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

usage() {
  cat <<'EOF'
Usage:
  reset-ns.sh -n <namespace> [options]

Required:
  -n <namespace>     Namespace to reset (REQUIRED; no implicit default)

Options:
  --delete-pvcs      Delete all PVCs in the namespace (DANGEROUS: wipes state)
  --delete-config    Delete ConfigMaps and Secrets (VERY DANGEROUS)
  --keep-registry    Preserve registry workloads/services in the target namespace
  --clear-node-reservations
                    Best-effort clear node reservations by uncordoning nodes
  --no-clear-node-reservations
                    Disable node reservation cleanup (default)
  -h, --help         Show this help

Notes:
  • This script NEVER deletes the namespace itself — only resources inside it.
  • It will NOT delete the CNPG operator (cluster-wide), but if CNPG CRDs exist,
    it WILL delete CNPG Cluster resources IN THE TARGET NAMESPACE so pods stop respawning.
  • It will NEVER delete Service "kubernetes" in the default namespace.

Examples:
  ./reset-ns.sh -n default
  ./reset-ns.sh -n default --delete-pvcs
EOF
}

NS=""
DELETE_PVCS=false
DELETE_CONFIG=false
KEEP_REGISTRY=false
CLEAR_NODE_RESERVATIONS=false

[[ $# -eq 0 ]] && usage && exit 1

while [[ $# -gt 0 ]]; do
  case "$1" in
    -n) NS="${2:-}"; shift 2 ;;
    --delete-pvcs) DELETE_PVCS=true; shift ;;
    --delete-config) DELETE_CONFIG=true; shift ;;
    --keep-registry) KEEP_REGISTRY=true; shift ;;
    --clear-node-reservations) CLEAR_NODE_RESERVATIONS=true; shift ;;
    --no-clear-node-reservations) CLEAR_NODE_RESERVATIONS=false; shift ;;
    -h|--help) usage; exit 0 ;;
    *) echo "Unknown argument: $1"; echo; usage; exit 1 ;;
  esac
done

if [[ -z "${NS}" ]]; then
  echo "ERROR: -n <namespace> is required"
  echo
  usage
  exit 1
fi

# Refuse truly critical system namespaces; allow "default" if explicitly passed.
case "$NS" in
  kube-system|kube-public|kube-node-lease)
    echo "REFUSING to operate on protected namespace: $NS"
    exit 2
    ;;
esac

echo "Resetting namespace: $NS"
echo "  DELETE_PVCS=$DELETE_PVCS"
echo "  DELETE_CONFIG=$DELETE_CONFIG"
echo "  KEEP_REGISTRY=$KEEP_REGISTRY"
echo "  CLEAR_NODE_RESERVATIONS=$CLEAR_NODE_RESERVATIONS"
echo

if ! kubectl get namespace "$NS" >/dev/null 2>&1; then
  echo "Namespace '$NS' does not exist; skipping."
  exit 0
fi

is_registry_resource() {
  local kind="$1"
  local name="$2"

  [[ "$KEEP_REGISTRY" == "true" ]] || return 1

  if [[ "$name" == "registry" ]]; then
    return 0
  fi

  local app_label=""
  app_label=$(kubectl -n "$NS" get "$kind" "$name" -o jsonpath='{.metadata.labels.app}' 2>/dev/null || true)
  [[ "$app_label" == "registry" ]]
}

scale_down_workloads() {
  local kind="$1"
  local item
  while IFS= read -r item; do
    [[ -z "$item" ]] && continue
    if is_registry_resource "$kind" "$item"; then
      echo "  preserving ${kind}/${item}"
      continue
    fi
    kubectl -n "$NS" scale "$kind" "$item" --replicas=0 2>/dev/null || true
  done < <(kubectl -n "$NS" get "$kind" -o jsonpath='{range .items[*]}{.metadata.name}{"\n"}{end}' 2>/dev/null || true)
}

delete_kind_resources() {
  local kind="$1"
  local item
  while IFS= read -r item; do
    [[ -z "$item" ]] && continue
    if is_registry_resource "$kind" "$item"; then
      echo "  preserving ${kind}/${item}"
      continue
    fi
    kubectl -n "$NS" delete "$kind" "$item" --ignore-not-found --wait=false 2>/dev/null || true
  done < <(kubectl -n "$NS" get "$kind" -o jsonpath='{range .items[*]}{.metadata.name}{"\n"}{end}' 2>/dev/null || true)
}

# -------------------------
# CNPG: stop respawning in THIS namespace by deleting CNPG Cluster CRs
# Detect via CRD existence (more reliable than kubectl api-resources on some setups)
# -------------------------
if kubectl get crd clusters.postgresql.cnpg.io >/dev/null 2>&1; then
  echo "CNPG detected (CRD clusters.postgresql.cnpg.io exists)."
  echo "Deleting CNPG resources in namespace '$NS' (operator NOT touched)..."

  # List first (helpful visibility; won't fail the script)
  kubectl -n "$NS" get clusters.postgresql.cnpg.io 2>/dev/null || true

  # Delete Cluster CRs (this is what causes StatefulSets/Pods to be recreated)
  kubectl -n "$NS" delete clusters.postgresql.cnpg.io --all --ignore-not-found --wait=false

  # Related CNPG CRs (safe best-effort)
  if kubectl get crd poolers.postgresql.cnpg.io >/dev/null 2>&1; then
    kubectl -n "$NS" delete poolers.postgresql.cnpg.io --all --ignore-not-found --wait=false || true
  fi
  if kubectl get crd backups.postgresql.cnpg.io >/dev/null 2>&1; then
    kubectl -n "$NS" delete backups.postgresql.cnpg.io --all --ignore-not-found --wait=false || true
  fi
  if kubectl get crd scheduledbackups.postgresql.cnpg.io >/dev/null 2>&1; then
    kubectl -n "$NS" delete scheduledbackups.postgresql.cnpg.io --all --ignore-not-found --wait=false || true
  fi

  # Small pause so the operator observes deletion and stops reconciling
  sleep 2
else
  echo "CNPG not detected via CRD check; skipping CNPG cleanup."
fi

# -------------------------
# Scale down controllers to reduce churn
# -------------------------
echo "Scaling down Deployments/StatefulSets..."
scale_down_workloads deployment
scale_down_workloads statefulset

# -------------------------
# Delete common workload controllers
# -------------------------
echo "Deleting workload controllers..."
delete_kind_resources deployment
delete_kind_resources statefulset
delete_kind_resources daemonset
delete_kind_resources replicaset
delete_kind_resources job
delete_kind_resources cronjob

# -------------------------
# Delete services safely (NEVER delete "kubernetes" service in default)
# -------------------------
echo "Deleting services (excluding service/kubernetes)..."
for s in $(kubectl -n "$NS" get svc -o jsonpath='{range .items[*]}{.metadata.name}{"\n"}{end}' 2>/dev/null || true); do
  if [[ "$NS" == "default" && "$s" == "kubernetes" ]]; then
    echo "  skipping protected service: default/kubernetes"
    continue
  fi
  if is_registry_resource service "$s"; then
    echo "  preserving service/$s"
    continue
  fi
  kubectl -n "$NS" delete svc "$s" --ignore-not-found --wait=false
done

echo "Deleting ingress & networkpolicy..."
kubectl -n "$NS" delete ingress,networkpolicy --all --ignore-not-found --wait=false

# -------------------------
# Delete HPA / PDB
# -------------------------
echo "Deleting HPA / PDB (if any)..."
kubectl -n "$NS" delete hpa,pdb --all --ignore-not-found --wait=false 2>/dev/null || true

# -------------------------
# Optional config wipe
# -------------------------
if [[ "$DELETE_CONFIG" == "true" ]]; then
  echo "Deleting ConfigMaps..."
  kubectl -n "$NS" delete configmap --all --ignore-not-found --wait=false

  echo "Deleting Secrets (excluding service-account tokens)..."
  for s in $(kubectl -n "$NS" get secret -o jsonpath='{range .items[*]}{.metadata.name}{"\n"}{end}' 2>/dev/null || true); do
    type=$(kubectl -n "$NS" get secret "$s" -o jsonpath='{.type}' 2>/dev/null || true)
    [[ "$type" == "kubernetes.io/service-account-token" ]] && continue
    kubectl -n "$NS" delete secret "$s" --ignore-not-found --wait=false
  done
fi

# -------------------------
# Optional PVC wipe
# -------------------------
if [[ "$DELETE_PVCS" == "true" ]]; then
  echo "Deleting PVCs..."
  kubectl -n "$NS" delete pvc --all --ignore-not-found --wait=false
fi

# -------------------------
# Final pod cleanup
# -------------------------
echo "Deleting remaining pods..."
deleted_pods=()
for p in $(kubectl -n "$NS" get pod -o jsonpath='{range .items[*]}{.metadata.name}{"\n"}{end}' 2>/dev/null || true); do
  if is_registry_resource pod "$p"; then
    echo "  preserving pod/$p"
    continue
  fi
  kubectl -n "$NS" delete pod "$p" --ignore-not-found --wait=false 2>/dev/null || true
  deleted_pods+=("$p")
done

echo "Waiting for pods to terminate..."
if [[ ${#deleted_pods[@]} -gt 0 ]]; then
  deadline=$((SECONDS + 180))
  for p in "${deleted_pods[@]}"; do
    while kubectl -n "$NS" get pod "$p" >/dev/null 2>&1; do
      if (( SECONDS >= deadline )); then
        echo "  timeout waiting for pod/$p to terminate; continuing"
        break
      fi
      sleep 2
    done
    if ! kubectl -n "$NS" get pod "$p" >/dev/null 2>&1; then
      echo "  pod/$p terminated"
    fi
  done
fi

if [[ "$CLEAR_NODE_RESERVATIONS" == "true" ]]; then
  echo "Clearing node reservations (uncordon all nodes)..."
  while IFS= read -r node; do
    [[ -z "$node" ]] && continue
    kubectl uncordon "$node" >/dev/null 2>&1 || true
  done < <(kubectl get nodes -o jsonpath='{range .items[*]}{.metadata.name}{"\n"}{end}' 2>/dev/null || true)
fi

echo
echo "Namespace '$NS' reset complete (namespace preserved)."