mpvScripts.sponsorblock: add update script

pkgs/applications/video/mpv/scripts/sponsorblock.nix

@@ -39,7 +39,10 @@ stdenvNoCC.mkDerivation {
     cp -r sponsorblock.lua sponsorblock_shared $out/share/mpv/scripts/
   '';
 
-  passthru.scriptName = "sponsorblock.lua";
+  passthru = {
+    scriptName = "sponsorblock.lua";
+    updateScript = ./update-sponsorblock.sh;
+  };
 
   meta = with lib; {
     description = "Script for mpv to skip sponsored segments of YouTube videos";

pkgs/applications/video/mpv/scripts/update-sponsorblock.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p common-updater-scripts git jq nix nix-prefetch-git
+git_url='https://github.com/po5/mpv_sponsorblock.git'
+git_branch='master'
+git_dir='/var/tmp/mpv_sponsorblock.git'
+nix_file="$(dirname "${BASH_SOURCE[0]}")/sponsorblock.nix"
+pkg='mpvScripts.sponsorblock'
+
+set -euo pipefail
+
+info() {
+    if [ -t 2 ]; then
+        set -- '\033[32m%s\033[39m\n' "$@"
+    else
+        set -- '%s\n' "$@"
+    fi
+    printf "$@" >&2
+}
+
+old_rev=$(nix-instantiate --eval --strict --json -A "$pkg.src.rev" | jq -r)
+old_version=$(nix-instantiate --eval --strict --json -A "$pkg.version" | jq -r)
+today=$(LANG=C date -u +'%Y-%m-%d')
+
+info "fetching $git_url..."
+if [ ! -d "$git_dir" ]; then
+    git init --initial-branch="$git_branch" "$git_dir"
+    git -C "$git_dir" remote add origin "$git_url"
+fi
+git -C "$git_dir" fetch --depth=1 origin "$git_branch"
+
+# use latest commit before today, we should not call the version *today*
+# because there might still be commits coming
+# use the day of the latest commit we picked as version
+new_rev=$(git -C "$git_dir" log -n 1 --format='format:%H' --before="${today}T00:00:00Z" "origin/$git_branch")
+new_version="unstable-$(git -C "$git_dir" log -n 1 --format='format:%cs' "$new_rev")"
+info "latest commit before $today: $new_rev"
+
+if [ "$new_rev" = "$old_rev" ]; then
+    info "$pkg is up-to-date."
+    exit
+fi
+
+new_sha256=$(nix-prefetch-git --rev "$new_rev" "$git_dir" | jq -r .sha256)
+update-source-version "$pkg" \
+    "$new_version" \
+    "$new_sha256" \
+    --rev="$new_rev"
+git add "$nix_file"
+git commit --verbose --message "$pkg: $old_version -> $new_version"