6 files changed, 83 insertions, 5 deletions

diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index 6473c2d1..93b83da4 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -36,6 +36,7 @@ use helix_core::{
 };
 
 use crate::editor::Config;
+use crate::events::{DocumentDidChange, SelectionDidChange};
 use crate::{DocumentId, Editor, Theme, View, ViewId};
 
 /// 8kB of buffer space for encoding and decoding `Rope`s.
@@ -1096,6 +1097,10 @@ impl Document {
         // TODO: use a transaction?
         self.selections
             .insert(view_id, selection.ensure_invariants(self.text().slice(..)));
+        helix_event::dispatch(SelectionDidChange {
+            doc: self,
+            view: view_id,
+        })
     }
 
     /// Find the origin selection of the text in a document, i.e. where
@@ -1149,6 +1154,14 @@ impl Document {
         let success = transaction.changes().apply(&mut self.text);
 
         if success {
+            if emit_lsp_notification {
+                helix_event::dispatch(DocumentDidChange {
+                    doc: self,
+                    view: view_id,
+                    old_text: &old_doc,
+                });
+            }
+
             for selection in self.selections.values_mut() {
                 *selection = selection
                     .clone()
@@ -1164,6 +1177,10 @@ impl Document {
                     view_id,
                     selection.clone().ensure_invariants(self.text.slice(..)),
                 );
+                helix_event::dispatch(SelectionDidChange {
+                    doc: self,
+                    view: view_id,
+                });
             }
 
             self.modified_since_accessed = true;
@@ -1276,6 +1293,7 @@ impl Document {
             }
 
             if emit_lsp_notification {
+                // TODO: move to hook
                 // emit lsp notification
                 for language_server in self.language_servers() {
                     let notify = language_server.text_document_did_change(
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index 0ab4be8b..44c706d7 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -2,6 +2,7 @@ use crate::{
     align_view,
     document::{DocumentSavedEventFuture, DocumentSavedEventResult, Mode, SavePoint},
     graphics::{CursorKind, Rect},
+    handlers::Handlers,
     info::Info,
     input::KeyEvent,
     register::Registers,
@@ -960,6 +961,7 @@ pub struct Editor {
     /// field is set and any old requests are automatically
     /// canceled as a result
     pub completion_request_handle: Option<oneshot::Sender<()>>,
+    pub handlers: Handlers,
 }
 
 pub type Motion = Box<dyn Fn(&mut Editor)>;
diff --git a/helix-view/src/events.rs b/helix-view/src/events.rs
new file mode 100644
index 00000000..8b789cc0
--- /dev/null
+++ b/helix-view/src/events.rs
@@ -0,0 +1,9 @@
+use helix_core::Rope;
+use helix_event::events;
+
+use crate::{Document, ViewId};
+
+events! {
+    DocumentDidChange<'a> { doc: &'a mut Document, view: ViewId, old_text: &'a Rope  }
+    SelectionDidChange<'a> { doc: &'a mut Document, view: ViewId }
+}
diff --git a/helix-view/src/handlers.rs b/helix-view/src/handlers.rs
new file mode 100644
index 00000000..ae3eb545
--- /dev/null
+++ b/helix-view/src/handlers.rs
@@ -0,0 +1,12 @@
+use std::sync::Arc;
+
+use helix_event::send_blocking;
+use tokio::sync::mpsc::Sender;
+
+use crate::handlers::lsp::SignatureHelpInvoked;
+use crate::Editor;
+
+pub mod dap;
+pub mod lsp;
+
+pub struct Handlers {}
diff --git a/helix-view/src/handlers/lsp.rs b/helix-view/src/handlers/lsp.rs
index 8b137891..95838564 100644
--- a/helix-view/src/handlers/lsp.rs
+++ b/helix-view/src/handlers/lsp.rs
@@ -1 +1,40 @@
+use crate::{DocumentId, ViewId};
 
+#[derive(Debug, Clone, Copy)]
+pub struct CompletionTrigger {
+    /// The char position of the primary cursor when the
+    /// completion was triggered
+    pub trigger_pos: usize,
+    pub doc: DocumentId,
+    pub view: ViewId,
+    /// Whether the cause of the trigger was an automatic completion (any word
+    /// char for words longer than minimum word length).
+    /// This is false for trigger chars send by the LS
+    pub auto: bool,
+}
+
+pub enum CompletionEvent {
+    /// Auto completion was triggered by typing a word char
+    /// or a completion trigger
+    Trigger(CompletionTrigger),
+    /// A completion was manually requested (c-x)
+    Manual,
+    /// Some text was deleted and the cursor is now at `pos`
+    DeleteText { pos: usize },
+    /// Invalidate the current auto completion trigger
+    Cancel,
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum SignatureHelpInvoked {
+    Automatic,
+    Manual,
+}
+
+pub enum SignatureHelpEvent {
+    Invoked,
+    Trigger,
+    ReTrigger,
+    Cancel,
+    RequestComplete { open: bool },
+}
diff --git a/helix-view/src/lib.rs b/helix-view/src/lib.rs
index 6a68e7d6..82827b5d 100644
--- a/helix-view/src/lib.rs
+++ b/helix-view/src/lib.rs
@@ -1,17 +1,15 @@
 #[macro_use]
 pub mod macros;
 
+pub mod base64;
 pub mod clipboard;
 pub mod document;
 pub mod editor;
 pub mod env;
+pub mod events;
 pub mod graphics;
 pub mod gutter;
-pub mod handlers {
-    pub mod dap;
-    pub mod lsp;
-}
-pub mod base64;
+pub mod handlers;
 pub mod info;
 pub mod input;
 pub mod keyboard;