name: Automatically create CHANGELOG for O2 releases

on:
  push:
  workflow_dispatch:
    inputs:
      LAST_RELEASE_DATE:
        description: 'Time of the last release'
        required: true
        default: ''
  schedule:
    - cron:  '0 0 * * *'

jobs:
  build:
    runs-on: macOS-latest
    if: github.repository == 'AliceO2Group/AliceO2'

    steps:
    - uses: actions/checkout@v5
    - name: Set up Python 3.10
      uses: actions/setup-python@v6
      with:
        python-version: '3.10'
    - uses: actions/cache@v5
      name: Configure pip caching
      with:
        path: ~/.cache/pip
        key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
        restore-keys: |
          ${{ runner.os }}-pip-
    - uses: octokit/graphql-action@v2.x
      id: get_latest_o2_releases
      with:
        query: |
              {
                repository(name: "AliceO2", owner: "AliceO2Group") {
                  releases(last:14) {
                    edges {
                      node {
                        tagName
                        publishedAt
                      }
                    }
                  }
                }
              }
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    - uses: octokit/graphql-action@v2.x
      id: get_latest_o2_prs
      with:
        query: |
              {
                repository(name: "AliceO2", owner: "AliceO2Group") {
                  pullRequests(last: 100) {
                    edges {
                      node {
                        state
                        mergedAt
                        title
                        number
                        author {
                          login
                        }
                        files(last: 100) {
                          edges {
                            node {
                             path
                            }
                          }
                        }
                      }
                    }
                  }
                }
              }
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    - name: Update Changelog
      run: |
        set -x
        mkdir -p doc/data
        # We create new files once per month, mostly so that
        # we can keep the query results small. It does not
        # matter if we get results from different months,
        # as what matters is how we merge them.
        CURRENT_MONTH=`date +%Y-%m`
        cat <<\EOF > doc/data/${CURRENT_MONTH}-o2_releases.json
        ${{ steps.get_latest_o2_releases.outputs.data }}
        EOF
        cat <<\EOF > doc/data/${CURRENT_MONTH}-o2_prs.json
        ${{ steps.get_latest_o2_prs.outputs.data }}
        EOF
        # FIXME: this should really be one second after the last release
        #        being published
        LAST_RELEASE="${{ github.event.inputs.LAST_RELEASE_DATE }}"
        MERGED_AFTER=${LAST_RELEASE:-$(date -v -14d +%Y-%m-%d)}
        # Here we convert all the json files to per subsystem
        # logs, using the MERGED_AFTER date to further filter them.
        # Notice we can have duplicates in each file,
        # as they will be removed in the next iteration.
        # FIXME: it's probably enough to iterate on the last two
        #        months, at least for bi-weekly releases.
        for f in doc/data/*_prs.json; do
          for x in Algorithm Analysis Common DataFormats Detectors EventVisualisation Examples Framework Generators Steer Testing Utilities; do
            cat $f | jq ".repository.pullRequests.edges[].node | select(.files.edges[].node.path | test(\"$x\")) | del(.files) | select(.state == \"MERGED\" and .mergedAt >= \"${MERGED_AFTER}\")" > /tmp/${x}_prs.json
            if [ ! X`jq -s length /tmp/${x}_prs.json` = X0 ]; then
              cat /tmp/${x}_prs.json | jq -r '"- [#\(.number)](https://github.com/AliceO2Group/AliceO2/pull/\(.number)) \(.mergedAt | split("T")[0]): \(.title) by [@\(.author.login)](https://github.com/\(.author.login))"' | sort -u >> /tmp/${x}_prs.md
            fi
          done
        done
        # Here we do the merging by iterating on the subsystems adding
        # an header for each and removing the duplicates.
        printf "# Changes since ${MERGED_AFTER}\n\n" > CHANGELOG.md
        for x in Algorithm Analysis Common DataFormats Detectors EventVisualisation Examples Framework Generators Steer Testing Utilities; do
          [ ! -f /tmp/${x}_prs.md ] && continue
          printf "## Changes in $x\n\n" >> CHANGELOG.md
          cat /tmp/${x}_prs.md | sort -k3 | uniq >> CHANGELOG.md
        done
    - name: Commit and push if changed
      run: |-
        git add CHANGELOG.md doc/data
        git diff
        git config --global user.email "github-action-bot@example.com"
        git config --global user.name "GitHub Action Bot"
        git commit -m "Updated README" -a || echo "No changes to commit"
        git push origin HEAD:changelog -f
        # If the PR already exists, the force-push will have updated it.
        # It's fine if this step fails.
        GH_TOKEN=${{ secrets.GITHUB_TOKEN }} gh pr create -B dev -H changelog -t 'Auto-generated changelog' -b 'The following changelog has been automatically generated.' || true