import type { QueryClient } from "@tanstack/react-query";
import type { CheckoutStatusResponse, CheckoutStatusUpdate } from "@getpaseo/protocol/messages";
import equal from "fast-deep-equal/es6";
import {
  checkoutCommitsQueryKey,
  checkoutPrStatusQueryKey,
  checkoutStatusQueryKey,
  invalidatePrPaneTimelineForCheckout,
} from "@/git/query-keys";
import { type CheckoutPrStatusPayload, normalizeCheckoutPrStatusPayload } from "@/git/pr-status";
import { resetDraftAgentCommandsForCheckout } from "@/agent-commands/cache";

export type CheckoutStatusPayload = CheckoutStatusResponse["payload"];
export type { CheckoutPrStatusPayload } from "@/git/pr-status";

export interface CheckoutStatusClient {
  getCheckoutStatus: (cwd: string) => Promise<CheckoutStatusPayload>;
}

export async function fetchCheckoutStatus({
  client,
  cwd,
}: {
  client: CheckoutStatusClient;
  serverId: string;
  cwd: string;
}): Promise<CheckoutStatusPayload> {
  const payload = normalizeCheckoutBaseRef(await client.getCheckoutStatus(cwd));
  return payload;
}

export async function ensureCheckoutStatus({
  queryClient,
  client,
  serverId,
  cwd,
}: {
  queryClient: QueryClient;
  client: CheckoutStatusClient;
  serverId: string;
  cwd: string;
}): Promise<CheckoutStatusPayload> {
  return await queryClient.fetchQuery({
    queryKey: checkoutStatusQueryKey(serverId, cwd),
    queryFn: () => fetchCheckoutStatus({ client, serverId, cwd }),
    staleTime: Infinity,
  });
}

export function applyCheckoutStatusUpdateFromEvent({
  queryClient,
  serverId,
  message,
}: {
  queryClient: QueryClient;
  serverId: string;
  message: CheckoutStatusUpdate;
}): void {
  const payload = normalizeCheckoutBaseRef(message.payload);
  const prStatus = payload.prStatus
    ? normalizeCheckoutPrStatusPayload(payload.prStatus)
    : undefined;
  const cachePayload = prStatus ? { ...payload, prStatus } : payload;
  const previousStatus = queryClient.getQueryData<CheckoutStatusPayload>(
    checkoutStatusQueryKey(serverId, payload.cwd),
  );
  queryClient.setQueryData(checkoutStatusQueryKey(serverId, payload.cwd), cachePayload);
  if (previousStatus?.currentBranch !== payload.currentBranch) {
    void resetDraftAgentCommandsForCheckout(queryClient, { serverId, cwd: payload.cwd });
  }
  void queryClient.invalidateQueries({
    queryKey: checkoutCommitsQueryKey(serverId, payload.cwd),
  });

  if (!prStatus) {
    return;
  }

  const previous = queryClient.getQueryData<CheckoutPrStatusPayload>(
    checkoutPrStatusQueryKey(serverId, prStatus.cwd),
  );
  queryClient.setQueryData(checkoutPrStatusQueryKey(serverId, prStatus.cwd), prStatus);

  // The PR activity timeline has no push channel; mark it stale when the pushed PR status
  // meaningfully changed. Active panes refetch immediately, evicted ones on next mount.
  if (hasPrStatusChanged(previous, prStatus)) {
    void invalidatePrPaneTimelineForCheckout(queryClient, { serverId, cwd: prStatus.cwd });
  }
}

function normalizeCheckoutBaseRef<T extends CheckoutStatusPayload>(payload: T): T {
  // COMPAT(workspaceBaseBranch): hosts <= v0.11.2 only send the display ref; remove after 2027-10-14.
  return !payload.isGit || payload.baseRefExact === undefined
    ? payload
    : { ...payload, baseRef: payload.baseRefExact };
}

// requestId changes on every emission and carries no PR state.
function prStatusWithoutVolatileFields(
  prStatus: CheckoutPrStatusPayload,
): Omit<CheckoutPrStatusPayload, "requestId"> {
  const { requestId: _requestId, ...rest } = prStatus;
  return rest;
}

function hasPrStatusChanged(
  previous: CheckoutPrStatusPayload | undefined,
  next: CheckoutPrStatusPayload,
): boolean {
  if (!previous) {
    return true;
  }
  return !equal(prStatusWithoutVolatileFields(previous), prStatusWithoutVolatileFields(next));
}