import type { ReactiveControllerHost } from "@lit/reactive-element/reactive-controller";
import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
import type { ConditionEvaluation } from "../../../src/common/controllers/condition-evaluator-controller";
import { ConditionEvaluatorController } from "../../../src/common/controllers/condition-evaluator-controller";
import type { VisibilityCondition } from "../../../src/panels/lovelace/common/validate-condition";
import type { HomeAssistant } from "../../../src/types";

const cond = (c: any): VisibilityCondition => c as VisibilityCondition;

const tick = () =>
  new Promise<void>((resolve) => {
    setTimeout(resolve, 10);
  });

interface CapturedSubscription {
  condition: any;
  push: (message: {
    result?: boolean;
    error?: string | { code: string; message: string };
    template_errors?: string[];
  }) => void;
  unsub: ReturnType<typeof vi.fn>;
}

let subs: CapturedSubscription[];

const createHost = (): ReactiveControllerHost => ({
  addController: vi.fn(),
  removeController: vi.fn(),
  requestUpdate: vi.fn(),
  updateComplete: Promise.resolve(true),
});

const createHass = (overrides: Partial<HomeAssistant> = {}): HomeAssistant =>
  ({
    connection: {
      subscribeMessage: vi.fn((onChange: any, msg: any) => {
        const unsub = vi.fn();
        subs.push({ condition: msg.condition, push: onChange, unsub });
        return Promise.resolve(unsub);
      }),
    },
    states: {},
    user: { id: "user1" },
    locale: { time_zone: "local" },
    config: { time_zone: "America/New_York" },
    ...overrides,
  }) as unknown as HomeAssistant;

interface Harness {
  controller: ConditionEvaluatorController;
  host: ReactiveControllerHost;
  results: { result: ConditionEvaluation; error?: string }[];
  last: () => { result: ConditionEvaluation; error?: string } | undefined;
}

const setup = async (
  conditions: VisibilityCondition[],
  hass: HomeAssistant = createHass()
): Promise<Harness> => {
  const host = createHost();
  const results: { result: ConditionEvaluation; error?: string }[] = [];
  const controller = new ConditionEvaluatorController(host, {
    resubscribeDelay: 0,
    onResult: (result, error) => results.push({ result, error }),
  });
  controller.hostConnected();
  controller.observe(conditions, hass);
  await tick();
  return { controller, host, results, last: () => results[results.length - 1] };
};

describe("ConditionEvaluatorController", () => {
  beforeEach(() => {
    subs = [];
    global.matchMedia = vi.fn().mockImplementation((query) => ({
      matches: false,
      media: query,
      onchange: null,
      addListener: vi.fn(),
      removeListener: vi.fn(),
      addEventListener: vi.fn(),
      removeEventListener: vi.fn(),
      dispatchEvent: vi.fn(),
    }));
  });

  afterEach(() => {
    vi.restoreAllMocks();
  });

  it("evaluates an all-client tree without opening subscriptions", async () => {
    const { controller, last } = await setup([
      cond({ condition: "user", users: ["user1"] }),
    ]);
    expect(subs).toHaveLength(0);
    expect(controller.result).toBe("visible");
    expect(last()?.result).toBe("visible");
  });

  it("hides when an all-client condition is not met", async () => {
    const { controller } = await setup([
      cond({ condition: "user", users: ["other"] }),
    ]);
    expect(controller.result).toBe("hidden");
  });

  it("opens one subscription per server leaf with the translated core condition", async () => {
    const { controller } = await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ]);
    expect(subs).toHaveLength(1);
    expect(subs[0].condition).toEqual({
      condition: "state",
      entity_id: "light.a",
      state: "on",
    });
    // unknown until the first push
    expect(controller.result).toBe("unknown");
  });

  it("updates the result from server pushes", async () => {
    const { controller } = await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ]);
    subs[0].push({ result: true });
    expect(controller.result).toBe("visible");
    subs[0].push({ result: false });
    expect(controller.result).toBe("hidden");
  });

  it("groups sibling server conditions into a single subscription", async () => {
    await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
      cond({ condition: "template", value_template: "{{ true }}" }),
    ]);
    expect(subs).toHaveLength(1);
    expect(subs[0].condition).toEqual({
      condition: "and",
      conditions: [
        { condition: "state", entity_id: "light.a", state: "on" },
        { condition: "template", value_template: "{{ true }}" },
      ],
    });
  });

  it("combines a server subtree with a client leaf", async () => {
    // user1 matches → client leaf true; result follows the server push
    const { controller } = await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
      cond({ condition: "user", users: ["user1"] }),
    ]);
    expect(subs).toHaveLength(1);
    subs[0].push({ result: true });
    expect(controller.result).toBe("visible");
    subs[0].push({ result: false });
    expect(controller.result).toBe("hidden");
  });

  it("hides and surfaces the message on a subscription error", async () => {
    const { controller, last } = await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ]);
    subs[0].push({ error: "Invalid condition" });
    expect(controller.result).toBe("hidden");
    expect(controller.error).toBe("Invalid condition");
    expect(last()?.error).toBe("Invalid condition");
  });

  it("stays hidden on a subscription error even under a client-side not", async () => {
    // Don't treat an error as `false` that `not` would invert to visible.
    const { controller } = await setup([
      cond({
        condition: "not",
        conditions: [
          { condition: "user", users: ["other"] },
          { condition: "template", value_template: "{{ broken" },
        ],
      }),
    ]);
    expect(subs).toHaveLength(1);
    subs[0].push({ error: { code: "invalid_format", message: "bad" } });
    expect(controller.result).toBe("hidden");
    expect(controller.error).toBe("bad");
  });

  it("surfaces template errors without overriding the result", async () => {
    // Template render errors are flagged; they don't force hidden.
    const { controller, last } = await setup([
      cond({ condition: "template", value_template: "{{ x }}" }),
    ]);
    subs[0].push({ result: true, template_errors: ["'x' is undefined"] });
    expect(controller.result).toBe("visible");
    expect(controller.error).toBe("'x' is undefined");
    expect(last()?.error).toBe("'x' is undefined");
    subs[0].push({ result: true });
    expect(controller.error).toBeUndefined();
  });

  it("clears the error once the subscription recovers", async () => {
    const { controller } = await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ]);
    subs[0].push({ error: "boom" });
    expect(controller.error).toBe("boom");
    subs[0].push({ result: true });
    expect(controller.result).toBe("visible");
    expect(controller.error).toBeUndefined();
  });

  it("re-subscribes when the condition tree changes and tears the old one down", async () => {
    const hass = createHass();
    const host = createHost();
    const controller = new ConditionEvaluatorController(host, {
      resubscribeDelay: 0,
      onResult: () => undefined,
    });
    controller.hostConnected();

    controller.observe(
      [cond({ condition: "state", entity: "light.a", state: "on" })],
      hass
    );
    await tick();
    expect(subs).toHaveLength(1);
    const firstUnsub = subs[0].unsub;

    controller.observe(
      [cond({ condition: "state", entity: "light.b", state: "off" })],
      hass
    );
    await tick();

    expect(firstUnsub).toHaveBeenCalledTimes(1);
    expect(subs).toHaveLength(2);
    expect(subs[1].condition).toEqual({
      condition: "state",
      entity_id: "light.b",
      state: "off",
    });
  });

  it("publishes unknown and ignores stale pushes while a re-subscribe is pending", async () => {
    vi.useFakeTimers();
    try {
      const hass = createHass();
      const host = createHost();
      const results: ConditionEvaluation[] = [];
      const controller = new ConditionEvaluatorController(host, {
        resubscribeDelay: 1000,
        onResult: (result) => results.push(result),
      });
      controller.hostConnected();

      controller.observe(
        [cond({ condition: "state", entity: "light.a", state: "on" })],
        hass
      );
      await vi.advanceTimersByTimeAsync(1000);
      const stale = subs[0];
      stale.push({ result: true });
      expect(controller.result).toBe("visible");

      // Drop the old subscription immediately; don't keep its result.
      controller.observe(
        [cond({ condition: "state", entity: "light.a", state: "off" })],
        hass
      );
      await vi.advanceTimersByTimeAsync(0);
      expect(stale.unsub).toHaveBeenCalledTimes(1);
      expect(controller.result).toBe("unknown");
      expect(results[results.length - 1]).toBe("unknown");
      stale.push({ result: true });
      expect(controller.result).toBe("unknown");
      expect(subs).toHaveLength(1);

      await vi.advanceTimersByTimeAsync(1000);
      expect(subs).toHaveLength(2);
      subs[1].push({ result: false });
      expect(controller.result).toBe("hidden");
    } finally {
      vi.useRealTimers();
    }
  });

  it("re-subscribes an all-client tree change immediately", async () => {
    const hass = createHass();
    const host = createHost();
    const controller = new ConditionEvaluatorController(host, {
      resubscribeDelay: 1000,
      onResult: () => undefined,
    });
    controller.hostConnected();
    controller.observe([cond({ condition: "user", users: ["user1"] })], hass);
    expect(controller.result).toBe("visible");
    controller.observe([cond({ condition: "user", users: ["other"] })], hass);
    // no debounce for a tree with nothing to subscribe to
    expect(controller.result).toBe("hidden");
  });

  it("drops the subscription when observation is cleared, even under hass churn", async () => {
    const host = createHost();
    const controller = new ConditionEvaluatorController(host, {
      resubscribeDelay: 20,
      onResult: () => undefined,
    });
    controller.hostConnected();
    controller.observe(
      [cond({ condition: "state", entity: "light.a", state: "on" })],
      createHass()
    );
    await new Promise<void>((resolve) => {
      setTimeout(resolve, 30);
    });
    expect(subs).toHaveLength(1);

    // Clearing used to keep rescheduling because `undefined` meant "nothing pending".
    controller.observe(undefined, createHass());
    controller.observe(undefined, createHass());
    controller.observe(undefined, createHass());
    await tick();
    expect(subs[0].unsub).toHaveBeenCalledTimes(1);
    expect(subs).toHaveLength(1);
    expect(controller.result).toBe("unknown");
  });

  it("subscribes once hass arrives after the conditions were observed", async () => {
    const host = createHost();
    const controller = new ConditionEvaluatorController(host, {
      resubscribeDelay: 0,
      onResult: () => undefined,
    });
    const conditions = [
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ];
    // Host connected with its config set, hass not yet provided.
    controller.hostConnected();
    controller.observe(conditions, undefined);
    await tick();
    expect(subs).toHaveLength(0);
    expect(controller.result).toBe("unknown");

    controller.observe(conditions, createHass());
    await tick();
    expect(subs).toHaveLength(1);
    subs[0].push({ result: true });
    expect(controller.result).toBe("visible");
  });

  it("re-subscribes when a non-finite bound flips sign", async () => {
    // JSON.stringify maps both infinities to null, so the signature would match.
    const hass = createHass();
    const { controller } = await setup(
      [
        cond({
          condition: "numeric_state",
          entity: "sensor.a",
          above: 5,
          below: Infinity,
        }),
      ],
      hass
    );
    expect(subs).toHaveLength(1);
    controller.observe(
      [
        cond({
          condition: "numeric_state",
          entity: "sensor.a",
          above: 5,
          below: -Infinity,
        }),
      ],
      hass
    );
    await tick();
    expect(subs).toHaveLength(2);
  });

  it("does not re-subscribe when only hass changes", async () => {
    const conditions = [
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ];
    const hass = createHass();
    const { controller } = await setup(conditions, hass);
    expect(subs).toHaveLength(1);

    // same conditions reference, new hass object on the same connection →
    // recompute only, no new subscription
    controller.observe(conditions, { ...hass, states: {} } as HomeAssistant);
    await tick();
    expect(subs).toHaveLength(1);
  });

  it("re-subscribes when the connection object is replaced", async () => {
    const conditions = [
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ];
    const { controller } = await setup(conditions);
    expect(subs).toHaveLength(1);
    const firstUnsub = subs[0].unsub;

    // a replacement connection carries none of the old subscriptions
    controller.observe(conditions, createHass());
    await tick();
    expect(firstUnsub).toHaveBeenCalledTimes(1);
    expect(subs).toHaveLength(2);
  });

  it("tears down subscriptions on host disconnect", async () => {
    const { controller } = await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ]);
    const { unsub } = subs[0];
    controller.hostDisconnected();
    await tick();
    expect(unsub).toHaveBeenCalledTimes(1);
  });

  it("ignores pushes that arrive after teardown", async () => {
    const { controller } = await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ]);
    const stale = subs[0];
    controller.hostDisconnected();
    await tick();
    stale.push({ result: true });
    // still unknown — the stale push from the torn-down subscription is ignored
    expect(controller.result).toBe("unknown");
  });

  it("does not re-subscribe when a fresh array of equal content is passed", async () => {
    // A new array with the same content must not churn subscriptions.
    const make = () => [
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ];
    const hass = createHass();
    const { controller } = await setup(make(), hass);
    expect(subs).toHaveLength(1);
    const firstUnsub = subs[0].unsub;

    controller.observe(make(), { ...hass, states: {} } as HomeAssistant);
    await tick();

    expect(subs).toHaveLength(1);
    expect(firstUnsub).not.toHaveBeenCalled();
  });

  it("reports unknown after disconnect rather than a stale result", async () => {
    const { controller, last } = await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ]);
    subs[0].push({ result: true });
    expect(controller.result).toBe("visible");

    controller.hostDisconnected();
    await tick();

    expect(controller.result).toBe("unknown");
    expect(last()?.result).toBe("unknown");
  });

  it("notifies onResult only when the result actually changes", async () => {
    const { results } = await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ]);
    const countBefore = results.length;
    subs[0].push({ result: true });
    subs[0].push({ result: true });
    subs[0].push({ result: true });
    // one change (unknown → visible), the repeats are coalesced
    expect(results.length).toBe(countBefore + 1);
    expect(results[results.length - 1].result).toBe("visible");
  });

  it("requests a host update when the result changes", async () => {
    const { host } = await setup([
      cond({ condition: "state", entity: "light.a", state: "on" }),
    ]);
    (host.requestUpdate as ReturnType<typeof vi.fn>).mockClear();
    subs[0].push({ result: true });
    expect(host.requestUpdate).toHaveBeenCalled();
  });
});