import { describe, it, expect, vi } from "vitest";
import { ContentCache } from "./content-cache.js";

// -- Size accounting ---------------------------------------------------

describe("ContentCache size accounting", () => {
  it("set increases currentBytes by data length", () => {
    const cache = new ContentCache(1024);
    cache.set("a.md", "hello"); // 5 bytes
    expect(cache.currentBytes).toBe(5);
  });

  it("delete returns currentBytes to 0", () => {
    const cache = new ContentCache(1024);
    cache.set("a.md", "hello");
    cache.delete("a.md");
    expect(cache.currentBytes).toBe(0);
  });

  it("replacing an entry reflects the new size", () => {
    const cache = new ContentCache(1024);
    cache.set("a.md", "short");
    cache.set("a.md", "a much longer string");
    expect(cache.currentBytes).toBe("a much longer string".length);
  });

  it("deleting one of several entries leaves the sum of the rest", () => {
    const cache = new ContentCache(1024);
    cache.set("a.md", "aaa"); // 3
    cache.set("b.md", "bbbbb"); // 5
    cache.set("c.md", "cc"); // 2
    cache.delete("b.md");
    expect(cache.currentBytes).toBe(5); // 3 + 2
  });
});

// -- LRU eviction ------------------------------------------------------

describe("ContentCache LRU eviction", () => {
  it("evicts the least-recently-accessed entry when full", () => {
    let now = 1000;
    vi.spyOn(Date, "now").mockImplementation(() => now++);

    const cache = new ContentCache(10);
    cache.set("a.md", "aaaa"); // 4
    cache.set("b.md", "bbbb"); // 4
    // At 8/10. Adding 4 more would exceed, so LRU (a.md) should be evicted.
    cache.set("c.md", "cccc"); // 4
    expect(cache.has("a.md")).toBe(false);
    expect(cache.has("b.md")).toBe(true);
    expect(cache.has("c.md")).toBe(true);

    vi.restoreAllMocks();
  });

  it("accessing an entry refreshes it so it survives eviction", () => {
    let now = 1000;
    vi.spyOn(Date, "now").mockImplementation(() => now++);

    const cache = new ContentCache(10);
    cache.set("a.md", "aaaa"); // 4, accessedAt=1000
    cache.set("b.md", "bbbb"); // 4, accessedAt=1001
    // Touch a.md so b.md becomes the LRU
    cache.get("a.md"); // a.md accessedAt=1002
    cache.set("c.md", "cccc"); // 4 -- should evict b.md (1001), not a.md (1002)
    expect(cache.has("a.md")).toBe(true);
    expect(cache.has("b.md")).toBe(false);
    expect(cache.has("c.md")).toBe(true);

    vi.restoreAllMocks();
  });

  it("entry larger than maxSize still gets stored", () => {
    const cache = new ContentCache(5);
    cache.set("small.md", "ab"); // 2
    cache.set("big.md", "abcdefghij"); // 10 -- larger than maxSize
    expect(cache.has("small.md")).toBe(false);
    expect(cache.has("big.md")).toBe(true);
    expect(cache.currentBytes).toBe(10);
  });
});

// -- Path normalization ------------------------------------------------

describe("ContentCache path normalization", () => {
  it("backslash and slash variants hit the same cache entry", () => {
    const cache = new ContentCache(1024);
    cache.set("foo\\bar\\baz.md", "content");
    expect(cache.has("foo/bar/baz.md")).toBe(true);
    expect(cache.get("foo/bar/baz.md")).toBe("content");
  });
});