#!/usr/bin/env bash
# Longhorn preflight check — runs via SSH during --check mode before op starts.
# Verifies cluster connectivity and storage node availability.
# Exit 0 = checks pass. Exit 1 = hard fail (op should be aborted).
set -euo pipefail

LONGHORN_REPLICA_COUNT="${LONGHORN_REPLICA_COUNT:-2}"

# ── kubectl resolution (same chain as install-longhorn.sh) ───────────────────
if command -v k0s &>/dev/null && k0s kubectl version --client=true &>/dev/null; then
    kubectl() { k0s kubectl "$@"; }
    K0S_DATA_DIR="${K0S_DATA_DIR:-/var/lib/k0s}"
    if [ -z "${KUBECONFIG:-}" ] || [ ! -f "${KUBECONFIG}" ]; then
        if [ -f "${K0S_DATA_DIR}/pki/admin.conf" ]; then
            export KUBECONFIG="${K0S_DATA_DIR}/pki/admin.conf"
        else
            export KUBECONFIG="/tmp/k0s-longhorn-check.conf"
            k0s kubeconfig admin > "${KUBECONFIG}"
        fi
    fi
else
    for f in /etc/kubernetes/admin.conf /root/.kube/config; do
        if [ -f "$f" ]; then export KUBECONFIG="$f"; break; fi
    done
fi

echo "=== longhorn preflight: verifying cluster connectivity ==="
if ! kubectl cluster-info --request-timeout=5s &>/dev/null; then
    echo "❌ Cluster not reachable — check kubeconfig and API server"
    exit 1
fi
echo "✓ cluster reachable"

echo "=== longhorn preflight: verifying storage node availability (need >= ${LONGHORN_REPLICA_COUNT}) ==="
ready=$(kubectl get nodes -l node.longhorn.io/create-default-disk=true \
    --no-headers 2>/dev/null | grep -v NotReady | wc -l | tr -d ' ')

if [ "${ready}" -lt "${LONGHORN_REPLICA_COUNT}" ]; then
    echo "❌ ${ready} storage node(s) Ready — need ${LONGHORN_REPLICA_COUNT}"
    echo ""
    echo "Nodes with label node.longhorn.io/create-default-disk=true:"
    kubectl get nodes -l node.longhorn.io/create-default-disk=true --no-headers 2>/dev/null || true
    echo ""
    echo "Provision missing strg nodes first:"
    echo "  just provision-storage libre-wuji-strg-0"
    echo "  just provision-storage libre-wuji-strg-1"
    echo "  just deploy-storage libre-wuji-strg-0"
    echo "  just deploy-storage libre-wuji-strg-1"
    exit 1
fi
echo "✓ ${ready} storage node(s) Ready (need ${LONGHORN_REPLICA_COUNT})"