feat: calculate branch reusable workflow

.github/workflows/calculate-branch.yaml

@@ -0,0 +1,57 @@
+name: Calculate Branch
+on:
+  workflow_call:
+    inputs:
+      branch:
+        description: The branch name
+        required: true
+        type: string
+      repo:
+        description: The GitHub repository name
+        required: true
+        type: string
+    outputs:
+      branch: ${{ steps.calculate_branch.outputs.branch }}
+      found: ${{ steps.calculate_branch.outputs.found }}
+      sha: ${{ steps.calculate_branch.outputs.sha }}
+      sha_short: ${{ steps.calculate_branch.outputs.sha_short }}
+    secrets:
+      github_token:
+        required: true
+
+jobs:
+  calculate-branch:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Calculate Branch
+        id: calculate_branch
+        env:
+          GH_TOKEN: ${{ secrets.github_token }}
+        run: |
+          requested_branch="${{ inputs.branch }}"
+          repo="${{ inputs.repo }}"
+          branch_name=
+          found=
+
+          echo "Checking to see if the branch \"${requested_branch}\" exists in this project."
+
+          branch_info=$(gh api "/repos/encodium/${repo}/branches/$requested_branch" --jq '{name: .name, sha: .commit.sha}')
+          branch_name_candidate=$(echo "$branch_info" | jq -r '.name')
+          sha=$(echo "$branch_info" | jq -r '.sha')
+          sha_short=$(echo "$branch_info" | jq -r '.sha[:7]')
+
+          echo "Branch name from response: ${branch_name_candidate}"
+          echo "SHA from response: ${sha}"
+          echo "SHA (short) from response: ${sha_short}"
+
+          if [[ "$branch_name_candidate" == "$requested_branch" ]];
+          then
+            echo "Branch \"${branch_name_candidate}\" found."
+            branch_name="$branch_name_candidate"
+            found=true
+          fi
+
+          echo "branch=$branch_name" >> "$GITHUB_OUTPUT"
+          echo "found=$found" >> "$GITHUB_OUTPUT"
+          echo "sha=$sha" >> "$GITHUB_OUTPUT"
+          echo "sha_short=$sha_short" >> "$GITHUB_OUTPUT"