import {
  chatConnectionStateLabelKey,
  type ChatChannelDetailVM,
  type ChatMessageDayGroupVM,
  type ChatMessageVM,
  type ChatPresenceVM,
} from "@hivegrid/view-models";

import type { ChatRealtimeConnection } from "./chatChannelRealtimeReducer";

export type ChatChannelRealtimeViewOverlay = {
  readonly messages: readonly ChatMessageVM[];
  readonly messageGroups: readonly ChatMessageDayGroupVM[];
  readonly presence: readonly ChatPresenceVM[];
  readonly typingLabels: readonly string[];
  readonly connection: ChatRealtimeConnection;
};

/** Applies transport-only state to the loader-owned render contract. Repository
 * records never cross this boundary. */
export function overlayChatChannelDetailRealtime(vm: ChatChannelDetailVM, overlay: ChatChannelRealtimeViewOverlay): ChatChannelDetailVM {
  if (vm.status !== "ready") return vm;
  const canRetry = overlay.connection.state === "offline" || overlay.connection.state === "reconnecting";
  const composer =
    overlay.connection.state === "blocked"
      ? {
          ...vm.data.composer,
          enabled: false,
          disabledReasonKey: "chat.composer.connectionBlocked",
          canSend: false,
          canAttachFiles: false,
          canRecordVoice: false,
          canMention: false,
          canMarkAsTask: false,
        }
      : vm.data.composer;
  return {
    status: "ready",
    data: {
      ...vm.data,
      messages: overlay.messages,
      messageGroups: overlay.messageGroups,
      presence: overlay.presence.map(({ userId, status }) => ({ userId, status })),
      typingLabels: overlay.typingLabels,
      composer,
      connection: {
        ...vm.data.connection,
        state: overlay.connection.state,
        stateLabelKey: chatConnectionStateLabelKey(overlay.connection.state),
        reconnectAttempt: overlay.connection.reconnectAttempt,
        retryAtIso: overlay.connection.retryAtIso,
        canRetry,
      },
    },
  };
}