feat: `list-sessions` show newest sessions last, for better user experience (#3194)

* feat: sort `list-sessions` from oldest to newest

by putting the most recent sessions last, the user won't need to scroll back up
to see active sessions when there are a lot of resurrectable sessions.

* feat: add an `--reverse` option to the `list-sessions` subcommand

the `--reverse` flag reverts sorting order back to the old "newest sessions
first".  also updated call sites of `list_sessions` and `print_sessions` with
`reverse: true`, to keep the original behavior everywhere else except the output
of `list-sessions` subcommand.

* chore: update the help message

---------

Co-authored-by: Jae-Heon Ji <atx6419@gmail.com>

4 files changed, 21 insertions, 6 deletions

diff --git a/src/commands.rs b/src/commands.rs
index f27f0c550..d37a422a0 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -207,14 +207,14 @@ pub(crate) fn send_action_to_session(
                         "Session '{}' not found. The following sessions are active:",
                         session_name
                     );
-                    list_sessions(false, false);
+                    list_sessions(false, false, true);
                     std::process::exit(1);
                 }
             } else if let Ok(session_name) = envs::get_session_name() {
                 attach_with_cli_client(cli_action, &session_name, config);
             } else {
                 eprintln!("Please specify the session name to send actions to. The following sessions are active:");
-                list_sessions(false, false);
+                list_sessions(false, false, true);
                 std::process::exit(1);
             }
         },
@@ -357,6 +357,7 @@ fn attach_with_session_name(
                         .collect(),
                     false,
                     false,
+                    true,
                 );
                 process::exit(1);
             },
@@ -374,7 +375,7 @@ fn attach_with_session_name(
             ActiveSession::One(session_name) => ClientInfo::Attach(session_name, config_options),
             ActiveSession::Many => {
                 println!("Please specify the session to attach to, either by using the full name or a unique prefix.\nThe following sessions are active:");
-                list_sessions(false, false);
+                list_sessions(false, false, true);
                 process::exit(1);
             },
         },
diff --git a/src/main.rs b/src/main.rs
index 0f0d980b6..eacefc8a7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -167,9 +167,10 @@ fn main() {
     if let Some(Command::Sessions(Sessions::ListSessions {
         no_formatting,
         short,
+        reverse,
     })) = opts.command
     {
-        commands::list_sessions(no_formatting, short);
+        commands::list_sessions(no_formatting, short, reverse);
     } else if let Some(Command::Sessions(Sessions::ListAliases)) = opts.command {
         commands::list_aliases(opts);
     } else if let Some(Command::Sessions(Sessions::KillAllSessions { yes })) = opts.command {
diff --git a/src/sessions.rs b/src/sessions.rs
index 587220715..75e8ddf66 100644
--- a/src/sessions.rs
+++ b/src/sessions.rs
@@ -143,10 +143,18 @@ pub(crate) fn print_sessions(
     mut sessions: Vec<(String, Duration, bool)>,
     no_formatting: bool,
     short: bool,
+    reverse: bool,
 ) {
     // (session_name, timestamp, is_dead)
     let curr_session = envs::get_session_name().unwrap_or_else(|_| "".into());
-    sessions.sort_by(|a, b| a.1.cmp(&b.1));
+    sessions.sort_by(|a, b| {
+        if reverse {
+            // sort by `Duration` ascending (newest would be first)
+            a.1.cmp(&b.1)
+        } else {
+            b.1.cmp(&a.1)
+        }
+    });
     sessions
         .iter()
         .for_each(|(session_name, timestamp, is_dead)| {
@@ -246,7 +254,7 @@ pub(crate) fn delete_session(name: &str, force: bool) {
     }
 }
 
-pub(crate) fn list_sessions(no_formatting: bool, short: bool) {
+pub(crate) fn list_sessions(no_formatting: bool, short: bool, reverse: bool) {
     let exit_code = match get_sessions() {
         Ok(running_sessions) => {
             let resurrectable_sessions = get_resurrectable_sessions();
@@ -270,6 +278,7 @@ pub(crate) fn list_sessions(no_formatting: bool, short: bool) {
                         .collect(),
                     no_formatting,
                     short,
+                    reverse,
                 );
                 0
             }
diff --git a/zellij-utils/src/cli.rs b/zellij-utils/src/cli.rs
index 3d30bb391..f224b5ef1 100644
--- a/zellij-utils/src/cli.rs
+++ b/zellij-utils/src/cli.rs
@@ -106,6 +106,10 @@ pub enum Sessions {
         /// Print just the session name
         #[clap(short, long, value_parser, takes_value(false), default_value("false"))]
         short: bool,
+
+        /// List the sessions in reverse order (default is ascending order)
+        #[clap(short, long, value_parser, takes_value(false), default_value("false"))]
+        reverse: bool,
     },
     /// List existing plugin aliases
     #[clap(visible_alias = "la")]