import type { EventHandlers } from './types';
import { $bridge } from '@/bridge';
import { EmitterSubscription } from 'react-native';

type EventName = keyof EventHandlers;

// Emitting view ID is passed in JSON["_view_id"]
// So that no all visible views would emit this event
// Must be in every callback response in the form of UUID string
// const KEY_VIEW = 'view_id';

/**
 * @remarks
 * View emitter wraps NativeEventEmitter
 * and provides several modifications:
 * - Synthetic type restrictions to avoid misspelling
 * - Safe data deserialization with SDK decoders
 * - Logging emitting and deserialization processes
 * - Filters out events for other views by _id
 *
 * @internal
 */
export class ViewEmitter {
  private viewId: string;
  private eventListeners: Map<string, EmitterSubscription> = new Map();
  private handlers: Map<
    string,
    Array<{
      handler: EventHandlers[keyof EventHandlers];
      config: (typeof HANDLER_TO_EVENT_CONFIG)[keyof typeof HANDLER_TO_EVENT_CONFIG];
      onRequestClose: () => Promise<void>;
    }>
  > = new Map();

  constructor(viewId: string) {
    this.viewId = viewId;
  }

  public addListener(
    event: EventName,
    callback: EventHandlers[EventName],
    onRequestClose: () => Promise<void>,
  ): EmitterSubscription {
    const viewId = this.viewId;
    const config = HANDLER_TO_EVENT_CONFIG[event];

    if (!config) {
      throw new Error(`No event config found for handler: ${event}`);
    }

    const handlersForEvent = this.handlers.get(config.nativeEvent) ?? [];
    handlersForEvent.push({
      handler: callback,
      config,
      onRequestClose,
    });
    this.handlers.set(config.nativeEvent, handlersForEvent);

    if (!this.eventListeners.has(config.nativeEvent)) {
      const handlers = this.handlers; // Capture the reference
      const subscription = $bridge.addEventListener(
        config.nativeEvent,
        function (arg) {
          const eventViewId = this.rawValue['view']?.['id'] ?? null;
          if (viewId !== eventViewId) {
            return;
          }

          const eventHandlers = handlers.get(config.nativeEvent) ?? [];
          for (const { handler, config, onRequestClose } of eventHandlers) {
            if (
              config.propertyMap &&
              (arg as any)['action']?.type !== config.propertyMap['action']
            ) {
              continue;
            }

            const callbackArgs = extractCallbackArgs(
              config.handlerName,
              arg as Record<string, any>,
            );
            const cb = handler as (...args: typeof callbackArgs) => boolean;
            const shouldClose = cb.apply(null, callbackArgs);

            if (shouldClose) {
              onRequestClose();
            }
          }
        },
      );
      this.eventListeners.set(config.nativeEvent, subscription);
    }

    return this.eventListeners.get(config.nativeEvent)!;
  }

  public removeAllListeners() {
    this.eventListeners.forEach(subscription => subscription.remove());
    this.eventListeners.clear();
    this.handlers.clear();
    $bridge.removeAllEventListeners();
  }
}

type UiEventMapping = {
  [nativeEventId: string]: {
    handlerName: keyof EventHandlers;
    propertyMap?: {
      [key: string]: string;
    };
  }[];
};

const UI_EVENT_MAPPINGS: UiEventMapping = {
  paywall_view_did_perform_action: [
    {
      handlerName: 'onCloseButtonPress',
      propertyMap: {
        action: 'close',
      },
    },
    {
      handlerName: 'onAndroidSystemBack',
      propertyMap: {
        action: 'system_back',
      },
    },
    {
      handlerName: 'onUrlPress',
      propertyMap: {
        action: 'open_url',
      },
    },
    {
      handlerName: 'onCustomAction',
      propertyMap: {
        action: 'custom',
      },
    },
  ],
  paywall_view_did_select_product: [{ handlerName: 'onProductSelected' }],
  paywall_view_did_start_purchase: [{ handlerName: 'onPurchaseStarted' }],
  paywall_view_did_finish_purchase: [{ handlerName: 'onPurchaseCompleted' }],
  paywall_view_did_fail_purchase: [{ handlerName: 'onPurchaseFailed' }],
  paywall_view_did_start_restore: [{ handlerName: 'onRestoreStarted' }],
  paywall_view_did_appear: [{ handlerName: 'onPaywallShown' }],
  paywall_view_did_disappear: [{ handlerName: 'onPaywallClosed' }],
  paywall_view_did_finish_web_payment_navigation: [
    { handlerName: 'onWebPaymentNavigationFinished' },
  ],
  paywall_view_did_finish_restore: [{ handlerName: 'onRestoreCompleted' }],
  paywall_view_did_fail_restore: [{ handlerName: 'onRestoreFailed' }],
  paywall_view_did_fail_rendering: [{ handlerName: 'onRenderingFailed' }],
  paywall_view_did_fail_loading_products: [
    { handlerName: 'onLoadingProductsFailed' },
  ],
};

const HANDLER_TO_EVENT_CONFIG: Record<
  EventName,
  {
    nativeEvent: string;
    propertyMap?: { [key: string]: string };
    handlerName: EventName;
  }
> = Object.entries(UI_EVENT_MAPPINGS).reduce(
  (acc, [nativeEvent, mappings]) => {
    mappings.forEach(({ handlerName, propertyMap }) => {
      acc[handlerName] = {
        nativeEvent,
        propertyMap,
        handlerName,
      };
    });
    return acc;
  },
  {} as Record<
    EventName,
    {
      nativeEvent: string;
      propertyMap?: { [key: string]: string };
      handlerName: EventName;
    }
  >,
);

function extractCallbackArgs(
  handlerName: EventName,
  eventArg: Record<string, any>,
) {
  switch (handlerName) {
    case 'onProductSelected':
      return [eventArg['product_id']];
    case 'onPurchaseStarted':
      return [eventArg['product']];
    case 'onPurchaseCompleted':
      return [eventArg['purchased_result'], eventArg['product']];
    case 'onPurchaseFailed':
      return [eventArg['error'], eventArg['product']];
    case 'onRestoreCompleted':
      return [eventArg['profile']];
    case 'onRestoreFailed':
    case 'onRenderingFailed':
    case 'onLoadingProductsFailed':
      return [eventArg['error']];
    case 'onCustomAction':
    case 'onUrlPress':
      return [eventArg['action'].value];
    case 'onWebPaymentNavigationFinished':
      return [eventArg['product'], eventArg['error']];
    default:
      return [];
  }
}