ) { return 1 if $let eq $chain->[$_]{letter};   }; 
        for ( @{$rule->[$ord]{position}} ) { return 1 if $let eq $chain->[$_]{position}; }; 
    }
    else {
        for ( @{$rule->[-1]{letter}}   ) { return 1 if $let eq $chain->[$_]{letter};   }; 
        for ( @{$rule->[-1]{position}} ) { return 1 if $let eq $chain->[$_]{position}; }; 
    }
    return;
}