name: Update copyright years

on:
  schedule:
    - cron: '42 13 3 1 *' # 3rd of January at 13:42 UTC
  workflow_dispatch:
    inputs:
      year:
        type: number
        required: true
        description: 'The (new) year to update the copyright to'

permissions:
  contents: write
  pull-requests: write

jobs:
  update-copyrights:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
      - name: Determine years
        id: years
        env:
          TRIGGER_NAME: ${{ github.event_name }}
          YEAR_INPUT: ${{ inputs.year }}
        run: |
          if [ "${TRIGGER_NAME}" = 'workflow_dispatch' ]; then
            NEW_YEAR=${YEAR_INPUT}
          else
            NEW_YEAR=$(date '+%Y')
          fi
          echo "new-year=${NEW_YEAR}" >> "${GITHUB_OUTPUT}"
          echo "old-year=$((NEW_YEAR - 1))" >> "${GITHUB_OUTPUT}"
      - name: Checkout branch
        id: branch
        env:
          OLD_YEAR: ${{ steps.years.outputs.old-year }}
          NEW_YEAR: ${{ steps.years.outputs.new-year }}
        run: |
          BRANCH_NAME="update-copyright/${OLD_YEAR}-to-${NEW_YEAR}"
          echo "branch-name=${BRANCH_NAME}" >> "${GITHUB_OUTPUT}"
          git checkout -B "${BRANCH_NAME}"
      - name: Update copyrights
        run: ./Scripts/update-copyright.sh
        env:
          OLD_YEAR: ${{ steps.years.outputs.old-year }}
          NEW_YEAR: ${{ steps.years.outputs.new-year }}
      - name: Commit changes if needed
        id: commit
        env:
          ACTOR: ${{ github.actor }}
          OLD_YEAR: ${{ steps.years.outputs.old-year }}
          NEW_YEAR: ${{ steps.years.outputs.new-year }}
          BRANCH_NAME: ${{ steps.branch.outputs.branch-name }}
        run: |
          if [ -n "$(git status --porcelain)" ]; then
            git config --local user.email "${ACTOR}@noreply.github.com"
            git config --local user.name "${ACTOR}"
            git add .
            git commit -m "Update copyright from ${OLD_YEAR} to ${NEW_YEAR}"
            git push --set-upstream origin "${BRANCH_NAME}"
            echo 'has-changes=true' >> "${GITHUB_OUTPUT}"
          else
            echo 'has-changes=false' >> "${GITHUB_OUTPUT}"
          fi
      - name: Create PR if needed
        if: ${{ steps.commit.outputs.has-changes == 'true' }}
        env:
          OLD_YEAR: ${{ steps.years.outputs.old-year }}
          NEW_YEAR: ${{ steps.years.outputs.new-year }}
          REPO: ${{ github.repository }}
          SOURCE_BRANCH: ${{ steps.branch.outputs.branch-name }}
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          TARGET_BRANCH="$(gh repo view "${REPO}" --json 'defaultBranchRef' --jq '.defaultBranchRef.name')"
          PR_COUNT="$(gh pr list \
            --repo "${REPO}" \
            --state 'open' \
            --head "${SOURCE_BRANCH}" \
            --base "${TARGET_BRANCH}" \
            --json 'number' \
            --jq 'length')"
          if [ "${PR_COUNT}" -eq 0 ]; then
            gh pr create \
              --repo "${REPO}" \
              --head "${SOURCE_BRANCH}" \
              --base "${TARGET_BRANCH}" \
              --title "Update copyright years from ${OLD_YEAR} to ${NEW_YEAR}" \
              --body "This is an automated PR that updates the copyright years from \`${OLD_YEAR}\` to \`${NEW_YEAR}\`."
          fi