## vim:ft=zsh
## wrapper around man, finfo, etc
## Usage: help <topic>
typeset -a methods
typeset method topic
typeset -i found check_only all
methods=(man zshfunction zshbuiltin apt)

while [[ $1 == -* ]] {
	case $1 in
		-a|--all) all=1 ;;
		-c|--check-only) check_only=1 ;;
		-t|--topic) topic=$2; shift ;;
		-|--) shift; break ;;
		*) echo "unknown option: $1" ;;
	esac
	shift
}

function help_check_man      { man -w $1 &> /dev/null }
function help_check_zshfunction { whichf $1 &> /dev/null }
function help_check_zshbuiltin  { (( ${+builtins[$1]} )) }
function help_check_apt {
	[[ $commands[$1] != ${HOME}* ]] && [[ -n $commands[$1] ]] && [[ -n $commands[apt-file ]]
}

function help_show_man       { man $1 }
function help_show_zshfunction  { finfo $1 }
function help_show_zshbuiltin   { man zshbuiltins | less -p "       $1" }
function help_show_apt {
	apt-cache show ${(s/:/)$(apt-file search -F $commands[$1])[1]}
}

if [[ -z $1 ]] {
	echo "Usage: help <command>" > /dev/stderr
	return 1
}

for method in $methods; {
	if [[ -n $topic && $method != $topic ]] {
		continue
	}
	if help_check_$method $1; then
		((found++))
		if ((check_only)) {
			echo $method
			continue
		}
		help_show_$method $1
		((all)) || break
	fi
}

if ((found == 0)) {
	echo "Sorry, no clue." > /dev/stderr
	return 1
}