Structure and changes detector (#13)

* Structure and changes detector

* Better message

* Final state

.github/workflows/check-schemas-structure.yml

@@ -0,0 +1,68 @@
+name: Check Schemas Structure
+
+on:
+  pull_request:
+
+jobs:
+  check-structure:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        fetch-depth: 0  
+
+    - name: Check for required files
+      run: |
+        missing_files=0
+        for entity in schemas/*; do
+          if [ -d "$entity" ]; then
+            if [ ! -f "$entity/README.md" ]; then
+              echo "Missing README.md in $entity"
+              missing_files=1
+            fi
+            if [ ! -f "$entity/CODEOWNERS" ]; then
+              echo "Missing CODEOWNERS in $entity"
+              missing_files=1
+            fi
+          fi
+        done
+        exit $missing_files
+
+    - name: Check no changes to schemas
+      run: |
+        invalid_changes=0
+        changes=""
+        echo "Checking for changes in schema files..."
+        
+        # Fetch the base branch to compare
+        git fetch origin ${{ github.event.pull_request.base.ref }}
+        
+        # Get the list of changed files in the PR within 'schemas/**/*'
+        changed_files=$(git diff --name-only --diff-filter=M origin/${{ github.event.pull_request.base.ref }}...HEAD -- 'schemas/**/*')
+        
+        echo "Changed files: $changed_files"
+        
+        for file in $changed_files; do
+        if [ -f "$file" ] && [ "$(basename "$file")" != "README.md" ] && [ "$(basename "$file")" != "CODEOWNERS" ]; then
+            echo "Change detected in $file..."
+            changes="$changes\nUnexpected change in $file"
+            invalid_changes=1
+        fi
+        done
+        
+        echo "changes<<EOF" >> $GITHUB_ENV
+        echo -e "$changes" >> $GITHUB_ENV
+        echo "EOF" >> $GITHUB_ENV
+
+    - name: Comment on PR if there are unexpected changes
+      if: env.changes != ''
+      uses: actions/github-script@v6
+      with:
+        script: |
+            github.rest.pulls.createReview({
+                pull_number: context.issue.number,
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                body: `Unexpected changes detected, you should not update a schema file, consider creating a new version instead:\n${{ env.changes }}`,
+                event: 'REQUEST_CHANGES'
+            })