look at fs on demand, don't watch it

ScanDir (well, fs notifications in raku) is too slow to keep up with
actual fs changes (especially when e.g. a file is being downloaded)

there's actually no need to watch fs changes, we can just sync the db
with the file system we look at each directory

1 files changed, 101 insertions, 0 deletions

diff --git a/lib/App/MediaControl/Model.rakumod b/lib/App/MediaControl/Model.rakumod
new file mode 100644
index 0000000..6d1c771
--- /dev/null
+++ b/lib/App/MediaControl/Model.rakumod
@@ -0,0 +1,101 @@
+use v6.d;
+use App::MediaControl::FS;
+use App::MediaControl::DB;
+
+class App::MediaControl::Model {
+    has App::MediaControl::FS $.fs is required;
+    has App::MediaControl::DB $.db is required;
+
+    method get-children-of($id) {
+        my @db-children = self.db.get-children-of($id);
+        # [{id,path,name,is_dir,watched_time}]
+
+        my $path;
+        if (@db-children) {
+            $path = @db-children[0]<path>; # they all have the same path
+        } elsif ($id.defined) {
+            my $entry = self.db.get-entry($id);
+            $path = "{$entry<path>}{$entry<name>}";
+        } else {
+            $path = '/';
+        }
+
+        my @fs-children = self.fs.get-children-of($path);
+        # [{name,is_dir}]
+
+        my ($db-idx, $fs-idx, $changed) = 0, 0, False;
+
+        sub add-to-db() {
+            self.db.add-entry(
+                :$path,
+                name => @fs-children[$fs-idx]<name>,
+                is-dir => @fs-children[$fs-idx].<is_dir>,
+            );
+            $changed=True;
+            ++$fs-idx;
+        }
+        sub remove-from-db() {
+            self.db.remove-entry(@db-children[$db-idx]<id>);
+            $changed=True;
+            ++$db-idx;
+        }
+        
+        while ($db-idx < @db-children && $fs-idx < @fs-children) {
+            given @db-children[$db-idx]<name> leg @fs-children[$fs-idx]<name> {
+                when Order::Same {
+                    ++$db-idx; ++$fs-idx;
+                }
+
+                when Order::Less {
+                    remove-from-db();
+                }
+
+                when Order::More {
+                    add-to-db();
+                }
+            }
+        }
+
+        while ($db-idx < @db-children) {
+            remove-from-db();
+        }
+
+        while ($fs-idx < @fs-children) {
+            add-to-db();
+        }
+
+        if $changed {
+            @db-children = self.db.get-children-of($id);
+        }
+
+        return @db-children;
+    }
+
+    method get-parents-of(Int:D() $id) {
+        return self.db.get-parents-of($id);
+    }
+
+    method get-entry(Int:D() $id) {
+        return self.db.get-entry($id);
+    }
+
+    method mark-entry-watched(Int:D() $id) {
+        return self.db.mark-entry-watched($id);
+    }
+
+    method get-recently-watched-folders(Int:D() $limit=20) {
+        my @db-folders = self.db.get-recently-watched-folders($limit);
+        my $changed = False;
+        for @db-folders -> $f {
+            next if self.fs.exists("{$f<path>}{$f<name>}");
+            self.db.remove-entry($f<id>);
+            $changed = True;
+        }
+
+        if $changed {
+            @db-folders = self.db.get-recently-watched-folders($limit);
+        }
+
+        return @db-folders;
+    }
+}