name: Comment driven automations
on:
  issue_comment:
    types: [ created ]

jobs:
  comment-driven-automation:
    if: |
      github.event.issue.pull_request &&
      startsWith(github.event.comment.body, '@opentelemetrybot ')

    runs-on: ubuntu-latest
    steps:
      - name: Get command
        env:
          BODY: ${{ github.event.comment.body }}
        run: |
          # intentionally only looking at the first line of the body
          command=$(echo "$BODY" | head -1 | sed "s/^@opentelemetrybot //")
          echo "COMMAND=$command" >> $GITHUB_ENV

      - uses: actions/checkout@v3
        with:
          # history is needed for the update command to run "git merge"
          fetch-depth: ${{ env.COMMAND == 'update' && '0' || '1' }}

      - name: Check out PR branch
        if: |
          env.COMMAND == 'spotless' ||
          env.COMMAND == 'license' ||
          env.COMMAND == 'apidiff' ||
          env.COMMAND == 'update'
        env:
          NUMBER: ${{ github.event.issue.number }}
          GH_TOKEN: ${{ github.token }}
        run: |
          gh pr checkout $NUMBER

      - name: Set up Gradle cache
        if: |
          env.COMMAND == 'spotless' ||
          env.COMMAND == 'license' ||
          env.COMMAND == 'apidiff'
        uses: gradle/gradle-build-action@v2
        with:
          cache-read-only: true

      - name: Use CLA approved github bot
        if: |
          env.COMMAND == 'spotless' ||
          env.COMMAND == 'license' ||
          env.COMMAND == 'apidiff' ||
          env.COMMAND == 'update'
        run: .github/scripts/use-cla-approved-github-bot.sh

      - name: Run command
        env:
          NUMBER: ${{ github.event.issue.number }}
          GH_TOKEN: ${{ secrets.OPENTELEMETRYBOT_GITHUB_TOKEN }}
        run: |
          available_commands="Available commands:
            * \`@opentelemetrybot spotless\` - runs \`./gradlew spotlessApply\`
            * \`@opentelemetrybot license\` - runs \`./gradlew generateLicenseReport\`
            * \`@opentelemetrybot apidiff\` - runs \`./gradlew jApiCmp\`
            * \`@opentelemetrybot update\` - updates branch with merge commit
            * \`@opentelemetrybot rerun\` - re-runs failed checks (NOT IMPLEMENTED YET)
            * \`@opentelemetrybot help\` - displays available commands
          "
          # TODO add thumbs up on triggering comment
          if [[ "$COMMAND" == "spotless" ]]; then
            ./gradlew spotlessApply
            if git diff --quiet; then
              gh pr comment $NUMBER --body "Already up-to-date"
              exit 0 # success
            fi
            git commit -a -m "./gradlew spotlessApply"
            git push
          elif [[ "$COMMAND" == "license" ]]; then
            ./gradlew generateLicenseReport
            git add licenses
            # there's always going to one line difference due to the timestamp included in the report
            if [[ $(git diff --cached --shortstat licenses) == " 1 file changed, 1 insertion(+), 1 deletion(-)" ]]
            then
              gh pr comment $NUMBER --body "Already up-to-date"
              exit 0 # success
            fi
            git commit -m "./gradlew generateLicenseReport"
            git push
          elif [[ "$COMMAND" == "apidiff" ]]; then
            ./gradlew jApiCmp
            git add docs/apidiffs
            if git diff --cached --quiet; then
              gh pr comment $NUMBER --body "Already up-to-date"
              exit 0 # success
            fi
            git commit -m "./gradlew jApiCmp"
            git push
          elif [[ "$COMMAND" == "update" ]]; then
            # TODO check for up-to-date
            git merge --no-edit origin/main
            git push
          elif [[ "$COMMAND" == "rerun" ]]; then
            echo TODO
            # gh run rerun  --failed
          elif [[ "$COMMAND" == "help" ]]; then
            gh pr comment $NUMBER --body "$available_commands"
          else
            body="Unknown command: \`$COMMAND\`

            $available_commands
            "
            gh pr comment $NUMBER --body "$body"
          fi