/**
 * RTO.A1 — Multi-thread apparatus verification.
 *
 * Validates that the experimental fixture can deterministically represent:
 *   - a fixed case understanding
 *   - three open investigation items (none compulsory)
 *   - one engine recommendation
 *   - user selection of any item
 *   - chosen-item becomes visually primary in presentation
 *   - other items remain visible as context
 *   - no claim that production reasoning ownership changed
 */

import { describe, it, expect, beforeEach } from "vitest";
import {
  MULTI_THREAD_FIXTURE,
  MULTI_THREAD_CASE,
  MULTI_THREAD_ITEMS,
  buildScenarioFixture,
} from "@/lib/mocks/scenarios.js";

describe("RTO.A1 multi-thread apparatus", () => {
  /* Reset shared experimental state between tests */
  beforeEach(() => {
    const exp = MULTI_THREAD_FIXTURE._experimental;
    if (exp) exp.selectedThreadId = null;
  });
  describe("fixed case representation", () => {
    it("exposes a case summary without implying a single active unknown", () => {
      expect(MULTI_THREAD_FIXTURE.centralStatement).toBeDefined();
      expect(MULTI_THREAD_FIXTURE._experimental.caseContext.caseSummary.length).toBeGreaterThan(0);
      expect(MULTI_THREAD_FIXTURE.active).toBeNull();
    });

    it("uses the existing launch-vs-wait central statement", () => {
      expect(MULTI_THREAD_CASE.centralStatement).toContain("launching");
      expect(MULTI_THREAD_CASE.centralStatement).toContain("waiting twelve months");
    });
  });

  describe("open investigation items", () => {
    it("represents exactly three open items", () => {
      expect(MULTI_THREAD_ITEMS.length).toBe(3);
    });

    it("each item has an id, label and description", () => {
      MULTI_THREAD_ITEMS.forEach((item) => {
        expect(item.id).toBeDefined();
        expect(item.label).toBeDefined();
        expect(item.description).toBeDefined();
      });
    });

    it("none is compulsory — all items are selectable", () => {
      MULTI_THREAD_ITEMS.forEach((item) => {
        // Items lack a `compulsory` flag; selection is always open
        expect(item.compulsory).not.toBe(true);
      });
    });

    it("items map to the three investigation areas from RTO.01", () => {
      const labels = MULTI_THREAD_ITEMS.map((i) => i.label.toLowerCase());
      expect(labels).toContainEqual(expect.stringContaining("enterprise customer"));
      expect(labels).toContainEqual(expect.stringContaining("competitor timing"));
      expect(labels).toContainEqual(expect.stringContaining("financial viability"));
    });
  });

  describe("engine recommendation", () => {
    it("marks exactly one item as the engine recommendation", () => {
      const recommended = MULTI_THREAD_FIXTURE._experimental.recommendedThreadId;
      expect(recommended).toBe("mt-ent-customer-signing");

      const matched = MULTI_THREAD_ITEMS.find(
        (i) => i.id === recommended
      );
      expect(matched).toBeDefined();
    });

    it("the recommendation is the first item by ordering", () => {
      const ordered = [...MULTI_THREAD_ITEMS].sort(
        (a, b) => a.recommendationOrder - b.recommendationOrder
      );
      expect(ordered[0].id).toBe("mt-ent-customer-signing");
    });
  });

  describe("experimental user selection", () => {
    it("allows selection of any available thread", () => {
      const exp = MULTI_THREAD_FIXTURE._experimental;
      // Initially no selection
      expect(exp.selectedThreadId).toBeNull();

      // Simulate user selecting the second item
      exp.selectedThreadId = "mt-competitor-timing";
      expect(exp.selectedThreadId).toBe("mt-competitor-timing");

      // Verify it is still a valid available thread
      const found = MULTI_THREAD_ITEMS.find(
        (i) => i.id === exp.selectedThreadId
      );
      expect(found).toBeDefined();
      expect(found.label).toContain("Competitor timing");
    });

    it("changing selection does not affect other items", () => {
      const exp = MULTI_THREAD_FIXTURE._experimental;
      const othersBefore = MULTI_THREAD_ITEMS.map((i) => ({
        id: i.id,
        recommended: i.id === exp.recommendedThreadId,
      }));

      // Switch to third item
      exp.selectedThreadId = "mt-financial-comparison";
      expect(exp.selectedThreadId).toBe("mt-financial-comparison");

      const othersAfter = MULTI_THREAD_ITEMS.map((i) => ({
        id: i.id,
        recommended: i.id === exp.recommendedThreadId,
      }));

      // Structure is preserved — only selectedThreadId changed
      expect(othersBefore).toEqual(othersAfter);
    });
  });

  describe("chosen-thread primary state", () => {
    it("marks the selected item as visually primary when set", () => {
      const exp = MULTI_THREAD_FIXTURE._experimental;
      const targetId = "mt-ent-customer-signing";
      exp.selectedThreadId = targetId;

      const primaryItem = MULTI_THREAD_ITEMS.find(
        (i) => i.id === targetId
      );
      expect(primaryItem).toBeDefined();
    });

    it("other items remain visible as case-file context", () => {
      const exp = MULTI_THREAD_FIXTURE._experimental;
      exp.selectedThreadId = "mt-competitor-timing";

      // All three items are still present — none were removed
      expect(MULTI_THREAD_ITEMS.length).toBe(3);

      // The non-selected items are still available
      const remaining = MULTI_THREAD_ITEMS.filter(
        (i) => i.id !== exp.selectedThreadId
      );
      expect(remaining.length).toBe(2);
    });
  });

  describe("production boundary", () => {
    it("does not set production activeUnknownNodeId semantics", () => {
      const graph = MULTI_THREAD_FIXTURE.situationGraph;
      expect(graph.activeUnknownNodeId).toBeNull();
    });

    it("keeps _experimental separate from situationGraph", () => {
      const exp = MULTI_THREAD_FIXTURE._experimental;
      expect(exp.apparatusMode).toBe("selection");
      expect(exp.selectedThreadId).toBeNull();
      // The experimental state is NOT in situationGraph
      expect(MULTI_THREAD_FIXTURE.situationGraph.exp).toBeUndefined();
    });
  });

  describe("buildScenarioFixture integration", () => {
    it("returns the multi-thread fixture for scenario 'multi-thread'", () => {
      const fixture = buildScenarioFixture("multi-thread", 0);
      expect(fixture).not.toBeNull();
      expect(fixture.success).toBe(true);
      expect(fixture._experimentalState).toBeDefined();
      expect(fixture._experimentalState.availableThreads.length).toBe(3);
      expect(fixture._experimentalState.recommendedThreadId).toBe("mt-ent-customer-signing");
    });

    it("preserves the case context through buildScenarioFixture", () => {
      const fixture = buildScenarioFixture("multi-thread", 0);
      expect(fixture.situationGraph.centralStatement).toBe(
        MULTI_THREAD_CASE.centralStatement
      );
    });

    it("does not return a production question when multi-thread is active", () => {
      const fixture = buildScenarioFixture("multi-thread", 0);
      expect(fixture.selectedQuestion).toBeNull();
      expect(fixture.noQuestionReason).toContain("Multi-thread");
    });

    it("returns null for unknown scenario name", () => {
      expect(buildScenarioFixture("nonexistent-scenario", 0)).toBeNull();
    });

    it("returns null when scenario has no turns or scenario field", () => {
      // This should not break — SCENARIOS entries without either field
      const oldEntry = { someField: "value" };
      expect(buildScenarioFixture("__nonexistent__", 0)).toBeNull();
    });
  });

  describe("scenario fixture structure correctness", () => {
    it("includes nodes and edges in the situation graph", () => {
      const g = MULTI_THREAD_FIXTURE.situationGraph;
      expect(g.nodes.length).toBeGreaterThan(0);
      expect(g.edges.length).toBeGreaterThan(0);
    });

    it("nodes contain valid observation kind entries", () => {
      const observationNodes = MULTI_THREAD_FIXTURE.situationGraph.nodes.filter(
        (n) => n.kind === "observation"
      );
      expect(observationNodes.length).toBeGreaterThanOrEqual(2);
    });

    it("includes the experimental scenario identifier", () => {
      expect(MULTI_THREAD_FIXTURE._experimental.scenario).toBe("multi-thread");
    });
  });
});