name: Merge release to pg

on:
  push:
    branches:
      - release  # Trigger on push to the release branch

jobs:
  merge-release-to-pg:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout release branch
        uses: actions/checkout@v3
        with:
          ref: release  # Checkout the release branch

      - name: Fetch all branches
        run: git fetch --all

      - name: Checkout pg branch
        run: git checkout pg

      - name: Get new commits from release
        id: get_commits
        run: |
          COMMITS=$(git log pg..release --oneline | awk '{print $1}')
          echo "COMMITS=\"$COMMITS\"" >> $GITHUB_ENV

      - name: Merge commits one by one
        id: merge_commits
        run: |
          # Initialize an empty list for conflicted commits
          conflicted_commits=()

          # Convert the string of commits to an array
          IFS=' ' read -r -a commit_array <<< "$COMMITS"

          # Loop through each commit
          for commit in "${commit_array[@]}"; do
            echo "Merging commit $commit"
            git cherry-pick $commit || {
              echo "Conflict detected with commit $commit"
              conflicted_commits+=($commit)
              git cherry-pick --abort
            }
          done

          # Save conflicted commits to environment variable
          echo "CONFLICTED_COMMITS=\"${conflicted_commits[@]}\"" >> $GITHUB_ENV

      - name: Push changes
        if: success() && steps.merge_commits.outputs.CONFLICTED_COMMITS == ''
        run: |
          git push origin pg

      - name: Notify on merge conflicts
        if: steps.merge_commits.outputs.CONFLICTED_COMMITS != ''
        env:
          REPOSITORY_URL: ${{ github.repositoryUrl }}
        run: |
          # Prepare the message for Slack
          message="Merge conflict detected while merging release into pg branch. Conflicted commits:\n"
          for commit in $CONFLICTED_COMMITS; do
            commit_url="$REPOSITORY_URL/commit/$commit"
            message+="$commit_url\n"
          done

          # Send the message to Slack
          # This unwieldy horror of a sed command, converts standard Markdown links to Slack's unwieldy link syntax.
          slack_message="$(echo "$message" | sed -E 's/\[([^]]+)\]\(([^)]+)\)/<\2|\1>/g')"

          # This is the ChannelId of the proj postgres channel.
          body="$(jq -nc \
            --arg channel C06Q3A97USE \
            --arg text "$slack_message" \
            '$ARGS.named'
          )"

          curl --version
          curl -v https://slack.com/api/chat.postMessage \
            --header 'Authorization: Bearer ${{ secrets.SLACK_APPSMITH_ALERTS_TOKEN }}' \
            --header 'Content-Type: application/json; charset=utf-8' \
            --data-raw "$body"