Get 'cash' working again

Now implemented via a hidden user called '-cash'.

This also introduces the concept of hidden accounts, that begin with '+' or
'-', for result accounts and balance accounts. Future versions can further
use this for more detailed bookkeeping. The idea behind the sign is that
'-' accounts should be inverted to get the intuitive value. So if the account
'-cash' has -13.37, that means there should be +13.37 in the cash box (or,
well, once the rest of this is implemented and the initial values are then set
correctly.)

lib/RevBank/Cart.pm

@@ -8,6 +8,7 @@ no warnings qw(experimental::signatures);
 use Carp ();
 use List::Util ();
 use RevBank::Global;
+use RevBank::Users;
 use RevBank::Cart::Entry;
 
 sub new($class) {
@@ -65,6 +66,12 @@ sub checkout($self, $user) {
         return;
     }
 
+    if ($user =~ /^[-+]/) {
+        # Hidden internal accounts
+        my $canonical = RevBank::Users::parse_user($user);
+        $user = $canonical // RevBank::Users::create($user);
+    }
+
     my $entries = $self->{entries};
 
     my %deltas;

lib/RevBank/Messages.pm

@@ -13,8 +13,10 @@ use base 'RevBank::Plugin';
 
 BEGIN {
     RevBank::Plugins::register("RevBank::Messages");
+    *hidden = \&RevBank::Users::is_hidden;
 }
 
+
 sub command { return NEXT; }
 sub id { 'built in messages' }
 
@@ -53,6 +55,8 @@ sub hook_reject($class, $plugin, $reason, $abort, @) {
 }
 
 sub hook_user_balance($class, $username, $old, $delta, $new, @) {
+    return if hidden $username;
+
     my $sign = $delta->cents >= 0 ? '+' : '-';
     my $rood = $new->cents < 0 ? '31;' : '';
     my $abs  = $delta->abs;
@@ -63,6 +67,8 @@ sub hook_user_balance($class, $username, $old, $delta, $new, @) {
 }
 
 sub hook_user_created($class, $username, @) {
+    return if hidden $username;
+
     say "New account '$username' created.";
 }
 

lib/RevBank/Users.pm

@@ -36,13 +36,14 @@ sub create($username) {
     print {$fh} "$username 0.00 $now\n" or die $!;
     close $fh or die $!;
     RevBank::Plugins::call_hooks("user_created", $username);
+    return $username;
 }
 
 sub update($username, $delta, $transaction_id) {
     open my $in,  'revbank.accounts' or die $!;
     open my $out, ">.revbank.$$" or die $!;
-    my $old;
-    my $new;
+    my $old = RevBank::Amount->new(0);
+    my $new = RevBank::Amount->new(0);
     while (defined (my $line = readline $in)) {
         my @a = split " ", $line;
         if (lc $a[0] eq lc $username) {
@@ -82,6 +83,10 @@ sub parse_user($username) {
     return $users->{ lc $username }->[0];
 }
 
+sub is_hidden($username) {
+    return $username =~ /^[-+]/;
+}
+
 1;