// Responsibility: validate the independently YAML-owned Workbench Kafka debug stream.
// This capability is intentionally separate from the five product realtime capabilities.

export const WORKBENCH_KAFKA_DEBUG_ENVS = Object.freeze({
  enabled: "HWLAB_WORKBENCH_KAFKA_DEBUG_REPLAY_ENABLED",
  topic: "HWLAB_KAFKA_HWLAB_DEBUG_EVENT_TOPIC",
  groupIdPrefix: "HWLAB_KAFKA_HWLAB_DEBUG_GROUP_PREFIX",
  replayLimit: "HWLAB_WORKBENCH_KAFKA_DEBUG_REPLAY_LIMIT",
  replayTimeoutMs: "HWLAB_WORKBENCH_KAFKA_DEBUG_REPLAY_TIMEOUT_MS"
});

export function workbenchKafkaDebugCapability(env = process.env) {
  const enabled = requiredBoolean(env?.[WORKBENCH_KAFKA_DEBUG_ENVS.enabled], WORKBENCH_KAFKA_DEBUG_ENVS.enabled);
  const topic = requiredIsolatedKafkaName(
    env?.[WORKBENCH_KAFKA_DEBUG_ENVS.topic],
    WORKBENCH_KAFKA_DEBUG_ENVS.topic,
    249,
    ["hwlab.event.v1", env?.HWLAB_KAFKA_HWLAB_EVENT_TOPIC, env?.HWLAB_KAFKA_EVENT_TOPIC]
  );
  const groupIdPrefix = requiredIsolatedKafkaName(
    env?.[WORKBENCH_KAFKA_DEBUG_ENVS.groupIdPrefix],
    WORKBENCH_KAFKA_DEBUG_ENVS.groupIdPrefix,
    180,
    [env?.HWLAB_KAFKA_HWLAB_EVENT_GROUP_ID]
  );
  const replayLimit = requiredPositiveInteger(env?.[WORKBENCH_KAFKA_DEBUG_ENVS.replayLimit], WORKBENCH_KAFKA_DEBUG_ENVS.replayLimit);
  const replayTimeoutMs = requiredPositiveInteger(env?.[WORKBENCH_KAFKA_DEBUG_ENVS.replayTimeoutMs], WORKBENCH_KAFKA_DEBUG_ENVS.replayTimeoutMs);
  return { enabled, topic, groupIdPrefix, replayLimit, replayTimeoutMs, valuesPrinted: false };
}

function requiredBoolean(value, name) {
  const normalized = String(value ?? "").trim().toLowerCase();
  if (normalized === "true" || normalized === "1") return true;
  if (normalized === "false" || normalized === "0") return false;
  throw capabilityError(`${name} is required and must be explicitly true or false.`, name);
}

function requiredKafkaName(value, name, maxLength) {
  const text = String(value ?? "").trim();
  if (!text || text.length > maxLength || !/^[A-Za-z0-9._-]+$/u.test(text)) {
    throw capabilityError(`${name} is required and must be a valid Kafka identifier.`, name);
  }
  return text;
}

function requiredIsolatedKafkaName(value, name, maxLength, productValues) {
  const text = requiredKafkaName(value, name, maxLength);
  const products = new Set(productValues.map((candidate) => String(candidate ?? "").trim()).filter(Boolean));
  if (products.has(text) || !/(?:^|[.-])debug(?:[.-]|$)/u.test(text)) {
    throw capabilityError(`${name} must identify an isolated debug Kafka resource and must not reuse a product topic or group.`, name);
  }
  return text;
}

function requiredPositiveInteger(value, name) {
  const number = Number(value);
  if (!Number.isInteger(number) || number <= 0) throw capabilityError(`${name} is required and must be a positive integer.`, name);
  return number;
}

function capabilityError(message, envName) {
  return Object.assign(new Error(message), {
    code: "workbench_kafka_debug_capability_invalid",
    envName,
    statusCode: 503,
    valuesRedacted: true
  });
}