#!/usr/bin/env bash
# vim:ts=4

# This is just a replacement - for quite a while, while already abandoning aptitude, I still kept
# aptitude installed just for typing "aptitude why $package". This script just does this.

# Converting because we need ${ARGARR[*]}
ARGARR=( "$@" )

MYERR="\\033[1;31mE:\\033[0m"

function myhelp {
	printf "USAGE: %b ( why PACKAGE [PACKAGE ..] | help )\\n\\n" "$(basename "$0")"
	(
		printf "why:;Lists the recursive depends of a package, i.e. why it is installed.\\n"
		printf " ;Wrapper to 'apt[-cache] rdepends --installed PACKAGE'\\n"
		printf "help:;This help"
	)|column -ts\;
	printf "\\n"
}
if [ -z "$1" ];then
	printf "%b No parameter supplied.\\n" "$MYERR" >&2
	exit 10
fi

case "$1" in
	help|"-h"|"--help")
		myhelp
		exit 0
	;;
	why)
		if [ -z "$2" ];then
			printf "%b No package name(s) supplied.\\n" "$MYERR" >&2
			exit 12
		fi
		for i in "${@:2}";do
			IFS=$'\n'
			# shellcheck disable=SC2207
			WHYARR=( $(apt rdepends --installed "$i" 2>/dev/null) )
			if [ "$?" -ne 0 ];then
				apt rdepends --installed "$i" >/dev/null
				exit 2
			fi
			unset IFS
			WHYDEPS="$(printf "%b\\n" "${WHYARR[@]}"|grep -P "^[\ \t]*Depends:")"
			WHYBREAKS="$(printf "%b\\n" "${WHYARR[@]}"|grep -P "^[\ \t]*Breaks:")"
			#WHYARCHS="$(printf "%b\\n" "${WHYARR[@]}"|grep -P "^[\ \t]*$i:")"
			printf "%b\\n" "$i"
			for (( j=0;j<${#i};++j ));do printf "=";done;printf "\\n"
			printf "Installed packages with dependencies:\\n"
			if [ -n "$WHYDEPS" ];then
				printf "%b\\n" "$WHYDEPS"
			else
				printf "  NO INSTALLED DEPENDENCIES\\n"
			fi
			if [ -n "$WHYBREAKS" ];then
				printf "Supplemental information:\\n"
	 			printf "%b\\n" "$WHYBREAKS"
			fi
			printf "\\n"
		done
	;;
	*)
		printf "%b Arguments not understood: %b\\n" "$MYERR" "${ARGARR[*]}" >&2
		exit 11
	;;
esac