optimize prompt divider and git alignment calculations

Refactor the draw_prompt_divider function for improved performance
by reducing subshells and using faster timestamp retrieval. Update
the calculate_git_alignment function to cache static values and
simplify branch name extraction for better efficiency.

bashrc

@@ -125,52 +125,40 @@ function show_date() {
 
 export HISTCONTROL=ignoreboth:erasedups
 
-# Function to draw a terminal-width divider line with timestamp
+# Optimized divider function - reduced subshells and calculations
 function draw_prompt_divider() {
-  local width=${COLUMNS:-80}  # Use terminal width, fallback to 80
-  local timestamp=$(date '+%H:%M:%S')
+  local timestamp prefix_length line_length i
+  printf -v timestamp '%(%H:%M:%S)T' -1  # Faster than $(date)
   local prefix="$timestamp ├"
-  local prefix_length=${#prefix}
-  local line_length=$((width - prefix_length))
+  prefix_length=${#prefix}
+  line_length=$(( ${COLUMNS:-80} - prefix_length ))
   
-  # Print timestamp + junction + line to fill remaining width
+  # Print prefix then fill with box-drawing characters
   printf '%s' "$prefix"
-  printf '%.0s─' $(seq 1 $line_length)
+  for ((i=0; i<line_length; i++)); do printf '─'; done
   echo
 }
 
-# Function to calculate git status alignment based on hostname and branch lengths
+# Cache static values that don't change during session
+_CACHED_USER_HOST="$USER@$HOSTNAME"
+_CACHED_USER_HOST_LENGTH=${#_CACHED_USER_HOST}
+
+# Optimized git alignment calculation
 function calculate_git_alignment() {
-  # Get the raw hostname length (without color codes) - use actual prompt format
-  local user_host="$USER@$HOSTNAME"
-  local hostname_only="$HOSTNAME"  # Just the hostname part after @
-  local hostname_length=${#hostname_only}
+  # Only calculate if git status exists
+  [[ -z "$GITSTATUS_PROMPT" ]] && { GIT_ALIGNMENT_PADDING=""; return; }
   
-  # Extract branch name from GITSTATUS_PROMPT if it exists
-  local branch_name=""
-  if [[ -n "$GITSTATUS_PROMPT" ]]; then
-    # Remove all escape sequences: \001, \002, and ANSI color codes
-    local cleaned_prompt=$(echo "$GITSTATUS_PROMPT" | sed -e 's/\x01//g' -e 's/\x02//g' -e 's/\x1b\[[0-9;]*m//g')
-    
-    # Extract first word as branch name and trim any whitespace
-    branch_name=$(echo "$cleaned_prompt" | awk '{print $1}' | tr -d '[:space:]')
-  fi
+  # Fast branch name extraction using bash parameter expansion
+  local cleaned="${GITSTATUS_PROMPT//[$'\001\002']/}"  # Remove \001 \002
+  cleaned="${cleaned//$'\e['[0-9\;]*m/}"               # Remove ANSI codes
+  local branch_name="${cleaned%% *}"                   # Get first word (branch)
   
-  local branch_length=${#branch_name}
+  # Calculate padding (cache the static hostname length)
+  local needed_padding=$((_CACHED_USER_HOST_LENGTH - ${#branch_name}))
+  [[ $needed_padding -lt 8 ]] && needed_padding=8
   
-  # Calculate padding to align the END of branch name with END of hostname
-  # We want: [padding spaces] + branch_name to end at same position as hostname
-  # Total user@hostname length is where we want to align to
-  local total_user_host_length=${#user_host}  # "ray@MachineOne" = 14 chars
-  local needed_padding=$((total_user_host_length - branch_length))
-  
-  # Ensure minimum indentation of 8 spaces even if branch is very long
-  if [[ $needed_padding -lt 8 ]]; then
-    needed_padding=8
-  fi
-  
-  # Generate the padding string
-  GIT_ALIGNMENT_PADDING=$(printf '%*s' $needed_padding '')
+  # Use printf once to generate padding
+  printf -v GIT_ALIGNMENT_PADDING '%*s' $needed_padding ''
 }
 
 # Load custom gitstatus configuration