import { describe, it, expect } from "vitest";
import { promises as fs } from "node:fs";
import { fileURLToPath } from "node:url";
import { dirname, join } from "node:path";
import {
  PROMPT_VERSIONS,
  buildPrompt,
  DEFAULT_PROMPT_VERSION,
} from "@/lib/reconstruction/prompt.js";
import {
  reconstructionV2Schema,
  parseReconstructionV2,
} from "@/lib/reconstruction/schema.js";

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
const PROMPTS_DIR = join(__dirname, "../prompts");

// ──────────────────────────────────────────────
// v0.3 prompt loading tests
// ──────────────────────────────────────────────

describe("v0.3 prompt", () => {
  it("v0.3 is in PROMPT_VERSIONS", () => {
    expect(PROMPT_VERSIONS).toContain("v0.3");
  });

  it("DEFAULT_PROMPT_VERSION is v0.3 on this branch", () => {
    expect(DEFAULT_PROMPT_VERSION).toBe("v0.3");
  });

  it("v0.2 remains available in PROMPT_VERSIONS", () => {
    expect(PROMPT_VERSIONS).toContain("v0.2");
  });

  it("v0.3 prompt file loads from disk", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.3.md"),
      "utf-8",
    );
    expect(typeof content).toBe("string");
    expect(content.length).toBeGreaterThan(500);
  });

  it("v0.3 prompt contains normalisation guidance", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.3.md"),
      "utf-8",
    );
    expect(content.toLowerCase()).toContain("normalise");
    expect(content.toLowerCase()).toContain("rate");
    expect(content.toLowerCase()).toContain("denominator") ||
      expect(content.toLowerCase()).toContain("exposure");
  });

  it("v0.3 prompt contains discipline guidance", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.3.md"),
      "utf-8",
    );
    // Should mention not generating speculative interpretations
    expect(content).toMatch(/interpretation/i);
    // Should mention one question discipline
    expect(content).toMatch(/exactly.*one.*question|one.*only.*question|single.*question/i) ||
      expect(content).toMatch(/Do NOT combine/i);
  });

  it("buildPrompt returns v0.3 prompt with scenario substituted", async () => {
    const result = await buildPrompt("Test scenario text", "v0.3");
    expect(result.version).toBe("v0.3");
    expect(result.prompt).toContain("Test scenario text");
    // Should contain the normalisation section guidance
    expect(result.prompt.toLowerCase()).toContain("normalise");
  });

  it("buildPrompt returns v0.2 prompt when requested", async () => {
    const result = await buildPrompt("Test scenario text", "v0.2");
    expect(result.version).toBe("v0.2");
    expect(result.prompt).toContain("Test scenario text");
  });

  it("buildPrompt default is v0.3", async () => {
    const result = await buildPrompt("Test scenario text");
    expect(result.version).toBe("v0.3");
  });
});

// ──────────────────────────────────────────────
// v0.2 prompt still works
// ──────────────────────────────────────────────

describe("v0.2 backward compatibility", () => {
  it("v0.2 prompt file exists and loads", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.2.md"),
      "utf-8",
    );
    expect(typeof content).toBe("string");
    expect(content.length).toBeGreaterThan(500);
  });

  it("buildPrompt returns v0.2 version string", async () => {
    const result = await buildPrompt("test", "v0.2");
    expect(result.version).toBe("v0.2");
  });
});

// ──────────────────────────────────────────────
// Schema validation tests for v0.3-shaped output
// ──────────────────────────────────────────────

describe("v0.3 schema validation", () => {
  it("validates a complete valid reconstruction with empty interpretations", () => {
    const input = {
      inputClassification: {
        primaryType: "unexplained_change",
        secondaryTypes: ["reported_claim"],
        reasoningModes: ["identify_difference"],
        classificationReason: "Two metrics changed without explanation.",
        confidence: "medium",
      },
      reconstruction: {
        summary: "Both complaints and production increased.",
        actors: [],
        systemsOrObjects: [
          { id: "complaints_metric", description: "Volume of complaints", confidence: "high" },
        ],
        expectedStates: [],
        observedStates: [
          { id: "obs1", description: "Complaint volume rose by 35%", confidence: "medium" },
          { id: "obs2", description: "Production volume rose by 40%", confidence: "medium" },
        ],
        differences: [
          {
            id: "diff1",
            description:
              "Production grew faster than complaints, so the complaint-to-production ratio may have improved.",
            confidence: "medium",
          },
        ],
        knownTransitions: [],
        unexplainedTransitions: [
          {
            id: "trans1",
            description: "Complaint volume shifted to a higher level without explained cause",
            confidence: "medium",
            entity: "complaints_metric",
            previousState: "Baseline volume (unknown)",
            currentState: "+35% increase",
          },
        ],
        contradictions: [],
        importantUnknowns: [
          {
            id: "unk1",
            description:
              "Absolute baseline volumes and time period needed to compute complaint rate per unit",
            confidence: "low",
          },
        ],
        plausibleInterpretations: [], // intentionally empty — evidence too thin
      },
      evidence: [
        {
          id: "ev1",
          description: "Complaints increased by 35%",
          evidenceType: "reported_statement",
          source: "User input",
          attribution: null,
          confidence: "medium",
          importance: "important",
        },
        {
          id: "ev2",
          description: "Production increased by 40%",
          evidenceType: "reported_statement",
          source: "User input",
          attribution: null,
          confidence: "medium",
          importance: "important",
        },
        {
          id: "ev3",
          description:
            "Production growth rate (40%) exceeded complaint growth rate (35%), implying the denominator may have grown faster than complaints.",
          evidenceType: "inferred_relationship",
          attribution: null,
          confidence: "medium",
          importance: "important",
        },
      ],
      nextQuestion: {
        id: "q1",
        question: "What was the complaint rate per unit before and after the production increase?",
        targets: ["system"],
        reason:
          "Without normalising complaints by production volume, the absolute complaint count change is misleading. The rate per unit determines whether the situation improved, stayed stable, or worsened.",
        expectedInformationValue: "high",
        reasoningMode: "decompose_aggregate",
      },
    };

    const result = reconstructionV2Schema.safeParse(input);
    expect(result.success).toBe(true);
  });

  it("rejects output missing required fields", () => {
    const input = {
      inputClassification: { primaryType: "other" },
      reconstruction: {},
      evidence: [],
      nextQuestion: { id: "q1" },
    };

    const result = reconstructionV2Schema.safeParse(input);
    expect(result.success).toBe(false);
  });

  it("validates empty arrays for all reconstruction categories", () => {
    const input = {
      inputClassification: {
        primaryType: "other",
        classificationReason: "test",
        confidence: "low",
      },
      reconstruction: {
        summary: "empty test",
        actors: [],
        systemsOrObjects: [],
        expectedStates: [],
        observedStates: [],
        differences: [],
        knownTransitions: [],
        unexplainedTransitions: [],
        contradictions: [],
        importantUnknowns: [],
        plausibleInterpretations: [],
      },
      evidence: [],
      nextQuestion: {
        id: "q1",
        question: "What is the production volume?",
        targets: ["system"],
        reason: "need baseline",
        expectedInformationValue: "medium",
      },
    };

    const result = reconstructionV2Schema.safeParse(input);
    expect(result.success).toBe(true);
  });

  it("validates evidence distinguishing direct_observation from inferred_relationship", () => {
    const input = {
      inputClassification: {
        primaryType: "unexplained_change",
        classificationReason: "test",
        confidence: "low",
      },
      reconstruction: {
        summary: "test summary",
        actors: [],
        systemsOrObjects: [],
        expectedStates: [],
        observedStates: [{ id: "o1", description: "x", confidence: "high" }],
        differences: [],
        knownTransitions: [],
        unexplainedTransitions: [],
        contradictions: [],
        importantUnknowns: [],
        plausibleInterpretations: [],
      },
      evidence: [
        {
          id: "ev1",
          description: "Observed fact",
          evidenceType: "direct_observation",
          confidence: "high",
          importance: "critical",
        },
        {
          id: "ev2",
          description: "Derived relationship",
          evidenceType: "inferred_relationship",
          confidence: "medium",
          importance: "supporting",
        },
      ],
      nextQuestion: {
        id: "q1",
        question: "What is the denominator?",
        targets: ["system"],
        reason: "need context",
        expectedInformationValue: "high",
      },
    };

    const result = reconstructionV2Schema.safeParse(input);
    expect(result.success).toBe(true);
  });
});

// ──────────────────────────────────────────────
// parseReconstructionV2 helper tests
// ──────────────────────────────────────────────

describe("parseReconstructionV2", () => {
  it("parses a valid v0.3-shaped JSON string", async () => {
    const fixture = {
      inputClassification: {
        primaryType: "unexplained_change",
        classificationReason: "test",
        confidence: "medium",
      },
      reconstruction: {
        summary: "both increased",
        actors: [],
        systemsOrObjects: [],
        expectedStates: [],
        observedStates: [
          { id: "o1", description: "x rose 35%", confidence: "high" },
          { id: "o2", description: "y rose 40%", confidence: "high" },
        ],
        differences: [{ id: "d1", description: "y grew faster", confidence: "medium" }],
        knownTransitions: [],
        unexplainedTransitions: [],
        contradictions: [],
        importantUnknowns: [],
        plausibleInterpretations: [],
      },
      evidence: [
        { id: "e1", description: "x rose 35%", evidenceType: "reported_statement", confidence: "medium", importance: "important" },
        { id: "e2", description: "y rose 40%", evidenceType: "reported_statement", confidence: "medium", importance: "important" },
      ],
      nextQuestion: {
        id: "q1",
        question: "What is the denominator?",
        targets: ["system"],
        reason: "need rate context",
        expectedInformationValue: "high",
      },
    };

    const raw = JSON.stringify(fixture);
    const parsed = parseReconstructionV2(raw);

    expect(parsed.inputClassification.primaryType).toBe("unexplained_change");
    expect(parsed.reconstruction.summary).toBe("both increased");
    expect(parsed.nextQuestion.question).toBe("What is the denominator?");
  });

  it("rejects non-JSON string", () => {
    expect(() => parseReconstructionV2("{not valid json")).toThrow(SyntaxError);
  });
});

// ──────────────────────────────────────────────
// v0.3 prompt contains required guidance text
// ──────────────────────────────────────────────

describe("v0.3 prompt guidance completeness", () => {
  it("mentions normalise counts when scale changed", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.3.md"),
      "utf-8",
    );
    expect(content.toLowerCase()).toMatch(/normali[sz]e|normalis[ei]ng/);
  });

  it("mentions distinguishing total count from rate", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.3.md"),
      "utf-8",
    );
    expect(content.toLowerCase()).toContain("rate");
    expect(content.toLowerCase()).toMatch(/count.*not.*caus|correlation.*caus|distinguish.*count/);
  });

  it("mentions avoiding correlation-as-causation", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.3.md"),
      "utf-8",
    );
    expect(content.toLowerCase()).toMatch(/correlation.*caus|treating.*correlation.*caus/);
  });

  it("mentions prefer one narrow next question over compound", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.3.md"),
      "utf-8",
    );
    // Should mention single vs compound
    expect(content).toMatch(/exactly.*one|single.*question|Do NOT combine|combine.*multiple/i);
  });

  it("mentions leaving empty interpretations when evidence is thin", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.3.md"),
      "utf-8",
    );
    expect(content).toMatch(/empty.*array|do not generate.*interpretation|fill a list/i);
  });

  it("mentions identifying the denominator or exposure metric", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.3.md"),
      "utf-8",
    );
    expect(content.toLowerCase()).toMatch(/denominator|exposure/);
  });

  it("uses the exact scenario text as a reference example only (not in rules)", async () => {
    const content = await fs.readFile(
      join(PROMPTS_DIR, "reconstruct-v0.3.md"),
      "utf-8",
    );
    // The prompt should be domain-independent — it should not mention specific industries as rules
    // but may have an example section. We verify the prompt does not hard-code a specific question text.
    expect(content).not.toMatch(/What was the complaint rate per unit before and after/);
  });
});

// ──────────────────────────────────────────────
// Fixture: expected good structure for target scenario
// ──────────────────────────────────────────────

describe("target scenario fixture validation", () => {
  const goodFixture = JSON.parse(JSON.stringify({
    inputClassification: {
      primaryType: "unexplained_change",
      secondaryTypes: ["reported_claim"],
      reasoningModes: ["identify_difference", "decompose_aggregate"],
      classificationReason:
        "Two operational quantities changed at different percentages without a shared baseline or denominator.",
      confidence: "medium",
    },
    reconstruction: {
      summary:
        "Both complaint counts and production volumes increased, but production grew slightly faster than complaints — without absolute baselines the per-unit complaint rate cannot be determined.",
      actors: [],
      systemsOrObjects: [
        { id: "so1", description: "Production system or output volume", confidence: "high" },
        { id: "so2", description: "Complaint reporting mechanism", confidence: "high" },
      ],
      expectedStates: [],
      observedStates: [
        { id: "obs1", description: "Complaint count increased by 35%", confidence: "high" },
        { id: "obs2", description: "Production volume increased by 40%", confidence: "high" },
      ],
      differences: [
        {
          id: "diff1",
          description:
            "Production grew faster than complaints (+40% vs +35%), so the ratio of complaints per unit may have decreased or remained stable. The absolute complaint count alone is not a reliable indicator of whether conditions have changed.",
          confidence: "high",
        },
      ],
      knownTransitions: [],
      unexplainedTransitions: [
        {
          id: "ut1",
          description: "Complaint volume shifted to a higher level without explained cause",
          confidence: "medium",
          entity: "complaints_metric",
          previousState: "unknown baseline",
          currentState: "+35%",
        },
      ],
      contradictions: [],
      importantUnknowns: [
        {
          id: "unk1",
          description:
            "Absolute complaint count and production volume baselines needed to compute the per-unit rate",
          confidence: "low",
        },
        {
          id: "unk2",
          description: "Time period over which these changes occurred",
          confidence: "low",
        },
      ],
      plausibleInterpretations: [], // intentionally empty — no sufficient evidence for interpretations
    },
    evidence: [
      {
        id: "ev1",
        description: "Complaints increased by 35%",
        evidenceType: "reported_statement",
        source: "Scenario input",
        attribution: null,
        confidence: "high",
        importance: "important",
      },
      {
        id: "ev2",
        description: "Production increased by 40%",
        evidenceType: "reported_statement",
        source: "Scenario input",
        attribution: null,
        confidence: "high",
        importance: "important",
      },
      {
        id: "ev3",
        description: "Complaint count grew more slowly than production volume, suggesting per-unit rates may have improved or stayed stable.",
        evidenceType: "inferred_relationship",
        attribution: null,
        confidence: "medium",
        importance: "important",
      },
    ],
    nextQuestion: {
      id: "q1",
      question: "What was the absolute complaint volume and production volume (or baseline) before these percentage changes?",
      targets: ["system", "measurement"],
      reason:
        "Without baseline counts to compute a rate per unit, we cannot determine whether conditions have worsened, stayed stable, or improved. The rate comparison is the smallest unresolved comparison needed to evaluate the situation.",
      expectedInformationValue: "high",
      reasoningMode: "decompose_aggregate",
    },
  }));

  it("fixture validates against v0.3 schema", () => {
    const result = reconstructionV2Schema.safeParse(goodFixture);
    expect(result.success).toBe(true);
  });

  it("fixture has exactly one next question with non-empty text", () => {
    expect(goodFixture.nextQuestion.question.length).toBeGreaterThan(10);
    expect(goodFixture.nextQuestion.reason.length).toBeGreaterThan(10);
    expect(goodFixture.nextQuestion.expectedInformationValue).toBe("high");
  });

  it("fixture has empty plausibleInterpretations (evidence too thin)", () => {
    expect(goodFixture.reconstruction.plausibleInterpretations).toEqual([]);
  });

  it("fixture evidence includes both direct observations and one inferred relationship", () => {
    const types = goodFixture.evidence.map((e) => e.evidenceType);
    expect(types).toContain("reported_statement");
    expect(types).toContain("inferred_relationship");
  });

  it("fixture relationship notes complaint count grew more slowly than production", () => {
    const diffDescs = goodFixture.reconstruction.differences.map((d) => d.description);
    const found = diffDescs.some(
      (d) =>
        d.toLowerCase().includes("fast") ||
        d.toLowerCase().includes("slower") ||
        d.toLowerCase().includes("ratio") ||
        d.toLowerCase().includes("per-unit") ||
        d.toLowerCase().includes("per unit"),
    );
    expect(found).toBe(true);
  });

  it("fixture does not assert quality deterioration", () => {
    const allText = [
      goodFixture.reconstruction.summary,
      ...goodFixture.reconstruction.differences.map((d) => d.description),
      goodFixture.nextQuestion.reason,
    ].join(" ").toLowerCase();
    // Should not contain strong deterioration language without caveats
    expect(allText).not.toMatch(/quality.*deteriorat|quality.*worsen|definitely.*bad/);
  });

  it("fixture includes relationship that production grew faster", () => {
    const allText = [
      goodFixture.reconstruction.summary,
      ...goodFixture.reconstruction.differences.map((d) => d.description),
    ].join(" ").toLowerCase();
    expect(allText).toMatch(/produ.*grow|ratio|per-unit|per unit|\+40.*\+35/);
  });
});

// ──────────────────────────────────────────────
// Diagnostics: prompt version tracking
// ──────────────────────────────────────────────

describe("diagnostics prompt version", () => {
  it("DEFAULT_PROMPT_VERSION is exported correctly", () => {
    expect(DEFAULT_PROMPT_VERSION).toBe("v0.3");
  });

  it("PROMPT_VERSIONS includes both v0.2 and v0.3", () => {
    const hasV2 = PROMPT_VERSIONS.includes("v0.2");
    const hasV3 = PROMPT_VERSIONS.includes("v0.3");
    expect(hasV2).toBe(true);
    expect(hasV3).toBe(true);
  });

  it("RECONSTRUCTION_PROMPT_VERSION env var overrides default", async () => {
    // The actual override happens at module load time, so we can't easily test this
    // in isolation. Instead, verify the constant reflects env or defaults to v0.3.
    expect(PROMPT_VERSIONS).toContain("v0.2");
  });
});