#!/usr/bin/env bash

# Report packages installing same file and not marked with
# conflicts or replaces.
# Without argument, find conflicts between packages in local
# repository at hostdir/binpkgs and packages indexed in xlocate.
# With single path as argument, read that local repository.
# With -a flag, find conflicts between packages indexed in xlocate.

if [ "$#" = 0 ]; then
	binpkgs="$PWD/hostdir/binpkgs"
elif [ "$1" = -a ]; then
	all=1
elif [ -d "$1" ]; then
	binpkgs="$1"
else
	echo "Usage:"
	echo "$0"
	echo "  check packages in ./hostdir/binpkgs"
	echo "$0 path/to/hostdir/binpkgs"
	echo "  check packages there"
	echo "$0 -a"
	echo "  check all packages indexed in xlocate"
	exit 1
fi

declare -A newly_built conflicts_cache providers_cache pairs owners
repositories=("--repository=${binpkgs}/bootstrap" "--repository=${binpkgs}" "--repository=${binpkgs}/nonfree")
rv=0

template_exists() {
	[ -f "srcpkgs/$1/template" ]
}

partial_check() {
	[ -z "$all" ]
}

providers_of() {
	# print the pkgname and packages that `provides` it
	local pkgname=$1
	if [ "${providers_cache[$pkgname]}" = '' ]; then
		local line provider_pkgver provided_pkgver provider_pkgname provided_pkgname
		local -A providers
		providers[$pkgname]=$pkgname
		while read -r line; do
			line=${line%%'('*}
			provider_pkgver=${line%': '*}
			provided_pkgver=${line#*': '}
			provider_pkgname=${provider_pkgver%-*}
			provided_pkgname=${provided_pkgver%-*}
			# comes from $(xbps-query -s $pkgname), so $pkgname can be substring
			if [ "$provided_pkgname" = "$pkgname" ]; then
				providers[$provider_pkgname]=$provider_pkgname
			fi
		done < <(xbps-query "${repositories[@]}" -p provides -R -s "$pkgname")
		# leading space ensures ${[]} != ''
		providers_cache[$pkgname]=" ${providers[*]}"
	fi
	echo ${providers_cache[$pkgname]}
}

conflicts_of() {
	# print list of packages that are _marked_ as conflicting with given one
	local pkgname=$1
	if [ "${conflicts_cache[$pkgname]}" = '' ]; then
		local in_conflict provider
		local -A all
		while read -r in_conflict; do
			in_conflict=${in_conflict%'<'*}
			in_conflict=${in_conflict%'>'*}
			providers_of "$in_conflict" > /dev/null # executing in same process to fill cache
			for provider in $(providers_of "$in_conflict"); do
				all[$provider]=$provider
			done
		done < <(xbps-query "${repositories[@]}" -p conflicts,replaces -R "$pkgname")
		# leading space ensures ${[]} != ''
		conflicts_cache[$pkgname]=" ${all[*]}"
	fi
	echo ${conflicts_cache[$pkgname]}
}

conflict_between() {
	# exit successfully if packages are _marked_ as conflicting
	conflicts_of "$1" > /dev/null # executing in same process to fill cache
	case " $(conflicts_of "$1") " in
		*" $2 "*) return 0
	esac
	conflicts_of "$2" > /dev/null # executing in same process to fill cache
	case " $(conflicts_of "$2") " in
		*" $1 "*) return 0
	esac
	return 1
}

list_newly_built_files() {
	# print one line per file in newly built packages
	# each line contains pkgname and file path
	local pkgver pkgname
	while read -r pkgver; do
		pkgname=${pkgver%-*}
		xbps-query "${repositories[@]}" -i -f "$pkgname" | sed s'/ -> .*//;'" s/^/$pkgname /"
	done < <(xbps-query "${repositories[@]}" -i -R -s '' | cut -d' ' -f 2)
}

list_interesting_files() {
	# list files potentially contained in more than one package
	# each line contains pkgver/pkgname and file path
	if partial_check; then
		list_newly_built_files
	else
		xlocate / | sed s'/ -> .*//' | grep -F -f <(xlocate / | sed 's/[^[:space:]]*[[:space:]]*//' | sed s'/ -> .*//' | sort | uniq -d)
	fi
}

group_by_file_full() {
	# create associative array `owners` mapping file to list of packages
	# for packages potentially conflicting with newly built ones
	local pkgver file pkgname
	while read -r pkgver file; do
		pkgname=${pkgver%-*}
		if template_exists "$pkgname"; then
			owners[$file]+=" $pkgname"
		fi
	done < <(list_interesting_files)
}

group_by_file_partial() {
	# create associative array `owners` mapping file to list of packages
	# for all packages in xlocate
	local pkgname file
	## newly built packages
	while read -r pkgver; do
		pkgname=${pkgver%-*}
		newly_built[$pkgname]=$pkgname
	done < <(xbps-query "${repositories[@]}" -i -R -s '' | cut -d' ' -f 2)
	while read -r pkgname file; do
		owners[$file]+=" $pkgname"
	done < <(list_newly_built_files)
	## rest of repository
	while read -r pkgver file; do
		pkgname=${pkgver%-*}
		if [ -z "${newly_built[$pkgname]}" ] && template_exists "$pkgname"; then
			owners[$file]+=" $pkgname"
		fi
	done < <(xlocate / | sed s'/ -> .*//' | grep -F -f <(list_newly_built_files | cut -d ' ' -f 2-))
}

group_by_pair() {
	# find package pairs owning same file and not marked as conflicting
	local pkg file a b
	while read -r pkg file; do
		for a in ${owners[$file]}; do
			for b in ${owners[$file]}; do
				if ! [ "$a" "<" "$b" ]; then
					continue
				fi
				if partial_check && [ -z "${newly_built[$a]}" ] && [ -z "${newly_built[$b]}" ]; then
					continue
				fi
				if ! conflict_between "$a" "$b"; then
					unset pair_files
					local -A pair_files
					eval "${pairs["$a $b"]}"
					pair_files[$file]="$file"
					pairs["$a $b"]="${pair_files[@]@A}"
				fi
			done
		done
	done < <(list_interesting_files)
}

print_out() {
	local pair file
	if [ "${#pairs[@]}" = 0 ]; then
		echo 1>&2 "No conflicts found in" "${repositories[@]#*=}"
		exit 0
	fi
	while read -r pair; do
		rv=1
		echo "${pair% *} and ${pair#* } conflict for"
		unset pair_files
		eval "${pairs[$pair]}"
		for file in "${pair_files[@]}"; do
			echo "  $file"
		done | sort
	done < <(printf '%s\n' "${!pairs[@]}" | sort)
}

if partial_check; then
	group_by_file_partial
else
	group_by_file_full
fi
group_by_pair
print_out

exit $rv