frontend/src/engine/traces.test.ts

import { describe, expect, it } from "vitest";
import { defaultProfile, rateSource } from "./learning";
import { defaultState, defaultTaste } from "./state";
import { buildTraces } from "./traces";
import type { FeedItem } from "./types";

const item = (over: Partial<FeedItem>): FeedItem => ({
  uid: "u1",
  id: "claude_done",
  source: "Claude",
  say: "The goblin rests.",
  tier: "playful",
  tags: ["useful", "warm"],
  decision: "notify",
  time: "12:00",
  rating: null,
  ...over,
});

describe("buildTraces", () => {
  const fs = defaultState();
  const taste = defaultTaste();
  const now = new Date("2026-06-06T12:00:00Z");

  it("snapshots event, fairy dials, taste, and per-source bias", () => {
    let profile = defaultProfile();
    profile = rateSource(profile, "Discord", "annoying"); // seed -8 → -20
    const [t] = buildTraces([item({ source: "Discord", id: "discord_noise" })], fs, taste, profile, now);
    expect(t.v).toBe(1);
    expect(t.ts).toBe("2026-06-06T12:00:00.000Z");
    expect(t.event).toMatchObject({ id: "discord_noise", source: "Discord", decision: "notify" });
    expect(t.sourceBias).toBe(-20);
    expect(t.fairy.mischief).toBe(fs.mischief);
    expect(t.taste).toEqual(taste);
  });

  it("carries channel and outcome when present, null when absent", () => {
    const outcome = { type: "dismissed" as const, rating: null, latencyMs: 420, visible: true };
    const [a, b] = buildTraces(
      [item({ channel: "toast", outcome }), item({ uid: "u2" })],
      fs,
      taste,
      defaultProfile(),
      now,
    );
    expect(a.event.channel).toBe("toast");
    expect(a.outcome).toEqual(outcome);
    expect(b.event.channel).toBeNull();
    expect(b.outcome).toBeNull();
  });

  it("includes silent decisions too — ignore/scroll distributions matter for the notify head", () => {
    const [t] = buildTraces(
      [item({ decision: "ignore", channel: "feed" })],
      fs,
      taste,
      defaultProfile(),
      now,
    );
    expect(t.event.decision).toBe("ignore");
    expect(t.outcome).toBeNull();
  });
});