Add channel notes view

co-authored-by: Max <max@zed.dev>

crates/collab_ui/src/channel_view.rs

@@ -0,0 +1,69 @@
+use channel::channel_buffer::ChannelBuffer;
+use editor::Editor;
+use gpui::{
+    actions,
+    elements::{ChildView, Label},
+    AnyElement, AppContext, Element, Entity, ModelHandle, View, ViewContext, ViewHandle,
+};
+use language::Language;
+use std::sync::Arc;
+use workspace::item::{Item, ItemHandle};
+
+actions!(channel_view, [Deploy]);
+
+pub(crate) fn init(cx: &mut AppContext) {
+    // TODO
+}
+
+pub struct ChannelView {
+    editor: ViewHandle<Editor>,
+    channel_buffer: ModelHandle<ChannelBuffer>,
+}
+
+impl ChannelView {
+    pub fn new(
+        channel_buffer: ModelHandle<ChannelBuffer>,
+        language: Arc<Language>,
+        cx: &mut ViewContext<Self>,
+    ) -> Self {
+        let buffer = channel_buffer.read(cx).buffer();
+        buffer.update(cx, |buffer, cx| buffer.set_language(Some(language), cx));
+        let editor = cx.add_view(|cx| Editor::for_buffer(buffer, None, cx));
+        Self {
+            editor,
+            channel_buffer,
+        }
+    }
+}
+
+impl Entity for ChannelView {
+    type Event = editor::Event;
+}
+
+impl View for ChannelView {
+    fn ui_name() -> &'static str {
+        "ChannelView"
+    }
+
+    fn render(&mut self, cx: &mut ViewContext<'_, '_, Self>) -> AnyElement<Self> {
+        ChildView::new(self.editor.as_any(), cx).into_any()
+    }
+}
+
+impl Item for ChannelView {
+    fn tab_content<V: 'static>(
+        &self,
+        _: Option<usize>,
+        style: &theme::Tab,
+        cx: &gpui::AppContext,
+    ) -> AnyElement<V> {
+        let channel_name = self
+            .channel_buffer
+            .read(cx)
+            .channel(cx)
+            .map_or("[Deleted channel]".to_string(), |channel| {
+                format!("#{}", channel.name)
+            });
+        Label::new(channel_name, style.label.to_owned()).into_any()
+    }
+}