From 0ee2e1ef3bb38994f34a04f323e17d0bd87d38ca Mon Sep 17 00:00:00 2001
From: Michael Sippel <micha@fragmental.art>
Date: Fri, 9 Aug 2024 01:14:10 +0200
Subject: [PATCH] add seq2list projection

---
 src/projection/mod.rs      |   1 +
 src/projection/seq2list.rs | 164 +++++++++++++++++++++++++++++++++++++
 2 files changed, 165 insertions(+)
 create mode 100644 src/projection/seq2list.rs

diff --git a/src/projection/mod.rs b/src/projection/mod.rs
index d6d3875..899ca12 100644
--- a/src/projection/mod.rs
+++ b/src/projection/mod.rs
@@ -8,6 +8,7 @@ pub mod vec2bin;
 pub mod vec2json;
 pub mod vec2list;
 pub mod list2seq;
+pub mod seq2list;
 pub mod seq2idx;
 pub mod enumerate_sequence;
 pub mod filter_sequence;
diff --git a/src/projection/seq2list.rs b/src/projection/seq2list.rs
new file mode 100644
index 0000000..32fb3a6
--- /dev/null
+++ b/src/projection/seq2list.rs
@@ -0,0 +1,164 @@
+use {
+    crate::{
+        view::{
+            InnerViewPort, Observer, ObserverBroadcast, ObserverExt, OuterViewPort, View, ViewPort,
+            sequence::SequenceView,
+            list::{ListView, ListDiff}
+        },
+        buffer::vec::VecDiff,
+        projection::list2seq::List2Seq,
+    },
+    std::sync::Arc,
+    std::sync::RwLock,
+};
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+/// Adapter View implementing `List` for `Vec`
+pub struct Seq2List<T>
+where
+    T: Clone + Send + Sync + 'static,
+{
+    pub(crate) cur_len: usize,
+    src_view: Option<Arc<dyn SequenceView<Item = T>>>,
+    cast: Arc<RwLock<ObserverBroadcast<dyn ListView<T>>>>,
+}
+
+impl<T> Seq2List<T>
+where
+    T: Clone + Send + Sync + 'static,
+{
+    pub fn new(port: InnerViewPort<dyn ListView<T>>) -> Arc<RwLock<Self>> {
+        let s2l = Arc::new(RwLock::new(Seq2List {
+            cur_len: 0,
+            src_view: None,
+            cast: port.get_broadcast(),
+        }));
+        port.set_view(Some(s2l.clone()));
+        s2l
+    }
+}
+
+impl<T> Observer<dyn SequenceView<Item = T>> for Seq2List<T>
+where
+    T: Clone + Send + Sync + 'static,
+{
+    fn reset(&mut self, view: Option<Arc<dyn SequenceView<Item = T>>>) {
+        let old_len = self.cur_len;
+        self.src_view = view;
+        let new_len = if let Some(src_view) = self.src_view.as_ref() {
+            src_view.len().unwrap_or(0)
+        } else {
+            0
+        };
+
+        //self.cast.notify_each(0..std::cmp::max(old_len, new_len));
+
+        self.cur_len = 0;
+        self.cast.notify(&ListDiff::Clear);
+        for i in 0..new_len {
+            self.cast.notify(&ListDiff::Insert{ idx: i, val: self.src_view.get(&i).unwrap() });
+        }
+        self.cur_len = new_len;
+    }
+
+    fn notify(&mut self, idx: &usize) {
+        if let Some(v) = self.src_view.get(idx) {
+            if *idx < self.cur_len {
+                self.cast.notify(&ListDiff::Update{ idx: *idx, val: self.src_view.get(idx).unwrap() })
+            } else {
+                self.cur_len += 1;
+                self.cast.notify(&ListDiff::Insert{ idx: *idx, val: self.src_view.get(idx).unwrap() })
+            }
+        } else {
+            self.cur_len -= 1;
+//            assert!( *idx >= self.cur_len );
+            self.cast.notify(&ListDiff::Remove(self.cur_len));
+        }
+    }
+}
+
+impl<T> View for Seq2List<T>
+where
+    T: Clone + Send + Sync + 'static,
+{
+    type Msg = ListDiff<T>;
+}
+
+impl<T> ListView<T> for Seq2List<T>
+where
+    T: Clone + Send + Sync + 'static,
+{
+
+    fn get(&self, idx: &usize) -> Option<T> {
+        self.src_view.as_ref()?.get(idx).clone()
+    }
+
+    fn len(&self) -> Option<usize> {
+        Some(self.cur_len)
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+
+impl<T> OuterViewPort<dyn SequenceView<Item = T>>
+where
+    T: Clone + Send + Sync + 'static,
+{
+    pub fn to_list(&self) -> OuterViewPort<dyn ListView<T>> {
+        let port = ViewPort::new();
+        port.add_update_hook(Arc::new(self.0.clone()));
+
+        let s2l = Seq2List::new(port.inner());
+        self.add_observer(s2l.clone());
+        port.into_outer()
+    }
+}
+
+//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
+/*
+#[cfg(test)]
+mod tests {
+    use crate::buffer::vec::VecBuffer;
+    use crate::view::{
+        port::UpdateTask,
+        list::ListView,
+        sequence::*
+    };
+
+    #[test]
+    fn vec_to_list_to_seq() {
+        let mut buf = VecBuffer::<char>::new();
+        let seq_view = buf.get_port().to_list().to_sequence();
+
+        assert_eq!(seq_view.get_view().len(), Some(0));
+
+        buf.push('a');
+
+        seq_view.0.update();
+        assert_eq!(seq_view.get_view().len(), Some(1));
+        assert_eq!(seq_view.get_view().get(&0), Some('a'));
+        assert_eq!(seq_view.get_view().get(&1), None);
+        
+        
+        buf.push('b');
+
+        seq_view.0.update();
+        assert_eq!(seq_view.get_view().len(), Some(2));
+        assert_eq!(seq_view.get_view().get(&0), Some('a'));
+        assert_eq!(seq_view.get_view().get(&1), Some('b'));
+        assert_eq!(seq_view.get_view().get(&2), None);
+
+
+        buf.push('c');
+        buf.remove(0);
+
+        seq_view.0.update();
+        assert_eq!(seq_view.get_view().len(), Some(2));
+        assert_eq!(seq_view.get_view().get(&0), Some('b'));
+        assert_eq!(seq_view.get_view().get(&1), Some('c'));
+        assert_eq!(seq_view.get_view().get(&2), None);
+    }
+}
+*/
+