refactor: improve validation checks

The validation functions have been changed to be more modular and more
resistant to invalid input. Instead of using printf to redirect error
messages to stderr and using `exit 1`, use the function `_die` which has
been changed as well. A function called `is_installed` was added as well
to check if the needed binaries are present on the system.

1 files changed, 81 insertions, 55 deletions

diff --git a/tessen b/tessen
index ee6b74c..58500ec 100755
--- a/tessen
+++ b/tessen
@@ -44,7 +44,7 @@ get_pass_file() {
   tsn_passfile="$(printf "%s\n" "${tmp_list[@]}" | "$tsn_backend" "$tsn_backend_opts")"
 
   if ! [[ -s "$tsn_prefix/$tsn_passfile".gpg ]]; then
-    exit 1
+    _die
   fi
 }
 
@@ -126,7 +126,7 @@ get_key() {
     fi
   done
   if [[ "$flag" == "false" ]]; then
-    exit 1
+    _die
   fi
 }
 
@@ -223,26 +223,52 @@ print_help() {
   printf '%s\n' "For more details, visit https://github.com/ayushnix/tessen"
 }
 
-validate_backend() {
-  local -a bmn_opt
-
-  if [[ "$tsn_backend" == "bemenu" ]]; then
-    bmn_opt=("-i -l 10 -w --scrollbar=autohide -n")
-    export BEMENU_OPTS="${BEMENU_OPTS:-${bmn_opt[*]}}"
-    readonly tsn_backend="bemenu"
-    readonly tsn_backend_opts=""
-  elif [[ "$tsn_backend" == "rofi" ]]; then
-    readonly tsn_backend="rofi"
-    readonly tsn_backend_opts="-dmenu"
-  elif [[ "$tsn_backend" == "wofi" ]]; then
-    readonly tsn_backend="wofi"
-    readonly tsn_backend_opts="-d"
+is_installed() {
+  if command -v "$1" > /dev/null 2>&1; then
+    return 0
   else
-    printf '%s\n' "Please specify a backend: bemenu|rofi|wofi" >&2
-    exit 1
+    return 1
   fi
 }
 
+set_bemenu() {
+  local -a bmn_opt=("-i -l 10 -w --scrollbar=autohide -n")
+  readonly tsn_backend="bemenu"
+  # use BEMENU_OPTS if set by the user, otherwise use $bmn_opt
+  export BEMENU_OPTS="${BEMENU_OPTS:-${bmn_opt[*]}}"
+  # manually using bemenu options doesn't seem to work
+  readonly tsn_backend_opts=""
+}
+
+set_rofi() {
+  readonly tsn_backend="rofi" tsn_backend_opts="-dmenu"
+}
+
+set_wofi() {
+  readonly tsn_backend="wofi" tsn_backend_opts="-d"
+}
+
+assign_backend() {
+  if is_installed "bemenu"; then
+    set_bemenu
+  elif is_installed "rofi"; then
+    set_rofi
+  elif is_installed "wofi"; then
+    set_wofi
+  else
+    _die "Please install either 'bemenu', 'rofi', or 'wofi' to use ${0##*/}"
+  fi
+}
+
+validate_backend() {
+  case "$1" in
+    bemenu) set_bemenu ;;
+    rofi) set_rofi ;;
+    wofi) set_wofi ;;
+    *) _die "Please specify a valid backend: bemenu | rofi | wofi" ;;
+  esac
+}
+
 validate_cliptime() {
   local clip_regex
 
@@ -251,61 +277,65 @@ validate_cliptime() {
   if [[ "$tsn_cliptime" =~ $clip_regex ]]; then
     return 0
   else
-    printf '%s\n' "invalid clipboard time provided" >&2
-    exit 1
+    _die "Invalid clipboard time provided"
   fi
 }
 
-clean() {
-  {
-    sleep "$tsn_cliptime" || exit 1
-    wl-copy --clear
-  } > /dev/null 2>&1 &
-  disown
-  unset -v tsn_passfile tsn_username tsn_password tsn_passdata
+validate_action() {
+  case "$1" in
+    autotype) readonly tsn_action="autotype" ;;
+    copy) readonly tsn_action="copy" ;;
+    both) readonly tsn_action="both" ;;
+    "") readonly tsn_action="" ;;
+    *) _die "Please specify a valid action: autotype | copy | both" ;;
+  esac
 }
 
-die() {
+_clear() {
   wl-copy --clear
-  unset -v tsn_passfile tsn_username tsn_password tsn_passdata
+  unset -v tsn_passfile tsn_username tsn_password tsn_passdata chosen_key
+}
+
+_die() {
+  if [[ -n "$1" ]]; then
+    printf "%s\n" "$1" >&2
+  fi
+  _clear
+  exit 1
 }
 
 main() {
   local _opt
 
-  # exit if the password store directory doesn't exist
   if ! [[ -d "$tsn_prefix" ]]; then
-    printf '%s\n' "password store not found" >&2
-    exit 1
+    _die "password store directory not found"
   fi
 
-  # parse any options given by the user
   while [[ "$#" -gt 0 ]]; do
     _opt="$1"
     case "$_opt" in
       -b | --backend)
-        [[ "$#" -lt 2 ]] && {
-          printf '%s\n' "Please specify a backend: bemenu|rofi|wofi" >&2
-          exit 1
-        }
-        tsn_backend="$2"
-        validate_backend
+        if [[ "$#" -lt 2 ]] || ! is_installed "$2"; then
+          _die "Please specify a valid backend: bemenu | rofi | wofi"
+        fi
+        validate_backend "$2"
         shift
         ;;
       --backend=*)
-        tsn_backend="${_opt##--backend=}"
-        validate_backend
+        if ! is_installed "${_opt##--backend=}"; then
+          _die "Please specify a valid backend: bemenu | rofi | wofi"
+        fi
+        validate_backend "${_opt##--backend=}"
         ;;
       -a | --action)
-        [[ "$#" -lt 2 ]] && {
-          printf '%s\n' "Please specify a valid option: autotype|copy|both" >&2
-          exit 1
-        }
-        tsn_action="$2"
+        if [[ "$#" -lt 2 ]]; then
+          _die "Please specify a valid action: autotype | copy | both"
+        fi
+        validate_action "$2"
         shift
         ;;
       --action=*)
-        tsn_action="${_opt##--action=}"
+        validate_action "${_opt##--action=}"
         ;;
       -h | --help)
         print_help
@@ -319,23 +349,19 @@ main() {
         shift
         break
         ;;
-      *)
-        printf '%s\n' "invalid argument detected" >&2
-        exit 1
-        ;;
+      *) _die "invalid argument detected" ;;
     esac
     shift
   done
   unset -v _opt
 
-  if unset -v tsn_backend_opts 2> /dev/null; then
-    validate_backend
+  if [[ -z "$tsn_backend" ]]; then
+    assign_backend
   fi
   validate_cliptime
-
   readonly tsn_action
 
-  trap 'die' EXIT TERM
+  trap '_clear' EXIT TERM
   get_pass_file
   get_pass_data
   key_menu