import { describe, expect, it, vi } from "vitest";
import React from "react";
import { render, screen, waitFor, fireEvent } from "@testing-library/react";
import "@testing-library/jest-dom";

// jsdom does not implement scrollIntoView — mock it globally
Element.prototype.scrollIntoView = vi.fn();

// ---------------------------------------------------------------------------
// Test target — bounded to ReasoningWorkspace milestone overview seam
// ---------------------------------------------------------------------------

function makeGraphResult(overrides = {}) {
  return {
    success: true,
    situationGraph: {
      centralStatement: "Complaints increased while production increased.",
      currentSummary: "Nodes: 2 observation | Unknowns: 0 resolved",
      activeUnknownNodeId: null,
      resolvedNodeIds: ["n-unknown"],
      nodes: [
        { id: "n-1", label: "Complaints up 35%", kind: "observation", status: "supported" },
        { id: "n-unknown", label: "Complaint rate denominator", kind: "unknown", status: "resolved" },
      ],
      edges: [],
      reconstruction: { plausibleInterpretations: [{ id: "i1", description: "Denominator was narrowed" }] },
    },
    selectedQuestion: null,
    updatedSituationGraph: null,
    newlySurfacedNodeIds: [],
    diagnostics: { modelName: "test", validationStatus: "valid" },
    ...overrides,
  };
}

let ReasoningWorkspace;

vi.mock("react-i18next", () => ({
  useTranslation: () => ({ t: (k) => k }),
  initPromise: Promise.resolve(),
}));

describe("investigation overview UI seam (v0.54b)", () => {
  beforeAll(async () => {
    const mod = await import("@/components/reasoning-workspace.jsx");
    ReasoningWorkspace = mod.default;
  });

  function renderWorkspace(overrides = {}) {
    const props = {
      scenario: "Complaints increased while production increased.",
      status: "success",
      updateStatus: "idle",
      cuSynthesisLoading: false,
      currentUnderstanding: "Production quality declined.",
      result: makeGraphResult(),
      answer: "",
      setAnswer: vi.fn(),
      onAnswerSubmit: vi.fn(),
      lastSubmittedAnswer: "",
      onRestart: vi.fn(),
      focusedContributions: [],
      onFocusedContribution: vi.fn(),
      findings: [],
      onUpdateFindingDisposition: vi.fn(),
      onUpdateFindingProposition: vi.fn(),
      onSummaryUpdate: vi.fn(),
      onImmediateGraphChange: vi.fn(),
      onSituationGraphChange: vi.fn(),
      initialPostAnalyseStatus: "success",
      overviewState: null,
      setOverviewState: vi.fn(),
      overviewLoading: false,
      handleRequestOverview: vi.fn(),
      ...overrides,
    };
    return render(React.createElement(ReasoningWorkspace, props));
  }

  // 1. zero-Open-Questions milestone renders the review action
  it("renders Review current understanding button when open unknowns are zero and clarified questions exist", async () => {
    renderWorkspace();
    await waitFor(() => {
      const btn = screen.getByRole("button", { name: /Review current understanding/i });
      expect(btn).toBeInTheDocument();
    });
  });

  // 7. no overview is requested before the user clicks
  it("does not request overview before user clicks (handleRequestOverview not called)", async () => {
    const mockHandleRequest = vi.fn();
    renderWorkspace({ handleRequestOverview: mockHandleRequest });
    expect(mockHandleRequest).not.toHaveBeenCalled();
  });

  // 2. clicking it calls the overview endpoint once
  it("calls handleRequestOverview on button click", async () => {
    const mockHandleRequest = vi.fn();
    renderWorkspace({ handleRequestOverview: mockHandleRequest });
    const btn = await screen.findByRole("button", { name: /Review current understanding/i });
    fireEvent.click(btn);
    expect(mockHandleRequest).toHaveBeenCalledTimes(1);
  });

  // 3. loading state is visible
  it("shows loading text while overviewLoading is true", async () => {
    renderWorkspace({ overviewState: null, overviewLoading: true, handleRequestOverview: vi.fn() });
    await waitFor(() => {
      expect(screen.getByText(/Generating overview/i)).toBeInTheDocument();
    });
  });

  // 4. returned understanding is rendered under the established-understanding section
  it("renders overview understanding in What we understand section", async () => {
    renderWorkspace({
      overviewState: {
        success: true,
        understanding: "We understand that complaints rose alongside production increases.",
        plausibleInterpretations: null,
      },
    });
    await waitFor(() => {
      const surface = screen.getByTestId("investigation-overview");
      expect(surface).toBeInTheDocument();
    });
    const surface2 = document.querySelector('[data-testid="investigation-overview"]');
    expect(surface2.textContent).toContain("What we understand");
    expect(surface2.textContent).toContain("We understand that complaints rose alongside production increases.");
  });

  // 5. returned plausibleInterpretations is rendered separately and clearly qualified
  it("renders plausible interpretations as a separate qualified section", async () => {
    renderWorkspace({
      overviewState: {
        success: true,
        understanding: "Production quality declined.",
        plausibleInterpretations: "The denominator may have been narrowed, explaining the apparent complaint increase.",
      },
    });
    const surface = screen.getByTestId("investigation-overview");
    expect(surface).toBeInTheDocument();
    expect(surface.textContent).toContain("What remains plausible");
    expect(surface.textContent).toContain("The denominator may have been narrowed");
  });

  // 6. existing Current Understanding remains
  it("existing Current Understanding text remains visible alongside overview", async () => {
    renderWorkspace({
      currentUnderstanding: "Production quality declined.",
      overviewState: {
        success: true,
        understanding: "We understand that complaints rose alongside production increases.",
        plausibleInterpretations: null,
      },
    });
    const cuSurface = document.querySelector('[id="cu-scroll-target"]');
    expect(cuSurface).toBeInTheDocument();
    expect(cuSurface.textContent).toContain("Production quality declined.");
  });

  // 8. overview response does not mutate Current Understanding
  it("does not call setCurrentUnderstanding or mutate existing CU", async () => {
    const mockSetCU = vi.fn();
    renderWorkspace({
      currentUnderstanding: "Production quality declined.",
      overviewState: {
        success: true,
        understanding: "Overview synthesis result.",
        plausibleInterpretations: null,
      },
      setCurrentUnderstanding: mockSetCU,
    });
    expect(mockSetCU).not.toHaveBeenCalled();
  });

  // 9. clarified questions remain visible
  it("clarified questions remain rendered when overview is shown", async () => {
    renderWorkspace({
      overviewState: {
        success: true,
        understanding: "Overview.",
        plausibleInterpretations: null,
      },
    });
    expect(screen.getByText(/Questions we have clarified/i)).toBeInTheDocument();
  });
});