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

ROOT=$(CDPATH='' cd -- "$(dirname -- "$0")/.." && pwd)
KUBECTL="$ROOT/.tools/bin/kubectl"
CONTEXT=kind-who-need-help
CLUSTER_CONTAINER=who-need-help-control-plane
NAMESPACE=who-need-help
WEB_DEPLOYMENT=who-need-help-who-need-help-web
WORKER_DEPLOYMENT=who-need-help-who-need-help-worker
SERVICE=who-need-help-who-need-help
OWNERSHIP_MARKER="$ROOT/.tools/who-need-help.owned"
ROLLOUT_TIMEOUT=${KIND_ROLLOUT_TIMEOUT:-180s}
PROBE_INTERVAL=${KIND_ROLLOUT_PROBE_INTERVAL_SECONDS:-0.05}
PROBE_TIMEOUT=${KIND_ROLLOUT_PROBE_TIMEOUT_SECONDS:-2}
PROBE_RETRIES=${KIND_ROLLOUT_PROBE_RETRIES:-2}
CLUSTER_JOIN_TIMEOUT=${KIND_CLUSTER_JOIN_TIMEOUT_SECONDS:-120}
LABEL=${1:-"kind-rollout-$(date -u +%Y%m%dT%H%M%SZ)"}

if [[ ! -x "$KUBECTL" ]]; then
  echo "The project-owned kubectl is missing. Run scripts/bootstrap-kubernetes-tools.sh." >&2
  exit 1
fi

if [[ ! -f "$OWNERSHIP_MARKER" ]]; then
  echo "The kind ownership marker is missing; refusing to mutate the cluster." >&2
  exit 1
fi

if [[ ! "$LABEL" =~ ^[A-Za-z0-9._-]+$ ]]; then
  echo "Run label may contain only letters, numbers, dot, underscore, and dash." >&2
  exit 1
fi

if [[ ! "$ROLLOUT_TIMEOUT" =~ ^[1-9][0-9]*[smh]$ ]]; then
  echo "KIND_ROLLOUT_TIMEOUT must be a positive Kubernetes duration in s, m, or h." >&2
  exit 1
fi

if ! awk -v value="$PROBE_INTERVAL" \
  'BEGIN {exit !(value ~ /^[0-9]+([.][0-9]+)?$/ && value > 0)}'; then
  echo "KIND_ROLLOUT_PROBE_INTERVAL_SECONDS must be greater than zero." >&2
  exit 1
fi

if [[ ! "$PROBE_TIMEOUT" =~ ^[1-9][0-9]*$ ]]; then
  echo "KIND_ROLLOUT_PROBE_TIMEOUT_SECONDS must be a positive integer." >&2
  exit 1
fi

if [[ ! "$PROBE_RETRIES" =~ ^[0-9]+$ ]]; then
  echo "KIND_ROLLOUT_PROBE_RETRIES must be a non-negative integer." >&2
  exit 1
fi

if [[ ! "$CLUSTER_JOIN_TIMEOUT" =~ ^[1-9][0-9]*$ ]]; then
  echo "KIND_CLUSTER_JOIN_TIMEOUT_SECONDS must be a positive integer." >&2
  exit 1
fi

kube=("$KUBECTL" --context "$CONTEXT" --namespace "$NAMESPACE")

if ! "$KUBECTL" config get-contexts -o name | grep -Fxq "$CONTEXT"; then
  echo "The expected local kind context does not exist." >&2
  exit 1
fi

if [[ "$(docker inspect --format '{{index .Config.Labels "io.x-k8s.kind.cluster"}}' \
  "$CLUSTER_CONTAINER")" != "who-need-help" ]]; then
  echo "The kind control-plane container does not belong to this project cluster." >&2
  exit 1
fi

output_dir="$ROOT/output/resilience/$LABEL"
mkdir -p "$output_dir"
chmod 700 "$ROOT/output" "$ROOT/output/resilience" "$output_dir"
probe_marker="$output_dir/.probe-running"
probe_log="$output_dir/readiness.jsonl"
run_started_at=$(date -u +%Y-%m-%dT%H:%M:%SZ)
touch "$probe_marker"

deployment_snapshot() {
  "${kube[@]}" get deployment "$WEB_DEPLOYMENT" "$WORKER_DEPLOYMENT" -o json |
    jq '[
      .items[] | {
        name: .metadata.name,
        generation: .metadata.generation,
        revision: .metadata.annotations["deployment.kubernetes.io/revision"],
        replicas: .spec.replicas,
        ready: .status.readyReplicas,
        available: .status.availableReplicas,
        updated: .status.updatedReplicas,
        strategy: .spec.strategy,
        image: .spec.template.spec.containers[0].image
      }
    ]' >"$1"
}

database_snapshot() {
  # Variables are intentionally expanded inside the PostGIS container.
  # shellcheck disable=SC2016
  "${kube[@]}" exec -i postgis-0 -- sh -c \
    'psql --no-psqlrc --tuples-only --no-align --set ON_ERROR_STOP=1 \
      --username "$POSTGRES_USER" --dbname "$POSTGRES_DB"' >"$1" <<'SQL'
BEGIN READ ONLY;
SELECT 'users' AS table_name, count(*) AS row_count FROM users
UNION ALL SELECT 'users_tokens', count(*) FROM users_tokens
UNION ALL SELECT 'help_requests', count(*) FROM help_requests
UNION ALL SELECT 'messages', count(*) FROM messages
UNION ALL SELECT 'categories', count(*) FROM categories
UNION ALL SELECT 'help_assignments', count(*) FROM help_assignments
UNION ALL SELECT 'activities', count(*) FROM activities
UNION ALL SELECT 'reports', count(*) FROM reports
UNION ALL SELECT 'social_identities', count(*) FROM social_identities
UNION ALL SELECT 'tracking_sessions', count(*) FROM tracking_sessions
UNION ALL SELECT 'tracking_positions', count(*) FROM tracking_positions
UNION ALL SELECT 'schema_migrations', count(*) FROM schema_migrations
ORDER BY table_name;
COMMIT;
SQL
}

pod_snapshot() {
  "${kube[@]}" get pods \
    -l app.kubernetes.io/instance=who-need-help \
    -o json |
    jq '[
      .items[]
      | select(
          .metadata.labels["app.kubernetes.io/component"] == "web" or
          .metadata.labels["app.kubernetes.io/component"] == "worker"
        )
      | {
          name: .metadata.name,
          uid: .metadata.uid,
          component: .metadata.labels["app.kubernetes.io/component"],
          ready: ([.status.containerStatuses[]?.ready] | all),
          restarts: ([.status.containerStatuses[]?.restartCount] | add // 0)
        }
    ] | sort_by(.component, .name)' >"$1"
}

stop_probe() {
  unlink "$probe_marker" 2>/dev/null || true

  if [[ -n "${probe_pid:-}" ]]; then
    wait "$probe_pid" 2>/dev/null || true
  fi
}

cleanup() {
  local status=$?
  trap - EXIT HUP INT TERM
  stop_probe
  exit "$status"
}

trap cleanup EXIT HUP INT TERM

deployment_snapshot "$output_dir/deployments-before.json"

if ! jq -e '
  length == 2 and
  all(
    .replicas >= 2 and
    .ready == .replicas and
    .available == .replicas and
    .updated == .replicas and
    .strategy.type == "RollingUpdate" and
    .strategy.rollingUpdate.maxUnavailable == 0 and
    .strategy.rollingUpdate.maxSurge == 1
  )
' "$output_dir/deployments-before.json" >/dev/null; then
  echo "The local deployments are not ready for the recorded rolling strategy." >&2
  exit 1
fi

database_snapshot "$output_dir/database-before.txt"
pod_snapshot "$output_dir/pods-before.json"

node_port=$(
  "${kube[@]}" get service "$SERVICE" \
    -o jsonpath='{.spec.ports[?(@.name=="http")].nodePort}'
)
published=$(
  docker port "$CLUSTER_CONTAINER" "${node_port}/tcp" |
    head -n 1
)
host_port=${published##*:}

if [[ ! "$host_port" =~ ^[1-9][0-9]*$ ]]; then
  echo "The kind HTTP NodePort has no observed Docker host mapping." >&2
  exit 1
fi

base_url="http://127.0.0.1:$host_port"

sample_readiness() {
  while [[ -e "$probe_marker" ]]; do
    observed_at=$(date -u +%Y-%m-%dT%H:%M:%S.%3NZ)
    body_file="$output_dir/kind-readiness-body.$$"
    error_file="$output_dir/kind-readiness-error.$$"
    set +e
    result=$(
      curl --silent --show-error \
        --max-time "$PROBE_TIMEOUT" \
        --retry "$PROBE_RETRIES" \
        --retry-all-errors \
        --retry-connrefused \
        --retry-delay 0 \
        --output "$body_file" \
        --write-out '%{http_code} %{num_retries}' \
        "$base_url/healthz/ready" 2>"$error_file"
    )
    curl_status=$?
    set -e
    read -r status retries <<<"$result"

    if [[ "$curl_status" -ne 0 ]]; then
      status=000
    fi

    if [[ -f "$body_file" ]]; then
      body=$(tr -d '\n' <"$body_file")
    else
      body=
    fi

    error=$(tr -d '\n' <"$error_file")
    unlink "$body_file" 2>/dev/null || true
    unlink "$error_file" 2>/dev/null || true
    jq -cn \
      --arg observed_at "$observed_at" \
      --arg status "$status" \
      --arg body "$body" \
      --arg error "$error" \
      --argjson retries "${retries:-0}" \
      '{
        observed_at: $observed_at,
        status: $status,
        retries: $retries,
        body: $body,
        error: $error
      }' >>"$probe_log"
    sleep "$PROBE_INTERVAL"
  done
}

{
  printf 'observed_at=%s\n' "$run_started_at"
  printf 'context=%s\n' "$CONTEXT"
  printf 'namespace=%s\n' "$NAMESPACE"
  printf 'rollout_timeout=%s\n' "$ROLLOUT_TIMEOUT"
  printf 'probe_interval_seconds=%s\n' "$PROBE_INTERVAL"
  printf 'probe_timeout_seconds=%s\n' "$PROBE_TIMEOUT"
  printf 'probe_retries=%s\n' "$PROBE_RETRIES"
  printf 'cluster_join_timeout_seconds=%s\n' "$CLUSTER_JOIN_TIMEOUT"
  printf 'node_port=%s\n' "$node_port"
  printf 'observed_host_port=%s\n' "$host_port"
  "$KUBECTL" version --client
} >"$output_dir/environment.txt"

sample_readiness &
probe_pid=$!

"${kube[@]}" rollout restart "deployment/$WEB_DEPLOYMENT" \
  >"$output_dir/web-rollout-restart.txt"
"${kube[@]}" rollout status "deployment/$WEB_DEPLOYMENT" \
  "--timeout=$ROLLOUT_TIMEOUT" >"$output_dir/web-rollout-status.txt"

"${kube[@]}" rollout restart "deployment/$WORKER_DEPLOYMENT" \
  >"$output_dir/worker-rollout-restart.txt"
"${kube[@]}" rollout status "deployment/$WORKER_DEPLOYMENT" \
  "--timeout=$ROLLOUT_TIMEOUT" >"$output_dir/worker-rollout-status.txt"

old_pod_deadline=$((SECONDS + CLUSTER_JOIN_TIMEOUT))

while ((SECONDS < old_pod_deadline)); do
  "${kube[@]}" get pods \
    -l app.kubernetes.io/instance=who-need-help \
    -o json >"$output_dir/pods-current.json"

  retained_count=$(
    jq \
      --slurpfile before "$output_dir/pods-before.json" \
      '[
        .items[].metadata.uid as $uid
        | select($before[0] | any(.uid == $uid))
      ] | length' "$output_dir/pods-current.json"
  )

  if [[ "$retained_count" == "0" ]]; then
    break
  fi

  sleep 1
done

unlink "$output_dir/pods-current.json" 2>/dev/null || true

if [[ "$retained_count" != "0" ]]; then
  echo "Old application pods did not terminate after the rollout." >&2
  exit 1
fi

mapfile -t current_application_pods < <(
  "${kube[@]}" get pods \
    -l app.kubernetes.io/instance=who-need-help \
    -o json |
    jq -r '
      .items[]
      | select(
          .metadata.labels["app.kubernetes.io/component"] == "web" or
          .metadata.labels["app.kubernetes.io/component"] == "worker"
        )
      | "pod/" + .metadata.name
    '
)

if [[ "${#current_application_pods[@]}" -ne 4 ]]; then
  echo "Expected four replacement application pods; observed ${#current_application_pods[@]}." >&2
  exit 1
fi

"${kube[@]}" wait \
  --for=condition=Ready \
  --timeout="$ROLLOUT_TIMEOUT" \
  "${current_application_pods[@]}" \
  >"$output_dir/pods-ready.txt"

deployment_snapshot "$output_dir/deployments-after.json"
pod_snapshot "$output_dir/pods-after.json"
database_snapshot "$output_dir/database-after.txt"

if ! diff -u "$output_dir/database-before.txt" "$output_dir/database-after.txt" \
  >"$output_dir/database-diff.txt"; then
  echo "The rolling verification changed tracked database counts." >&2
  exit 1
fi

jq -n \
  --slurpfile before "$output_dir/pods-before.json" \
  --slurpfile after "$output_dir/pods-after.json" \
  '{
    before_count: ($before[0] | length),
    after_count: ($after[0] | length),
    retained_uids: (
      [$before[0][].uid] as $old
      | [$after[0][].uid | select(. as $uid | $old | index($uid))]
    ),
    after_all_ready: ($after[0] | all(.ready and .restarts == 0))
  }' >"$output_dir/pod-replacement-summary.json"

if ! jq -e '
  .before_count == 4 and
  .after_count == 4 and
  .retained_uids == [] and
  .after_all_ready
' "$output_dir/pod-replacement-summary.json" >/dev/null; then
  echo "The rollout did not replace all four application pods cleanly." >&2
  exit 1
fi

web_pod=$(
  "${kube[@]}" get pod \
    -l app.kubernetes.io/component=web \
    --field-selector=status.phase=Running \
    -o jsonpath='{.items[0].metadata.name}'
)
expected_peers=$(
  jq '[.[].replicas] | add - 1' "$output_dir/deployments-after.json"
)
cluster_deadline=$((SECONDS + CLUSTER_JOIN_TIMEOUT))

while ((SECONDS < cluster_deadline)); do
  peer_count=$(
    "${kube[@]}" exec "$web_pod" -- /app/bin/who_need_help rpc \
      'IO.puts(length(Node.list()))' 2>/dev/null |
      tail -n 1
  )

  if [[ "$peer_count" == "$expected_peers" ]]; then
    break
  fi

  sleep 1
done

if [[ "$peer_count" != "$expected_peers" ]]; then
  echo "All rolled application pods did not join the BEAM cluster." >&2
  exit 1
fi

"${kube[@]}" exec "$web_pod" -- /app/bin/who_need_help rpc \
  'IO.inspect(%{node: node(), peers: Node.list(), peer_count: length(Node.list())})' \
  >"$output_dir/cluster-after.txt"
"$ROOT/scripts/verify-realtime-cluster.sh" kind \
  >"$output_dir/pubsub-after.txt"
"$ROOT/scripts/verify-beam-runtime.sh" kind \
  "$output_dir/beam-runtime-after.json" >/dev/null

stop_probe
probe_pid=

jq -s '{
  samples: length,
  failures: (map(select(.status != "200")) | length),
  retried_samples: (map(select(.retries > 0)) | length),
  total_retries: (map(.retries) | add),
  nodes: (map(.body | fromjson? | .node) | map(select(. != null)) | unique)
}' "$probe_log" >"$output_dir/readiness-summary.json"

"${kube[@]}" get pods \
  -l app.kubernetes.io/component=web \
  -o json |
  jq '[.items[].status.podIP | "who_need_help@" + .] | sort' \
    >"$output_dir/current-web-nodes.json"

if ! jq -e \
  --slurpfile current "$output_dir/current-web-nodes.json" '
    .samples > 0 and
    .failures == 0 and
    ($current[0] | length) == 2 and
    (($current[0] - .nodes) | length) == 0
  ' "$output_dir/readiness-summary.json" >/dev/null; then
  echo "Kind readiness was unavailable or did not reach both web replicas." >&2
  exit 1
fi

"${kube[@]}" logs \
  --selector app.kubernetes.io/instance=who-need-help \
  --all-containers \
  --since-time "$run_started_at" \
  --prefix >"$output_dir/application.log" 2>&1

trap - EXIT HUP INT TERM
printf 'Kind rollout evidence: %s\n' "$output_dir"