/**
 * DOM shim for the module-split tests.
 *
 * Extends the markdown harness shim with a CAPTURING console (so scenarios
 * can assert on the `[statum]` warnings/errors the seam emits) and a small
 * element tree builder. Like tests/markdown/shim.js, `document.readyState`
 * is 'loading' so statum-core.js only registers a DOMContentLoaded listener
 * instead of booting.
 */
export function installShim() {
  var listeners = {};
  var log = { errors: [], warns: [], messages: [] };

  function makeElement(tag) {
    return {
      tagName: (tag || 'div').toUpperCase(),
      style: {}, dataset: {}, attributes: [],
      children: [],
      textContent: '', innerHTML: '',
      get firstChild() { return this.children[0] || null; },
      classList: { add: function () {}, remove: function () {}, contains: function () { return false; } },
      contains: function () { return false; },
      appendChild: function (c) { this.children.push(c); return c; },
      removeChild: function (c) {
        var i = this.children.indexOf(c);
        if (i >= 0) this.children.splice(i, 1);
        return c;
      },
      remove: function () {
        if (this.parentNode) this.parentNode.removeChild(this);
      },
      replaceWith: function () {},
      cloneNode: function () { return makeElement(this.tagName); },
      nextElementSibling: null,
      parentNode: null,
      addEventListener: function () {}, removeEventListener: function () {},
      setAttribute: function (n, v) {
        this.attributes = this.attributes.filter(function (a) { return a.name !== n; });
        this.attributes.push({ name: n, value: String(v) });
      },
      removeAttribute: function (n) {
        this.attributes = this.attributes.filter(function (a) { return a.name !== n; });
      },
      hasAttribute: function (n) {
        return this.attributes.some(function (a) { return a.name === n; });
      },
      getAttribute: function (n) {
        var hit = this.attributes.filter(function (a) { return a.name === n; })[0];
        return hit ? hit.value : null;
      },
      querySelectorAll: function () { return []; },
      querySelector: function () { return null; }
    };
  }

  globalThis.__shim = {
    log: log,
    makeElement: makeElement,
    body: makeElement('body')
  };

  globalThis.console = {
    log: function () { log.messages.push(['log', Array.prototype.slice.call(arguments)]); },
    info: function () { log.messages.push(['info', Array.prototype.slice.call(arguments)]); },
    debug: function () { log.messages.push(['debug', Array.prototype.slice.call(arguments)]); },
    warn: function () {
      log.warns.push(Array.prototype.slice.call(arguments).join(' '));
      log.messages.push(['warn', Array.prototype.slice.call(arguments)]);
    },
    error: function () {
      log.errors.push(Array.prototype.slice.call(arguments).join(' '));
      log.messages.push(['error', Array.prototype.slice.call(arguments)]);
    }
  };
  globalThis.document = {
    readyState: 'loading', cookie: '',
    head: makeElement('head'), body: globalThis.__shim.body,
    documentElement: makeElement('html'),
    addEventListener: function (t, f) { (listeners[t] = listeners[t] || []).push(f); },
    removeEventListener: function () {},
    getElementById: function () { return null; },
    querySelectorAll: function () { return []; },
    querySelector: function () { return null; },
    createElement: function (tag) { return makeElement(tag); },
    createTextNode: function (t) { return { nodeType: 3, textContent: t }; }
  };
  globalThis.window = globalThis;
  globalThis.location = { href: 'http://localhost/', protocol: 'http:', addEventListener: function () {} };
  globalThis.navigator = { userAgent: 'qjs' };
  globalThis.addEventListener = function (t, f) { (listeners[t] = listeners[t] || []).push(f); };
  globalThis.removeEventListener = function () {};
  globalThis.__STATUM_TEST__ = true;

  // Minimal fetch/Headers stub so scenarios can prove core's headless boot
  // (the full-featured DOM version lives in tests/dom/shim.js).
  var fetchHandler = null;
  function Headers() { this._h = {}; }
  Headers.prototype.set = function (n, v) { this._h[String(n).toLowerCase()] = String(v); };
  Headers.prototype.append = function (n, v) {
    var k = String(n).toLowerCase();
    this._h[k] = this._h[k] ? this._h[k] + ', ' + v : String(v);
  };
  Headers.prototype.get = function (n) {
    var k = Object.keys(this._h).filter(function (x) { return x === String(n).toLowerCase(); })[0];
    return k !== undefined ? this._h[k] : null;
  };
  globalThis.Headers = Headers;

  function okResponse(directives) {
    return {
      ok: true,
      status: 200,
      headers: { get: function (n) { return String(n).toLowerCase() === 'content-type' ? 'application/vnd.statum+json' : null; } },
      json: function () { return Promise.resolve(directives || []); }
    };
  }
  globalThis.fetch = function (url, init) {
    var res = fetchHandler ? fetchHandler(String(url), init || {}) : okResponse([]);
    return Promise.resolve(res);
  };
  globalThis.__shim.setFetch = function (fn) { fetchHandler = fn; };
  globalThis.__shim.okResponse = okResponse;
}