From bff1a54ee765c8d71c0d6105d9be0ecf496033d1 Mon Sep 17 00:00:00 2001
From: Alxy Savin <saleksey67@gmail.com>
Date: Sat, 14 Mar 2026 01:32:10 +0300
Subject: [PATCH] Add configurable terminal cursor shape

---
 config.example.toml |  1 +
 docs/iamb.5         | 10 ++++++++++
 src/config.rs       | 24 ++++++++++++++++++++++++
 src/main.rs         | 19 ++++++++++++++++---
 4 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/config.example.toml b/config.example.toml
index c4ebd653..2d6f2ba1 100644
--- a/config.example.toml
+++ b/config.example.toml
@@ -5,6 +5,7 @@ user_id = "@user:matrix.org"
 url = "https://matrix.org"
 
 [settings]
+cursor_shape = "default"
 default_room = "#iamb-users:0x.badd.cafe"
 external_edit_file_suffix = ".md"
 log_level = "warn"
diff --git a/docs/iamb.5 b/docs/iamb.5
index 8357f965..10536ed1 100644
--- a/docs/iamb.5
+++ b/docs/iamb.5
@@ -128,6 +128,16 @@ key and can be overridden as described in
 .It Sy external_edit_file_suffix
 Suffix to append to temporary file names when using the :editor command. Defaults to .md.
 
+.It Sy cursor_shape
+Control the terminal cursor shape used by iamb.
+Possible values are:
+.Dq Sy default ,
+.Dq Sy block ,
+.Dq Sy line , and
+.Dq Sy underline .
+Defaults to
+.Dq Sy default .
+
 .It Sy default_room
 The room to show by default instead of the
 .Sy :welcome
diff --git a/src/config.rs b/src/config.rs
index e7a4a47b..0ec42ee2 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -558,6 +558,7 @@ impl SortOverrides {
 
 #[derive(Clone)]
 pub struct TunableValues {
+    pub cursor_shape: CursorShape,
     pub log_level: Level,
     pub message_shortcode_display: bool,
     pub normal_after_send: bool,
@@ -585,6 +586,7 @@ pub struct TunableValues {
 
 #[derive(Clone, Default, Deserialize)]
 pub struct Tunables {
+    pub cursor_shape: Option<CursorShape>,
     pub log_level: Option<LogLevel>,
     pub message_shortcode_display: Option<bool>,
     pub normal_after_send: Option<bool>,
@@ -614,6 +616,7 @@ pub struct Tunables {
 impl Tunables {
     fn merge(self, other: Self) -> Self {
         Tunables {
+            cursor_shape: self.cursor_shape.or(other.cursor_shape),
             log_level: self.log_level.or(other.log_level),
             message_shortcode_display: self
                 .message_shortcode_display
@@ -648,6 +651,7 @@ impl Tunables {
 
     fn values(self) -> TunableValues {
         TunableValues {
+            cursor_shape: self.cursor_shape.unwrap_or_default(),
             log_level: self.log_level.map(Level::from).unwrap_or(Level::INFO),
             message_shortcode_display: self.message_shortcode_display.unwrap_or(false),
             normal_after_send: self.normal_after_send.unwrap_or(false),
@@ -677,6 +681,16 @@ impl Tunables {
     }
 }
 
+#[derive(Copy, Clone, Debug, Default, Deserialize, Eq, PartialEq)]
+#[serde(rename_all = "lowercase")]
+pub enum CursorShape {
+    #[default]
+    Default,
+    Block,
+    Line,
+    Underline,
+}
+
 #[derive(Clone)]
 pub struct DirectoryValues {
     pub cache: PathBuf,
@@ -1345,6 +1359,16 @@ mod tests {
         assert!(serde_json::from_str::<NotifyVia>(r#""""#).is_err());
     }
 
+    #[test]
+    fn test_parse_cursor_shape() {
+        assert_eq!(CursorShape::Default, CursorShape::default());
+        assert_eq!(CursorShape::Default, serde_json::from_str(r#""default""#).unwrap());
+        assert_eq!(CursorShape::Block, serde_json::from_str(r#""block""#).unwrap());
+        assert_eq!(CursorShape::Line, serde_json::from_str(r#""line""#).unwrap());
+        assert_eq!(CursorShape::Underline, serde_json::from_str(r#""underline""#).unwrap());
+        assert!(serde_json::from_str::<CursorShape>(r#""beam""#).is_err());
+    }
+
     #[test]
     fn test_load_example_config_toml() {
         let path = PathBuf::from("config.example.toml");
diff --git a/src/main.rs b/src/main.rs
index 0a316c76..dce2a3ac 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -38,7 +38,7 @@ use tracing_subscriber::FmtSubscriber;
 
 use modalkit::crossterm::{
     self,
-    cursor::Show as CursorShow,
+    cursor::{SetCursorStyle, Show as CursorShow},
     event::{
         poll,
         read,
@@ -99,7 +99,7 @@ use crate::{
         ProgramContext,
         ProgramStore,
     },
-    config::{ApplicationSettings, Iamb},
+    config::{ApplicationSettings, CursorShape, Iamb},
     windows::IambWindow,
     worker::{create_room, ClientWorker, LoginStyle, Requester},
 };
@@ -976,6 +976,12 @@ async fn login_normal(
 /// Set up the terminal for drawing the TUI, and getting additional info.
 fn setup_tty(settings: &ApplicationSettings, enable_enhanced_keys: bool) -> std::io::Result<()> {
     let title = format!("iamb ({})", settings.profile.user_id.as_str());
+    let cursor_style = match settings.tunables.cursor_shape {
+        CursorShape::Default => SetCursorStyle::DefaultUserShape,
+        CursorShape::Block => SetCursorStyle::SteadyBlock,
+        CursorShape::Line => SetCursorStyle::SteadyBar,
+        CursorShape::Underline => SetCursorStyle::SteadyUnderScore,
+    };
 
     // Enable raw mode and enter the alternate screen.
     crossterm::terminal::enable_raw_mode()?;
@@ -993,7 +999,13 @@ fn setup_tty(settings: &ApplicationSettings, enable_enhanced_keys: bool) -> std:
         crossterm::execute!(stdout(), EnableMouseCapture)?;
     }
 
-    crossterm::execute!(stdout(), EnableBracketedPaste, EnableFocusChange, SetTitle(title))
+    crossterm::execute!(
+        stdout(),
+        EnableBracketedPaste,
+        EnableFocusChange,
+        SetTitle(title),
+        cursor_style
+    )
 }
 
 // Do our best to reverse what we did in setup_tty() when we exit or crash.
@@ -1010,6 +1022,7 @@ fn restore_tty(enable_enhanced_keys: bool, enable_mouse: bool) {
         stdout(),
         DisableBracketedPaste,
         DisableFocusChange,
+        SetCursorStyle::DefaultUserShape,
         LeaveAlternateScreen,
         CursorShow,
     );