import type { MonitoringView } from "@batch-cooking/shared";
import "../../src/i18n/i18n";
import type {
  MonitoringConnectionState,
  MonitoringSocketClientLike,
} from "../../src/api/monitoring-socket";
import { MonitoringPage } from "../../src/pages/admin/monitoring/MonitoringPage";

// MonitoringPage takes its WebSocket client as a prop specifically so it
// can be driven like this — no real socket.io server involved. See that
// prop's own doc comment in MonitoringPage.tsx for why.
class FakeMonitoringSocketClient implements MonitoringSocketClientLike {
  public connectCallCount = 0;
  public disconnectCallCount = 0;
  private readonly _updateListeners = new Set<(data: MonitoringView) => void>();
  private readonly _stateListeners = new Set<(state: MonitoringConnectionState) => void>();

  public connect(): void {
    this.connectCallCount += 1;
  }

  public disconnect(): void {
    this.disconnectCallCount += 1;
  }

  public onUpdate(listener: (data: MonitoringView) => void): () => void {
    this._updateListeners.add(listener);
    return () => this._updateListeners.delete(listener);
  }

  public onConnectionStateChange(listener: (state: MonitoringConnectionState) => void): () => void {
    this._stateListeners.add(listener);
    return () => this._stateListeners.delete(listener);
  }

  /** Test-only: simulates the server pushing a snapshot. */
  public emitUpdate(data: MonitoringView): void {
    for (const listener of this._updateListeners) listener(data);
  }

  /** Test-only: simulates a connection-state change. */
  public emitState(state: MonitoringConnectionState): void {
    for (const listener of this._stateListeners) listener(state);
  }
}

function monitoringFixture(): MonitoringView {
  return {
    generatedAt: "2026-09-05T09:15:00.000Z",
    services: [
      {
        key: "postgres",
        status: "up",
        latencyMs: 3.2,
        detail: null,
        checkedAt: "2026-09-05T09:15:00.000Z",
      },
      {
        key: "api",
        status: "up",
        latencyMs: 0,
        detail: "uptime 3 h · RSS 120 Mo",
        checkedAt: "2026-09-05T09:15:00.000Z",
      },
      {
        key: "intent-service",
        status: "down",
        latencyMs: null,
        detail: "fetch failed",
        checkedAt: "2026-09-05T09:15:00.000Z",
      },
      {
        key: "tech-step-llm-worker",
        status: "degraded",
        latencyMs: null,
        detail: "dernier battement il y a 9 j",
        checkedAt: "2026-09-05T09:15:00.000Z",
        lastRunAt: "2026-08-19T03:00:00.000Z",
        lastResult: { job: "audit-low-confidence", ok: true, counts: { suggestions: 2 } },
      },
    ],
  };
}

describe("MonitoringPage", () => {
  it("shows a loading placeholder before the first update arrives, and connects on mount", () => {
    const client = new FakeMonitoringSocketClient();
    cy.mount(<MonitoringPage socketClient={client} />);

    cy.contains("Chargement").should("be.visible");
    cy.get(".monitoring-grid").should("not.exist");
    // `.should(...)` (not a bare `cy.then` + chai `expect`) so Cypress
    // retries: `connect()` is called from a `useEffect`, which commits
    // asynchronously after `cy.mount` itself has already resolved.
    cy.wrap(client).its("connectCallCount").should("equal", 1);
  });

  it("renders one card per service once a snapshot arrives", () => {
    const client = new FakeMonitoringSocketClient();
    cy.mount(<MonitoringPage socketClient={client} />);
    cy.then(() => {
      client.emitState("connected");
      client.emitUpdate(monitoringFixture());
    });

    cy.get(".monitoring-card").should("have.length", 4);
    cy.contains(".monitoring-card", "Base de données").should("have.class", "monitoring-card--up");
    cy.contains(".monitoring-card", "Service NLP (spaCy)").should(
      "have.class",
      "monitoring-card--down",
    );
    cy.get(".monitoring-connection-badge").should("not.exist");
  });

  it("shows a reconnecting badge without hiding the last known board", () => {
    const client = new FakeMonitoringSocketClient();
    cy.mount(<MonitoringPage socketClient={client} />);
    cy.then(() => {
      client.emitState("connected");
      client.emitUpdate(monitoringFixture());
    });
    cy.get(".monitoring-card").should("have.length", 4);

    cy.then(() => client.emitState("reconnecting"));

    cy.get(".monitoring-connection-badge--reconnecting").should("be.visible");
    // The board itself is still the one from before the drop — never
    // replaced by a loading state just because the connection blipped.
    cy.get(".monitoring-card").should("have.length", 4);
  });

  it("shows an error placeholder when the connection fails before any data ever arrived", () => {
    const client = new FakeMonitoringSocketClient();
    cy.mount(<MonitoringPage socketClient={client} />);
    cy.then(() => client.emitState("error"));

    cy.contains("Impossible de charger").should("be.visible");
    cy.get(".monitoring-grid").should("not.exist");
  });
});