// The saved last answer of a polled request: what is shown from a past visit,
// and when it is not.
import assert from "node:assert/strict";
import { test } from "node:test";
import {
  clearAnswers,
  MAX_AGE_MS,
  readAnswer,
  writeAnswer,
} from "../src/ui/polled/answer-cache.ts";

// A `Storage` that lives in a map.
function fakeStorage() {
  const m = new Map();
  return {
    m,
    getItem: (k) => (m.has(k) ? m.get(k) : null),
    setItem: (k, v) => void m.set(k, v),
    removeItem: (k) => void m.delete(k),
    key: (i) => [...m.keys()][i] ?? null,
    get length() {
      return m.size;
    },
  };
}
const NOW = 1_800_000_000_000;

test("an answer written is read back, and nothing is read before one is written", () => {
  const storage = fakeStorage();
  assert.equal(readAnswer("a", { storage, now: NOW, build: "b1" }), null);
  writeAnswer("a", [{ name: "iris" }], { storage, now: NOW, build: "b1" });
  assert.deepEqual(readAnswer("a", { storage, now: NOW + 5000, build: "b1" }), [
    { name: "iris" },
  ]);
});

test("an answer from another build, or older than a day, is not shown", () => {
  const storage = fakeStorage();
  writeAnswer("a", { x: 1 }, { storage, now: NOW, build: "b1" });
  assert.equal(readAnswer("a", { storage, now: NOW, build: "b2" }), null);
  assert.deepEqual(
    readAnswer("a", { storage, now: NOW + MAX_AGE_MS, build: "b1" }),
    { x: 1 },
  );
  assert.equal(
    readAnswer("a", { storage, now: NOW + MAX_AGE_MS + 1, build: "b1" }),
    null,
  );
});

test("a value that does not parse, or is not an entry, is no answer", () => {
  const storage = fakeStorage();
  storage.setItem("swarm-ui:answer:a", "{not json");
  assert.equal(readAnswer("a", { storage, now: NOW, build: "b1" }), null);
  storage.setItem(
    "swarm-ui:answer:a",
    JSON.stringify({ at: NOW, build: "b1" }),
  );
  assert.equal(readAnswer("a", { storage, now: NOW, build: "b1" }), null);
  storage.setItem("swarm-ui:answer:a", "7");
  assert.equal(readAnswer("a", { storage, now: NOW, build: "b1" }), null);
});

test("a write that fails (over quota) is dropped without an error", () => {
  const storage = {
    setItem() {
      throw new Error("QuotaExceededError");
    },
  };
  writeAnswer("a", { x: 1 }, { storage, now: NOW, build: "b1" });
});

test("clearing forgets the answers and leaves every other key alone", () => {
  const storage = fakeStorage();
  writeAnswer("a", 1, { storage, now: NOW, build: "b1" });
  writeAnswer("b", 2, { storage, now: NOW, build: "b1" });
  storage.setItem("swarm-ui:term-groups", "[]");
  clearAnswers(storage);
  assert.deepEqual([...storage.m.keys()], ["swarm-ui:term-groups"]);
});