import { describe, expect, it, vi } from "vitest";
import {
  filterEligibleFindings,
  buildSynthesisPrompt,
  synthesizeCurrentUnderstanding,
  validateSynthesisResponse,
} from "@/lib/graph/current-understanding-synthesis.js";

// ── Fixtures ────────────────────────────────────────────────

/** A graph where only centralStatement is present — no known/supported nodes */
const emptyGraph = {
  centralStatement: "Complaints increased by 35% while production increased by 40%.",
};

/** Full scenario fixture matching the fixed semantic regression case */
const fullScenario = {
  centralStatement:
    "Complaints increased by 35% while production increased by 40%.",
  nodes: [
    { id: "n1", label: "Complaint count increased by 35%", description: "Primary metric baseline", kind: "metric", status: "known", confidence: "high", value: 35, unit: "%" },
    { id: "n2", label: "Production count increased by 40%", description: "Secondary metric baseline", kind: "metric", status: "supported", confidence: "medium", value: 40, unit: "%" },
    { id: "n3", label: "Baseline period denominator volume", description: "Question about the baseline", kind: "unknown", status: "unknown", confidence: "low" },
    { id: "n4", label: "Time period over which these percentage changes occurred", description: "Resolved question — user answered", kind: "question", status: "resolved", confidence: "high" },
    { id: "n5", label: "Product mix may explain the complaint increase", description: "Provisional hypothesis for later investigation", kind: "hypothesis", status: "provisional", confidence: "low" },
  ],
  edges: [
    { fromNodeId: "n1", toNodeId: "n2", relationship: "compares_with", confidence: "high", description: "Correlation between complaints and production" },
  ],
  activeUnknownNodeId: "n3",
  resolvedNodeIds: ["n4"],
  currentSummary: "Sentinel: currentSummary must not appear in synthesis",
  reasoningState: { stage: "analysis", status: "active", outcome: "pending" },
};

/** Minimal eligible Finding — userDisposition null (working premise) */
const workingFinding = () => ({
  id: "find-working",
  proposition: "The reported percentage changes correspond to the last financial quarter.",
  evaluation: "considered",
  userDisposition: null,
  sourceObservation: "obs-1",
  contributionId: "contrib-001",
});

/** Minimal eligible Finding — userDisposition agree */
const agreedFinding = () => ({
  id: "find-agreed",
  proposition: "The percentage increase in complaints exceeds the threshold.",
  evaluation: "considered",
  userDisposition: "agree",
  sourceObservation: "obs-2",
  contributionId: "contrib-002",
});

/** Fake provider factory for tests */
const makeFakeProvider = (defaultResponse) => ({
  generateReconstruction: vi.fn(async () => {
    return typeof defaultResponse === "function"
      ? defaultResponse()
      : JSON.stringify({ currentUnderstanding: "Synthesized output" });
  }),
});

// ── Eligibility tests (unchanged — domain invariant) ────────

describe("filterEligibleFindings — eligibility contract", () => {
  it("includes null disposition → eligible", () => {
    const result = filterEligibleFindings([workingFinding()]);
    expect(result).toHaveLength(1);
    expect(result[0].userDisposition).toBeNull();
  });

  it("includes agree disposition → eligible", () => {
    const result = filterEligibleFindings([agreedFinding()]);
    expect(result).toHaveLength(1);
    expect(result[0].userDisposition).toBe("agree");
  });

  it("excludes not_quite disposition → ineligible", () => {
    expect(filterEligibleFindings([{ userDisposition: "not_quite" }])).toHaveLength(0);
  });

  it("excludes not_relevant disposition → ineligible", () => {
    expect(filterEligibleFindings([{ userDisposition: "not_relevant" }])).toHaveLength(0);
  });

  it("excludes rejected evaluation → excluded", () => {
    expect(filterEligibleFindings([{ evaluation: "rejected" }])).toHaveLength(0);
  });

  it("mixed dispositions — only eligible pass through", () => {
    const results = filterEligibleFindings([
      { id: "f1", userDisposition: null },
      { id: "f2", userDisposition: "agree" },
      { id: "f3", userDisposition: "not_quite" },
      { id: "f4", userDisposition: "not_relevant" },
      { evaluation: "rejected", id: "f5" },
    ]);
    expect(results.map((f) => f.id)).toEqual(["f1", "f2"]);
  });

  it("null/undefined/empty input returns empty array", () => {
    expect(filterEligibleFindings(null)).toEqual([]);
    expect(filterEligibleFindings(undefined)).toEqual([]);
    expect(filterEligibleFindings([])).toEqual([]);
  });
});

// ── Evidence projection — status filtering ──────────────────

describe("buildSynthesisPrompt — evidence-authority boundary", () => {
  // ── A. known retained ────────────────────────────────────

  it("known node appears in the synthesis prompt (label, kind, value, unit)", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).toContain("Complaint count increased by 35%");
    expect(prompt).toContain("kind=metric");
    expect(prompt).toContain("[known]");
  });

  // ── B. supported retained ────────────────────────────────

  it("supported node appears in the synthesis prompt", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).toContain("Production count increased by 40%");
    expect(prompt).toContain("[supported]");
  });

  // ── C. unknown excluded ──────────────────────────────────

  it("unknown node content does NOT appear anywhere in synthesis", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).not.toContain("Baseline period denominator volume");
    expect(prompt).not.toContain('status":"unknown"');
    expect(prompt).not.toContain("question about the baseline");
  });

  // ── D. provisional excluded ──────────────────────────────

  it("provisional hypothesis does NOT appear as CU evidence", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).not.toContain("Product mix may explain");
    expect(prompt).not.toContain('status":"provisional"');
  });

  // ── E. resolved-question text excluded ───────────────────

  it("resolved node label/description does NOT appear as CU evidence", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).not.toContain("Time period over which these percentage changes occurred");
    expect(prompt).not.toContain('status":"resolved"');
    expect(prompt).not.toContain("Resolved question");
  });

  // ── F. learned Finding retained ──────────────────────────

  it("eligible Finding appears in synthesis — proves we exclude resolved question while retaining the answer", () => {
    const prompt = buildSynthesisPrompt(fullScenario, [workingFinding()]);
    expect(prompt).toContain("The reported percentage changes correspond to the last financial quarter.");
    expect(prompt).not.toContain("Time period over which these percentage changes occurred");
  });

  // ── G. control/reasoning content excluded ────────────────

  it("control/reasoning sentinels are absent from synthesis prompt", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).not.toContain("currentSummary");
    expect(prompt).not.toContain("Sentinel: currentSummary must not appear in synthesis");
    expect(prompt).not.toContain("reasoningState");
    expect(prompt).not.toContain("activeUnknownNodeId");
    expect(prompt).not.toContain('"n3"'); // active unknown node id sentinel
    expect(prompt).not.toContain("resolvedNodeIds");
    expect(prompt).not.toContain('"n4"'); // resolved node id sentinel
  });

  // ── H. centralStatement retained as framing ─────────────

  it("centralStatement remains available as framing context", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).toContain("Complaints increased by 35% while production increased by 40%");
  });

  // ── I. node.proposition dead read removed ────────────────

  it("prompt does NOT depend on a proposition property on SituationGraph nodes", () => {
    const noPropositionGraph = {
      centralStatement: "Only framing.",
      nodes: [
        { id: "a1", label: "Label only node", description: "No proposition field", kind: "observation", status: "known", confidence: "medium" },
      ],
    };
    const prompt = buildSynthesisPrompt(noPropositionGraph, []);
    expect(prompt).toContain("Only framing.");
    expect(prompt).toContain("Label only node");
    // The projection must work correctly even when nodes lack a 'propertion' field entirely.
  });

  // ── Structural correctness of the text-formatted evidence section ─

  it("evidence section contains Known Facts and Supported Inferences headers", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).toContain("Known Facts:");
    expect(prompt).toContain("Supported Inferences:");
  });

  it("evidence section does not contain raw graph fields (edges, resolvedNodeIds, activeUnknownNodeId, reasoningState)", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    // These are all control/structural graph fields that must not appear in the evidence section
    expect(prompt).not.toContain("edges");
    expect(prompt).not.toContain("resolvedNodeIds");
    expect(prompt).not.toContain("activeUnknownNodeId");
    expect(prompt).not.toContain("reasoningState");
  });

  it("node representation includes all canonical fields — kind, label, status, value, unit", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    // Each node line contains: kind=..., label="...", value=... [status]
    expect(prompt).toContain("kind=metric");
    expect(prompt).toContain('label="Complaint count increased by 35%"');
    expect(prompt).toContain("[known]");
    expect(prompt).toContain("[supported]");
    expect(prompt).toContain("value=35 (");
    expect(prompt).toContain("Primary metric baseline");
  });

  it("provider sees structured evidence section header", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).toContain("Provider-Active Evidence:");
    expect(prompt).not.toContain("Canonical Situation Graph");
  });

  // ── Edge case: empty graph (no known/supported nodes) ────

  it("handles graph with no evidence nodes gracefully", () => {
    const prompt = buildSynthesisPrompt(emptyGraph, []);
    expect(prompt).not.toContain("(no evidence)");
    expect(prompt).toContain("Complaints increased by 35% while production increased by 40%");
  });

  // ── Edge case: only supported, no known ──────────────────

  it("handles graph with only supported nodes", () => {
    const supportedOnly = {
      centralStatement: "Metric drift detected.",
      nodes: [
        { id: "s1", label: "Drift exceeds threshold", description: "Supported inference", kind: "metric", status: "supported", confidence: "low" },
      ],
    };
    const prompt = buildSynthesisPrompt(supportedOnly, []);
    expect(prompt).toContain("Drift exceeds threshold");
  });

  // ── Finding integration tests ────────────────────────────

  it("agreed Finding appears in synthesis with Correct Evidence label", () => {
    const prompt = buildSynthesisPrompt(fullScenario, [agreedFinding()]);
    expect(prompt).toContain("The percentage increase in complaints exceeds the threshold.");
    expect(prompt).toContain("Confirmed Evidence");
  });

  it("working premise Finding appears with Working Premises label", () => {
    const prompt = buildSynthesisPrompt(fullScenario, [workingFinding()]);
    expect(prompt).toContain("The reported percentage changes correspond to the last financial quarter.");
    expect(prompt).toContain("Working Premises");
  });

  // ── Immutability ─────────────────────────────────────────

  it("graph structurally unchanged after synthesis prompt build", () => {
    const graphSnapshot = JSON.parse(JSON.stringify(fullScenario));
    buildSynthesisPrompt(fullScenario, []);
    expect(JSON.stringify(fullScenario)).toBe(JSON.stringify(graphSnapshot));
  });

  it("findings structurally unchanged after synthesis prompt build", () => {
    const findings = [workingFinding()];
    const snapshot = JSON.parse(JSON.stringify(findings));
    buildSynthesisPrompt(fullScenario, findings);
    expect(JSON.stringify(findings)).toBe(JSON.stringify(snapshot));
  });

  // ── Immutability during full seam ────────────────────────

  it("graph and findings unchanged after synthesizeCurrentUnderstanding", async () => {
    const graphSnapshot = JSON.parse(JSON.stringify(fullScenario));
    const findings = [workingFinding()];
    const findingsSnapshot = JSON.parse(JSON.stringify(findings));

    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings },
      { provider: fake }
    );

    expect(JSON.stringify(fullScenario)).toBe(JSON.stringify(graphSnapshot));
    expect(JSON.stringify(findings)).toBe(JSON.stringify(findingsSnapshot));
  });
});

// ── Prompt authority rule verification ─────────────────────

describe("buildSynthesisPrompt — prompt semantics", () => {
  it("prompt contains evidence-authority boundary rule (not open questions)", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).toContain("Current Understanding describes only established or supported understanding");
    expect(prompt).toContain("Do not introduce or describe open questions, unresolved uncertainties, assumptions, provisional hypotheses");
  });

  it("prompt clarifies centralStatement is framing context only", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    expect(prompt).toContain("Framing");
    // Must explicitly say the centralStatement is not independent evidence
    expect(prompt).toContain("framing context, not independent evidence");
  });

  it("prompt does NOT include edges in the evidence section", () => {
    const prompt = buildSynthesisPrompt(fullScenario, []);
    // Edges should not be mentioned in the structured evidence projection
    expect(prompt).not.toContain("Edge");
    expect(prompt).not.toMatch(/relationship:.*compares_with/);
  });
});

// ── Output validation tests (unchanged) ────────────────────

describe("validateSynthesisResponse", () => {
  it("accepts valid narrative JSON object", () => {
    const result = validateSynthesisResponse({ currentUnderstanding: "The data shows X" });
    expect(result.valid).toBe(true);
    expect(result.data.currentUnderstanding).toBe("The data shows X");
  });

  it("accepts valid narrative JSON string", () => {
    const result = validateSynthesisResponse('{"currentUnderstanding": "parsed"}');
    expect(result.valid).toBe(true);
    expect(result.data.currentUnderstanding).toBe("parsed");
  });

  it("rejects missing currentUnderstanding field", () => {
    const result = validateSynthesisResponse({ summary: "wrong field" });
    expect(result.valid).toBe(false);
  });

  it("rejects empty string narrative", () => {
    const result = validateSynthesisResponse({ currentUnderstanding: "" });
    expect(result.valid).toBe(false);
  });

  it("rejects malformed JSON string", () => {
    const result = validateSynthesisResponse("not json at all [[[");
    expect(result.valid).toBe(false);
  });

  it("rejects null input", () => {
    expect(validateSynthesisResponse(null).valid).toBe(false);
  });

  it("rejects undefined input", () => {
    expect(validateSynthesisResponse(undefined).valid).toBe(false);
  });
});

// ── Domain function tests (full seam) ──────────────────────

describe("synthesizeCurrentUnderstanding — full seam", () => {
  // ── Evidence inclusion/exclusion at seam level ───────────

  it("known node content flows to provider via synthesis prompt", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [] },
      { provider: fake }
    );
    const prompt = fake.generateReconstruction.mock.calls[0][0];
    expect(prompt).toContain("Complaint count increased by 35%");
    expect(prompt).toContain("[known]");
  });

  it("supported node content flows to provider via synthesis prompt", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [] },
      { provider: fake }
    );
    const prompt = fake.generateReconstruction.mock.calls[0][0];
    expect(prompt).toContain("Production count increased by 40%");
    expect(prompt).toContain("[supported]");
  });

  it("unknown nodes do NOT appear in provider-visible synthesis", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [] },
      { provider: fake }
    );
    const prompt = fake.generateReconstruction.mock.calls[0][0];
    expect(prompt).not.toContain("Baseline period denominator volume");
  });

  it("provisional hypothesis does NOT appear in synthesis prompt", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [] },
      { provider: fake }
    );
    const prompt = fake.generateReconstruction.mock.calls[0][0];
    expect(prompt).not.toContain("Product mix may explain");
  });

  it("resolved-question text does NOT appear in synthesis prompt", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [] },
      { provider: fake }
    );
    const prompt = fake.generateReconstruction.mock.calls[0][0];
    expect(prompt).not.toContain("Time period over which these percentage changes occurred");
  });

  it("eligible Finding appears in synthesis", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [workingFinding()] },
      { provider: fake }
    );
    const prompt = fake.generateReconstruction.mock.calls[0][0];
    expect(prompt).toContain("The reported percentage changes correspond to the last financial quarter.");
  });

  it("control/reasoning sentinels excluded from synthesis", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [] },
      { provider: fake }
    );
    const prompt = fake.generateReconstruction.mock.calls[0][0];
    expect(prompt).not.toContain("currentSummary");
    expect(prompt).not.toContain("reasoningState");
  });

  // ── Immutability ─────────────────────────────────────────

  it("graph structurally unchanged after synthesis", async () => {
    const graphSnapshot = JSON.parse(JSON.stringify(fullScenario));
    const fake = makeFakeProvider();

    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [] },
      { provider: fake }
    );

    expect(JSON.stringify(fullScenario)).toBe(JSON.stringify(graphSnapshot));
  });

  it("findings structurally unchanged after synthesis", async () => {
    const findings = [workingFinding()];
    const findingsSnapshot = JSON.parse(JSON.stringify(findings));
    const fake = makeFakeProvider();

    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings },
      { provider: fake }
    );

    expect(JSON.stringify(findings)).toBe(JSON.stringify(findingsSnapshot));
  });

  // ── Input validation (unchanged) ────────────────────────

  it("missing situationGraph → throws 400", async () => {
    await expect(
      synthesizeCurrentUnderstanding({}, { provider: makeFakeProvider() })
    ).rejects.toThrow(/situationGraph is required/);
  });

  it("non-object situationGraph → throws 400", async () => {
    await expect(
      synthesizeCurrentUnderstanding({ situationGraph: "not an object" }, { provider: makeFakeProvider() })
    ).rejects.toThrow(/situationGraph is required/);
  });

  it("findings as non-array → throws 400", async () => {
    await expect(
      synthesizeCurrentUnderstanding({ situationGraph: fullScenario, findings: "string" }, { provider: makeFakeProvider() })
    ).rejects.toThrow(/findings must be an array/);
  });

  it("provider generateReconstruction throws → statusCode 502", async () => {
    const fake = makeFakeProvider(async () => { throw new Error("provider down"); });
    await expect(
      synthesizeCurrentUnderstanding(
        { situationGraph: fullScenario, findings: [] },
        { provider: fake }
      )
    ).rejects.toThrow(/Synthesis provider call failed|provider down/);
  });

  it("no provider provided — falls through to getProvider()", async () => {
    await expect(
      synthesizeCurrentUnderstanding(
        { situationGraph: fullScenario, findings: [] },
        {}
      )
    ).rejects.toThrow(/OLLAMA_BASE_URL/);
  });

  // ── Configured model resolution (unchanged) ─────────────

  it("default synthesis path resolves configured modelName", async () => {
    const fake = makeFakeProvider();
    const savedModel = process.env.OLLAMA_MODEL;
    process.env.OLLAMA_MODEL = "configured-model-v0.50";
    try {
      await synthesizeCurrentUnderstanding(
        { situationGraph: fullScenario, findings: [] },
        { provider: fake }
      );
      const receivedModel = fake.generateReconstruction.mock.calls[0][1];
      expect(receivedModel).toBeDefined();
      expect(receivedModel).not.toBeNull();
    } finally {
      if (savedModel == null) {
        delete process.env.OLLAMA_MODEL;
      } else {
        process.env.OLLAMA_MODEL = savedModel;
      }
    }
  });

  it("explicit modelName dependency overrides default", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [] },
      { provider: fake, modelName: "test-model-v0.50" }
    );
    expect(fake.generateReconstruction.mock.calls[0][1]).toBe("test-model-v0.50");
  });

  // ── Provider sees evidence projection, not raw graph ─────

  it("provider receives structured evidence projection (not full graph dump)", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [] },
      { provider: fake }
    );
    const prompt = fake.generateReconstruction.mock.calls[0][0];
    // Evidence section must be structured, not a raw JSON dump of the whole graph
    expect(prompt).toContain("Provider-Active Evidence");
    expect(prompt).not.toContain("Canonical Situation Graph");
  });

  it("provider receives centralStatement as framing context", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [] },
      { provider: fake }
    );
    const prompt = fake.generateReconstruction.mock.calls[0][0];
    expect(prompt).toContain("Complaints increased by 35%");
    expect(prompt).toContain("Framing");
  });

  it("provider receives centralStatement framing for no-evidence graph", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: emptyGraph, findings: [] },
      { provider: fake }
    );
    const prompt = fake.generateReconstruction.mock.calls[0][0];
    // Even with no evidence nodes, centralStatement framing flows through
    expect(prompt).toContain("Central Statement");
  });

  it("null/undefined findings → synthesis proceeds with empty evidence", async () => {
    const fake = makeFakeProvider();
    await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: null },
      { provider: fake }
    );
    expect(fake.generateReconstruction).toHaveBeenCalledTimes(1);
  });

  it("fake provider returns valid narrative → { currentUnderstanding }", async () => {
    const fake = makeFakeProvider();
    const result = await synthesizeCurrentUnderstanding(
      { situationGraph: fullScenario, findings: [workingFinding()] },
      { provider: fake }
    );
    expect(result).toEqual({ currentUnderstanding: "Synthesized output" });
  });

  it("fake provider returns empty narrative → rejected", async () => {
    const fake = makeFakeProvider(async () => JSON.stringify({ currentUnderstanding: "" }));
    await expect(
      synthesizeCurrentUnderstanding(
        { situationGraph: fullScenario, findings: [] },
        { provider: fake }
      )
    ).rejects.toThrow(/Synthesis validation failed/);
  });

  it("fake provider returns malformed JSON → rejected", async () => {
    const fake = makeFakeProvider(async () => "{ not valid json");
    await expect(
      synthesizeCurrentUnderstanding(
        { situationGraph: fullScenario, findings: [] },
        { provider: fake }
      )
    ).rejects.toThrow(/Synthesis validation failed/);
  });

  it("fake provider returns object without currentUnderstanding → rejected", async () => {
    const fake = makeFakeProvider(async () => JSON.stringify({ wrongField: "value" }));
    await expect(
      synthesizeCurrentUnderstanding(
        { situationGraph: fullScenario, findings: [] },
        { provider: fake }
      )
    ).rejects.toThrow(/Synthesis validation failed/);
  });
});