#!/bin/sh

APKG_CONF="${APKG_CONF:-/etc/apkg.conf}"
temp_repos_file=$(mktemp)
write_permission=0

die() {
	[ "$1" ] && echo "error: $1"
	rm -f "$temp_repos_file"
	exit 1
}

find_default_remote() {
	cd "${1}" || die "cannot cd to <${1}> the repo"
	default_remote=$(git branch --list "$(git branch --show-current)" \
	 "--format=%(upstream:remotename)")
}

find_current_branch() {
	cd "${1}" || die "cannot cd to the <${1}> repo"
	current_branch=$(git remote show "${default_remote}" | sed -n '/HEAD branch/s/.*: //p')
}

check_write_permissions() {
	random_file=$(find "${1}" -type f -print0 | shuf -z -n 1)
	test -w "$random_file" || write_permission=$((write_permission+1))
}

source_and_sanity_checks() {
[ ! -e "$(realpath "${APKG_CONF}")" ] && die "There is no configuration file in ${APKG_CONF}! Exiting..."

. "${APKG_CONF}"

[ -z "${APKG_REPO}" ] && die "There are no repos configured in $APKG_CONF, exiting..."

for r in ${APKG_REPO}; do 
printf "%s\n" "$r" >> "$temp_repos_file"
check_write_permissions "$r"; done
[ "$write_permission" = 0 ] || die "You need to execute the script as root!"
printf "%s\n" "Configured repos:" && awk ' {print $0} ' "$temp_repos_file"
grep -q "alicelinux/repos/core" "$temp_repos_file" || die "No official repos configured in $APKG_CONF"
}

sync_official() {
	# This assumes the current repo structure.
	dir_for_official_repo=$(grep alicelinux/repos/core "$temp_repos_file")
	[ -d "$dir_for_official_repo" ] || die "No $dir_for_official_repo exists, exiting..."
	dir_for_official_repo=$(echo "$dir_for_official_repo" | sed "s/repos\/core//")
	printf "%s\n" "[~> Syncing official repos in <$dir_for_official_repo> ...]" 
	find_default_remote "$dir_for_official_repo"
	find_current_branch "$dir_for_official_repo"
	git pull "$default_remote" "$current_branch" || die "Cannot pull from $default_remote/$current_branch for the ofixial repos"
	[ "$?" = 0 ] && printf "%s\n" "[~> Successfully synced the <official> repo!]"	
}

sync_or_skip() {
	# Remove all official repo lines from the temp_repos_file
	unofficial_repos=$(grep -v alicelinux/repos "$temp_repos_file" | tr "\n" " ")
	for r in $unofficial_repos; do
		if [ -d "$r"/.git ]; then
			find_default_remote "$r"
			find_current_branch "$r"
			git pull "$default_remote" "$current_branch" || die "Cannot pull from $default_remote/$current_branch"
		else
			printf "%s\n" "[~>Repo in <$r> is not a git repo, skipping...]"
		fi
	done
}

source_and_sanity_checks
sync_official
sync_or_skip
[ "$?" = 0 ] && echo "[~> Repo(s) succesfully synced!]" && rm -f "temp_repos_file"