feat(version): introduce version check subcommand

The version subcommand handles pkgver related commands, the first
subcommand being `check`. Check runs nvchecker if a `.nvchecker.toml`
file exists and compares the current pkgver with the latest release.

Introduces nvchecker as optional dependency which has to be installed in
order to use this particular subcommand.

BREAKING CHANGE: formerly pkgctl version would output the version of the
pkgctl tool, now it is used as a version related subcommand.

Fixes #140

Component: pkgctl version
Component: pkgctl version check
Co-authored-by: Christian Heusel <christian@heusel.eu>

2 files changed, 117 insertions, 11 deletions

diff --git a/src/lib/version/version.sh b/src/lib/version.sh
index d00a460..826b306 100644
--- a/src/lib/version/version.sh
+++ b/src/lib/version.sh
@@ -7,41 +7,50 @@ DEVTOOLS_INCLUDE_VERSION_SH=1
 
 _DEVTOOLS_LIBRARY_DIR=${_DEVTOOLS_LIBRARY_DIR:-@pkgdatadir@}
 
-source /usr/share/makepkg/util/message.sh
-
 set -e
 
 
 pkgctl_version_usage() {
 	local -r COMMAND=${_DEVTOOLS_COMMAND:-${BASH_SOURCE[0]##*/}}
     cat <<- _EOF_
-		Usage: ${COMMAND} [OPTIONS]
+		Usage: ${COMMAND} [COMMAND] [OPTIONS]
+
+		Package version related commands.
 
-		Shows the current version information of pkgctl
+		COMMANDS
+		    check    Check if there is a newer version availble
 
 		OPTIONS
 		    -h, --help    Show this help text
-_EOF_
-}
 
-pkgctl_version_print() {
-	cat <<- _EOF_
-		pkgctl @buildtoolver@
+		EXAMPLES
+		    $ ${COMMAND} check libfoo linux libbar
 _EOF_
 }
 
 pkgctl_version() {
+	if (( $# < 1 )); then
+		pkgctl_version_usage
+		exit 0
+	fi
+
 	while (( $# )); do
 		case $1 in
 			-h|--help)
 				pkgctl_version_usage
 				exit 0
 				;;
+			check)
+				_DEVTOOLS_COMMAND+=" $1"
+				shift
+				# shellcheck source=src/lib/version/check.sh
+				source "${_DEVTOOLS_LIBRARY_DIR}"/lib/version/check.sh
+				pkgctl_version_check "$@"
+				exit 0
+				;;
 			*)
 				die "invalid argument: %s" "$1"
 				;;
 		esac
 	done
-
-	pkgctl_version_print
 }
diff --git a/src/lib/version/check.sh b/src/lib/version/check.sh
new file mode 100644
index 0000000..f6619c2
--- /dev/null
+++ b/src/lib/version/check.sh
@@ -0,0 +1,97 @@
+#!/bin/bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+[[ -z ${DEVTOOLS_INCLUDE_VERSION_CHECK_SH:-} ]] || return 0
+DEVTOOLS_INCLUDE_VERSION_CHECK_SH=1
+
+_DEVTOOLS_LIBRARY_DIR=${_DEVTOOLS_LIBRARY_DIR:-@pkgdatadir@}
+# shellcheck source=src/lib/common.sh
+source "${_DEVTOOLS_LIBRARY_DIR}"/lib/common.sh
+
+source /usr/share/makepkg/util/message.sh
+
+set -e
+
+pkgctl_version_check_usage() {
+	local -r COMMAND=${_DEVTOOLS_COMMAND:-${BASH_SOURCE[0]##*/}}
+	cat <<- _EOF_
+		Usage: ${COMMAND} [OPTIONS] [PKGBASE]...
+
+		Uses nvchecker, a .nvchecker.toml file and the current PKGBUILD
+		pkgver to check if there is a newer package version available.
+
+		The current working directory is used if no PKGBASE is specified.
+
+		OPTIONS
+		    -h, --help          Show this help text
+
+		EXAMPLES
+		    $ ${COMMAND} neovim vim
+_EOF_
+}
+
+pkgctl_version_check() {
+	local path
+	local pkgbases=()
+
+	while (( $# )); do
+		case $1 in
+			-h|--help)
+				pkgctl_version_check_usage
+				exit 0
+				;;
+			--)
+				shift
+				break
+				;;
+			-*)
+				die "invalid argument: %s" "$1"
+				;;
+			*)
+				pkgbases=("$@")
+				break
+				;;
+		esac
+	done
+
+	if ! command -v nvchecker &>/dev/null; then
+		die "The \"$_DEVTOOLS_COMMAND\" command requires 'nvchecker'"
+	fi
+
+	# Check if used without pkgbases in a packaging directory
+	if (( ${#pkgbases[@]} == 0 )); then
+		if [[ -f PKGBUILD ]]; then
+			pkgbases=(".")
+		else
+			pkgctl_version_check_usage
+			exit 1
+		fi
+	fi
+
+	for path in "${pkgbases[@]}"; do
+		pushd "${path}" >/dev/null
+		run_nvchecker "${path}"
+		popd >/dev/null
+	done
+}
+
+run_nvchecker() {
+	local path=$1
+	local pkgbase latest_version
+
+	if [[ ! -f ".nvchecker.toml" || ! -f "PKGBUILD" ]]; then
+		die "No .nvchecker.toml or PKGBUILD found for ${path}"
+		exit 1
+	fi
+
+	# TODO: parse .SRCINFO file
+	# shellcheck source=contrib/makepkg/PKGBUILD.proto
+	. ./PKGBUILD
+	pkgbase=${pkgbase:-$pkgname}
+
+	latest_version=$(nvchecker -c .nvchecker.toml --logger json | jq --raw-output 'select( .version ) | .version')
+	if (( $(vercmp "${latest_version}" "${pkgver}") > 0 )); then
+		msg2 "New ${pkgbase} version ${latest_version} is available upstream"
+	fi
+}