refactor: use functions

autotag

@@ -8,95 +8,125 @@
 # https://github.com/MichaelCurrin/auto-tag/blob/master/LICENSE
 
 FALLBACK_TAG='v0.0.0'
-
 USAGE='USAGE:
     autotag LEVEL [-p] [-h]
 '
-HELP='HELP:
+HELP="HELP:
     Increment git tag using given increment level.
 
     Positional arguments:
-        LEVEL       : 'M' for major, 'm' for minor or 'b' for bug.
+        LEVEL        : 'M' for major, 'm' for minor or 'b' for bug.
 
     Flags:
-        -h --help   : Show help and exit.
-        -p --preview: Do a dry run to show the new tag label only, without creating it.
-'
-
-if [[ "$#" -eq 0 ]] || [[ "$1" == '-h' ]] || [[ "$1" == '--help' ]]; then
-  echo "$USAGE"
-  echo "$HELP"
-  exit 1
-fi
-
-LEVEL_CHOICE="$1"
-
-if [[ "$2" ]]; then
-  if [[ "$2" == '-p' ]] || [[ "$2" == '--preview' ]]; then
-    PREVIEW='true'
-  else
-    echo "🛑 Invalid arguments: \"$*\""
-    echo
+        -h --help    : Show help and exit.
+        -p --preview : Do a dry run to show the new tag label only, without creating it.
+"
+USER_ARGS="$*"
+
+# Dynamic variables. Unfortunately all are global but at least there are functions now so the script
+# is easier to work with. Also they don't have to be set here even, but are set for clarity.
+LEVEL_CHOICE=''
+PREVIEW=''
+MAJOR=''
+MINOR=''
+BUG=''
+
+need_help() {
+  if [[ "$#" -eq 0 ]] || [[ "$1" == '-h' ]] || [[ "$1" == '--help' ]]; then
     echo "$USAGE"
     echo "$HELP"
     exit 1
   fi
-else
-  PREVIEW='false'
-fi
-
-echo '🚛 Fetching tags...'
-
-git fetch --tags
-
-echo '🔍 Finding most recent tag...'
-
-LAST_TAG=$(git describe --abbrev=0 --tags 2>/dev/null)
-LAST_TAG="${LAST_TAG:-$FALLBACK_TAG}"
-LAST_TAG="${LAST_TAG/v/}"
-
-# Replace dot with space then split into array.
-LAST_TAG_ARR=(${LAST_TAG//./ })
-
-MAJOR="${LAST_TAG_ARR[0]}"
-MINOR="${LAST_TAG_ARR[1]}"
-BUG="${LAST_TAG_ARR[2]}"
-
-echo "👴 Last tag: v$MAJOR.$MINOR.$BUG"
-
-# Although the exit only happens after fetching, this needs to happen here so variables are set.
-# Otherwise a refactor is needed to check M|m|b and exit if needed, then actually calculate here.
-case "$LEVEL_CHOICE" in
-"M")
-  ((MAJOR += 1))
-  MINOR=0
-  BUG=0
-  ;;
-"m")
-  ((MINOR += 1))
-  BUG=0
-  ;;
-"b")
-  ((BUG += 1))
-  ;;
-*)
-  echo "🛑 Invalid arguments: '$*'"
+}
+
+invalid_args_error() {
+  echo "🛑 Invalid arguments: '$USER_ARGS'"
   echo
   echo "$USAGE"
   exit 1
-  ;;
-esac
-
-NEW_TAG="v$MAJOR.$MINOR.$BUG"
-echo "⭐ New tag: $NEW_TAG"
-
-# For some reason these emojis need a double space after to avoid looking squashed, at least on
-# macOS.
-if [[ "$PREVIEW" == true ]]; then
-  echo '⏭️  Skipping tag creation'
-else
-  echo '🏷️  Creating annotated tag...'
+}
+
+process_args() {
+  LEVEL_CHOICE="$1"
+
+  if [[ "$2" ]]; then
+    if [[ "$2" == '-p' ]] || [[ "$2" == '--preview' ]]; then
+      PREVIEW='true'
+    else
+      invalid_args_error
+    fi
+  else
+    PREVIEW='false'
+  fi
+}
+
+get_last_tag() {
+  LAST_TAG=$(git describe --abbrev=0 --tags 2>/dev/null)
+  LAST_TAG="${LAST_TAG:-$FALLBACK_TAG}"
+  LAST_TAG="${LAST_TAG/v/}"
+
+  # Replace dot with space then split into array.
+  LAST_TAG_ARR=(${LAST_TAG//./ })
+
+  MAJOR="${LAST_TAG_ARR[0]}"
+  MINOR="${LAST_TAG_ARR[1]}"
+  BUG="${LAST_TAG_ARR[2]}"
+}
+
+set_level() {
+  # Although the exit only happens after fetching, this needs to happen here so variables are set.
+  # Otherwise a refactor is needed to check M|m|b and exit if needed, then actually calculate here.
+  case "$LEVEL_CHOICE" in
+  "M")
+    ((MAJOR += 1))
+    MINOR=0
+    BUG=0
+    ;;
+  "m")
+    ((MINOR += 1))
+    BUG=0
+    ;;
+  "b")
+    ((BUG += 1))
+    ;;
+  *)
+    invalid_args_error
+    ;;
+  esac
+}
+
+make_tag() {
   git tag \
     -a "$NEW_TAG" \
     -m "$NEW_TAG"
-fi
+}
+
+run() {
+  echo '🚛 Fetching tags...'
+  git fetch --tags
+
+  echo '🔍 Finding most recent tag...'
+  get_last_tag
+  echo "👴 Last tag: v$MAJOR.$MINOR.$BUG"
+
+  set_level
+  NEW_TAG="v$MAJOR.$MINOR.$BUG"
+  echo "⭐ New tag: $NEW_TAG"
+
+  # For some reason these emojis need a double space after to avoid looking squashed, at least on
+  # macOS.
+  if [[ "$PREVIEW" == true ]]; then
+    echo '⏭️  Skipping tag creation'
+  else
+    echo '🏷️  Creating annotated tag...'
+    make_tag
+  fi
+}
+
+main() {
+  need_help $@
+  process_args $@
+  run
+}
+
+main $@