import { useAtomValue } from "@effect/atom-react";
import { enabledEnvironmentIds } from "@t3tools/client-runtime/state/connections";
import { arrayElementsEqual } from "@t3tools/client-runtime/state/entities";
import {
  createEnvironmentThreadDetailAtoms,
  createEnvironmentThreadShellAtoms,
  createEnvironmentThreadStateAtoms,
  EMPTY_ENVIRONMENT_THREAD_STATE,
  type EnvironmentThreadState,
  createOlderSettledThreadAtoms,
  createThreadEnvironmentAtoms,
  createThreadFamilyAtoms,
} from "@t3tools/client-runtime/state/threads";
import type { EnvironmentId, OrchestrationV2ThreadShell, ThreadId } from "@t3tools/contracts";
import * as Option from "effect/Option";
import { AsyncResult, Atom } from "effect/reactivity";
import { useEffect } from "react";

import { environmentCatalog } from "../connection/catalog";
import { connectionAtomRuntime } from "../connection/runtime";
import { appAtomRegistry } from "../rpc/atomRegistry";
import { environmentShell } from "./shell";

export const threadFamilies = createThreadFamilyAtoms(
  connectionAtomRuntime,
  environmentShell.stateAtom,
);
export const olderSettledThreads = createOlderSettledThreadAtoms(
  connectionAtomRuntime,
  environmentShell.stateAtom,
);
export const threadEnvironment = createThreadEnvironmentAtoms(
  connectionAtomRuntime,
  threadFamilies.snapshotAtom,
);
const environmentThreads = createEnvironmentThreadStateAtoms(connectionAtomRuntime);
export const environmentThreadDetails = createEnvironmentThreadDetailAtoms(
  environmentThreads.stateAtom,
);
export const environmentThreadShells = createEnvironmentThreadShellAtoms({
  catalogValueAtom: environmentCatalog.catalogValueAtom,
  snapshotAtom: threadEnvironment.snapshotAtom,
});

/** Keeps the subagent tree under `rootThreadId` in the thread list while the caller shows it. */
export function useThreadFamily(
  environmentId: EnvironmentId | null,
  rootThreadId: ThreadId | null,
): void {
  // oxlint-disable-next-line t3code/no-unreasoned-state-sync -- mounts the subagent tree into the thread family registry while the caller shows it
  useEffect(() => {
    if (environmentId === null || rootThreadId === null) return;
    return threadFamilies.mount(appAtomRegistry, environmentId, rootThreadId);
  }, [environmentId, rootThreadId]);
}

const EMPTY_THREAD_STATE_ATOM = Atom.make(AsyncResult.success(EMPTY_ENVIRONMENT_THREAD_STATE)).pipe(
  Atom.withLabel("web-environment-thread:empty"),
);

export function useEnvironmentThread(
  environmentId: EnvironmentId | null,
  threadId: ThreadId | null,
): EnvironmentThreadState {
  const result = useAtomValue(
    environmentId !== null && threadId !== null
      ? environmentThreads.stateAtom(environmentId, threadId)
      : EMPTY_THREAD_STATE_ATOM,
  );
  const state = AsyncResult.getOrElse(result, () => EMPTY_ENVIRONMENT_THREAD_STATE);
  return state;
}

const isRunning = (status: string) =>
  status === "preparing" || status === "queued" || status === "starting" || status === "running";

type KeptThreads = ReadonlyMap<EnvironmentId, ReadonlySet<ThreadId>>;

function isDetailDone<E>(result: AsyncResult.AsyncResult<EnvironmentThreadState, E>): boolean {
  if (!AsyncResult.isSuccess(result)) return true;
  const { status, data, error } = result.value;
  if (status === "deleted" || Option.isSome(error)) return true;
  return (
    status === "live" &&
    !Option.exists(data, (thread) => thread.runs.some((run) => isRunning(run.status)))
  );
}

/** Keeps stopped threads mounted until their independent detail stream is live and also reports stopped. */
export function createRunningThreadKeepAliveAtom<E>(input: {
  readonly environmentIdsAtom: Atom.Atom<ReadonlyArray<EnvironmentId>>;
  readonly threadsAtom: (
    environmentId: EnvironmentId,
  ) => Atom.Atom<ReadonlyArray<Pick<OrchestrationV2ThreadShell, "id" | "status">>>;
  readonly stateAtom: (
    environmentId: EnvironmentId,
    threadId: ThreadId,
  ) => Atom.Atom<AsyncResult.AsyncResult<EnvironmentThreadState, E>>;
}) {
  const runningThreadIdsAtom = Atom.family((environmentId: EnvironmentId) => {
    let previous: ReadonlyArray<ThreadId> = [];
    return Atom.make((get) => {
      const running = get(input.threadsAtom(environmentId)).flatMap((thread) =>
        isRunning(thread.status) ? [thread.id] : [],
      );
      if (arrayElementsEqual(previous, running)) return previous;
      previous = running;
      return running;
    }).pipe(Atom.withLabel(`web-running-thread-ids:${environmentId}`));
  });

  return Atom.make((get): KeptThreads => {
    const previous = Option.getOrUndefined(get.self<KeptThreads>());
    const kept = new Map<EnvironmentId, ReadonlySet<ThreadId>>();
    for (const environmentId of get(input.environmentIdsAtom)) {
      const threadIds = new Set(get(runningThreadIdsAtom(environmentId)));
      for (const threadId of previous?.get(environmentId) ?? []) {
        if (threadIds.has(threadId)) continue;
        const stateAtom = input.stateAtom(environmentId, threadId);
        // A get dependency would hold stopped streams open until another change rebuilds this atom.
        if (isDetailDone(get.once(stateAtom))) continue;
        threadIds.add(threadId);
        get.subscribe(stateAtom, (state) => {
          if (isDetailDone(state)) get.refreshSelf();
        });
      }
      for (const threadId of threadIds) get.mount(input.stateAtom(environmentId, threadId));
      kept.set(environmentId, threadIds);
    }
    return kept;
  }).pipe(Atom.withLabel("web-running-thread-keep-alive"));
}

export const runningThreadKeepAliveAtom = createRunningThreadKeepAliveAtom({
  environmentIdsAtom: Atom.map(environmentCatalog.catalogValueAtom, (catalog) => [
    ...enabledEnvironmentIds(catalog),
  ]),
  threadsAtom: environmentThreadShells.environmentThreadsAtom,
  stateAtom: environmentThreads.stateAtom,
});