add element fusion rules

2 files changed, 27 insertions, 2 deletions

diff --git a/lib/Games/SMTNocturne/Fusion/Chart.pm b/lib/Games/SMTNocturne/Fusion/Chart.pm
index 0284d3b..dd21ec5 100644
--- a/lib/Games/SMTNocturne/Fusion/Chart.pm
+++ b/lib/Games/SMTNocturne/Fusion/Chart.pm
@@ -33,8 +33,15 @@ multi method fuse (ClassName $self: SMTDemon $demon1 is coerce,
 
 multi method fuse (ClassName $self: Element $demon1 is coerce,
                                     SMTDemon $demon2 is coerce) {
-    # XXX: fix
-    return;
+    my $direction = $demon2->elemental_fusion_direction($demon1->name);
+    return unless defined $direction;
+
+    if ($direction eq 'down') {
+        return $demon2->level_down;
+    }
+    else {
+        return $demon2->level_up;
+    }
 }
 
 multi method fuse (ClassName $self: Mitama $demon1 is coerce,
diff --git a/lib/Games/SMTNocturne/Fusion/Demon.pm b/lib/Games/SMTNocturne/Fusion/Demon.pm
index bc386d1..23df00c 100644
--- a/lib/Games/SMTNocturne/Fusion/Demon.pm
+++ b/lib/Games/SMTNocturne/Fusion/Demon.pm
@@ -99,6 +99,24 @@ sub lookup {
     return wantarray ? @possible : (@possible == 1 ? $possible[0] : undef);
 }
 
+sub level_up {
+    my $self = shift;
+    my @possible = $self->lookup(
+        type  => $self->type,
+        level => sub { $_ > $self->level },
+    );
+    return $possible[0];
+}
+
+sub level_down {
+    my $self = shift;
+    my @possible = $self->lookup(
+        type  => $self->type,
+        level => sub { $_ < $self->level },
+    );
+    return $possible[$#possible];
+}
+
 __PACKAGE__->meta->make_immutable;
 
 1;