#!/bin/bash

# All the prefixes to consider
prefixes=(
	"$HOME"
	"$HOME/.local.`uname -m`"
	"$HOME/.local"
	"$HOME/.prefix.`uname -m`"
	"$HOME/.prefix"
	"$HOME"/.gem/ruby/*
)

######################################################################

in_array() {
	local needle=$1; shift
	local haystack=("$@")
	local straw
	for straw in "${haystack[@]}"; do
		[[ "$needle" == "$straw" ]] && return 0
	done
	return 1
}

# Import existing values
IFS=: paths=($PATH)
IFS=: manpaths=($MANPATH)
IFS=: rubylibs=($RUBYLIB)
IFS=: perl5libs=($PERL5LIB)

# Scan through prefixes
for prefix in "${prefixes[@]}"; do
	# PATH
	for dir in "$prefix/bin" "$prefix/sbin"; do
		if [[ -d "$dir" ]] && ! in_array "$dir" "${paths[@]}"; then
			paths=("$dir" "${paths[@]}")
		fi
	done
	# MANPATH
	dir="$prefix/share/man"
	if [[ -d "$dir" ]] && ! in_array "$dir" "${manpaths[@]}"; then
		manpaths=("$dir" "${manpaths[@]}")
	fi
	# RUBYLIB
	dir="$prefix/lib"
	if [[ -d "$dir" ]] && ! in_array "$dir" "${rubylibs[@]}"; then
		rubylibs=("$dir" "${rubylibs[@]}")
	fi
	# PERL5LIB
	for dir in "$prefix"/lib*/perl5; do
		if [[ -d "$dir" ]] && in_array "$dir" "${manpaths[@]}"; then
			perl5libs=("$dir" "${perl5libs[@]}")
		fi
	done
done

# Finally, print our values
IFS=: PATH="${paths[*]}"
IFS=: MANPATH="${manpaths[*]}"
IFS=: RUBYLIB="${rubylibs[*]}"
IFS=: PERL5LIB="${perl5libs[*]}"

# The sed bit here is the only time we call an external program
{
	declare -p PATH
	declare -p MANPATH
	declare -p RUBYLIB
	declare -p PERL5LIB
} | sed 's/^declare \(-\S* \)*//'