import { cleanup, fireEvent, render, screen, waitFor } from "@testing-library/react";
import { useState } from "react";
import { afterEach, describe, expect, it, vi } from "vitest";
import { SettingsSaveProvider } from "@/components/settings/settings-save-provider";
import { useWatcherEnabledDrafts } from "./use-watcher-enabled-drafts";

const watch = { id: "watch-1", enabled: true };
const saveChangesLabel = "Save changes";

afterEach(cleanup);

function Harness({ save }: { save: (enabled: boolean) => Promise<void> }) {
  const drafts = useWatcherEnabledDrafts({
    id: "test-watches",
    items: [watch],
    saveEnabled: (_watch, enabled) => save(enabled),
  });
  return (
    <button
      data-dirty={drafts.dirtyIds.has(watch.id)}
      onClick={() => drafts.toggleEnabled(drafts.items[0])}
    >
      {drafts.items[0].enabled ? "Disable" : "Enable"}
    </button>
  );
}

function ReconciliationHarness({ save }: { save: (enabled: boolean) => Promise<void> }) {
  const [items, setItems] = useState([watch]);
  const drafts = useWatcherEnabledDrafts({
    id: "test-watches",
    items,
    saveEnabled: (_watch, enabled) => save(enabled),
  });
  return (
    <>
      <button onClick={() => drafts.toggleEnabled(drafts.items[0])}>
        {drafts.items[0].enabled ? "Disable" : "Enable"}
      </button>
      <button
        data-testid="authoritative-paused"
        onClick={() => setItems([{ ...watch, enabled: false }])}
      />
      <button
        data-testid="authoritative-active"
        onClick={() => setItems([{ ...watch, enabled: true }])}
      />
    </>
  );
}

function InFlightReconciliationHarness({
  onSaveReady,
}: {
  onSaveReady: (resolve: () => void) => void;
}) {
  const [items, setItems] = useState([watch]);
  const drafts = useWatcherEnabledDrafts({
    id: "test-watches",
    items,
    saveEnabled: (_watch, _enabled) =>
      new Promise<void>((resolve) => {
        onSaveReady(resolve);
      }),
  });
  return (
    <>
      <button onClick={() => drafts.toggleEnabled(drafts.items[0])}>
        {drafts.items[0].enabled ? "Disable" : "Enable"}
      </button>
      <button
        data-testid="authoritative-paused"
        onClick={() => setItems([{ ...watch, enabled: false }])}
      />
      <button
        data-testid="authoritative-active"
        onClick={() => setItems([{ ...watch, enabled: true }])}
      />
    </>
  );
}

describe("useWatcherEnabledDrafts", () => {
  it("returns to a clean state when a watcher is toggled twice", () => {
    const save = vi.fn().mockResolvedValue(undefined);
    render(
      <SettingsSaveProvider>
        <Harness save={save} />
      </SettingsSaveProvider>,
    );

    fireEvent.click(screen.getByRole("button", { name: "Disable" }));
    fireEvent.click(screen.getByRole("button", { name: "Enable" }));

    expect(screen.queryByRole("button", { name: saveChangesLabel })).toBeNull();
    expect(save).not.toHaveBeenCalled();
  });

  it("exposes the changed watcher id for row and control highlighting", () => {
    render(
      <SettingsSaveProvider>
        <Harness save={vi.fn().mockResolvedValue(undefined)} />
      </SettingsSaveProvider>,
    );

    const toggle = screen.getByRole("button", { name: "Disable" });
    expect(toggle.getAttribute("data-dirty")).toBe("false");
    fireEvent.click(toggle);
    expect(screen.getByRole("button", { name: "Enable" }).getAttribute("data-dirty")).toBe("true");
  });

  it("keeps failed changes dirty and retries them", async () => {
    const save = vi.fn().mockRejectedValueOnce(new Error("offline")).mockResolvedValue(undefined);
    render(
      <SettingsSaveProvider>
        <Harness save={save} />
      </SettingsSaveProvider>,
    );

    fireEvent.click(screen.getByRole("button", { name: "Disable" }));
    expect(save).not.toHaveBeenCalled();
    fireEvent.click(screen.getByRole("button", { name: saveChangesLabel }));

    await waitFor(() => expect(screen.getByText("Couldn't save")).toBeTruthy());
    expect(screen.getByRole("button", { name: "Retry save" })).toBeTruthy();
    fireEvent.click(screen.getByRole("button", { name: "Retry save" }));

    await waitFor(() => expect(save).toHaveBeenCalledTimes(2));
    await waitFor(() =>
      expect(screen.queryByRole("button", { name: saveChangesLabel })).toBeNull(),
    );
  });

  it("keeps a saved watcher state visible while the authoritative list is stale", async () => {
    const save = vi.fn().mockResolvedValue(undefined);
    render(
      <SettingsSaveProvider>
        <Harness save={save} />
      </SettingsSaveProvider>,
    );

    fireEvent.click(screen.getByRole("button", { name: "Disable" }));
    fireEvent.click(screen.getByRole("button", { name: saveChangesLabel }));

    await waitFor(() => expect(save).toHaveBeenCalledWith(false));
    expect(screen.getByRole("button", { name: "Enable" })).toBeTruthy();
    expect(screen.queryByRole("button", { name: saveChangesLabel })).toBeNull();
  });

  it("reconciles the saved baseline when authoritative items catch up", async () => {
    const save = vi.fn().mockResolvedValue(undefined);
    render(
      <SettingsSaveProvider>
        <ReconciliationHarness save={save} />
      </SettingsSaveProvider>,
    );

    fireEvent.click(screen.getByRole("button", { name: "Disable" }));
    fireEvent.click(screen.getByRole("button", { name: saveChangesLabel }));
    await waitFor(() => expect(screen.getByRole("button", { name: "Enable" })).toBeTruthy());

    fireEvent.click(screen.getByTestId("authoritative-paused"));
    await waitFor(() => expect(screen.getByRole("button", { name: "Enable" })).toBeTruthy());

    fireEvent.click(screen.getByTestId("authoritative-active"));
    await waitFor(() => expect(screen.getByRole("button", { name: "Disable" })).toBeTruthy());
  });

  it("reconciles when authoritative data catches up before save resolves", async () => {
    let resolveSave = () => {};
    render(
      <SettingsSaveProvider>
        <InFlightReconciliationHarness onSaveReady={(resolve) => (resolveSave = resolve)} />
      </SettingsSaveProvider>,
    );

    fireEvent.click(screen.getByRole("button", { name: "Disable" }));
    fireEvent.click(screen.getByRole("button", { name: saveChangesLabel }));
    fireEvent.click(screen.getByTestId("authoritative-paused"));
    resolveSave();
    await waitFor(() => expect(screen.getByRole("button", { name: "Enable" })).toBeTruthy());

    fireEvent.click(screen.getByTestId("authoritative-active"));
    await waitFor(() => expect(screen.getByRole("button", { name: "Disable" })).toBeTruthy());
  });
});