#!/bin/sh

PROGRAM=setup-apkrepos
PREFIX=@PREFIX@
: ${LIBDIR=$PREFIX/lib}
. "$LIBDIR/libalpine.sh"

: ${MIRRORS_URL:=https://mirrors.alpinelinux.org/mirrors.txt}

if [ "$ROOT" != "/" ]; then
	apk_root_opt="--root $ROOT"
fi

get_hostname_from_url() {
	local n="${1#*://}"
	echo ${n%%/*}
}

get_mirror_count() {
	set -- $MIRRORS
	echo $#
}

ask_setup_method() {
	cat <<-__EOF__
		r) Add random from the above list
		f) Detect and add fastest mirror from above list
		e) Edit ${ROOT}etc/apk/repositories with text editor

	__EOF__
	ask "Enter mirror number (1-$(get_mirror_count)) or URL to add (or r/f/e/done)" "$1"
}

add_random_mirror() {
	local i=0
	local count=$(get_mirror_count)
	if [ ${count:-0} -eq 0 ]; then
		echo "Warning! no mirror found" >&2
		return 1
	fi
	local random_mirror_index="$(awk -v count=$count 'BEGIN {srand(); printf("%.0f", rand() * count)}')"

	printf %s "Picking random mirror... "
	for mirror in $MIRRORS; do
		if [ $i -eq $random_mirror_index ]; then
			break
		fi
		i=$(( $i + 1 ))
	done
	add_mirror $mirror
}

time_cmd() {
	local start="$(cut -d ' ' -f1 /proc/uptime)"
	$@ >&2 || return
	awk -v start=$start -v end=$(cut -d ' ' -f1 /proc/uptime) \
		'BEGIN {print end - start; exit}'
}

find_fastest_mirror() {
	local url=
	local arch="$(apk --print-arch)"
	for url in $MIRRORS; do
		# warm up the dns cache
		$MOCK nslookup $(get_hostname_from_url $url) >/dev/null 2>&1
		local time="$(time_cmd wget --spider -q -T 5 -t 1 \
			${url%/}/edge/main/$arch/APKINDEX.tar.gz)"
		if [ -n "$time" ]; then
			echo "$time $url"
		fi
	done | tee /dev/stderr | sort -nk1,1 | head -n1 | cut -d' ' -f2
}

add_fastest_mirror() {
	echo "Finding fastest mirror... "
	local fastest="$(find_fastest_mirror)"
	if [ -z "$fastest" ]; then
		echo "Warning! No mirror found" >&2
		return 1
	fi
	add_mirror "$fastest"
}

# show mirrors
show_mirror_list() {
	local mirror i=0
	[ -z "$MIRRORS" ] && return
	echo ""
	echo "Available mirrors:"
	for mirror in $MIRRORS; do
		i=$(($i + 1))
		echo "$i) $(get_hostname_from_url $mirror)"
	done
	echo ""
}

add_from_list() {
	local mirror_index="$1"
	if [ $mirror_index -lt 1 ] || [ $mirror_index -gt $(get_mirror_count) ]; then
		return 1
	fi
	set $MIRRORS
	eval "mirror=\${$mirror_index}"
	add_mirror "$mirror"
}

get_alpine_release() {
	# use the main version already configured, or get the version from /etc/alpine-release
	local version="$(grep -Eom1 '[^/]+/main/?$' "${ROOT}"etc/apk/repositories 2>/dev/null | grep -Eo '^[^/]+' \
		|| cat "${ROOT}"etc/alpine-release 2>/dev/null)"
	case "$version" in
		*_git*|*_alpha*) release="edge";;
		[0-9]*.[0-9]*.[0-9]*)
			# release in x.y.z format, cut last digit
			release=v${version%.[0-9]*};;
		*)	# fallback to edge
			release="edge";;
	esac
}

add_mirror() {
	local mirror="$1"
	mkdir -p "${APKREPOS_PATH%/*}"
	echo "${mirror%/}/${release}/main" >> $APKREPOS_PATH
	echo "${community_prefix}${mirror%/}/${release}/community" >> $APKREPOS_PATH
	case "$release" in
	v[0-9]*)
		echo "#${mirror%/}/edge/main" >> $APKREPOS_PATH;
		echo "#${mirror%/}/edge/community" >> $APKREPOS_PATH;;
	esac
	echo "#${mirror%/}/edge/testing" >> $APKREPOS_PATH
	echo "" >> $APKREPOS_PATH
	echo "Added mirror $(get_hostname_from_url $mirror)"
}

add_from_url() {
	mkdir -p "${APKREPOS_PATH%/*}"
	echo "$1" >> $APKREPOS_PATH
	echo "" >> $APKREPOS_PATH
}

edit_repositories() {
	local md5="$(md5sum $APKREPOS_PATH 2>/dev/null)"
	mkdir -p "${APKREPOS_PATH%/*}"
	${EDITOR:-vi} "$APKREPOS_PATH"
	# return true if file changed
	test "$(md5sum $APKREPOS_PATH 2>/dev/null)" != "$md5"
}

usage() {
	cat <<-__EOF__
		usage: setup-apkrepos [-ch] [-f|-r|-1|REPO...]

		Setup apk repositories

		options:
		 -c  Enable the community repo
		 -f  Detect and add fastest mirror
		 -h  Show this help
		 -r  Add a random mirror and do not prompt
		 -1  Add first mirror on the list (normally a CDN)
	__EOF__
	exit $1
}

community_prefix="#"
add_fastest=false
add_first=false
add_random=false
while getopts "c1fhr" opt; do
	case $opt in
		c) community_prefix="";;
		f) add_fastest=true
			if $add_first || $add_random; then
				usage "1" >&2
			fi
			;;
		1) add_first=true
			if $add_fastest || $add_random; then
				usage "1" >&2
			fi
			;;
		h) usage 0;;
		r) add_random=true
			if $add_first || $add_fastest; then
				usage "1" >&2
			fi
			;;
		'?') usage "1" >&2;;
	esac
done
shift $(($OPTIND - 1))

if [ -z "$MIRRORS" ]; then
	MIRRORS=$(wget -qO- $MIRRORS_URL)
fi

APKREPOS_PATH="${ROOT}"etc/apk/repositories
if [ -r "$APKREPOS_PATH" ]; then
	APKREPOS=$(cat "$APKREPOS_PATH")
fi

get_alpine_release
changed=false

if [ $# -gt 0 ]; then
	# replace the apk repos with the specified ones
	rm -f "$APKREPOS_PATH"
	mkdir -p "${APKREPOS_PATH%/*}"
	for i; do
		echo "$i" >> "$APKREPOS_PATH" && changed=true
	done
fi

if $add_first; then
	set -- $MIRRORS
	if [ $# -eq 0 ]; then
		echo "Warning! No mirror found" >&2
		exit 1
	fi
	add_mirror "$1" || exit
	changed=true
fi

if $add_random; then
	add_random_mirror || exit
	changed=true
fi

if $add_fastest; then
	add_fastest_mirror || exit
	changed=true
fi

if $add_first || $add_random || $add_fastest; then
	interactive=false
else
	interactive=true
fi

while $interactive && ! $changed; do
	if [ -z "$MIRRORS" ]; then
		MIRRORS=$(wget -qO- $MIRRORS_URL)
	fi

	show_mirror_list | more
	ask_setup_method ${APKREPO_DEFAULT_ANSWER:-1}

	case "$resp" in
		"done") break;;
		[0-9]*) add_from_list "$resp" && changed=true;;
		/*|http://*|ftp://*|https://*) add_from_url "$resp" \
			&& changed=true;;
		r) add_random_mirror && changed=true;;
		f) add_fastest_mirror && changed=true;;
		e) edit_repositories && changed=true;;
	esac
done

if $changed; then
	printf %s "Updating repository indexes... "
	apk update --quiet $apk_root_opt && echo "done."
fi