import test from "node:test";
import assert from "node:assert/strict";

import { BreadcrumbTrail } from "../static/js/wiki/breadcrumb-trail.js";

class MemoryStorage {
  constructor() {
    this.values = new Map();
  }

  getItem(key) {
    return this.values.has(key) ? this.values.get(key) : null;
  }

  setItem(key, value) {
    this.values.set(key, String(value));
  }
}

test("stored breadcrumbs are limited to current readable pages", () => {
  const storage = new MemoryStorage();
  storage.setItem("racket-wiki-breadcrumb-trail", JSON.stringify([
    "first", "removed", 42, "second"
  ]));
  const trail = new BreadcrumbTrail(storage);

  assert.deepEqual(trail.load(["first", "second"]), ["first", "second"]);
  assert.equal(
    storage.getItem("racket-wiki-breadcrumb-trail"),
    JSON.stringify(["first", "second"]));
});

test("invalid stored JSON starts with an empty trail", () => {
  const storage = new MemoryStorage();
  storage.setItem("racket-wiki-breadcrumb-trail", "not JSON");
  const trail = new BreadcrumbTrail(storage);

  assert.deepEqual(trail.load(["first"]), []);
});

test("page visits append, truncate revisits and clear at home", () => {
  const storage = new MemoryStorage();
  const trail = new BreadcrumbTrail(storage);
  trail.load(["home", "first", "second", "third"]);

  trail.record("first", "home");
  trail.record("second", "home");
  trail.record("third", "home");
  assert.deepEqual(trail.slugs, ["first", "second", "third"]);

  assert.deepEqual(trail.record("second", "home"), ["first", "second"]);
  const returnedSlugs = trail.slugs;
  returnedSlugs.push("outside-change");
  assert.deepEqual(trail.slugs, ["first", "second"]);
  assert.deepEqual(trail.record("home", "home"), []);
});

test("the trail retains at most eight non-home pages", () => {
  const storage = new MemoryStorage();
  const trail = new BreadcrumbTrail(storage);
  const pages = Array.from({ length: 10 }, (_value, index) => `page-${index}`);
  trail.load(["home", ...pages]);

  for (const page of pages) trail.record(page, "home");

  assert.deepEqual(trail.slugs, pages.slice(-8));
});

test("selecting a breadcrumb discards only its successors", () => {
  const storage = new MemoryStorage();
  const trail = new BreadcrumbTrail(storage);
  trail.load(["home", "first", "second", "third"]);
  trail.record("first", "home");
  trail.record("second", "home");
  trail.record("third", "home");

  assert.deepEqual(trail.truncate("first", "home"), ["first"]);
  assert.deepEqual(trail.truncate("missing", "home"), ["first"]);
});