Refactor theme_vim to follow template layout

theme_vim

@@ -1,73 +1,43 @@
 #!/usr/bin/env bash
 readonly dependency=("chriskempson/base16-vim")
+readonly app="vim"
 
-path="$1"
+readonly path="$1"
-package="$2"
+readonly package="$2"
-theme="$3"
+readonly theme="$3"
-permanent="$4"
+readonly permanent="$4"
 
-file_exists() {
+## Main Entrypoint
-  if [[ -f "$1" ]]; then
+#
-    true
+#  Finds the right theme template file and starts theme
-  else
+#  switching and, if necessary, permanent setting processes.
-    false
+main() {
-  fi
+  dbg_msg $app "Starting Processor"
-}
-# check for existence of pattern $2 in file $1
-line_exists() {
-  local file="$1"
-  local line="$2"
-
-  if ! file_exists "$file" || ! grep -qe "$line" "$file"; then
-    false
-  else
-    true
-  fi
-}
-# prepare newline at eof to make adding newlines easier
-eol_exists_or_append() {
-  local file="$1"
-  local eof
-  eof=$(tail -c 1 "$file")
-
-  if [ -n "$eof" ]; then
-    printf "\\n" >>"$file"
-  fi
-}
-# append line $2 to file $1
-line_exists_or_append() {
-  local file="$1"
-  local line="$2"
-  local new="${3:-$2}"
-
-  if ! line_exists "$file" "$line"; then
-    eol_exists_or_append "$file"
-    echo "$new" >>"$file"
-  fi
-}
-
-theme_vim() {
-  dbg_msg="VIM: $package - "
   tfile="$path/$package/colors/base16-$theme.vim"
 
-  check_tfile
-
-  if [[ "$permanent" == "true" ]]; then set_vim_theme; fi
-  recolor_vim_w_tmux
-
-  [[ "$DEBUG" == true ]] && echo "$dbg_msg"
-}
-
-check_tfile() {
   if ! file_exists "$tfile"; then
-    dbg_msg="$dbg_msg theme $theme for vim not found.\n"
+    dbg_msg $app "error" "Theme template $theme not found in package $package"
     exit 1
   fi
+
+  if [[ "$permanent" == "true" ]]; then save; fi
+  theme
+
+  dbg_msg $app "Processor Done"
 }
 
-recolor_vim_w_tmux() {
+## Theme switcher
+#
+#  Makes sure that if any application instance is
+#  currently running, it switches to new theme.
+theme() {
+  dbg_msg $app "Switching theme"
   # this whole thing only works when tmux is running
-  pgrep tmux >/dev/null || return
+
+  pgrep tmux >/dev/null || {
+    dbg_msg $app "warn" "No instance of tmux running, can not dynamically re-theme vim"
+    return
+  }
 
   while read -r l; do
     # we need to close panels that are in a mode and get them out to send keys to vim
@@ -79,37 +49,64 @@ recolor_vim_w_tmux() {
 
     # find all panes which currently have nvim/vim running
   done < <(tmux list-panes -a -F '#D:#T:#{pane_current_command}:#{pane_in_mode}' | grep ':VIM:\|:nvim:')
+
+  dbg_msg $app "Successfully switched theme"
 }
 
-set_vim_theme() {
+## Theme setter
+#
+#  Takes care of permanently writing the desired
+#  base16 theme into application settings.
+save() {
+  dbg_msg $app "Saving theme"
   local vim_dirs="${XDG_CONFIG_HOME:-/$HOME/.config}/nvim $HOME/.vim"
 
   for vim_dir in $vim_dirs; do
     if [[ -d "$vim_dir" ]]; then
       cat "$tfile" >"$vim_dir/colorscheme.vim"
       echo "colorscheme base16-$theme" >>"$vim_dir/colorscheme.vim"
+      dbg_msg $app "Saved theme to $vim_dir/colorscheme.vim"
 
-      call_from_vim_init "$vim_dir"
+      include "$vim_dir"
-
+    else
-      dbg_msg="$dbg_msg Set theme $theme\n"
+      dbg_msg $app "warn" "No configuration directory found"
     fi
   done
 }
 
-# make sure we're calling our new colorscheme whenever starting vim
+## Theme includer
-call_from_vim_init() {
+#
+#  Makes sure that theme is actually included in
+#  default application startup routine.
+#  This is the most invasive step of theming since it
+#  rewrites within existing configuration files.
+include() {
   local vim_dir="$1"
+  dbg_msg $app "Including theme in configuration"
 
   if file_exists "$vim_dir/init.vim"; then
     line_exists_or_append "$vim_dir/init.vim" "runtime colorscheme.vim"
+    dbg_msg $app "Successfully included theme in configuration"
   elif file_exists "$HOME/.vimrc"; then
     line_exists_or_append "$HOME/.vimrc" "runtime colorscheme.vim"
+    dbg_msg $app "Successfully included theme in configuration"
+  else
+    dbg_msg $app "warn" "No default configuration file found"
   fi
 }
 
-# Check deps
+## Dependency Checker
+#
+#  Makes sure the processor is called for the correct
+#  base16 package, or refuses to run if it is not.
 if printf '%s\n' "${dependency[@]}" | grep -q -P "^$package$"; then
-  theme_vim
+  # Safe sourcing: https://stackoverflow.com/a/12694189
+  DIR="${BASH_SOURCE%/*}"
+  if [[ ! -d "$DIR" ]]; then DIR="$PWD"; fi
+  # shellcheck source=utilities.sh
+  . "$DIR/utilities.sh"
+
+  main
 else
-  printf "Processor does not work for %s, please use another." "$package"
+  dbg_msg $app "error" "Processor does not work for package $package"
 fi