import { BrowserPlugin, Payload } from '@snowplow/browser-tracker-core';
import { hasMobileInterface, trackWebViewEvent } from '@snowplow/webview-tracker';
import { Logger, SelfDescribingEvent, SelfDescribingJson } from '@snowplow/tracker-core';
import { base64urldecode } from './utils';
import { AtomicProperties } from '@snowplow/webview-tracker/dist/api';

type WebViewPluginOptions = {
  /**
   * Provide a list of tracker namespaces to forward events to.
   * By default, the events will be forwarded to the default mobile tracker.
   */
  trackerNamespaces?: string[];
};

/**
 * Forwards events to Snowplow mobile trackers running in a WebView.
 * @param configuration - Configuration. Specify certain tracker namespaces to forward events to.
 */
export function WebViewPlugin(configuration?: WebViewPluginOptions): BrowserPlugin {
  let LOG: Logger;

  return {
    logger: (logger: Logger) => {
      LOG = logger;
    },

    filter: (payload) => {
      if (hasMobileInterface() === true) {
        LOG.debug(`Payload (event ID: ${payload.eid}) was filtered out and forwarded to WebView tracker.`);

        let atomicProperties: AtomicProperties = {
          eventName: payload.e as string,
          trackerVersion: payload.tv as string,
          useragent: (payload.ua as string) ?? window.navigator.userAgent,
          pageUrl: payload.url as string | undefined,
          pageTitle: payload.page as string | undefined,
          referrer: payload.refr as string | undefined,
          category: payload.se_ca as string | undefined,
          action: payload.se_ac as string | undefined,
          label: payload.se_la as string | undefined,
          property: payload.se_pr as string | undefined,
          value: payload.se_va !== undefined ? parseFloat(payload.se_va as string) : undefined,
          pingXOffsetMin: payload.pp_mix !== undefined ? parseInt(payload.pp_mix as string) : undefined,
          pingXOffsetMax: payload.pp_max !== undefined ? parseInt(payload.pp_max as string) : undefined,
          pingYOffsetMin: payload.pp_miy !== undefined ? parseInt(payload.pp_miy as string) : undefined,
          pingYOffsetMax: payload.pp_may !== undefined ? parseInt(payload.pp_may as string) : undefined,
        };
        let event = getSelfDescribingEventData(payload);
        let entities = getEntities(payload);
        let trackers: Array<string> | undefined = configuration?.trackerNamespaces;

        trackWebViewEvent({ properties: atomicProperties, event: event, context: entities }, trackers);

        return false;
      } else {
        return true;
      }
    },
  };
}

function getSelfDescribingEventData(payload: Payload): SelfDescribingEvent | undefined {
  if (payload.ue_pr) {
    return JSON.parse(payload.ue_pr as string).data;
  } else if (payload.ue_px) {
    let decoded = base64urldecode(payload.ue_px as string);
    return JSON.parse(decoded).data;
  }
  return undefined;
}

function getEntities(payload: Payload): SelfDescribingJson[] {
  if (payload.co) {
    return JSON.parse(payload.co as string)['data'];
  } else if (payload.cx) {
    let decoded = base64urldecode(payload.cx as string);
    return JSON.parse(decoded)['data'];
  }
  return [];
}