import { useEffect, useCallback, RefObject } from 'react';

export interface KeyboardShortcut {
  key: string;
  ctrl?: boolean;
  shift?: boolean;
  alt?: boolean;
  handler: () => void;
  description?: string;
}

export function useKeyboardShortcuts(shortcuts: KeyboardShortcut[], enabled = true) {
  const handleKeyDown = useCallback((e: KeyboardEvent) => {
    if (!enabled) return;
    if (
      e.target instanceof HTMLInputElement ||
      e.target instanceof HTMLTextAreaElement ||
      (e.target as HTMLElement).isContentEditable
    ) {
      return;
    }

    for (const shortcut of shortcuts) {
      const keyMatch = e.key.toLowerCase() === shortcut.key.toLowerCase() ||
        e.code.toLowerCase() === shortcut.key.toLowerCase();
      const ctrlMatch = shortcut.ctrl ? (e.ctrlKey || e.metaKey) : true;
      const shiftMatch = shortcut.shift ? e.shiftKey : !e.shiftKey;
      const altMatch = shortcut.alt ? e.altKey : !e.altKey;

      if (keyMatch && ctrlMatch && shiftMatch && altMatch) {
        e.preventDefault();
        shortcut.handler();
        break;
      }
    }
  }, [shortcuts, enabled]);

  useEffect(() => {
    window.addEventListener('keydown', handleKeyDown);
    return () => window.removeEventListener('keydown', handleKeyDown);
  }, [handleKeyDown]);
}

export function useFocusTrap<T extends HTMLElement>(ref: RefObject<T | null>, active: boolean) {
  useEffect(() => {
    if (!active || !ref.current) return;

    const focusableElements = ref.current.querySelectorAll<HTMLElement>(
      'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
    );
    const firstElement = focusableElements[0];
    const lastElement = focusableElements[focusableElements.length - 1];

    const handleTabKey = (e: KeyboardEvent) => {
      if (e.key !== 'Tab') return;

      if (e.shiftKey) {
        if (document.activeElement === firstElement) {
          e.preventDefault();
          lastElement?.focus();
        }
      } else {
        if (document.activeElement === lastElement) {
          e.preventDefault();
          firstElement?.focus();
        }
      }
    };

    ref.current.addEventListener('keydown', handleTabKey);
    firstElement?.focus();

    return () => {
      ref.current?.removeEventListener('keydown', handleTabKey);
    };
  }, [ref, active]);
}

export function announceToScreenReader(message: string, priority: 'polite' | 'assertive' = 'polite') {
  const el = document.createElement('div');
  el.setAttribute('role', 'status');
  el.setAttribute('aria-live', priority);
  el.setAttribute('aria-atomic', 'true');
  el.style.cssText = 'position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0;';
  document.body.appendChild(el);
  
  setTimeout(() => {
    el.textContent = message;
    setTimeout(() => document.body.removeChild(el), 1000);
  }, 100);
}