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

// ---------------------------------------------------------------------------
// Minimal isolated mocks for Report page only.
// No Portfolio, no restart behaviour, no storage provider, no module-cache hacks.
// ---------------------------------------------------------------------------

let mockLastLoadedId = undefined;
let mockLastSavedSnapshot = null;

function setMockSnapshot(snap) {
  if (snap) {
    localStorage.setItem(
      "confidence-engine-investigation",
      JSON.stringify(snap),
    );
    mockLoadResult = snap;
  } else {
    localStorage.removeItem("confidence-engine-investigation");
    mockLoadResult = null;
  }
}

let mockLoadResult = null;

vi.mock("@/lib/storage/investigation-storage", () => ({
  listInvestigations: () => [],
  loadInvestigation: (id) => {
    mockLastLoadedId = id;
    return mockLoadResult;
  },
  saveInvestigation: (snapshot) => {
    mockLastSavedSnapshot = snapshot;
  },
  clearInvestigation: () => {},
}));

function makeSnapshot(overrides = {}) {
  const situationGraph = {
    evidence: [
      { id: "e1", claim: "Complaints rose.", type: "finding" },
      { id: "e2", claim: "Production increased.", type: "finding" },
    ],
    reconstruction: {
      plausibleInterpretations: ["The denominator may have been narrowed."],
    },
  };

  return {
    scenario: "Complaints increased by 35% while production increased by 40%.",
    situationGraph,
    selectedQuestion: null,
    summary: "Production quality declined.",
    updatedAt: new Date().toISOString(),
    schemaVersion: 1,
    investigationReport: null,
    investigationRevision: 0,
    findings: [],
    ...overrides,
  };
}

async function cleanup() {
  localStorage.removeItem("confidence-engine-investigation");
}

/* ── v0.60h-a — Report identity and lifecycle isolation ─────────────────── */

describe("Report page identity and lifecycle — v0.60h-a", () => {
  let ReportPage;

  beforeEach(async () => {
    mockLastLoadedId = undefined;
    mockLastSavedSnapshot = null;
    setMockSnapshot(null);
    global.fetch = vi.fn();
    const mod = await import("@/app/investigations/[id]/report/page.jsx");
    ReportPage = mod.default;
  });

  afterEach(async () => {
    cleanup();
  });

  /* ── A: route identity on initial load (no existing report → first generation) ── */

  it("route identity verified on first generation", async () => {
    setMockSnapshot(makeSnapshot({
      id: "inv-report-a",
      investigationReport: null,
      investigationRevision: 4,
      findings: [],
    }));

    global.fetch.mockResolvedValue({
      ok: true,
      json: () => Promise.resolve({ success: true, understanding: "Summary.", plausibleInterpretations: "None." }),
    });

    render(React.createElement(ReportPage, { params: { id: "inv-report-a" } }));
    await screen.findByText(/Summary\./i);

    // A — loadInvestigation invoked with route ID
    expect(mockLastLoadedId).toBe("inv-report-a");

    // A — no unscoped singleton load observed (only call is for inv-report-a)
    expect(mockLastLoadedId).toBe("inv-report-a");

    // C/D — exactly one overview POST
    const calls = global.fetch.mock.calls.filter((c) => c[0] === "/api/cases/overview");
    expect(calls).toHaveLength(1);

    // C — saved snapshot retains route id
    expect(mockLastSavedSnapshot.id).toBe("inv-report-a");

    // D — generatedFromRevision correct
    expect(mockLastSavedSnapshot.investigationReport.generatedFromRevision).toBe(4);
  });

  /* ── B: existing persisted Report (no new generation) ── */

  it("renders existing report without generation", async () => {
    setMockSnapshot(makeSnapshot({
      id: "inv-report-a",
      investigationReport: { understanding: "Persisted summary.", hasPlausibleInterpretations: false, generatedFromRevision: 4 },
      investigationRevision: 4,
    }));

    render(React.createElement(ReportPage, { params: { id: "inv-report-a" } }));
    await screen.findByText(/Persisted summary\./i);

    // B — loadInvestigation invoked with route ID
    expect(mockLastLoadedId).toBe("inv-report-a");

    // E — no overview call when report exists and revisions match
    const calls = global.fetch.mock.calls.filter((c) => c[0] === "/api/cases/overview");
    expect(calls).toHaveLength(0);
  });

  /* ── C: first generation with empty findings ── */

  it("first generation with findings=[] posts exactly once and saves correctly", async () => {
    setMockSnapshot(makeSnapshot({
      id: "inv-report-a",
      investigationReport: null,
      situationGraph: { evidence: [], reconstruction: {} },
      investigationRevision: 4,
      findings: [],
    }));

    global.fetch.mockResolvedValue({
      ok: true,
      json: () => Promise.resolve({ success: true, understanding: "Generated.", plausibleInterpretations: null }),
    });

    render(React.createElement(ReportPage, { params: { id: "inv-report-a" } }));
    await screen.findByText(/Generated\./i);

    // C — exactly one POST /api/cases/overview
    const calls = global.fetch.mock.calls.filter((c) => c[0] === "/api/cases/overview");
    expect(calls).toHaveLength(1);

    // C — crossed storage mock: id === "inv-report-a"
    expect(mockLastSavedSnapshot.id).toBe("inv-report-a");

    // D — generatedFromRevision === investigationRevision
    expect(mockLastSavedSnapshot.investigationReport.generatedFromRevision).toBe(4);
  });

  /* ── D: manual Update report ── */

  it("manual update reloads same id and saves back", async () => {
    setMockSnapshot(makeSnapshot({
      id: "inv-report-a",
      investigationReport: { understanding: "R1.", hasPlausibleInterpretations: false, generatedFromRevision: 4 },
      investigationRevision: 5, // mismatch → "Update available"
      findings: [{ id: "f-1", proposition: "P1" }],
    }));

    global.fetch.mockResolvedValue({
      ok: true,
      json: () => Promise.resolve({ success: true, understanding: "R2.", plausibleInterpretations: null }),
    });

    render(React.createElement(ReportPage, { params: { id: "inv-report-a" } }));
    await screen.findByText(/Update available/i);

    const updateBtn = screen.getByRole("button", { name: /Update report/i });
    fireEvent.click(updateBtn);
    await screen.findByText(/R2\./i);

    // D — reload by same id
    expect(mockLastLoadedId).toBe("inv-report-a");

    // D — save back to same ID with updated revision
    expect(mockLastSavedSnapshot.id).toBe("inv-report-a");
    expect(mockLastSavedSnapshot.investigationReport.generatedFromRevision).toBe(5);

    // D — exactly one overview POST for the update
    const calls = global.fetch.mock.calls.filter((c) => c[0] === "/api/cases/overview");
    expect(calls).toHaveLength(1);
  });

  /* ── E: generation failure preserves existing Report ── */

  it("generation failure preserves existing Report", async () => {
    setMockSnapshot(makeSnapshot({
      id: "inv-report-a",
      investigationReport: null,
      situationGraph: { evidence: [], reconstruction: {} },
      investigationRevision: 1,
      findings: [],
    }));

    global.fetch.mockResolvedValue({ ok: false });

    render(React.createElement(ReportPage, { params: { id: "inv-report-a" } }));
    await screen.findByText(/Report generation failed/i);

    // E — no partial save on failure
    expect(mockLastSavedSnapshot).toBeNull();
  });

  /* ── F: update failure preserves existing Report ── */

  it("update failure preserves existing report", async () => {
    setMockSnapshot(makeSnapshot({
      id: "inv-report-a",
      investigationReport: { understanding: "R1.", hasPlausibleInterpretations: false, generatedFromRevision: 4 },
      investigationRevision: 5, // mismatch → "Update available"
      findings: [{ id: "f-1", proposition: "P1" }],
    }));

    global.fetch.mockResolvedValue({ ok: false });

    render(React.createElement(ReportPage, { params: { id: "inv-report-a" } }));
    await screen.findByText(/Update available/i);

    const updateBtn = screen.getByRole("button", { name: /Update report/i });
    fireEvent.click(updateBtn);

    // F — no save on update failure (saved snapshot unchanged from initial)
    expect(mockLastSavedSnapshot).toBeNull();
  });
});