Support composing messages in an external editor (#155)

src/base.rs

@@ -202,6 +202,7 @@ pub enum RoomAction {
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub enum SendAction {
     Submit,
+    SubmitFromEditor,
     Upload(String),
     UploadImage(usize, usize, Cow<'static, [u8]>),
 }
@@ -222,6 +223,16 @@ pub enum IambAction {
     ToggleScrollbackFocus,
 }
 
+impl IambAction {
+    /// Indicates whether this action will draw over the screen.
+    pub fn scribbles(&self) -> bool {
+        match self {
+            IambAction::Send(SendAction::SubmitFromEditor) => true,
+            _ => false,
+        }
+    }
+}
+
 impl From<HomeserverAction> for IambAction {
     fn from(act: HomeserverAction) -> Self {
         IambAction::Homeserver(act)

src/commands.rs

@@ -266,6 +266,18 @@ fn iamb_reply(desc: CommandDescription, ctx: &mut ProgContext) -> ProgResult {
     return Ok(step);
 }
 
+fn iamb_editor(desc: CommandDescription, ctx: &mut ProgContext) -> ProgResult {
+    if !desc.arg.text.is_empty() {
+        return Result::Err(CommandError::InvalidArgument);
+    }
+
+
+    let sact = IambAction::from(SendAction::SubmitFromEditor);
+    let step = CommandStep::Continue(sact.into(), ctx.context.take());
+
+    return Ok(step);
+}
+
 fn iamb_rooms(desc: CommandDescription, ctx: &mut ProgContext) -> ProgResult {
     if !desc.arg.text.is_empty() {
         return Result::Err(CommandError::InvalidArgument);
@@ -537,6 +549,11 @@ fn add_iamb_commands(cmds: &mut ProgramCommands) {
         aliases: vec![],
         f: iamb_welcome,
     });
+    cmds.add_command(ProgramCommand {
+        name: "editor".into(),
+        aliases: vec![],
+        f: iamb_editor,
+    });
 }
 
 pub fn setup_commands() -> ProgramCommands {

src/main.rs

@@ -224,6 +224,9 @@ struct Application {
 
     /// The tab layout before the last executed [TabAction].
     last_layout: Option<TabLayoutDescription<IambInfo>>,
+
+    /// Whether we need to do a full redraw (e.g., after running a subprocess).
+    dirty: bool,
 }
 
 impl Application {
@@ -263,6 +266,7 @@ impl Application {
             screen,
             focused: true,
             last_layout: None,
+            dirty: true,
         })
     }
 
@@ -314,7 +318,8 @@ impl Application {
 
     async fn step(&mut self) -> Result<TerminalKey, std::io::Error> {
         loop {
-            self.redraw(false, self.store.clone().lock().await.deref_mut())?;
+            self.redraw(self.dirty, self.store.clone().lock().await.deref_mut())?;
+            self.dirty = false;
 
             if !poll(Duration::from_secs(1))? {
                 // Redraw in case there's new messages to show.
@@ -479,6 +484,10 @@ impl Application {
         ctx: ProgramContext,
         store: &mut ProgramStore,
     ) -> IambResult<EditInfo> {
+        if action.scribbles() {
+            self.dirty = true;
+        }
+
         let info = match action {
             IambAction::ToggleScrollbackFocus => {
                 self.screen.current_window_mut()?.focus_toggle();

src/windows/room/chat.rs

@@ -7,6 +7,7 @@ use std::path::{Path, PathBuf};
 use modalkit::editing::store::RegisterError;
 use std::process::Command;
 use tokio;
+use edit::edit as external_edit;
 
 use matrix_sdk::{
     attachment::AttachmentConfig,
@@ -429,14 +430,18 @@ impl ChatState {
         let mut show_echo = true;
 
         let (event_id, msg) = match act {
-            SendAction::Submit => {
+            SendAction::Submit | SendAction::SubmitFromEditor => {
                 let msg = self.tbox.get();
 
-                if msg.is_blank() {
+                let msg = if let SendAction::SubmitFromEditor = act {
+                    external_edit(msg.trim_end().to_string())?
+                } else if msg.is_blank() {
                     return Ok(None);
-                }
+                } else {
+                    msg.trim_end().to_string()
+                };
 
-                let mut msg = text_to_message(msg.trim_end().to_string());
+                let mut msg = text_to_message(msg);
 
                 if let Some((_, event_id)) = &self.editing {
                     msg.relates_to = Some(Relation::Replacement(Replacement::new(