import React, { useCallback } from 'react';
import { useEditor } from '@craftjs/core';

interface LayerNodeProps {
  nodeId: string;
  depth: number;
}

const LayerNode: React.FC<LayerNodeProps> = ({ nodeId, depth }) => {
  const { node, selectedId, actions } = useEditor((state) => {
    const n = state.nodes[nodeId];
    const selectedIds = state.events.selected;
    const selId = selectedIds ? Array.from(selectedIds)[0] : null;
    return {
      node: n,
      selectedId: selId,
    };
  });

  const handleClick = useCallback((e: React.MouseEvent) => {
    e.stopPropagation();
    actions.selectNode(nodeId);
  }, [actions, nodeId]);

  if (!node) return null;

  const isSelected = selectedId === nodeId;
  const nodeType = node.data.type;
  const resolvedName = typeof nodeType === 'object' && nodeType !== null && 'resolvedName' in nodeType
    ? (nodeType as any).resolvedName
    : typeof nodeType === 'string' ? nodeType : undefined;
  const displayName = (node.data.props?.aiName as string) || node.data.displayName || (node.data.type as any)?.resolvedName || 'Node';
  const childNodeIds: string[] = node.data.nodes || [];
  const linkedNodeIds: string[] = Object.values(node.data.linkedNodes || {}) as string[];
  const allChildren = [...childNodeIds, ...linkedNodeIds];
  const isRoot = nodeId === 'ROOT';

  return (
    <div>
      <div
        onClick={handleClick}
        style={{
          display: 'flex',
          alignItems: 'center',
          padding: '5px 8px',
          paddingLeft: `${8 + depth * 16}px`,
          fontSize: 12,
          fontWeight: isSelected ? 600 : 400,
          color: isSelected ? 'var(--color-accent)' : 'var(--color-text)',
          background: isSelected ? 'var(--color-accent-subtle)' : 'transparent',
          borderLeft: isSelected ? '2px solid var(--color-accent)' : '2px solid transparent',
          cursor: 'pointer',
          transition: 'all var(--transition-fast)',
          whiteSpace: 'nowrap',
          overflow: 'hidden',
          textOverflow: 'ellipsis',
          userSelect: 'none',
        }}
        onMouseEnter={(e) => {
          if (!isSelected) {
            (e.currentTarget as HTMLElement).style.background = 'var(--color-bg-hover)';
          }
        }}
        onMouseLeave={(e) => {
          if (!isSelected) {
            (e.currentTarget as HTMLElement).style.background = 'transparent';
          }
        }}
      >
        {/* Indentation indicator */}
        {allChildren.length > 0 && (
          <span style={{ marginRight: 4, fontSize: 8, color: 'var(--color-text-dim)' }}>
            &#9660;
          </span>
        )}
        {allChildren.length === 0 && (
          <span style={{ marginRight: 4, fontSize: 8, color: 'transparent' }}>
            &#9660;
          </span>
        )}

        {/* Component type icon and name */}
        <span style={{ overflow: 'hidden', textOverflow: 'ellipsis' }}>
          {isRoot ? 'Canvas (Root)' : displayName}
        </span>
      </div>

      {/* Render children */}
      {allChildren.map((childId) => (
        <LayerNode key={childId} nodeId={childId} depth={depth + 1} />
      ))}
    </div>
  );
};

export const LayersPanel: React.FC = () => {
  const { nodeIds } = useEditor((state) => {
    return {
      nodeIds: Object.keys(state.nodes),
    };
  });

  const hasRoot = nodeIds.includes('ROOT');

  if (!hasRoot) {
    return (
      <div className="panel-placeholder">
        No content on canvas
      </div>
    );
  }

  return (
    <div
      style={{
        display: 'flex',
        flexDirection: 'column',
        margin: '-12px',
      }}
    >
      <div
        style={{
          padding: '8px 12px',
          fontSize: 11,
          fontWeight: 600,
          textTransform: 'uppercase',
          letterSpacing: '0.5px',
          color: 'var(--color-text-muted)',
          borderBottom: '1px solid var(--color-border)',
        }}
      >
        Component Tree
      </div>
      <LayerNode nodeId="ROOT" depth={0} />
    </div>
  );
};