name: Merge translations back to older branch

on:
  schedule:
    # After the 04:00 CPython sync and 05:00 maintenance runs, so the newest
    # 3.15 translations are what get copied.
    - cron: '30 5 * * *'
  workflow_dispatch:
    inputs:
      dst_branch:
        description: 'Branch that receives the translations'
        required: false
        default: '3.14'
      dry_run:
        description: 'Report only, do not commit or push'
        type: boolean
        default: false
      overwrite:
        description: 'On conflicts take the 3.15 translation instead of keeping the existing one'
        type: boolean
        default: false

permissions:
  contents: write

# Shared with sync-with-cpython.yml and maintenance.yml: they push to 3.15,
# this one reads 3.15, so they must not overlap.
concurrency:
  group: repo-writes
  cancel-in-progress: false

env:
  SRC_BRANCH: '3.15'
  DST_BRANCH: ${{ github.event.inputs.dst_branch || '3.14' }}

jobs:
  merge-back:
    runs-on: ubuntu-latest
    timeout-minutes: 15
    steps:
      # fetch-depth 0 brings every branch down as origin/*, which is how the
      # script finds 3.14 (it creates the local branch itself).
      - name: Checkout translation repo
        uses: actions/checkout@v4
        with:
          ref: ${{ env.SRC_BRANCH }}
          fetch-depth: 0

      - name: Configure git identity
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"

      - name: Merge ${{ env.SRC_BRANCH }} translations into ${{ env.DST_BRANCH }}
        env:
          DRY_RUN: ${{ github.event.inputs.dry_run }}
          OVERWRITE: ${{ github.event.inputs.overwrite }}
        run: |
          args=(--src "$SRC_BRANCH" --dst "$DST_BRANCH" --fetch
                --conflicts-file "$RUNNER_TEMP/conflicts.txt")
          if [ "$DRY_RUN" = "true" ]; then
            args+=(--dry-run)
          else
            args+=(--push)
          fi
          if [ "$OVERWRITE" = "true" ]; then
            args+=(--overwrite)
          fi
          python3 scripts/po_merge_back.py "${args[@]}" | tee "$RUNNER_TEMP/report.txt"

      # Conflicts (both branches translated, different text) are kept as-is on
      # the destination; surface them so a human can decide.
      - name: Publish report
        if: always()
        run: |
          {
            echo "### Merge ${SRC_BRANCH}  ${DST_BRANCH}"
            if [ -f "$RUNNER_TEMP/report.txt" ]; then
              echo '```'
              tail -n 12 "$RUNNER_TEMP/report.txt"
              echo '```'
            fi
            if [ -s "$RUNNER_TEMP/conflicts.txt" ]; then
              echo "Conflicts (kept as ${DST_BRANCH})"
              echo
              echo '```'
              head -c 200000 "$RUNNER_TEMP/conflicts.txt"
              echo '```'
              echo ""
            fi
          } >> "$GITHUB_STEP_SUMMARY"