# vim:filetype=sh
# .bashrc for fancy prompt

# max length of cwd
_wdlen=36

## colors
_RESET=`echo -ne '\033[0m'`
_RED=`echo -ne '\033[0;31m'`
_GREEN=`echo -ne '\033[0;32m'`
_YELLOW=`echo -ne '\033[0;33m'`
_BLUE=`echo -ne '\033[0;34m'`
_MAGENTA=`echo -ne '\033[0;35m'`
_CYAN=`echo -ne '\033[0;36m'`
_GRAY=`echo -ne '\033[0;37m'`

## username and hostname colors depend on their values
_HCDEF="$_BLUE"

host2color()
{
	local colors sum
	colors=("$_RESET" "$_BLUE" "$_MAGENTA" "$_CYAN")
	sum=$(echo -n "$HOSTNAME" | sum)
	sum="${sum:0:1}"
	_HCDEF=${colors[sum % ${#colors[*]}]}
}

host2color
unset host2color

## user
if [ $UID -eq 0 ]; then
	_c_u="$_RED"
else
	_c_u="$_GREEN"
fi

## optimize access to load
if [ -r /proc/loadavg ]; then
	_get_loadavg() {
		_loadavg=$(< /proc/loadavg)
		_loadavg="${_loadavg%%[, ]*}"
	}
else
	_get_loadavg_fresh=0
	_get_loadavg() {
		if [ $_get_loadavg_fresh -lt $SECONDS ]; then
			_loadavg=$(trap "" SIGTSTP; uptime)
			_loadavg="${_loadavg##*: }"
			_loadavg="${_loadavg%%[, ]*}"
			_get_loadavg_fresh=$((SECONDS+5))
			_get_loadavg_save=$_loadavg
		else
			_loadavg=$_get_loadavg_save
		fi
	}
fi

## prompt (xterm/screen/... title and PS1)
_prompt() {
	## must store $? first, it will get changed
	local _r=$? _wdlb _wdla _jobs_ids

	## success/failure
	if [ $_r -eq 0 ]; then
		_c_p="$_GREEN"
	elif [ $_r -eq 127 ]; then
		_c_p="$_BLUE"
	else
		_c_p="$_RED"
	fi

	## misc info
	_jobs_ids=( $(jobs -p) )
	_jobs=${#_jobs_ids[*]}
	_get_loadavg

	## pwd
	_wd="${PWD/#$HOME/~}"
	if [ "${#_wd}" -gt $_wdlen ]; then
		_wdp="${_wd%/*/*}"
		_wd="${_wd/#$_wdp\/}"
		_wdm=" .. "

		let _wdlb=_wdlen/3 _wdla=_wdlen-_wdlb
		if [ "${#_wd}" -gt $_wdla ]; then
			_wd="${_wd:${#_wd}-_wdla}"
		else
			let _wdlb+="_wdla-${#_wd}"
		fi

		if [ "${#_wdp}" -gt $_wdlb ]; then
			_wdp="${_wdp:0:_wdlb}"
		fi
	else
		_wdp=""
		_wdm=""
	fi

	## title string
	_promptstr="$_loadavg/$_jobs/${USER}@${HOSTNAME%%.*}:${PWD/#$HOME/~}"

	## add window information from screen
	if [ -n "$WINDOW" ]; then
		_promptstr="$WINDOW $_promptstr"
	fi

	## hostname color from loadavg
	let _loadavg="10#${_loadavg//.}"
	if [ $_loadavg -ge 150 ]; then
		_c_h="$_RED"
	elif [ $_loadavg -gt 75 ]; then
		_c_h="$_YELLOW"
	else
		_c_h="$_HCDEF"
	fi

	## jobs (empty if no job)
	if [ $_jobs -gt 0 ]; then
		_c_j="$_RED"
		_jobs="$_jobs "
	else
		_c_j="$_RESET"
		_jobs=""
	fi
	return $_r
}

_prompt_xterm-color() {
	echo -ne "\033]0;$_promptstr\007"
}

_prompt_xterm() {
	echo -ne "\033]0;$_promptstr\007"
}

_prompt_screen() {
	echo -ne "\033_$_promptstr\033\\"
}

PROMPT_COMMAND="_prompt"
if type -t _prompt_$TERM > /dev/null; then
	PROMPT_COMMAND="$PROMPT_COMMAND; _prompt_$TERM"
fi

if type -t _prompt_$SCREENTERM > /dev/null; then
	PROMPT_COMMAND="$PROMPT_COMMAND; _prompt_$SCREENTERM"
fi

PS1='\[$_c_u\]\u\[$_RESET\] \[$_c_h\]\h\[$_RESET\] \[$_RESET\]$_wdp\[$_GRAY\]$_wdm\[$_RESET\]$_wd\[$_RESET\] \[$_c_j\]$_jobs\[$_c_p\]\$\[$_RESET\] '