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

KUBECONFIG_PATH="${KUBECONFIG:-${LAB_KUBECONFIG_PATH:-/home/jv/.kube/config}}"
CONTROL_PLANE_NODE="${LAB_CONTROL_PLANE_NODE:-debian}"
TAINT_KEY="${LAB_CONTROL_PLANE_TAINT_KEY:-node-role.kubernetes.io/control-plane}"
TAINT_EFFECT="${LAB_CONTROL_PLANE_TAINT_EFFECT:-NoSchedule}"

usage() {
    cat <<EOF
Usage: ./jeannie control-plane {status|taint|untaint|pods}

status   Show node taints and non-system pods currently scheduled on ${CONTROL_PLANE_NODE}.
taint    Add ${TAINT_KEY}:${TAINT_EFFECT} to keep normal app/data-plane pods off the control plane.
untaint  Remove ${TAINT_KEY}:${TAINT_EFFECT} from the control plane.
pods     List non-system pods currently scheduled on ${CONTROL_PLANE_NODE}.

Environment:
  LAB_CONTROL_PLANE_NODE=${CONTROL_PLANE_NODE}
EOF
}

require_kubectl() {
    if ! command -v kubectl >/dev/null 2>&1; then
        echo "kubectl is required." >&2
        exit 1
    fi
    if [ ! -s "$KUBECONFIG_PATH" ]; then
        echo "kubeconfig is missing: $KUBECONFIG_PATH" >&2
        exit 1
    fi
    if ! kubectl --kubeconfig "$KUBECONFIG_PATH" get node "$CONTROL_PLANE_NODE" >/dev/null 2>&1; then
        echo "control-plane node not found: ${CONTROL_PLANE_NODE}" >&2
        echo "Set LAB_CONTROL_PLANE_NODE if the node has a different name." >&2
        exit 1
    fi
}

show_taints() {
    kubectl --kubeconfig "$KUBECONFIG_PATH" get node "$CONTROL_PLANE_NODE" \
        -o jsonpath='{range .spec.taints[*]}{.key}{"="}{.value}{":"}{.effect}{"\n"}{end}' |
        sed '/^$/d' || true
}

show_non_system_pods() {
    kubectl --kubeconfig "$KUBECONFIG_PATH" get pods -A \
        --field-selector "spec.nodeName=${CONTROL_PLANE_NODE}" \
        -o custom-columns='NAMESPACE:.metadata.namespace,NAME:.metadata.name,STATUS:.status.phase' --no-headers |
        awk '$1 !~ /^(kube-system|calico-system|tigera-operator)$/ { print }'
}

case "${1:-status}" in
    status)
        require_kubectl
        echo "Node: ${CONTROL_PLANE_NODE}"
        echo
        echo "Taints:"
        if ! show_taints | sed 's/^/  /'; then
            true
        fi
        echo
        echo "Non-system pods currently on control plane:"
        if ! show_non_system_pods | sed 's/^/  /'; then
            true
        fi
        ;;
    taint)
        require_kubectl
        kubectl --kubeconfig "$KUBECONFIG_PATH" taint node "$CONTROL_PLANE_NODE" "${TAINT_KEY}:${TAINT_EFFECT}" --overwrite
        echo
        echo "Current taints:"
        show_taints | sed 's/^/  /'
        ;;
    untaint)
        require_kubectl
        kubectl --kubeconfig "$KUBECONFIG_PATH" taint node "$CONTROL_PLANE_NODE" "${TAINT_KEY}:${TAINT_EFFECT}-" || true
        echo
        echo "Current taints:"
        show_taints | sed 's/^/  /'
        ;;
    pods)
        require_kubectl
        show_non_system_pods
        ;;
    -h|--help|help)
        usage
        ;;
    *)
        usage >&2
        exit 1
        ;;
esac