Create code pngs (#14)

.github/workflows/latex-build.yml

@@ -4,12 +4,16 @@ on:
   push:
     tags:
       - "v*"
+  pull_request:
+    branches:
+      - main
 
 permissions:
   contents: write
+  pull-requests: write
 
 jobs:
-  build:
+  compile-latex:
     runs-on: ubuntu-latest
 
     steps:
@@ -26,15 +30,35 @@ jobs:
             texlive-latex-extra \
             texlive-lang-czechslovak
 
-      - name: Clean previous build files
-        run: rm -f presentation/*.pdf presentation/*.aux presentation/*.log
-
       - name: Compile Beamer Presentation
         run: |
           pdflatex -file-line-error -output-directory=presentation presentation/prezentace.tex
           pdflatex -file-line-error -output-directory=presentation presentation/prezentace.tex
 
-      - name: Create release with compiled presentation
+      - name: Create artifacts
+        uses: actions/upload-artifact@v4
+        id: artifacts
+        with:
+          name: prezentace
+          path: presentation/prezentace.pdf
+
+      - name: Comment on PR
+        uses: thollander/actions-comment-pull-request@v3
+        with:
+          message: "Presentation compiled successfully. You can download it here [prezentace.pdf](${{ steps.artifacts.outputs.artifact-url }})."
+        if: github.event_name == 'pull_request'
+
+  create-release:
+    runs-on: ubuntu-latest
+    needs: compile-latex
+    if: github.ref == 'refs/tags/v*'
+
+    steps:
+      - name: Download artifacts
+        uses: actions/download-artifact@v4
+        with:
+          name: prezentace
+      - name: Create release with compiled presentation (tag push only)
         uses: softprops/action-gh-release@v2
         with:
-          files: presentation/prezentace.pdf
+          files: prezentace.pdf