# Enables GitHub auto-merge for Autopilot PRs once the Product CI gate is green.
# Label a pull request with `autopilot` or `automerge` to opt in.
# This workflow is informational only — never add it to required status checks.
name: autopilot auto-merge

on:
  pull_request:
    types: [labeled, unlabeled, opened, synchronize, reopened, ready_for_review]
  check_suite:
    types: [completed]

permissions:
  contents: read
  pull-requests: write
  checks: read

concurrency:
  group: autopilot-auto-merge-${{ github.event.pull_request.number || github.run_id }}
  cancel-in-progress: false

jobs:
  auto-merge:
    name: Autopilot auto-merge
    runs-on: [self-hosted, evoo-ci, Linux]
    steps:
      - name: Resolve pull request
        id: pr
        env:
          GH_TOKEN: ${{ github.token }}
        run: |
          set -euo pipefail
          event_name="${{ github.event_name }}"
          number=""
          if [[ "$event_name" == "pull_request" ]]; then
            number="${{ github.event.pull_request.number }}"
          elif [[ "$event_name" == "check_suite" ]]; then
            number="$(jq -r '.check_suite.pull_requests[0].number // empty' "$GITHUB_EVENT_PATH")"
          fi
          if [[ -z "$number" ]]; then
            echo "No pull request in event; skipping."
            echo "enabled=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi
          pr_json="$(gh api "repos/${GITHUB_REPOSITORY}/pulls/${number}")"
          labels="$(jq -r '[.labels[].name] | join(",")' <<<"$pr_json")"
          enabled=false
          if [[ ",${labels}," == *",autopilot,"* || ",${labels}," == *",automerge,"* ]]; then
            enabled=true
          fi
          {
            echo "number=$number"
            echo "head_sha=$(jq -r .head.sha <<<"$pr_json")"
            echo "draft=$(jq -r .draft <<<"$pr_json")"
            echo "labels=$labels"
            echo "enabled=$enabled"
          } >> "$GITHUB_OUTPUT"

      - name: Skip unless Autopilot label is present
        if: steps.pr.outputs.enabled != 'true'
        run: echo "No autopilot/automerge label; skipping."

      - name: Skip draft pull requests
        if: steps.pr.outputs.enabled == 'true' && steps.pr.outputs.draft == 'true'
        run: echo "Draft pull request; auto-merge waits for ready_for_review."

      - name: Verify Product CI on head commit
        id: gate
        if: steps.pr.outputs.enabled == 'true' && steps.pr.outputs.draft != 'true'
        env:
          GH_TOKEN: ${{ github.token }}
          HEAD_SHA: ${{ steps.pr.outputs.head_sha }}
        run: |
          set -euo pipefail
          conclusions=()
          while IFS= read -r conclusion; do
            [[ -n "$conclusion" ]] && conclusions+=("$conclusion")
          done < <(
            gh api "repos/${GITHUB_REPOSITORY}/commits/${HEAD_SHA}/check-runs" --paginate \
              --jq '.check_runs[] | select(.name == "Product CI") | .conclusion'
          )
          if [[ "${#conclusions[@]}" -eq 0 ]]; then
            echo "Product CI has not finished yet."
            echo "ready=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi
          for conclusion in "${conclusions[@]}"; do
            case "$conclusion" in
              success)
                echo "Product CI succeeded."
                echo "ready=true" >> "$GITHUB_OUTPUT"
                exit 0
                ;;
              failure|cancelled|timed_out|action_required)
                echo "Product CI failed ($conclusion); not enabling auto-merge."
                exit 1
                ;;
            esac
          done
          echo "Product CI still pending."
          echo "ready=false" >> "$GITHUB_OUTPUT"

      - name: Enable auto-merge
        if: steps.pr.outputs.enabled == 'true' && steps.pr.outputs.draft != 'true' && steps.gate.outputs.ready == 'true'
        env:
          AUTOPILOT_MERGE_TOKEN: ${{ secrets.AUTOPILOT_MERGE_TOKEN }}
          DRY_RUN: ${{ vars.AUTOPILOT_MERGE_DRY_RUN }}
          PR_NUMBER: ${{ steps.pr.outputs.number }}
        run: |
          set -euo pipefail
          if [[ "$DRY_RUN" == 'true' ]]; then
            echo "AUTOPILOT_MERGE_DRY_RUN=true — would run: gh pr merge $PR_NUMBER --auto --squash"
            exit 0
          fi
          if [[ -n "$AUTOPILOT_MERGE_TOKEN" ]]; then
            export GH_TOKEN="$AUTOPILOT_MERGE_TOKEN"
            echo "Using AUTOPILOT_MERGE_TOKEN."
          else
            export GH_TOKEN="${{ github.token }}"
            echo "Using GITHUB_TOKEN. Add AUTOPILOT_MERGE_TOKEN if branch protection requires a PAT."
          fi
          gh pr merge "$PR_NUMBER" --repo "$GITHUB_REPOSITORY" --auto --squash
          echo "Auto-merge enabled (squash). GitHub merges when branch protection allows."