import React, { useRef } from 'react';

import type { MaterialLegend, MaterialsOverlayLayout } from '../../../shared/types';
import { DEFAULT_MATERIALS_OVERLAY_LAYOUT } from '../../../shared/types';
import { legendPanelVisualLayout } from '../../../shared/types/materialLegend';
import { useSceneOverlayView } from '../sceneOverlay/SceneOverlayViewContext';

import styles from './MaterialLegendPanel.module.css';

type Props = {
  legend: MaterialLegend;
  layout: MaterialsOverlayLayout;
  editable?: boolean;
  onLayoutChange?: (layout: MaterialsOverlayLayout) => void;
};

export function MaterialLegendPanel({
  legend,
  layout,
  editable = false,
  onLayoutChange,
}: Props) {
  const host = useSceneOverlayView();
  const view = host?.view ?? { w: 1, h: 1 };
  const viewport = host?.viewport ?? { x: 0, y: 0, w: view.w, h: view.h };
  const dragRef = useRef<{ startX: number; startY: number; origin: MaterialsOverlayLayout } | null>(
    null,
  );
  const effective = layout ?? DEFAULT_MATERIALS_OVERLAY_LAYOUT;
  const vis = legendPanelVisualLayout(effective, viewport);

  if (!legend.enabled || legend.items.length === 0) return null;

  return (
    <div
      className={styles.panel}
      style={{
        left: vis.left,
        top: vis.top,
        width: vis.width,
        transform: `translate(-50%, -50%) scale(${String(vis.scale)})`,
      }}
      onPointerDown={(e) => {
        if (!editable || !onLayoutChange) return;
        e.stopPropagation();
        (e.currentTarget as HTMLDivElement).setPointerCapture(e.pointerId);
        dragRef.current = {
          startX: e.clientX,
          startY: e.clientY,
          origin: { ...effective },
        };
      }}
      onPointerMove={(e) => {
        const d = dragRef.current;
        if (!d || !onLayoutChange) return;
        const dx = (e.clientX - d.startX) / Math.max(1, view.w);
        const dy = (e.clientY - d.startY) / Math.max(1, view.h);
        onLayoutChange({
          ...d.origin,
          cx: d.origin.cx + dx,
          cy: d.origin.cy + dy,
        });
      }}
      onPointerUp={() => {
        dragRef.current = null;
      }}
    >
      <div className={styles.title}>Легенда</div>
      {legend.items
        .slice()
        .sort((a, b) => a.number - b.number)
        .map((item) => (
          <div key={item.id} className={styles.item}>
            <div className={styles.num}>{item.number}</div>
            <div className={styles.text}>{item.text || '—'}</div>
          </div>
        ))}
    </div>
  );
}