/**
 * Профиль перерисовок React через минимальный __REACT_DEVTOOLS_GLOBAL_HOOK__ (Task 7).
 * Нужна профилирующая сборка (react-dom/profiling): только в ней fiber'ы несут actualDuration.
 * Init-script REACT_HOOK_SCRIPT ставится ДО загрузки приложения (ctx.addInitScript).
 * profileStart(page) / profileStop(page) -> {commits, top: [{component, renders, self_ms}] (топ-20 по self_ms), ...}.
 *
 * Правило «компонент отрисовался в коммите»: fiber.flags & PerformedWork (1) для function/class/forwardRef/
 * simple-memo (теги 0, 1, 11, 15). Обход как у DevTools: в потомков идём, только если fiber новый (нет alternate)
 * или fiber.child !== alternate.child (иначе поддерево пропущено bailout'ом, а его флаги устарели).
 * self_ms = actualDuration - сумма actualDuration обойдённых детей.
 */
export const REACT_HOOK_SCRIPT = `(() => {
  if (window.__REACT_DEVTOOLS_GLOBAL_HOOK__) return;
  const COMPONENT_TAGS = { 0: 1, 1: 1, 11: 1, 15: 1 };
  const st = {
    active: false, renderers: 0, commitsTotal: 0, commits: 0, sawActualDuration: false,
    stats: new Map(),
  };
  const nameOf = (f) => {
    const t = f.type;
    if (typeof t === 'function') return t.displayName || t.name || '(anonymous)';
    if (t && typeof t === 'object') {
      const r = t.render;
      const n = t.displayName || (r && (r.displayName || r.name));
      return n ? (f.tag === 11 ? 'ForwardRef(' + n + ')' : n) : '(anonymous)';
    }
    return '(anonymous)';
  };
  const visit = (root) => {
    const stack = [root];
    while (stack.length) {
      const f = stack.pop();
      const alt = f.alternate;
      const descend = alt === null || alt === undefined || f.child !== alt.child;
      if (COMPONENT_TAGS[f.tag] && (f.flags & 1) === 1) {
        let kids = 0;
        if (descend) for (let c = f.child; c; c = c.sibling) kids += c.actualDuration || 0;
        const self = Math.max((f.actualDuration || 0) - kids, 0);
        const name = nameOf(f);
        const s = st.stats.get(name) || { renders: 0, self_ms: 0 };
        s.renders += 1; s.self_ms += self;
        st.stats.set(name, s);
      }
      if (descend) for (let c = f.child; c; c = c.sibling) stack.push(c);
    }
  };
  window.__REACT_DEVTOOLS_GLOBAL_HOOK__ = {
    supportsFiber: true,
    isDisabled: false,
    renderers: new Map(),
    inject(r) { st.renderers += 1; this.renderers.set(st.renderers, r); return st.renderers; },
    checkDCE() {},
    onScheduleFiberRoot() {},
    onCommitFiberUnmount() {},
    onPostCommitFiberRoot() {},
    onCommitFiberRoot(id, root) {
      st.commitsTotal += 1;
      // профилирующая сборка: у HostRoot есть числовой actualDuration (в prod-сборке поля нет)
      if (!st.sawActualDuration) { const cur = root.current; if (cur && typeof cur.actualDuration === 'number' && cur.actualDuration >= 0) st.sawActualDuration = true; }
      if (!st.active) return;
      st.commits += 1;
      try { visit(root.current); } catch (e) { st.error = String(e); }
    },
  };
  window.__reactProfile = st;
})();`;

export interface RenderRow { component: string; renders: number; self_ms: number }
export interface ProfileResult {
  commits: number;
  total_renders: number;
  total_self_ms: number;
  top: RenderRow[];
  error?: string;
}
export interface HookInfo { renderers: number; commits_total: number; saw_actual_duration: boolean }

export async function profileStart(page: Page_): Promise<void> {
  await page.evaluate(() => {
    const st = (window as any).__reactProfile;
    if (!st) throw new Error('React hook is not installed (REACT_HOOK_SCRIPT)');
    st.stats = new Map(); st.commits = 0; st.error = undefined; st.active = true;
  });
}

export async function profileStop(page: Page_, topN = 20): Promise<ProfileResult> {
  return page.evaluate((n) => {
    const st = (window as any).__reactProfile;
    st.active = false;
    const rows = Array.from(st.stats.entries() as Iterable<[string, { renders: number; self_ms: number }]>)
      .map(([component, v]) => ({ component, renders: v.renders, self_ms: v.self_ms }))
      .sort((a, b) => b.self_ms - a.self_ms || b.renders - a.renders);
    return {
      commits: st.commits as number,
      total_renders: rows.reduce((a, r) => a + r.renders, 0),
      total_self_ms: rows.reduce((a, r) => a + r.self_ms, 0),
      top: rows.slice(0, n),
      ...(st.error ? { error: st.error as string } : {}),
    };
  }, topN);
}

export async function hookInfo(page: Page_): Promise<HookInfo> {
  return page.evaluate(() => {
    const st = (window as any).__reactProfile;
    return { renderers: st?.renderers ?? 0, commits_total: st?.commitsTotal ?? 0, saw_actual_duration: !!st?.sawActualDuration };
  });
}

import type { Page as Page_ } from '@playwright/test';