Fish shell to open in tmux and create new sessions

config/fish/config.fish

@@ -91,6 +91,8 @@ alias myip='curl ipinfo.io/ip; echo ""'
 alias lspmake='bear -- make -B'
 alias services-up='docker compose -f /home/jason/Documents/Compose/local-services/docker-compose.yaml up -d'
 alias services-down='docker compose -f /home/jason/Documents/Compose/local-services/docker-compose.yaml down'
+alias tc='tmux attach'
+alias td='tmux detach'
 
 # ==============================================================================
 # FUNCTIONS
@@ -189,3 +191,31 @@ set -g __fish_git_prompt_char_stagedstate '●'
 set -g __fish_git_prompt_char_untrackedfiles ''
 
 direnv hook fish | source
+
+# Auto-attach to tmux on interactive shell start
+if status is-interactive && not set -q TMUX
+    # Get all session names matching shell, shell-2, shell-3 etc
+    set sessions (tmux list-sessions -F '#S' 2>/dev/null)
+
+    if test (count $sessions) -eq 0
+        tmux new-session -s shell
+    else
+        # Check if any shell session is unattached and attach it
+        set target (tmux list-sessions -F '#{session_name} #{session_attached}' 2>/dev/null \
+            | grep '^shell' | grep ' 0$' | head -1 | awk '{print $1}')
+
+        if test -n "$target"
+            tmux attach -t $target
+        else
+            # All shell sessions attached — find next number
+            set nums 1
+            for s in $sessions
+                if string match -rq '^shell-(\d+)$' $s
+                    set nums $nums (string replace 'shell-' '' $s)
+                end
+            end
+            set next (math (string join \n $nums | sort -n | tail -1) + 1)
+            tmux new-session -s shell-$next
+        end
+    end
+end