import { useState, useCallback, useEffect } from 'react';
import { LayoutDefinition } from '../../../services/contracts/metadata';

export function useFormBuilderHistory() {
  const [currentLayout, setCurrentLayout] = useState<LayoutDefinition | null>(null);
  const [isDirty, setIsDirty] = useState(false);
  const [history, setHistory] = useState<LayoutDefinition[]>([]);
  const [historyIndex, setHistoryIndex] = useState(-1);

  const initHistory = useCallback((layout: LayoutDefinition) => {
    setCurrentLayout(layout);
    setHistory([layout]);
    setHistoryIndex(0);
    setIsDirty(false);
  }, []);

  const pushState = useCallback((newLayout: LayoutDefinition) => {
    setHistory((prev) => {
      const slice = prev.slice(0, historyIndex + 1);
      const updated = [...slice, newLayout];
      if (updated.length > 50) updated.shift();
      return updated;
    });
    setHistoryIndex((prev) => Math.min(prev + 1, 49));
    setCurrentLayout(newLayout);
    setIsDirty(true);
  }, [historyIndex]);

  const handleUndo = useCallback(() => {
    if (historyIndex > 0) {
      const targetIndex = historyIndex - 1;
      setHistoryIndex(targetIndex);
      setCurrentLayout(history[targetIndex]);
      setIsDirty(true);
    }
  }, [historyIndex, history]);

  const handleRedo = useCallback(() => {
    if (historyIndex < history.length - 1) {
      const targetIndex = historyIndex + 1;
      setHistoryIndex(targetIndex);
      setCurrentLayout(history[targetIndex]);
      setIsDirty(true);
    }
  }, [historyIndex, history]);

  // Keyboard shortcut listener for Ctrl+Z and Ctrl+Y
  useEffect(() => {
    const handleKeyDown = (e: KeyboardEvent) => {
      if ((e.ctrlKey || e.metaKey) && e.key === 'z' && !e.shiftKey) {
        e.preventDefault();
        handleUndo();
      } else if (
        ((e.ctrlKey || e.metaKey) && e.key === 'y') ||
        ((e.ctrlKey || e.metaKey) && e.shiftKey && e.key === 'z')
      ) {
        e.preventDefault();
        handleRedo();
      }
    };
    window.addEventListener('keydown', handleKeyDown);
    return () => window.removeEventListener('keydown', handleKeyDown);
  }, [handleUndo, handleRedo]);

  return {
    currentLayout,
    setCurrentLayout,
    isDirty,
    setIsDirty,
    history,
    historyIndex,
    pushState,
    handleUndo,
    handleRedo,
    initHistory,
    canUndo: historyIndex > 0,
    canRedo: historyIndex < history.length - 1,
  };
}