// node modules/test/test-ui-shell.js
// test-ui-shell: the UI shell must keep exactly one output stream alive across mode switches.
//
// Why this exists: every mode reparents #terminal-container into its own layout. Four ways that goes
// wrong are invisible in a screenshot — teardown that forgets to restore, a mode that clones the
// node, a failed mount that leaves the page chrome-less, and a footer that never docks (which strands
// a streaming AI answer with no stop button). These assertions pin all four.
const fs = require('fs'), path = require('path');
const CORE = path.join(__dirname, '..', 'core');

// ── minimal DOM: only what the shell is allowed to use ────────────────────────────
function makeEl(tag) {
    const el = {
        tagName: String(tag || 'div').toUpperCase(), id: '', children: [], parentNode: null,
        dataset: {}, style: {}, textContent: '', _html: '',
        get innerHTML() { return this._html; },
        set innerHTML(v) {
            this._html = String(v);
            for (const c of this.children) c.parentNode = null;
            this.children = [];
        },
        appendChild(c) {
            if (c.parentNode) c.parentNode.removeChild(c);
            c.parentNode = this; this.children.push(c); return c;
        },
        append(...cs) { cs.forEach(c => this.appendChild(c)); },
        insertBefore(c, ref) {
            if (c.parentNode) c.parentNode.removeChild(c);
            const i = ref ? this.children.indexOf(ref) : -1;
            if (i < 0) this.children.push(c); else this.children.splice(i, 0, c);
            c.parentNode = this; return c;
        },
        removeChild(c) {
            const i = this.children.indexOf(c);
            if (i >= 0) { this.children.splice(i, 1); c.parentNode = null; }
            return c;
        },
        remove() { if (this.parentNode) this.parentNode.removeChild(this); },
        contains(n) {
            if (!n) return false;
            if (n === this) return true;
            return this.children.some(c => c.contains && c.contains(n));
        },
        setAttribute(k, v) { this[k] = v; },
        addEventListener() {}, removeEventListener() {},
        querySelector(sel) {
            const want = String(sel).replace(/^#/, '');
            const find = n => {
                if (n.id === want) return n;
                for (const c of n.children) { const r = find(c); if (r) return r; }
                return null;
            };
            return find(this);
        },
        classList: {
            _s: new Set(),
            add(...c) { c.forEach(x => this._s.add(x)); },
            remove(...c) { c.forEach(x => this._s.delete(x)); },
            contains(c) { return this._s.has(c); },
            toggle(c) { if (this._s.has(c)) this._s.delete(c); else this._s.add(c); }
        }
    };
    return el;
}

const head = makeEl('head'), body = makeEl('body'), htmlEl = makeEl('html');
const byId = {};
global.document = {
    head, body, documentElement: htmlEl,
    createElement: tag => makeEl(tag),
    createTextNode: t => ({ textContent: String(t), children: [], parentNode: null }),
    getElementById: id => {
        // walk the tree, not a registry: a node the shell forgot to restore must read as absent
        const find = n => {
            if (n.id === id) return n;
            for (const c of n.children) { const r = find(c); if (r) return r; }
            return null;
        };
        return find(body);
    },
    addEventListener() {}, dispatchEvent() { return true; },
    querySelector: sel => body.querySelector(sel)
};
global.CustomEvent = class { constructor(type, opts) { this.type = type; this.detail = (opts || {}).detail; } };
global.window = global;
global.performance = { now: () => Date.now() };
const store = {};
global.localStorage = {
    getItem: k => (k in store ? store[k] : null),
    setItem: (k, v) => { store[k] = String(v); },
    removeItem: k => { delete store[k]; }
};

function stock(id) { const e = makeEl('div'); e.id = id; byId[id] = e; body.appendChild(e); return e; }
// canonical order taken from main.html:882-965
['terminal-container', 'input-area', 'quick-actions', 'status-bar'].forEach(stock);

// ── load the module the way the bundle does (class declaration, not module.exports) ──
const src = fs.readFileSync(path.join(CORE, 'module-uishell.js'), 'utf8');
const UIShellModule = new Function(src + '\nreturn UIShellModule;')();

let pass = 0, fail = 0;
function ok(name, cond, detail) {
    if (cond) { pass++; console.log('  PASS ' + name); }
    else { fail++; console.log('  FAIL ' + name + (detail ? ' — ' + detail : '')); }
}

const printed = [];
const fakeTerminal = {
    print: (m, t) => printed.push({ m, t }),
    capturePipeOutput: async () => 'captured',
    _parseArgs: s => String(s).trim().split(/\s+/).filter(Boolean)
};

const shell = new UIShellModule();
shell.init(fakeTerminal);

// A1 — command registered
shell.registerCommands();
ok('A1 ui command registered', typeof shell.commands['ui'] === 'function');

// A2 — mode registry + apply persists and sets the body attribute
let mounted = 0, unmounted = 0;
shell.registerMode({
    id: 'probe', label: 'Probe', level: 3, icon: '🧪', tagline: 'test mode',
    mount(api) {
        mounted++;
        const slot = api.el('div', { id: 'probe-slot' });
        api.root.appendChild(slot);
        api.attach(slot, api.stock.output);           // reparent the real terminal
        // Move a SECOND stock node: every real mode moves the input and the status bar too, and with
        // only one node moved the `next`-sibling restore heuristic looked correct while being wrong.
        const slot2 = api.el('div', { id: 'probe-slot2' });
        api.root.appendChild(slot2);
        const input = document.getElementById('input-area');
        if (input) slot2.appendChild(input);
        return () => { unmounted++; };
    }
});
ok('A2 apply returns true', shell.apply('probe') === true);
ok('A2 body data-ui-mode', document.body.dataset.uiMode === 'probe', document.body.dataset.uiMode);
ok('A2 persisted', localStorage.getItem('webx11_ui_mode') === 'probe');
ok('A3 mount ran once', mounted === 1);
ok('A4 terminal moved into the mode', byId['terminal-container'].parentNode &&
    byId['terminal-container'].parentNode.id === 'probe-slot');

// A5 — switching away must restore the stock node, in order, and not destroy it
shell.apply('classic');
ok('A5 teardown ran', unmounted === 1);
ok('A5 terminal survived teardown', !!document.getElementById('terminal-container'));
// ui-root is the shell's own container and legitimately sits in <body> too — compare stock only
const stockOrder = () => body.children.map(c => c.id)
    .filter(id => id && id !== 'ui-root').join(',');
ok('A5 body order restored',
    stockOrder() === 'terminal-container,input-area,quick-actions,status-bar', stockOrder());
ok('A5 root emptied', (shell._root.children || []).length === 0);
ok('A5 body attribute cleared', document.body.dataset.uiMode === 'classic');

// A6 — unknown mode: no persist, warning, still classic
store['webx11_ui_mode'] = 'classic';
ok('A6 unknown returns false', shell.apply('nope') === false);
ok('A6 unknown does not persist', localStorage.getItem('webx11_ui_mode') === 'classic');
// The warning is emitted asynchronously now: an unknown id is looked up in packages.json first
// (lazy load), so the message arrives a tick later — asserted in the async tail below.

// A7 — a mode that throws on mount must not leave the page chrome-less
shell.registerMode({
    id: 'boom', label: 'Boom', level: 9, icon: '💥', tagline: 'broken',
    mount() { throw new Error('mount exploded'); }
});
shell.apply('boom');
ok('A7 fell back to classic', document.body.dataset.uiMode === 'classic', document.body.dataset.uiMode);
ok('A7 terminal still present', !!document.getElementById('terminal-container'));

// A8 — a mode that deletes the terminal is rejected
shell.registerMode({
    id: 'killer', label: 'Killer', level: 9, icon: '☠', tagline: 'deletes the pane',
    mount() { byId['terminal-container'].remove(); return () => {}; }
});
shell.apply('killer');
ok('A8 destructive mode rejected', document.body.dataset.uiMode === 'classic');
ok('A8 error reported', printed.some(p => /terminal/i.test(p.m) && p.t === 'error'));

// A11 — a same-id clone passes a presence check; identity must reject it
shell.registerMode({
    id: 'clone', label: 'Clone', level: 9, icon: '👥', tagline: 'same id, different node',
    mount(api) {
        byId['terminal-container'].remove();
        const fake = document.createElement('div');
        fake.id = 'terminal-container';
        api.root.appendChild(fake);
        return () => {};
    }
});
ok('A11 clone rejected', shell.apply('clone') === false);
ok('A11 clone fallback is classic', document.body.dataset.uiMode === 'classic',
    document.body.dataset.uiMode);
ok('A11 no stale body class', !document.body.classList.contains('wx11-ui-clone'));

// A10 — the status bar (AI stop + network state) must exist inside every mode
shell.apply('probe');
const sb = document.getElementById('status-bar');
ok('A10 status bar docked in ui-foot',
    !!sb && sb.parentNode.id === 'ui-foot', sb ? sb.parentNode.id : 'missing');
shell.apply('classic');
const sb2 = document.getElementById('status-bar');
ok('A10 status bar returned to body', !!sb2 && sb2.parentNode === document.body,
    sb2 ? String(sb2.parentNode.id || 'body') : 'missing');
const foot = document.getElementById('ui-foot');
ok('A10 classic leaves no visible footer', !foot || foot.style.display === 'none');

// A9 — capture() routes a shell-authored command through the capture path
(async () => {
    const got = await shell.api().capture('ls -la');
    ok('A9 capture returns text', got === 'captured', String(got));
    await new Promise(r => setTimeout(r, 100));      // let the failed lazy load report itself
    ok('A6 warned', printed.some(p => /could not be loaded|not available|not loaded/.test(p.m)));
    console.log('\n' + pass + '/' + (pass + fail) + ' PASS');
    process.exit(fail ? 1 : 0);
})();