// Noticing that the same table is open twice.
//
// Two tabs each hold their own copy in memory and each save writes the whole thing,
// so the second one to act throws the first one's work away. This doesn't merge them
// — replacing a table under a dealer's hands mid-hand would be its own hazard — it
// notices, which is what lets them decide.
const test = require("node:test");
const assert = require("node:assert");
const { HoldemState } = require("./load");

function withWindow() {
    const listeners = [];
    globalThis.window = {
        addEventListener(type, fn) { if (type === "storage") listeners.push(fn); },
        removeEventListener(type, fn) {
            const i = listeners.indexOf(fn);
            if (i >= 0) listeners.splice(i, 1);
        },
    };
    return {
        listeners,
        fire(key) { listeners.forEach(fn => fn({ key })); },
    };
}

test.beforeEach(() => {
    HoldemState.otherTabActive = false;
    HoldemState.onOtherTab = null;
    HoldemState.tabWatcher = null;
});

test.after(() => {
    delete globalThis.window;
    HoldemState.otherTabActive = false;
    HoldemState.onOtherTab = null;
    HoldemState.tabWatcher = null;
});

test("a write to this table from elsewhere is noticed", () => {
    const win = withWindow();
    let told = 0;
    HoldemState.onOtherTab = () => { told++; };
    HoldemState.watchOtherTabs();

    win.fire(HoldemState.STORAGE_KEY);

    assert.equal(HoldemState.otherTabActive, true);
    assert.equal(told, 1);
});

test("somebody else's storage key is not our business", () => {
    const win = withWindow();
    let told = 0;
    HoldemState.onOtherTab = () => { told++; };
    HoldemState.watchOtherTabs();

    win.fire("some.other.app.state");
    win.fire(HoldemState.RECOVERY_KEY);

    assert.equal(HoldemState.otherTabActive, false);
    assert.equal(told, 0);
});

test("told once, however many times the other tab acts", () => {
    const win = withWindow();
    let told = 0;
    HoldemState.onOtherTab = () => { told++; };
    HoldemState.watchOtherTabs();

    for (let i = 0; i < 10; i++) win.fire(HoldemState.STORAGE_KEY);

    assert.equal(told, 1);
});

test("watching twice doesn't listen twice", () => {
    const win = withWindow();
    HoldemState.watchOtherTabs();
    HoldemState.watchOtherTabs();
    HoldemState.watchOtherTabs();

    assert.equal(win.listeners.length, 1);
});

test("no listener set is not an error", () => {
    const win = withWindow();
    HoldemState.onOtherTab = null;
    HoldemState.watchOtherTabs();

    assert.doesNotThrow(() => win.fire(HoldemState.STORAGE_KEY));
    assert.equal(HoldemState.otherTabActive, true);
});

test("no window at all is not an error", () => {
    // The same modules are loaded in Node by the test harness.
    delete globalThis.window;
    HoldemState.tabWatcher = null;

    assert.doesNotThrow(() => HoldemState.watchOtherTabs());
    assert.equal(HoldemState.otherTabActive, false);
});