forgejo: add passthru.updateScript

also add `meta.mainProgram`, since the resulting binary
is (currently?) called `gitea` not `forgejo`

Co-authored-by: Colin Arnott <urandom2@users.noreply.github.com>

pkgs/applications/version-management/forgejo/default.nix

@@ -1,15 +1,21 @@
-{ lib
-, stdenv
+{ bash
 , buildGoModule
+, common-updater-scripts
+, coreutils
+, curl
 , fetchurl
-, makeWrapper
 , git
-, bash
-, openssh
 , gzip
+, jq
+, lib
+, makeWrapper
+, nix
+, openssh
 , pam
 , pamSupport ? true
 , sqliteSupport ? true
+, stdenv
+, writeShellApplication
 }:
 
 buildGoModule rec {
@@ -59,12 +65,52 @@ buildGoModule rec {
       --prefix PATH : ${lib.makeBinPath [ bash git gzip openssh ]}
   '';
 
+  passthru.updateScript = lib.getExe (writeShellApplication {
+    name = "update-forgejo";
+    runtimeInputs = [
+      common-updater-scripts
+      coreutils
+      curl
+      jq
+      nix
+    ];
+    text = ''
+      releases=$(curl "https://codeberg.org/api/v1/repos/forgejo/forgejo/releases?draft=false&pre-release=false&limit=1" \
+        --silent \
+        --header "accept: application/json")
+
+      stable=$(jq '.[0]
+        | .tag_name[1:] as $version
+        | ("forgejo-src-\($version).tar.gz") as $filename
+        | { $version, html_url } + (.assets | map(select(.name | startswith($filename)) | {(.name | split(".") | last): .browser_download_url}) | add)' \
+        <<< "$releases")
+
+      archive_url=$(jq -r .gz <<< "$stable")
+      checksum_url=$(jq -r .sha256 <<< "$stable")
+      release_url=$(jq -r .html_url <<< "$stable")
+      version=$(jq -r .version <<< "$stable")
+
+      if [[ "${version}" = "$version" ]]; then
+        echo "No new version found (already at $version)"
+        exit 0
+      fi
+
+      echo "Release: $release_url"
+
+      sha256=$(curl "$checksum_url" --silent | cut --delimiter " " --fields 1)
+      sri_hash=$(nix hash to-sri --type sha256 "$sha256")
+
+      update-source-version "${pname}" "$version" "$sri_hash" "$archive_url"
+    '';
+  });
+
   meta = with lib; {
     description = "A self-hosted lightweight software forge";
     homepage = "https://forgejo.org";
     changelog = "https://codeberg.org/forgejo/forgejo/releases/tag/v${version}";
     license = licenses.mit;
-    maintainers = with maintainers; [ urandom ];
+    maintainers = with maintainers; [ indeednotjames urandom ];
     broken = stdenv.isDarwin;
+    mainProgram = "gitea";
   };
 }