ci: update CI workflow to check for changed files

.gitea/workflows/ci.yml

@@ -2,15 +2,33 @@ name: CI
 
 on:
   pull_request:
-    paths:
-      - 'backend/**'
-      - 'frontend/**'
-      - '.gitea/workflows/ci.yml'
 
 jobs:
+  changed_files:
+    name: Get Changed Files
+    runs-on: ubuntu-latest
+    outputs:
+      backend: ${{ steps.filter.outputs.backend }}
+      frontend: ${{ steps.filter.outputs.frontend }}
+      workflow: ${{ steps.filter.outputs.workflow }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Check for file changes
+        uses: dorny/paths-filter@v2
+        id: filter
+        with:
+          filters: |
+            backend:
+              - 'backend/**'
+            frontend:
+              - 'frontend/**'
+            workflow:
+              - '.gitea/workflows/**'
+
   checkstyle:
     name: "Checkstyle Main"
-    if: ${{ contains(github.event.pull_request.changed_files_json, 'backend/') || contains(github.event.pull_request.changed_files_json, '.gitea/workflows/ci.yml') }}
+    needs: changed_files
+    if: ${{ needs.changed_files.outputs.backend == 'true' || needs.changed_files.outputs.workflow == 'true' }}
     container:
       image: "cimg/openjdk:23.0-node"
     steps:
@@ -37,7 +55,8 @@ jobs:
 
   eslint:
     name: eslint
-    if: ${{ contains(github.event.pull_request.changed_files_json, 'frontend/') || contains(github.event.pull_request.changed_files_json, '.gitea/workflows/ci.yml') }}
+    needs: changed_files
+    if: ${{ needs.changed_files.outputs.frontend == 'true' || needs.changed_files.outputs.workflow == 'true' }}
     container:
       image: catthehacker/ubuntu:act-latest
     steps:
@@ -64,7 +83,8 @@ jobs:
 
   prettier:
     name: prettier
-    if: ${{ contains(github.event.pull_request.changed_files_json, 'frontend/') || contains(github.event.pull_request.changed_files_json, '.gitea/workflows/ci.yml') }}
+    needs: changed_files
+    if: ${{ needs.changed_files.outputs.frontend == 'true' || needs.changed_files.outputs.workflow == 'true' }}
     container:
       image: catthehacker/ubuntu:act-latest
     steps:
@@ -91,7 +111,8 @@ jobs:
 
   test-build:
     name: test-build
-    if: ${{ contains(github.event.pull_request.changed_files_json, 'frontend/') || contains(github.event.pull_request.changed_files_json, '.gitea/workflows/ci.yml') }}
+    needs: changed_files
+    if: ${{ needs.changed_files.outputs.frontend == 'true' || needs.changed_files.outputs.workflow == 'true' }}
     container:
       image: catthehacker/ubuntu:act-latest
     steps: