/**
 * KHAELOR
 * File: tests/repository/recent.test.ts
 * Description: RecentFilesTracker tests — LRU bounds, frecency decay, repeated-access boosts.
 *
 * Author: Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 */

import { describe, expect, it } from "vitest";
import { RecentFilesTracker } from "../../src/repository/index.js";

const T0 = 1_700_000_000_000;
const MINUTE = 60_000;
const HOUR = 60 * MINUTE;
const DAY = 24 * HOUR;

function tracker(maxEntries = 256, maxTimestampsPerFile = 16): RecentFilesTracker {
  return new RecentFilesTracker({ maxEntries, maxTimestampsPerFile, now: () => T0 });
}

describe("RecentFilesTracker LRU bound", () => {
  it("evicts the least recently accessed path at capacity", () => {
    const t = tracker(3);
    t.noteAccess("a", T0 - 4 * MINUTE);
    t.noteAccess("b", T0 - 3 * MINUTE);
    t.noteAccess("c", T0 - 2 * MINUTE);
    t.noteAccess("d", T0 - MINUTE);
    expect(t.size()).toBe(3);
    expect(t.has("a")).toBe(false);
    expect(t.has("d")).toBe(true);
  });

  it("re-accessing a path refreshes its LRU position", () => {
    const t = tracker(3);
    t.noteAccess("a", T0 - 4 * MINUTE);
    t.noteAccess("b", T0 - 3 * MINUTE);
    t.noteAccess("c", T0 - 2 * MINUTE);
    t.noteAccess("a", T0 - MINUTE); // refresh a
    t.noteAccess("d", T0); // should evict b, not a
    expect(t.has("a")).toBe(true);
    expect(t.has("b")).toBe(false);
  });
});

describe("RecentFilesTracker frecency", () => {
  it("scores recent accesses far higher than old ones", () => {
    const t = tracker();
    t.noteAccess("old.ts", T0 - 30 * DAY);
    t.noteAccess("recent.ts", T0 - 10 * MINUTE);
    expect(t.frecency("recent.ts")).toBeGreaterThan(t.frecency("old.ts"));
    expect(t.recent().map((r) => r.path)).toEqual(["recent.ts", "old.ts"]);
  });

  it("accumulates over repeated accesses", () => {
    const t = tracker();
    t.noteAccess("hot.ts", T0 - 3 * MINUTE);
    t.noteAccess("hot.ts", T0 - 2 * MINUTE);
    t.noteAccess("hot.ts", T0 - MINUTE);
    t.noteAccess("cold.ts", T0 - MINUTE);
    expect(t.frecency("hot.ts")).toBe(3 * t.frecency("cold.ts"));
    const hot = t.recent()[0];
    expect(hot).toMatchObject({ path: "hot.ts", count: 3 });
  });

  it("bounds the per-file timestamp window", () => {
    const t = tracker(256, 2);
    for (let i = 5; i >= 1; i -= 1) t.noteAccess("f.ts", T0 - i * MINUTE);
    expect(t.frecency("f.ts")).toBe(16); // only 2 retained accesses × weight 8
  });

  it("returns 0 for unknown paths", () => {
    expect(tracker().frecency("nope.ts")).toBe(0);
  });
});