1 files changed, 66 insertions, 0 deletions
diff --git a/lib/Tucana/CLI.rakumod b/lib/Tucana/CLI.rakumod
new file mode 100644
index 0000000..b791d50
--- /dev/null
+++ b/lib/Tucana/CLI.rakumod
@@ -0,0 +1,66 @@
+unit module Tucana::CLI;
+
+use Octans::Neighbors;
+
+# If no arguments are passed then run USAGE & exit.
+proto MAIN (|) is export {unless so @*ARGS {say $*USAGE; exit;}; {*}}
+
+multi sub MAIN (Bool :$version) {
+    say "Tucana v" ~ $?DISTRIBUTION.meta<version>;
+}
+
+multi sub MAIN (
+    Str $word, #= word for the puzzle
+    Bool :v($verbose), #= increase verbosity
+) {
+    my @puzzle := generate-puzzle($word);
+    "  $_".say for @puzzle;
+}
+
+# generate-puzzle generates a 3x3 puzzle with $word in there.
+sub generate-puzzle (
+    Str $word,
+) {
+    my @puzzle := [
+        [<_ _ _ _>],
+        [<_ _ _ _>],
+        [<_ _ _ _>],
+        [<_ _ _ _>],
+    ];
+
+    my Int ($y, $x) = edges(@puzzle).pick;
+    @puzzle[$y][$x] = $word.comb[0];
+
+    my @visited;
+    @visited[$y][$x] = True;
+
+    my Int $count = 1;
+    while $count < $word.chars {
+        neighbor: for neighbors(@puzzle, $y, $x).pick(*) -> ($pos-y, $pos-x) {
+            next neighbor if @visited[$pos-y][$pos-x];
+            @visited[$pos-y][$pos-x] = True;
+
+            @puzzle[$pos-y][$pos-x] = $word.comb[$count];
+            ($y, $x) = ($pos-y, $pos-x);
+            last neighbor;
+        }
+
+        $count++;
+    }
+
+    return @puzzle;
+}
+
+# edges takes a 2d grid & returns the list of edges, i.e. squares with
+# < 4 neighbors.
+sub edges (
+    @puzzle --> List
+) {
+    my List @edges;
+    for 0 .. @puzzle.end -> $y {
+        for 0 .. @puzzle[$y].end -> $x {
+            push @edges, ($y, $x) if neighbors(@puzzle, $y, $x).elems < 4;
+        }
+    }
+    return @edges;
+}