import { useState, useEffect, useCallback } from "react";

interface VirtualKeyboardState {
  isOpen: boolean;
  height: number;
  viewportHeight: number;
}

export function useVirtualKeyboard() {
  const [state, setState] = useState<VirtualKeyboardState>({
    isOpen: false,
    height: 0,
    viewportHeight: typeof window !== "undefined" ? window.innerHeight : 0,
  });

  const updateKeyboardState = useCallback(() => {
    const visualViewport = window.visualViewport;
    const windowHeight = window.innerHeight;

    if (visualViewport) {
      const viewportHeight = visualViewport.height;
      const keyboardHeight = windowHeight - viewportHeight;
      const isOpen = keyboardHeight > 100; // Threshold to avoid false positives

      setState({
        isOpen,
        height: keyboardHeight,
        viewportHeight,
      });
    } else {
      // Fallback: compare window height to a stored reference
      // This is less reliable but works on older browsers
      const currentHeight = windowHeight;
      const isOpen = currentHeight < state.viewportHeight - 100;

      setState((prev) => ({
        isOpen,
        height: isOpen ? prev.viewportHeight - currentHeight : 0,
        viewportHeight: isOpen ? prev.viewportHeight : currentHeight,
      }));
    }
  }, [state.viewportHeight]);

  useEffect(() => {
    const visualViewport = window.visualViewport;

    if (visualViewport) {
      visualViewport.addEventListener("resize", updateKeyboardState);
      visualViewport.addEventListener("scroll", updateKeyboardState);
    } else {
      window.addEventListener("resize", updateKeyboardState);
    }

    // Initial check
    updateKeyboardState();

    return () => {
      if (visualViewport) {
        visualViewport.removeEventListener("resize", updateKeyboardState);
        visualViewport.removeEventListener("scroll", updateKeyboardState);
      } else {
        window.removeEventListener("resize", updateKeyboardState);
      }
    };
  }, [updateKeyboardState]);

  return state;
}