From b4adff248faf82f7a174d4bada2296a536fcacb3 Mon Sep 17 00:00:00 2001
From: Christopher Bayliss <cjbdev@icloud.com>
Date: Thu, 16 May 2024 08:20:05 +1000
Subject: [PATCH] avoid cnorm on certain terminals

using a terminfo's cnorm doesn't reset the cursor for many terminals,
see issue: #10089
---
 helix-tui/src/backend/crossterm.rs | 32 +++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/helix-tui/src/backend/crossterm.rs b/helix-tui/src/backend/crossterm.rs
index c5c95bff0b838..38fb0ea63a1df 100644
--- a/helix-tui/src/backend/crossterm.rs
+++ b/helix-tui/src/backend/crossterm.rs
@@ -23,13 +23,38 @@ use std::{
     fmt,
     io::{self, Write},
 };
+use termini::TermInfo;
 
 fn term_program() -> Option<String> {
-    std::env::var("TERM_PROGRAM").ok()
+    // Some terminals don't set $TERM_PROGRAM
+    match std::env::var("TERM_PROGRAM") {
+        Err(_) => std::env::var("TERM").ok(),
+        Ok(term_program) => Some(term_program),
+    }
 }
 fn vte_version() -> Option<usize> {
     std::env::var("VTE_VERSION").ok()?.parse().ok()
 }
+fn reset_cursor_approach(terminfo: TermInfo) -> String {
+    let Some(termini::Value::Utf8String(se_str)) = terminfo.extended_cap("Se") else {
+        return "".to_string();
+    };
+
+    // check for terminals that misinterpret Se
+    let se_str = match term_program().as_deref() {
+        Some("tmux") => "",
+        _ => se_str,
+    };
+
+    format!(
+        "{}{}{}",
+        "\x1B[0 q",
+        se_str,
+        terminfo
+            .utf8_string_cap(termini::StringCapability::CursorNormal)
+            .unwrap()
+    )
+}
 
 /// Describes terminal capabilities like extended underline, truecolor, etc.
 #[derive(Clone, Debug)]
@@ -69,10 +94,7 @@ impl Capabilities {
                     || t.extended_cap("Su").is_some()
                     || vte_version() >= Some(5102)
                     || matches!(term_program().as_deref(), Some("WezTerm")),
-                reset_cursor_command: t
-                    .utf8_string_cap(termini::StringCapability::CursorNormal)
-                    .unwrap_or("\x1B[0 q")
-                    .to_string(),
+                reset_cursor_command: reset_cursor_approach(t),
             },
         }
     }