import env from '#start/env'

const exchangeStoreConfig = {
  /**
   * Maximum number of exchanges stored per device.
   * Oldest messages are deleted when this cap is exceeded.
   */
  maxMessagesPerDevice: env.get('EXCHANGE_STORE_MAX_MESSAGES', 5000),

  /**
   * TTL (time-to-live) in seconds for exchanges.
   * MongoDB TTL index auto-removes documents older than this value.
   * Default: 86400 seconds (24 hours).
   */
  ttlSeconds: env.get('EXCHANGE_STORE_TTL_SECONDS', 86400),

  /**
   * SSE (Server-Sent Events) configuration.
   */
  sse: {
    /**
     * Inactivity timeout in milliseconds.
     * Connection is closed if no new exchange is pushed within this period.
     * Default: 300000ms (5 minutes).
     */
    inactivityTimeoutMs: env.get('EXCHANGE_STORE_SSE_INACTIVITY_TIMEOUT_MS', 300_000),

    /**
     * Absolute timeout in milliseconds.
     * Connection is closed after this duration regardless of activity.
     * Default: 7200000ms (2 hours).
     */
    absoluteTimeoutMs: env.get('EXCHANGE_STORE_SSE_ABSOLUTE_TIMEOUT_MS', 7_200_000),

    /**
     * Maximum concurrent SSE connections per device.
     * Additional connections beyond this limit are rejected.
     */
    maxConnectionsPerDevice: env.get('EXCHANGE_STORE_SSE_MAX_CONNECTIONS_PER_DEVICE', 5),

    /**
     * Retry interval in milliseconds sent to clients via SSE `retry` field.
     * Clients use this value when reconnecting after a disconnect.
     * Default: 3000ms (3 seconds).
     */
    retryIntervalMs: env.get('EXCHANGE_STORE_SSE_RETRY_INTERVAL_MS', 3000),
  },

  /**
   * Retry policy for critical message persistence.
   */
  retry: {
    /**
     * Maximum number of retry attempts for critical messages.
     */
    maxAttempts: env.get('EXCHANGE_STORE_RETRY_MAX_ATTEMPTS', 3),

    /**
     * Base delay in milliseconds for exponential backoff.
     * Actual delays: baseDelayMs, baseDelayMs*2, baseDelayMs*4, ...
     * Default: 1000ms → retries at 1s, 2s, 4s.
     */
    baseDelayMs: env.get('EXCHANGE_STORE_RETRY_BASE_DELAY_MS', 1000),
  },

  /**
   * Read timeout in milliseconds for exchange retrieval queries.
   * If a query exceeds this duration, partial results are returned with `isTruncated: true`.
   * Default: 5000ms (5 seconds).
   */
  readTimeoutMs: env.get('EXCHANGE_STORE_READ_TIMEOUT_MS', 5000),

  /**
   * Feature flags for gradual rollout and rollback.
   */
  featureFlags: {
    /**
     * Enable/disable MongoDB persistence of exchanges.
     * When false, exchanges are not written to MongoDB (CWMP sessions unaffected).
     */
    persistence: env.get('FEATURE_EXCHANGE_PERSISTENCE', true),

    /**
     * Enable/disable SSE streaming endpoint.
     * When false, the SSE endpoint returns 503 and clients fall back to REST polling.
     */
    sseEnabled: env.get('FEATURE_SSE_ENABLED', true),

    /**
     * Data source for the Exchange API.
     * 'mongodb': read from structured MongoDB collection (new system).
     * 'file': read from legacy file-based logs (old system).
     */
    apiSource: env.get('FEATURE_EXCHANGE_API_SOURCE', 'mongodb') as 'mongodb' | 'file',
  },
}

export default exchangeStoreConfig