make pygmalion theme use two lines when needed

if the length of the prompt (excluding color escapes) exceeds 40
characters, emit the arrow prompt on its own line

This helps a lot on smaller terminals

themes/pygmalion.zsh-theme

@@ -1,9 +1,34 @@
 # Yay! High voltage and arrows!
 
-ZSH_THEME_GIT_PROMPT_PREFIX="%{$reset_color%}%{$fg[green]%}"
-ZSH_THEME_GIT_PROMPT_SUFFIX="%{$reset_color%} "
-ZSH_THEME_GIT_PROMPT_DIRTY="%{$fg[yellow]%}⚡%{$reset_color%}"
-ZSH_THEME_GIT_PROMPT_CLEAN=""
+prompt_setup_pygmalion(){
+  ZSH_THEME_GIT_PROMPT_PREFIX="%{$reset_color%}%{$fg[green]%}"
+  ZSH_THEME_GIT_PROMPT_SUFFIX="%{$reset_color%} "
+  ZSH_THEME_GIT_PROMPT_DIRTY="%{$fg[yellow]%}⚡%{$reset_color%}"
+  ZSH_THEME_GIT_PROMPT_CLEAN=""
+
+  base_prompt='%{$fg[magenta]%}%n%{$reset_color%}%{$fg[cyan]%}@%{$reset_color%}%{$fg[yellow]%}%m%{$reset_color%}%{$fg[red]%}:%{$reset_color%}%{$fg[cyan]%}%0~%{$reset_color%}%{$fg[red]%}|%{$reset_color%}'
+  post_prompt='%{$fg[cyan]%}⇒%{$reset_color%}  '
+
+  base_prompt_nocolor=$(echo "$base_prompt" | perl -pe "s/%\{[^}]+\}//g")
+  post_prompt_nocolor=$(echo "$post_prompt" | perl -pe "s/%\{[^}]+\}//g")
+
+  add-zsh-hook precmd prompt_pygmalion_precmd
+}
+
+prompt_pygmalion_precmd(){
+  local gitinfo=$(git_prompt_info)
+  local gitinfo_nocolor=$(echo "$gitinfo" | perl -pe "s/%\{[^}]+\}//g")
+  local exp_nocolor=$(print -P "$base_prompt_nocolor$gitinfo_nocolor$post_prompt_nocolor")
+  local prompt_length=${#exp_nocolor}
+
+  local nl=""
+
+  if [[ $prompt_length -gt 40 ]]; then
+    nl=$'\n%{\r%}';
+  fi
+  PROMPT="$base_prompt$gitinfo$nl$post_prompt"
+}
+
+prompt_setup_pygmalion
 
-PROMPT='%{$fg[magenta]%}%n%{$reset_color%}%{$fg[cyan]%}@%{$reset_color%}%{$fg[yellow]%}%m%{$reset_color%}%{$fg[red]%}:%{$reset_color%}%{$fg[cyan]%}%0~%{$reset_color%}%{$fg[red]%}|%{$reset_color%}$(git_prompt_info)%{$fg[cyan]%}⇒%{$reset_color%}  '