import { catchUserErrors } from '../tools/catchUserErrors'
import { setDebugMode } from '../tools/monitor'
import { assign } from '../tools/utils/polyfills'
import { display } from '../tools/display'

// replaced at build time
declare const __BUILD_ENV__SDK_VERSION__: string

export interface PublicApi {
  /**
   * Version of the Logs browser SDK
   */
  version: string

  /**
   * [For CDN async setup] Early RUM API calls must be wrapped in the `window.DD_RUM.onReady()` callback. This ensures the code only gets executed once the SDK is properly loaded.
   *
   * See [CDN async setup](https://docs.datadoghq.com/real_user_monitoring/browser/#cdn-async) for further information.
   */
  onReady: (callback: () => void) => void
}

export function makePublicApi<T extends PublicApi>(stub: Omit<T, keyof PublicApi>): T {
  const publicApi = assign(
    {
      version: __BUILD_ENV__SDK_VERSION__,

      // This API method is intentionally not monitored, since the only thing executed is the
      // user-provided 'callback'.  All SDK usages executed in the callback should be monitored, and
      // we don't want to interfere with the user uncaught exceptions.
      onReady(callback: () => void) {
        callback()
      },
    },
    stub
  )

  // Add a "hidden" property to set debug mode. We define it that way to hide it
  // as much as possible but of course it's not a real protection.
  Object.defineProperty(publicApi, '_setDebug', {
    get() {
      return setDebugMode
    },
    enumerable: false,
  })

  return publicApi as T
}

export function defineGlobal<Global, Name extends keyof Global>(global: Global, name: Name, api: Global[Name]) {
  const existingGlobalVariable = global[name] as { q?: Array<() => void>; version?: string } | undefined
  if (existingGlobalVariable && !existingGlobalVariable.q && existingGlobalVariable.version) {
    display.warn('SDK is loaded more than once. This is unsupported and might have unexpected behavior.')
  }
  global[name] = api
  if (existingGlobalVariable && existingGlobalVariable.q) {
    existingGlobalVariable.q.forEach((fn) => catchUserErrors(fn, 'onReady callback threw an error:')())
  }
}