From 5753fb5af8eb043d9b96390aa936bb265b551ff2 Mon Sep 17 00:00:00 2001
From: Michael Sippel <micha@fragmental.art>
Date: Mon, 16 Aug 2021 00:08:33 +0200
Subject: [PATCH] singleton: to_index() & to_grid()

---
 nested/src/singleton/mod.rs      |  2 +
 nested/src/singleton/to_index.rs | 85 ++++++++++++++++++++++++++++++++
 2 files changed, 87 insertions(+)
 create mode 100644 nested/src/singleton/to_index.rs

diff --git a/nested/src/singleton/mod.rs b/nested/src/singleton/mod.rs
index 5b55b2f..2a5b7a7 100644
--- a/nested/src/singleton/mod.rs
+++ b/nested/src/singleton/mod.rs
@@ -1,6 +1,8 @@
 
 pub mod buffer;
 pub mod map;
+pub mod to_index;
+//pub mod unwrap;
 
 use {
     std::{
diff --git a/nested/src/singleton/to_index.rs b/nested/src/singleton/to_index.rs
new file mode 100644
index 0000000..28372af
--- /dev/null
+++ b/nested/src/singleton/to_index.rs
@@ -0,0 +1,85 @@
+use {
+    std::sync::Arc,
+    std::sync::RwLock,
+    crate::{
+        singleton::{SingletonView},
+        index::{IndexView},
+        grid::{GridView},
+        core::{
+            Observer, ObserverExt, ObserverBroadcast,
+            View, ViewPort, OuterViewPort
+        }
+    }
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<Item: 'static> OuterViewPort<dyn SingletonView<Item = Item>> {
+    pub fn to_index(&self) -> OuterViewPort<dyn IndexView<(), Item = Item>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+
+        let map = Arc::new(RwLock::new(Singleton2Index {
+            src_view: None,
+            cast: port.inner().get_broadcast()
+        }));
+
+        self.add_observer(map.clone());
+        port.inner().set_view(Some(map));
+        port.into_outer()
+    }
+
+    pub fn to_grid(&self) -> OuterViewPort<dyn GridView<Item = Item>> {
+        self.to_index()
+            .map_key(
+                |_msg: &()| cgmath::Point2::new(0, 0),
+                |pt| if pt.x == 0 && pt.y == 0 { Some(()) } else { None }
+            )
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+pub struct Singleton2Index<SrcView>
+where SrcView: SingletonView + ?Sized
+{
+    src_view: Option<Arc<SrcView>>,
+    cast: Arc<RwLock<ObserverBroadcast<dyn IndexView<(), Item = SrcView::Item>>>>
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<SrcView> View for Singleton2Index<SrcView>
+where SrcView: SingletonView + ?Sized
+{
+    type Msg = ();
+}
+
+impl<SrcView> IndexView<()> for Singleton2Index<SrcView>
+where SrcView: SingletonView + ?Sized
+{
+    type Item = SrcView::Item;
+
+    fn area(&self) -> Option<Vec<()>> {
+        Some(vec![()])
+    }
+    fn get(&self, _msg: &()) -> Option<Self::Item> {
+        Some(self.src_view.as_ref().unwrap().get())
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<SrcView> Observer<SrcView> for Singleton2Index<SrcView>
+where SrcView: SingletonView + ?Sized
+{
+    fn reset(&mut self, view: Option<Arc<SrcView>>) {
+        self.src_view = view;
+        self.cast.notify(&());
+    }
+
+    fn notify(&mut self, msg: &()) {
+        self.cast.notify(msg);
+    }
+}
+