Simplify helpers under line cap

lib/common.sh

@@ -83,19 +83,20 @@ repeat_char() {
 }
 
 term_width() {
-  if [[ -n ${COLUMNS:-} ]]; then
-    printf '%s\n' "${COLUMNS}"
-    return
-  fi
-  if command_is_available tput; then
-    tput cols 2>/dev/null && return
-  fi
+  [[ -n ${COLUMNS:-} ]] && { printf '%s\n' "${COLUMNS}"; return; }
+  command_is_available tput && tput cols 2>/dev/null && return
   printf '80\n'
 }
 
 use_box_ui() {
-  [[ ${IPF_FORCE_PLAIN_UI} != 1 ]] || return 1
-  [[ $(term_width) -ge 60 ]]
+  [[ ${IPF_FORCE_PLAIN_UI} != 1 && $(term_width) -ge 60 ]]
+}
+
+box_width() {
+  local width
+  width=$(term_width)
+  (( width > 78 )) && width=78
+  printf '%s\n' "${width}"
 }
 
 pad_right() {
@@ -111,20 +112,14 @@ pad_right() {
   printf '%s%*s' "${text}" "${padding}" ''
 }
 
-box_top() {
-  local width=${1:-60}
-  printf '╔%s╗\n' "$(repeat_char '═' "$((width - 2))")"
+box_border() {
+  local left=$1 right=$2 width=${3:-60}
+  printf '%s%s%s\n' "${left}" "$(repeat_char '═' "$((width - 2))")" "${right}"
 }
 
-box_bottom() {
-  local width=${1:-60}
-  printf '╚%s╝\n' "$(repeat_char '═' "$((width - 2))")"
-}
-
-box_separator() {
-  local width=${1:-60}
-  printf '╠%s╣\n' "$(repeat_char '═' "$((width - 2))")"
-}
+box_top() { box_border '╔' '╗' "${1:-60}"; }
+box_bottom() { box_border '╚' '╝' "${1:-60}"; }
+box_separator() { box_border '╠' '╣' "${1:-60}"; }
 
 box_line() {
   local width=${1:-60}
@@ -134,19 +129,15 @@ box_line() {
 }
 
 print_section() {
-  local title=${1-}
+  local title=${1-} width
   if use_box_ui; then
-    local width
-    width=$(term_width)
-    if (( width > 78 )); then
-      width=78
-    fi
+    width=$(box_width)
     box_top "${width}"
     box_line "${width}" "${title}"
     box_bottom "${width}"
-  else
-    printf '== %s ==\n' "${title}"
+    return
   fi
+  printf '== %s ==\n' "${title}"
 }
 
 read_test_input() {
@@ -181,7 +172,7 @@ prompt_input() {
 
   if [[ -n ${default_value} ]]; then
     read -r -p "${prompt} [${default_value}]: " reply
-    reply=${reply:-${default_value}}
+    [[ -n ${reply} ]] || reply=${default_value}
   else
     read -r -p "${prompt}: " reply
   fi
@@ -338,17 +329,11 @@ validate_port() {
 }
 
 validate_proto() {
-  case ${1-} in
-    tcp|udp|both) return 0 ;;
-    *) return 1 ;;
-  esac
+  [[ ${1-} =~ ^(tcp|udp|both)$ ]]
 }
 
 validate_ipver() {
-  case ${1-} in
-    4|6|both) return 0 ;;
-    *) return 1 ;;
-  esac
+  [[ ${1-} =~ ^(4|6|both)$ ]]
 }
 
 require_root() {