import { snapshot } from 'rrweb-snapshot';
import initObservers from './observer';
import { mirror, on, getWindowWidth, getWindowHeight } from '../utils';
import {
  EventType,
  event,
  eventWithTime,
  recordOptions,
  IncrementalSource,
  listenerHandler,
} from '../types';

function wrapEvent(e: event): eventWithTime {
  return {
    ...e,
    timestamp: Date.now(),
  };
}

function record(options: recordOptions = {}): listenerHandler | undefined {
  const { emit } = options;
  // runtime checks for user options
  if (!emit) {
    throw new Error('emit function is required');
  }
  try {
    const handlers: listenerHandler[] = [];
    handlers.push(
      on('DOMContentLoaded', () => {
        emit(
          wrapEvent({
            type: EventType.DomContentLoaded,
            data: {},
          }),
        );
      }),
    );
    const init = () => {
      emit(
        wrapEvent({
          type: EventType.Meta,
          data: {
            href: window.location.href,
            width: getWindowWidth(),
            height: getWindowHeight(),
          },
        }),
      );
      const [node, idNodeMap] = snapshot(document);
      if (!node) {
        return console.warn('Failed to snapshot the document');
      }
      mirror.map = idNodeMap;
      emit(
        wrapEvent({
          type: EventType.FullSnapshot,
          data: {
            node,
            initialOffset: {
              left: document.documentElement!.scrollLeft,
              top: document.documentElement!.scrollTop,
            },
          },
        }),
      );
      handlers.push(
        initObservers({
          mutationCb: m =>
            emit(
              wrapEvent({
                type: EventType.IncrementalSnapshot,
                data: {
                  source: IncrementalSource.Mutation,
                  ...m,
                },
              }),
            ),
          mousemoveCb: positions =>
            emit(
              wrapEvent({
                type: EventType.IncrementalSnapshot,
                data: {
                  source: IncrementalSource.MouseMove,
                  positions,
                },
              }),
            ),
          mouseInteractionCb: d =>
            emit(
              wrapEvent({
                type: EventType.IncrementalSnapshot,
                data: {
                  source: IncrementalSource.MouseInteraction,
                  ...d,
                },
              }),
            ),
          scrollCb: p =>
            emit(
              wrapEvent({
                type: EventType.IncrementalSnapshot,
                data: {
                  source: IncrementalSource.Scroll,
                  ...p,
                },
              }),
            ),
          viewportResizeCb: d =>
            emit(
              wrapEvent({
                type: EventType.IncrementalSnapshot,
                data: {
                  source: IncrementalSource.ViewportResize,
                  ...d,
                },
              }),
            ),
          inputCb: v =>
            emit(
              wrapEvent({
                type: EventType.IncrementalSnapshot,
                data: {
                  source: IncrementalSource.Input,
                  ...v,
                },
              }),
            ),
        }),
      );
    };
    if (
      document.readyState === 'interactive' ||
      document.readyState === 'complete'
    ) {
      init();
    } else {
      handlers.push(
        on(
          'load',
          () => {
            emit(
              wrapEvent({
                type: EventType.Load,
                data: {},
              }),
            );
            init();
          },
          window,
        ),
      );
    }
    return () => {
      handlers.forEach(h => h());
    };
  } catch (error) {
    // TODO: handle internal error
    console.warn(error);
  }
}

export default record;