// Unit tests for server-side game logic. Uses node:test (no extra deps).
// Run with: node test/unit.test.js (NOT `node --test`) — see comment at bottom.
const test = require("node:test");
const assert = require("node:assert");

const {
  normalize,
  maskWord,
  pickRevealIndex,
  isCloseGuess,
} = require("../server/word-utils.js");
const roomStore = require("../server/room-store.js");
const { genCode, getRoom, setRoom, deleteRoom, allRooms, makeId } = roomStore;
const { makeRoom, makePlayer } = require("../server/game-state.js");

// Unref the room-store cleanup interval so node exits cleanly after tests.
function unrefAllHandles() {
  const handles = process._getActiveHandles ? process._getActiveHandles() : [];
  for (const h of handles) {
    if (h && typeof h.unref === "function") {
      try { h.unref(); } catch (_) {}
    }
  }
}
unrefAllHandles();

// --- word-utils tests ---

test("normalize: lowercases and trims", () => {
  assert.strictEqual(normalize("  HELLO  "), "hello");
  assert.strictEqual(normalize("Foo Bar"), "foo bar");
  assert.strictEqual(normalize("MULTI   SPACE"), "multi space");
  assert.strictEqual(normalize(""), "");
  assert.strictEqual(normalize(undefined), "");
  assert.strictEqual(normalize(null), "");
});

test("maskWord: blanks letters but preserves spaces", () => {
  const out = maskWord("ice cream");
  // letters become "_", space stays
  assert.strictEqual(out, "___ _____");
});

test("maskWord: with all indices revealed produces lowercased word", () => {
  const word = "Apple";
  const revealed = new Set([0, 1, 2, 3, 4]);
  const out = maskWord(word, revealed);
  assert.strictEqual(out, "apple");
});

test("maskWord: partial reveal mixes letters and underscores", () => {
  const out = maskWord("apple", new Set([0, 2]));
  // a _ p _ _
  assert.strictEqual(out, "a_p__");
});

test("pickRevealIndex: picks unrevealed non-space index", () => {
  const word = "ab cd";
  const revealed = new Set([0]);
  const idx = pickRevealIndex(word, revealed);
  // valid candidate indices: 1, 3, 4
  assert.ok([1, 3, 4].includes(idx), `unexpected index ${idx}`);
  assert.notStrictEqual(idx, 2); // never the space
});

test("pickRevealIndex: returns null when all letters revealed", () => {
  const word = "ab";
  const revealed = new Set([0, 1]);
  assert.strictEqual(pickRevealIndex(word, revealed), null);
});

test("revealHint flow: applying picked index reveals exactly N more letters", () => {
  // simulate revealing: count underscores decreases by exactly 1 each step
  let revealed = new Set();
  const word = "rocket";
  let prevMask = maskWord(word, revealed);
  let prevUnderscores = (prevMask.match(/_/g) || []).length;
  for (let i = 0; i < 3; i++) {
    const idx = pickRevealIndex(word, revealed);
    assert.notStrictEqual(idx, null);
    revealed.add(idx);
    const m = maskWord(word, revealed);
    const newUnderscores = (m.match(/_/g) || []).length;
    assert.strictEqual(newUnderscores, prevUnderscores - 1, "exactly 1 letter revealed");
    prevUnderscores = newUnderscores;
    prevMask = m;
  }
});

test("revealHint idempotence: re-applying same revealed set yields same mask", () => {
  const word = "tree";
  const revealed = new Set([0, 2]);
  const m1 = maskWord(word, revealed);
  const m2 = maskWord(word, revealed);
  assert.strictEqual(m1, m2);
});

test("isCloseGuess: edit distance 1-2 returns true", () => {
  assert.strictEqual(isCloseGuess("aple", "apple"), true); // 1 edit
  assert.strictEqual(isCloseGuess("aplee", "apple"), true); // 1 edit
  assert.strictEqual(isCloseGuess("apple", "apple"), false); // exact match -> not "close"
  assert.strictEqual(isCloseGuess("xyz", "apple"), false); // too far
});

// --- room-store tests ---

test("genCode: returns a unique 6-char alphanumeric code", () => {
  const seen = new Set();
  for (let i = 0; i < 10; i++) {
    const c = genCode();
    assert.strictEqual(typeof c, "string");
    assert.strictEqual(c.length, 6);
    assert.ok(/^[A-Z0-9]+$/.test(c), `code ${c} should be uppercase alnum`);
    seen.add(c);
  }
  assert.strictEqual(seen.size, 10, "codes should be unique");
});

test("setRoom + getRoom: returns same instance, case-insensitive lookup", () => {
  const code = genCode();
  const player = makePlayer({ nickname: "U", avatar: "x" });
  const room = makeRoom({ code, hostId: player.id, mode: "skribbl", settings: {} });
  room.players.push(player);
  setRoom(code, room);
  const got = getRoom(code);
  assert.strictEqual(got, room, "same instance");
  // lower-case lookup also works
  const gotLower = getRoom(code.toLowerCase());
  assert.strictEqual(gotLower, room);
  deleteRoom(code);
  assert.strictEqual(getRoom(code), undefined);
});

test("makeId: returns a non-empty string id", () => {
  const id1 = makeId();
  const id2 = makeId();
  assert.strictEqual(typeof id1, "string");
  assert.ok(id1.length > 0);
  assert.notStrictEqual(id1, id2);
});

test("allRooms: exposes the underlying Map", () => {
  const map = allRooms();
  assert.ok(map instanceof Map);
});

// Force exit after a short tick — room-store uses an unrefable setInterval
// that we already unrefed above, but be defensive.
process.on("beforeExit", () => process.exit(0));
setTimeout(() => process.exit(0), 1500).unref();