import { sendNodecgCommand, sendNodecgMessage } from '../../nodecg/browser/messages';
import { createPackBrowserReplicants } from '../../nodecg/browser/packReplicants';
import { messageNames } from '../../nodecg/messageNames';
import type {
  PackDownloadState,
  PackManifest,
  PackRegistry,
  PackUpdateInfo,
} from '../../shared/domain/packs/types';

export interface PackReplicantHandlers {
  onRegistryChanged: (value: PackRegistry | null) => void;
  onInstalledPacksChanged: (value: string[], previousValue: string[]) => void;
  onDownloadStatesChanged: (value: Record<string, PackDownloadState>) => void;
  onAvailableUpdatesChanged: (value: Record<string, PackUpdateInfo>) => void;
}

export interface PackService {
  subscribe: (handlers: PackReplicantHandlers) => Promise<() => void>;
  fetchRegistry: () => Promise<void>;
  downloadPack: (packId: string) => Promise<void>;
  uninstallPack: (packId: string) => Promise<void>;
  updatePack: (packId: string) => Promise<void>;
  readLocalManifest: (packId: string) => Promise<PackManifest>;
}

export const createPackService = (): PackService => {
  const subscribe = async (handlers: PackReplicantHandlers): Promise<() => void> => {
    const {
      registryRep,
      installedRep,
      statesRep,
      updatesRep,
      waitUntilReady,
    } = createPackBrowserReplicants();

    await waitUntilReady();

    handlers.onRegistryChanged(registryRep.value ?? null);
    handlers.onInstalledPacksChanged(installedRep.value ?? [], []);
    handlers.onDownloadStatesChanged(statesRep.value ?? {});
    handlers.onAvailableUpdatesChanged(updatesRep.value ?? {});

    const onRegistryChanged = (value: PackRegistry | null): void => {
      handlers.onRegistryChanged(value ?? null);
    };
    const onInstalledPacksChanged = (value: string[], previousValue?: string[]): void => {
      handlers.onInstalledPacksChanged(value ?? [], previousValue ?? []);
    };
    const onDownloadStatesChanged = (value: Record<string, PackDownloadState>): void => {
      handlers.onDownloadStatesChanged(value ?? {});
    };
    const onAvailableUpdatesChanged = (value: Record<string, PackUpdateInfo>): void => {
      handlers.onAvailableUpdatesChanged(value ?? {});
    };

    registryRep.on('change', onRegistryChanged);
    installedRep.on('change', onInstalledPacksChanged);
    statesRep.on('change', onDownloadStatesChanged);
    updatesRep.on('change', onAvailableUpdatesChanged);

    return () => {
      registryRep.off('change', onRegistryChanged);
      installedRep.off('change', onInstalledPacksChanged);
      statesRep.off('change', onDownloadStatesChanged);
      updatesRep.off('change', onAvailableUpdatesChanged);
    };
  };

  return {
    subscribe,
    fetchRegistry: () => sendNodecgCommand(messageNames.packs.fetchRegistry),
    downloadPack: (packId: string) => sendNodecgCommand(messageNames.packs.download, packId),
    uninstallPack: (packId: string) => sendNodecgCommand(messageNames.packs.uninstall, packId),
    updatePack: (packId: string) => sendNodecgCommand(messageNames.packs.update, packId),
    readLocalManifest: (packId: string) =>
      sendNodecgMessage<PackManifest>(messageNames.packs.readLocalManifest, packId),
  };
};