#!/usr/bin/env bash
# T21: EDS warming + atomic swap on scale 1->3 (hitless, no sidecar restart)
set -euo pipefail

NS=istio-vt-t21
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

cleanup() {
  echo "[cleanup] deleting namespace ${NS}"
  kubectl delete namespace "${NS}" --wait=false --ignore-not-found
}
trap cleanup EXIT

echo "[1/7] create namespace ${NS} (istio-injection=enabled)"
kubectl create namespace "${NS}"
kubectl label namespace "${NS}" istio-injection=enabled

echo "[2/7] apply manifest"
kubectl apply -f "${SCRIPT_DIR}/manifest.yaml"

echo "[3/7] wait for client Ready and echo rollout"
kubectl -n "${NS}" wait --for=condition=Ready pod/client --timeout=90s
kubectl -n "${NS}" rollout status deploy/echo --timeout=90s

CLIENT_START=$(kubectl -n "${NS}" get pod client -o jsonpath='{.status.startTime}')
echo "[4/7] CLIENT_START=${CLIENT_START}"

echo "[5/7] sanity curl"
kubectl -n "${NS}" exec client -c curl -- curl -s -o /dev/null -w "sanity_http_code=%{http_code}\n" --max-time 3 \
  "http://echo.${NS}.svc.homelab.local/"

echo "[6/7] start warm curl loop (local redirect, runs for duration of exec) then scale to 3"
# NOTE: must be launched as a true background OS process (nohup/disown or the
# harness's own background-job facility). A naive "( cmd & )" inside a shell
# that itself exits immediately after the tool call returns WILL be killed
# before it can run - confirmed empirically in this test run.
kubectl -n "${NS}" exec client -c curl -- sh -c \
  'for i in $(seq 1 100); do curl -s -o /dev/null -w "%{http_code}\n" --max-time 2 http://echo.'"${NS}"'.svc.homelab.local/; sleep 0.1; done' \
  > "${SCRIPT_DIR}/warm_curl.log" 2>"${SCRIPT_DIR}/warm_curl.err" &
WARM_PID=$!
sleep 1

kubectl -n "${NS}" scale deploy/echo --replicas=3

echo "[7/7] poll /clusters for our namespace's endpoint count during transition (10x, 1s)"
for i in $(seq 1 10); do
  cnt=$(kubectl -n "${NS}" exec client -c istio-proxy -- curl -s localhost:15000/clusters 2>/dev/null \
    | grep "outbound|80||echo.${NS}.svc.cluster.local" \
    | grep -oE '10\.[0-9]+\.[0-9]+\.[0-9]+' | sort -u | wc -l)
  echo "poll $i: our_ns_endpoint_count=${cnt}"
  sleep 1
done

kubectl -n "${NS}" rollout status deploy/echo --timeout=60s

wait "${WARM_PID}" || true
echo "=== warm_curl.log result (expect ONLY 200s) ==="
sort "${SCRIPT_DIR}/warm_curl.log" | uniq -c

echo "=== client startTime after scale (compare to ${CLIENT_START}, must be unchanged) ==="
kubectl -n "${NS}" get pod client -o jsonpath='{.status.startTime}'
echo

echo "=== final endpoint count (istioctl) ==="
# NOTE: Istio's internal cluster name suffix is svc.cluster.local even though
# this cluster's actual DNS domain is homelab.local (see harness-notes.md) -
# use the cluster.local-suffixed name here, not the svc.homelab.local FQDN.
istioctl proxy-config endpoint "client.${NS}" --cluster "outbound|80||echo.${NS}.svc.cluster.local"