#!/usr/bin/env bash
set -euo pipefail

# Aggiunge un hostname a spec.template.spec.hostAliases del Deployment cert-manager.
#
# Uso:
#   ./add-cert-manager-hostalias.sh <hostname>
#
# Esempio:
#   ./add-cert-manager-hostalias.sh main-gateway-nginx.nginx-gateway.svc.cluster.local
#   ./add-cert-manager-hostalias.sh api.internal

DEPLOYMENT_NAME="cert-manager"
DEPLOYMENT_NS="cert-manager"
TARGET_IP="10.43.37.118"
HOSTNAME_VAL="${1:-}"

if [[ -z "$HOSTNAME_VAL" ]]; then
  echo "Uso: $0 <hostname>" >&2
  exit 1
fi

if ! command -v kubectl >/dev/null 2>&1; then
  echo "Errore: kubectl non trovato nel PATH" >&2
  exit 1
fi

if ! command -v jq >/dev/null 2>&1; then
  echo "Errore: jq non trovato nel PATH" >&2
  echo "Installa jq e riprova." >&2
  exit 1
fi

# Idempotenza: controlla solo il blocco hostAliases associato a TARGET_IP.
EXISTING_HOSTNAMES="$(kubectl get deployment "$DEPLOYMENT_NAME" -n "$DEPLOYMENT_NS" -o jsonpath="{.spec.template.spec.hostAliases[?(@.ip=='${TARGET_IP}')].hostnames[*]}" 2>/dev/null || true)"
if echo " $EXISTING_HOSTNAMES " | grep -Fq " $HOSTNAME_VAL "; then
  echo "Hostname '$HOSTNAME_VAL' gia presente per IP ${TARGET_IP} in ${DEPLOYMENT_NS}/${DEPLOYMENT_NAME}. Nessuna modifica."
  exit 0
fi

DEPLOY_JSON="$(kubectl get deployment "$DEPLOYMENT_NAME" -n "$DEPLOYMENT_NS" -o json)"

UPDATED_HOST_ALIASES="$({
  echo "$DEPLOY_JSON" | jq -c --arg ip "$TARGET_IP" --arg hostname "$HOSTNAME_VAL" '
    (.spec.template.spec.hostAliases //= [])
    | if any(.spec.template.spec.hostAliases[]?; .ip == $ip) then
        .spec.template.spec.hostAliases |= map(
          if .ip == $ip then
            if ((.hostnames // []) | index($hostname)) then
              .
            else
              .hostnames = ((.hostnames // []) + [$hostname])
            end
          else
            .
          end
        )
      else
        .spec.template.spec.hostAliases += [{"ip": $ip, "hostnames": [$hostname]}]
      end
    | .spec.template.spec.hostAliases
  '
} )"

PATCH_PAYLOAD="$(jq -cn --argjson hostAliases "$UPDATED_HOST_ALIASES" '{spec:{template:{spec:{hostAliases:$hostAliases}}}}')"

kubectl patch deployment "$DEPLOYMENT_NAME" \
  -n "$DEPLOYMENT_NS" \
  --type=merge \
  -p "$PATCH_PAYLOAD" >/dev/null

echo "Hostname aggiunto con successo."
echo "  Deployment: ${DEPLOYMENT_NS}/${DEPLOYMENT_NAME}"
echo "  IP       : ${TARGET_IP}"
echo "  Hostname : ${HOSTNAME_VAL}"