#!/bin/sh
set -eu

die() {
	echo "$@" >&2
	exit 1
}

script=$0
path=${script%/*}
prefix=${path%/bin}
exman="${prefix}/share/exman"
[ -d "${exman}" ] || exman=$prefix

system=${1:-}
[ -n "${system}" ] || die 'What system do you want?'
shift

export MANPATH="${exman}/${system}"
[ -d "${MANPATH}" ] || die "No manuals for ${system}"

export MANSECT
for sect in "${MANPATH}"/man*/; do
	sect=${sect%/}
	sect=${sect##*/man}
	MANSECT="${MANSECT:-}${MANSECT:+:}${sect}"
done

# macOS man(1) refuses to search in directories such as "man3p", so do it
# manually here unless there are other flags passed.
hack() {
	case "${1:-}" in
		(-*) exec man "$@";;
		([0-9]*) MANSECT=$1; shift;;
	esac
	[ $# -gt 0 ] || die 'What manual page do you want?'
	for page in "$@"; do
		found=0
		IFS=:
		for sect in $MANSECT; do
			path="${MANPATH}/man${sect}/${page}"
			for ext in ".${sect}" ".${sect}.gz"; do
				[ -f "${path}${ext}" ] || continue
				man "${path}${ext}"
				found=1
				break
			done
			[ $found -eq 0 ] || break
		done
		[ $found -ne 0 ] || die "No manual entry for ${page}"
	done
}

if [ "$(uname)" = 'Darwin' ]; then
	hack "$@"
else
	exec man "$@"
fi