ci: Reenable flatpak builds

.gitlab-ci.yml

@@ -72,3 +72,44 @@ check-po:
     # in this case
     - cd po/
     - intltool-update -m 2>&1 | grep -qs '/.*\.c' && { intltool-update -m; exit 1; } || exit 0
+
+# For some reason including https://gitlab.gnome.org/GNOME/citemplates/raw/master/flatpak/flatpak_ci_initiative.yml fails with a network error (status code 500), therefore it's copied here
+.flatpak:
+  image: 'registry.gitlab.gnome.org/gnome/gnome-runtime-images/gnome:master'
+  stage: 'package'
+  interruptible: true
+  tags:
+    - flatpak
+  script:
+    - rewrite-flatpak-manifest ${MANIFEST_PATH} ${FLATPAK_MODULE} ${CONFIG_OPTS}
+    - flatpak-builder --user --disable-rofiles-fuse flatpak_app --repo=repo ${BRANCH:+--default-branch=$BRANCH} ${MANIFEST_PATH}
+    # Generate a Flatpak bundle
+    - flatpak build-bundle repo ${BUNDLE} --runtime-repo=${RUNTIME_REPO} ${APP_ID} ${BRANCH}
+    - tar cf repo.tar repo/
+
+  artifacts:
+    name: 'Flatpak artifacts'
+    expose_as: 'Get Flatpak bundle here'
+    when: 'always'
+    paths:
+      - "${BUNDLE}"
+      - 'repo.tar'
+      - '.flatpak-builder/build/${FLATPAK_MODULE}/_flatpak_build/meson-logs/meson-log.txt'
+      - '.flatpak-builder/build/${FLATPAK_MODULE}/_flatpak_build/meson-logs/testlog.txt'
+    expire_in: 14 days
+  cache:
+    key: "$CI_JOB_NAME"
+    paths:
+      - '.flatpak-builder/downloads'
+      - '.flatpak-builder/git'
+
+flatpak:master:
+  extends: .flatpak
+  stage: package
+  variables:
+    MANIFEST_PATH: "sm.puri.Calls.json"
+    RUNTIME_REPO: "https://nightly.gnome.org/gnome-nightly.flatpakrepo"
+    FLATPAK_MODULE: "calls"
+    MESON_ARGS: ""
+    APP_ID: "sm.puri.Calls"
+    BUNDLE: "calls.flatpak"