name: Promotion Gate

# dev PRs: no gate (engineer self-merges).
# uat PRs: QA approval required.
# main PRs: UAT approval required (uat→main promotions).

on:
  pull_request_review:
    types: [submitted, dismissed]
  pull_request:
    branches: [uat, main]
    types: [opened, reopened, synchronize]

jobs:
  promotion-gate:
    name: Promotion Gate
    runs-on: ubuntu-latest
    container: ubuntu:latest
    timeout-minutes: 5

    steps:
      - name: Install dependencies
        run: apt-get update -qq && apt-get install -y --no-install-recommends ca-certificates curl jq

      - name: Check promotion approval
        env:
          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
          REPO: ${{ github.repository }}
          BASE_REF: ${{ github.base_ref }}
        run: |
          if [ -z "${PR_NUMBER}" ] || [ "${PR_NUMBER}" = "null" ]; then
            echo "::notice::No PR number in context. Skipping promotion gate."
            exit 0
          fi

          echo "Checking promotion gate for PR #${PR_NUMBER} targeting ${BASE_REF} in ${REPO}"

          if [ -z "${BASE_REF}" ] && [ -n "${PR_NUMBER}" ] && [ "${PR_NUMBER}" != "null" ]; then
            BASE_REF=$(curl -sf \
              -H "Authorization: token ${GITEA_TOKEN}" \
              -H "Accept: application/json" \
              "https://git.farh.net/api/v1/repos/${REPO}/pulls/${PR_NUMBER}" | jq -r '.base.ref')
            echo "BASE_REF was empty; resolved from PR #${PR_NUMBER} API: ${BASE_REF}"
          fi

          # Determine required reviewer based on target branch
          case "${BASE_REF}" in
            dev)
              echo "Target is dev — no review required. Engineers self-merge."
              exit 0
              ;;
            uat)
              REQUIRED_REVIEWER="pe_regina"
              GATE_NAME="QA"
              ;;
            main)
              REQUIRED_REVIEWER="pe_regina"
              GATE_NAME="QA"
              # For plugin repos (Pipeline A), UAT approval is needed for uat→main
              # Check if the source branch is uat
              SOURCE_REF=$(curl -sf \
                -H "Authorization: token ${GITEA_TOKEN}" \
                -H "Accept: application/json" \
                "https://git.farh.net/api/v1/repos/${REPO}/pulls/${PR_NUMBER}" | jq -r '.head.ref')

              if [ "${SOURCE_REF}" = "uat" ]; then
                REQUIRED_REVIEWER="pe_patty"
                GATE_NAME="UAT"
              fi
              ;;
            *)
              echo "::notice::Target branch '${BASE_REF}' has no promotion gate configured."
              exit 0
              ;;
          esac

          echo "Required reviewer: ${REQUIRED_REVIEWER} (${GATE_NAME})"

          # For uat→main promotions, pe_patty may not be able to review (bot account).
          # Accept pe_nancy (CTO) as a valid alternative reviewer.
          ALT_REVIEWER=""
          if [ "${REQUIRED_REVIEWER}" = "pe_patty" ]; then
            ALT_REVIEWER="pe_nancy"
          fi

          REVIEWS=$(curl -sf \
            -H "Authorization: token ${GITEA_TOKEN}" \
            -H "Accept: application/json" \
            "https://git.farh.net/api/v1/repos/${REPO}/pulls/${PR_NUMBER}/reviews")

          if [ -z "${REVIEWS}" ] || [ "${REVIEWS}" = "null" ]; then
            echo "::warning::Could not fetch reviews for PR #${PR_NUMBER}."
            exit 1
          fi

          REVIEWER_APPROVED=$(printf '%s' "${REVIEWS}" | jq -r --arg user "${REQUIRED_REVIEWER}" \
            '[.[] | select(.user.login == $user)] | last | if .state then .state == "APPROVED" else false end')

          echo "${GATE_NAME} (${REQUIRED_REVIEWER}) approved: ${REVIEWER_APPROVED}"

          # Fallback: check if CTO approved as alternative for uat→main
          if [ "${REVIEWER_APPROVED}" != "true" ] && [ -n "${ALT_REVIEWER}" ]; then
            REVIEWER_APPROVED=$(printf '%s' "${REVIEWS}" | jq -r --arg user "${ALT_REVIEWER}" \
              '[.[] | select(.user.login == $user)] | last | if .state then .state == "APPROVED" else false end')
            if [ "${REVIEWER_APPROVED}" = "true" ]; then
              echo "CTO (${ALT_REVIEWER}) approved as fallback for UAT gate."
            fi
          fi

          if [ "${REVIEWER_APPROVED}" = "true" ]; then
            echo "Promotion gate passed: ${GATE_NAME} has approved."
          else
            echo "Promotion gate failed: waiting for ${GATE_NAME} approval from ${REQUIRED_REVIEWER}."
            exit 1
          fi