/**
 * Experiment 20 — Question Importance: passive classification test.
 *
 * Validates assessQuestionImportance against mock scenarios covering all four
 * categories plus edge cases required by the experiment brief.
 */

import { describe, expect, it } from "vitest";
import { assessQuestionImportance } from "@/lib/graph/question-importance.js";

/* ── Test helpers ─────────────────────────────────────────────── */

function makeNode(id, kind = "unknown", status = "unknown") {
  return {
    id, label: `Test unknown ${id}`, description: `Description for ${id}`, kind, status,
    confidence: "high", value: null, unit: null, evidenceIds: [],
    dependsOn: [], affects: [], childIds: [],
  };
}

function makeScenario(nodes, edges = [], resolved = [], active = null) {
  return {
    nodes, edges, resolvedNodeIds: resolved, activeUnknownNodeId: active,
    centralStatement: "Test scenario", currentSummary: "Test",
    reasoningState: null,
  };
}

/* ── Category: important (downstream dependency) ─────────────── */

describe("assessQuestionImportance — important via downstream unknown", () => {
  it("classifies a node as important when another unresolved unknown depends on it", () => {
    const root = makeNode("root", "unknown", "unknown");
    const child = makeNode("child", "unknown", "unknown");
    // Add via edge so the classifier's edge traversal picks it up
    const graph = makeScenario(
      [root, child],
      [{ id: "e-dep", fromNodeId: child.id, toNodeId: root.id, relationship: "depends_on", confidence: "medium", description: "" }],
    );
    const result = assessQuestionImportance({ node: root, graph });

    expect(result).toEqual({ category: "important" });
  });

  it("does not classify as important when the dependent unknown is already resolved", () => {
    const root = makeNode("root", "unknown", "unknown");
    const child = makeNode("child", "unknown", "resolved");
    child.dependsOn.push(root.id);

    const graph = makeScenario([root, child], [], ["child"]);
    const result = assessQuestionImportance({ node: root, graph });

    expect(result).not.toEqual({ category: "important" });
  });
});

/* ── Category: important (decision text pattern) ─────────────── */

describe("assessQuestionImportance — important via decision text", () => {
  it("classifies a node with 'whether to' as important when connected to the graph", () => {
    const node = makeNode("d1", "unknown", "unknown");
    node.label = "Whether to build the feature";
    node.description = "Need to decide whether to build the feature for users.";

    const observer = makeNode("obs-1", "observation", "known");
    const graph = makeScenario([node, observer], [
      { id: "e-1", fromNodeId: "obs-1", toNodeId: node.id, relationship: "supports", confidence: "medium", description: "" },
    ]);

    const result = assessQuestionImportance({ node, graph });
    expect(result).toEqual({ category: "important" });
  });

  it("classifies a node with 'build' as important when connected to the graph", () => {
    const node = makeNode("d2", "unknown", "unknown");
    node.label = "Build approach for Confidence Engine";
    node.description = "Need to decide how to build the feature.";

    const observer = makeNode("obs-1", "observation", "known");
    const graph = makeScenario([node, observer], [
      { id: "e-1", fromNodeId: "obs-1", toNodeId: node.id, relationship: "supports", confidence: "medium", description: "" },
    ]);

    const result = assessQuestionImportance({ node, graph });
    expect(result).toEqual({ category: "important" });
  });

  it("does not classify decision text as important when the node has zero connections", () => {
    const node = makeNode("d3", "unknown", "unknown");
    node.label = "Whether to build the feature";
    node.description = "";

    const graph = makeScenario([node]);
    const result = assessQuestionImportance({ node, graph });
    expect(result.category).toBe("incidental");
  });
});

/* ── Category: helpful (evidence text) ───────────────────────── */

describe("assessQuestionImportance — helpful via evidence text", () => {
  it("classifies a node with 'evidence' as helpful", () => {
    const node = makeNode("h1", "unknown", "unknown");
    node.label = "Evidence of adoption";
    node.description = "What evidence shows users adopt the feature.";

    const graph = makeScenario([node]);
    const result = assessQuestionImportance({ node, graph });
    expect(result).toEqual({ category: "helpful" });
  });

  it("classifies a node with 'metric' as helpful", () => {
    const node = makeNode("h2", "unknown", "unknown");
    node.label = "Success metric";
    node.description = "Need to define the success criterion.";

    const graph = makeScenario([node]);
    const result = assessQuestionImportance({ node, graph });
    expect(result).toEqual({ category: "helpful" });
  });

  it("classifies a node with ≥2 connections as helpful even without evidence text", () => {
    const node = makeNode("h3", "unknown", "unknown");
    node.label = "Supporting detail";
    node.description = "Contextual information for the decision.";

    const obs1 = makeNode("obs-1", "observation", "known");
    const obs2 = makeNode("obs-2", "observation", "known");

    // This node is connected to both observers via edges
    const graph = makeScenario(
      [node, obs1, obs2],
      [
        { id: "e-1", fromNodeId: "obs-1", toNodeId: node.id, relationship: "supports", confidence: "medium", description: "" },
        { id: "e-2", fromNodeId: "obs-2", toNodeId: node.id, relationship: "supports", confidence: "medium", description: "" },
      ],
    );

    const result = assessQuestionImportance({ node, graph });
    expect(result).toEqual({ category: "helpful" });
  });
});

/* ── Category: incidental (default) ──────────────────────────── */

describe("assessQuestionImportance — incidental (default)", () => {
  it("classifies a connected node as incidental when no patterns or dependencies match", () => {
    const node = makeNode("inc-1", "unknown", "unknown");
    node.label = "Minor formatting detail";
    node.description = "How the display should look.";

    const obs = makeNode("obs-1", "observation", "known");
    const graph = makeScenario(
      [node, obs],
      [{ id: "e-1", fromNodeId: "obs-1", toNodeId: node.id, relationship: "supports", confidence: "medium", description: "" }],
    );

    const result = assessQuestionImportance({ node, graph });
    expect(result).toEqual({ category: "incidental" });
  });

  it("classifies an unconnected unknown as incidental when text has no patterns", () => {
    const node = makeNode("inc-2", "unknown", "unknown");
    node.label = "Color scheme preference";
    node.description = "";

    const graph = makeScenario([node]);
    const result = assessQuestionImportance({ node, graph });
    expect(result).toEqual({ category: "incidental" });
  });
});

/* ── Edge case: cannot_determine (empty node text) ──────────── */

describe("assessQuestionImportance — cannot_determine", () => {
  it("returns cannot_determine when both label and description are empty", () => {
    const node = makeNode("empty-1", "unknown", "unknown");
    node.label = "";
    node.description = "";

    const graph = makeScenario([node]);
    const result = assessQuestionImportance({ node, graph });

    expect(result.category).toBe("cannot_determine");
  });
});

/* ── Edge case: missing input ────────────────────────────────── */

describe("assessQuestionImportance — missing input", () => {
  it("returns cannot_determine when no input object is provided", () => {
    const result = assessQuestionImportance(null);
    expect(result.category).toBe("cannot_determine");
  });

  it("returns cannot_determine when node.kind is not a string", () => {
    const node = { id: "x", kind: null };
    const graph = makeScenario([node]);
    const result = assessQuestionImportance({ node, graph });
    expect(result.category).toBe("cannot_determine");
  });

  it("returns cannot_determine when graph is missing", () => {
    const node = makeNode("x", "unknown", "unknown");
    const result = assessQuestionImportance({ node });
    expect(result.category).toBe("cannot_determine");
  });
});

/* ── Determinism ─────────────────────────────────────────────── */

describe("assessQuestionImportance — deterministic output", () => {
  it("produces the same result across multiple identical calls", () => {
    const node = makeNode("det-1", "unknown", "unknown");
    node.label = "Evidence of adoption";
    node.description = "";

    const graph = makeScenario([node]);

    const r1 = assessQuestionImportance({ node, graph });
    const r2 = assessQuestionImportance({ node, graph });

    expect(r1).toEqual(r2);
  });
});

/* ── Input immutability ──────────────────────────────────────── */

describe("assessQuestionImportance — input not mutated", () => {
  it("does not mutate the input node", () => {
    const node = makeNode("imm-1", "unknown", "unknown");
    node.label = "Evidence of adoption";
    node.description = "";
    const originalLabel = node.label;
    const originalDependsOn = [...node.dependsOn];

    const graph = makeScenario([node]);
    assessQuestionImportance({ node, graph });

    expect(node.label).toBe(originalLabel);
    expect(node.dependsOn).toEqual(originalDependsOn);
  });

  it("does not mutate the input graph", () => {
    const node = makeNode("imm-2", "unknown", "unknown");
    node.label = "Evidence of adoption";
    node.description = "";

    const obs = makeNode("obs-1", "observation", "known");
    const graph = makeScenario([node, obs]);

    const originalNodes = JSON.parse(JSON.stringify(graph.nodes));
    const originalEdges = JSON.parse(JSON.stringify(graph.edges));

    assessQuestionImportance({ node, graph });

    expect(JSON.stringify(graph.nodes)).toBe(JSON.stringify(originalNodes));
    expect(JSON.stringify(graph.edges)).toBe(JSON.stringify(originalEdges));
  });
});

/* ── Rule interaction: downstream depends_on edge-based ──────── */

describe("assessQuestionImportance — via graph edges", () => {
  it("detects downstream dependency through an edge relationship (unknown → unknown)", () => {
    const parent = makeNode("parent-unk", "unknown", "unknown");
    const child = makeNode("child-unk", "unknown", "unknown");

    const graph = makeScenario(
      [parent, child],
      [
        { id: "e-dep", fromNodeId: child.id, toNodeId: parent.id, relationship: "depends_on", confidence: "medium", description: "" },
      ],
    );

    const result = assessQuestionImportance({ node: parent, graph });
    expect(result).toEqual({ category: "important" });
  });
});