.bash_prompt

#!/usr/bin/env bash
# assume terminal supports ANSI esc-codes

last_exit() {
	local e=$?
	# inlining args breaks the prompt
	[ $e -ne 0 ] && printf "${1:-}%02x${2:-}" $e
	return $e
}

# bold; red exit; magenta jobs; blue WD to match `ls`
PS1='\n\[\e[1m\]${ last_exit "\[\e[31m\]" "\[\e[0;1m\] "; }${ [ \j -gt 0 ] && echo "\[\e[35m\]\j\[\e[0;1m\] "; }\[\e[34m\]\w\[\e[0;1m\]'

if command -v git >/dev/null; then
	# ⚡ fast O(1) commit-ish
	g_c_name() {
		# WARN: undocumented behavior!
		# exit-code is assumed to be 0, even in `.git/` (bare or not).
		git rev-parse --is-inside-work-tree &>/dev/null || return
		echo " ${1:-}${
			git symbolic-ref --quiet --no-recurse --short HEAD 2>/dev/null || \
			git describe --all --exact-match HEAD 2>/dev/null || \
			git rev-parse --short HEAD 2>/dev/null || \
			echo '?'
		}${2:-}"
	}
	# yellow, because Git is orange, and it complements blue
	PS1+='${ g_c_name "\[\e[33m\]" "\[\e[0;1m\]"; }'
fi

PS1+='\n\[\e[1m\]Δ \[\e[0m\]'
# terminals struggle styling across lines:
# https://github.com/mathiasbynens/dotfiles/issues/930