add version-bump action

version-bump/action.yml

@@ -0,0 +1,69 @@
+name: Version Bump
+description: Bump or get semver patch version with git tags
+
+inputs:
+  token:
+    description: GitHub/Gitea token for pushing tags
+    required: true
+  mode:
+    description: "bump (create tag) or get (read only)"
+    required: false
+    default: bump
+
+outputs:
+  version:
+    description: "e.g. 0.1.0 (no v prefix)"
+    value: ${{ steps.calc.outputs.version }}
+  version_with_sha:
+    description: "e.g. 0.1.0-a1b2c3d"
+    value: ${{ steps.calc.outputs.version_with_sha }}
+
+runs:
+  using: composite
+  steps:
+    - name: Configure git
+      shell: bash
+      run: |
+        git config user.name "CI Bot"
+        git config user.email "ci@git.sebse.de"
+        git remote set-url origin https://ci:${{ inputs.token }}@git.sebse.de/${{ github.repository }}
+
+    - name: Fetch tags
+      shell: bash
+      run: git fetch --tags --force
+
+    - name: Calculate version
+      id: calc
+      shell: bash
+      run: |
+        SHORT_SHA=$(echo "${GITHUB_SHA}" | cut -c1-7)
+        LATEST_TAG=$(git tag -l 'v*' --sort=-v:refname | head -n1)
+
+        if [ -z "$LATEST_TAG" ]; then
+          MAJOR=0
+          MINOR=0
+          PATCH=0
+        else
+          V="${LATEST_TAG#v}"
+          MAJOR=$(echo "$V" | cut -d. -f1)
+          MINOR=$(echo "$V" | cut -d. -f2)
+          PATCH=$(echo "$V" | cut -d. -f3)
+        fi
+
+        if [ "${{ inputs.mode }}" = "bump" ]; then
+          NEW_PATCH=$((PATCH + 1))
+        else
+          NEW_PATCH=$PATCH
+        fi
+
+        VERSION="${MAJOR}.${MINOR}.${NEW_PATCH}"
+        echo "version=${VERSION}" >> $GITHUB_OUTPUT
+        echo "version_with_sha=${VERSION}-${SHORT_SHA}" >> $GITHUB_OUTPUT
+        echo "VERSION=${VERSION}" >> $GITHUB_ENV
+
+    - name: Create and push tag
+      if: inputs.mode == 'bump'
+      shell: bash
+      run: |
+        git tag "v${VERSION}"
+        git push origin "v${VERSION}"