[tmux] Add remote session nesting

If calling a tmux session within a tmux session, pressing F12 will
toggle between sending commands to the outer or inner session. If the
outer session is inactive its status-bar will be slightly greyed out to
show that no commands will reach it. If the inner session is a remote
ssh session, it will set some additional stylings for the status-bar to
further differentiate the two.

.config/tmux/tmux.conf

@@ -157,3 +157,38 @@ set -g status-left "#[fg=#c8c8c8,bg=#2e2e2e] #S #[fg=#2e2e2e,bg=#2e2e2e,nobold,n
 set -g status-right "#[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]#{prefix_highlight} #[fg=#c8c8c8,bg=#2e2e2e]  %H:%M:%S #[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]#[fg=#c8c8c8,bg=#2e2e2e] %d-%b-%y #[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]#[fg=#c8c8c8,bg=#2e2e2e] #H "
 setw -g window-status-format "#[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]#[default] #I #W #[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]"
 setw -g window-status-current-format "#[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]#[fg=#c8c8c8,bg=#2e2e2e]    #I #W #[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]"
+
+########################
+## 5. Nested Sessions ##
+########################
+# from: https://github.com/samoshkin/tmux-config/blob/master/tmux/tmux.conf
+# all credit to samoshkin
+
+# Session is considered to be remote when we ssh into host
+if-shell 'test -n "$SSH_CLIENT"' \
+    'source-file $XDG_CONFIG_HOME/tmux/tmux.remote.conf'
+
+# We want to have single prefix key "C-a", usable both for local and remote session
+# we don't want to "C-a" + "a" approach either
+# Idea is to turn off all key bindings and prefix handling on local session,
+# so that all keystrokes are passed to inner/remote session
+
+# see: toggle on/off all keybindings · Issue #237 · tmux/tmux - https://github.com/tmux/tmux/issues/237
+
+# Also, change some visual styles when window keys are off
+bind -T root F12  \
+    set prefix None \;\
+    set key-table off \;\
+    set status-style fg="colour245",bg="colour238" \;\
+    set window-status-current-format "#[fg=$color_window_off_status_bg,bg=$color_window_off_status_current_bg]$separator_powerline_right#[default] #I:#W# #[fg=$color_window_off_status_current_bg,bg=$color_window_off_status_bg]$separator_powerline_right#[default]" \;\
+    set window-status-current-style fg="colour232",bg="colour254","bold" \;\
+    if -F '#{pane_in_mode}' 'send-keys -X cancel' \;\
+    refresh-client -S \;\
+
+bind -T off F12 \
+  set -u prefix \;\
+  set -u key-table \;\
+  set -u status-style \;\
+  set -u window-status-current-style \;\
+  set -u window-status-current-format \;\
+  refresh-client -S

.config/tmux/tmux.remote.conf

@@ -0,0 +1,10 @@
+# show status bar at bottom for remote session,
+set -g status-position bottom
+
+# Set port of SSH remote tunnel, where tmux will pipe buffers to transfer on local machine for copy
+set -g @copy_backend_remote_tunnel_port 11988
+
+# In remote mode we don't show "clock" and "battery status" widgets
+set -g status-left "#[fg=#c8c8c8,bg=#2e2e2e][SSH]#S #[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]#[fg=#c8c8c8,bg=#2e2e2e] #(whoami) #[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]#[fg=#c8c8c8,bg=#2e2e2e] #I:#P #[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]"
+set -g status-right "#{prefix_highlight} $wg_is_keys_off $wg_is_zoomed #{sysstat_cpu} | #{sysstat_mem} | #{sysstat_loadavg} | $wg_user_host | #{online_status}"
+set -g status-right "#[fg=#2e2e2e,bg=#2e2e2e,nobold,nounderscore,noitalics]#{prefix_highlight} #H "

.local/bin/test/tm.bats

@@ -0,0 +1,39 @@
+setup() {
+  fut="$BATS_TEST_DIRNAME/../tm"
+}
+
+teardown() {
+  rm -rf $BATS_TMPDIR/xdg/*
+}
+
+@test "runs correctly if invoked without arguments" {
+  run $fut
+  echo "$BATS_TEST_DIRNAME/../tm"
+  [ "$status" -eq 0 ]
+}
+
+@test "Errors out if passed a non-existent session file (and some session name)" {
+  run $fut IDONT_EXIST_HERE.session sessionname
+  echo "STATUS: $output"
+  [ "$status" -eq 1 ]
+  echo "OUTPUT: $output"
+  [ "$output" = "can not source session file: 'IDONT_EXIST_HERE.session' does not exist." ]
+}
+
+@test "Runs without errors when session file exists in PWD" {
+  touch $PWD/exists.session
+  run $fut exists.session sessionname
+  rm $PWD/exists.session
+
+  [ "$status" -eq 0 ]
+}
+
+@test "Runs without errors when session file exists in XDG_CONFIG_HOME/tmux/sessions/" {
+  export XDG_CONFIG_HOME=$BATS_TMPDIR
+  mkdir -p $XDG_CONFIG_HOME/tmux/sessions
+  sesdir=$XDG_CONFIG_HOME/tmux/sessions
+  touch $sesdir/exists.session
+  run $fut exists.session sessionname
+
+  [ "$status" -eq 0 ]
+}

.local/bin/tm

@@ -92,7 +92,7 @@ _set_session_vars() {
   # set up session name and config file - if passed in as arguments
   if [ "$#" -eq 2 ]; then
     if ! _file_exists "$1" && ! _file_exists "${session_dir}${1}"; then
-      echo "$0: can not source configuration file: '${1}' does not exist."
+      echo >&2 "can not source session file: '${1}' does not exist."
       exit 1
     fi
     _set_session_file_path "$1"