'use client';

import { useEffect, useRef, useState } from 'react';
import { Responsive, noCompactor } from 'react-grid-layout';
import type { ResponsiveLayouts } from 'react-grid-layout';
import 'react-grid-layout/css/styles.css';
import 'react-resizable/css/styles.css';
import { useTranslations } from 'next-intl';
import { WIDGET_CONSTRAINTS, type WidgetType } from './widget-registry';
import { WidgetWrapper } from './widgets/widget-wrapper';
import { TesseraLogo } from '@/components/brand/tessera-logo';

// quick-260916-bwo: Raster doppelt so fein wie zuvor (24 statt 12 Spalten,
// 20 statt 40 px Zeilenhoehe, 8 statt 16 px Abstand). Gespeicherte Anordnungen
// in alten Einheiten werden in `@/lib/grid-layout-migration` einmalig
// umgerechnet und mit `__gridVersion: 2` markiert. BREAKPOINTS unveraendert.
const BREAKPOINTS = { lg: 1200, md: 996, sm: 768, xs: 480, xxs: 0 };
const COLS = { lg: 24, md: 20, sm: 12, xs: 8, xxs: 2 };

interface DashboardGridProps {
  layouts: Record<string, Array<{ i: string; x: number; y: number; w: number; h: number }>>;
  widgets: Array<{ id: string; widgetType: string; config: Record<string, unknown> }>;
  isEditMode: boolean;
  onLayoutChange: (allLayouts: ResponsiveLayouts) => void;
  onRemoveWidget: (id: string) => void;
}

/**
 * Dashboard grid wrapper using react-grid-layout v2 Responsive component.
 * Renders widgets in a draggable/resizable grid when in edit mode.
 * Shows empty state when no widgets exist.
 *
 * v2 API: uses dragConfig/resizeConfig instead of isDraggable/isResizable.
 */
export function DashboardGrid({
  layouts,
  widgets,
  isEditMode,
  onLayoutChange,
  onRemoveWidget,
}: DashboardGridProps) {
  const t = useTranslations('widgets');
  const containerRef = useRef<HTMLDivElement>(null);
  const [width, setWidth] = useState(1200);

  // Measure container width (v2 requires explicit width — Pitfall 1)
  useEffect(() => {
    if (!containerRef.current) return;
    const observer = new ResizeObserver((entries) => {
      setWidth(entries[0].contentRect.width);
    });
    observer.observe(containerRef.current);
    return () => observer.disconnect();
  }, []);

  // Empty state (D-02)
  if (widgets.length === 0) {
    return (
      <div className="flex flex-col items-center justify-center min-h-[60vh] gap-4">
        {/* Bildmarke statt des frueheren handgezeichneten Vier-Quadrate-Symbols.
            Ohne Rahmen und ohne Kontur: die Marke steht hier frei auf dem
            Seitenhintergrund, nicht auf einer eigenen Flaeche. */}
        <TesseraLogo variant="mark" size={64} plateOutline={false} />
        <h2 className="text-lg font-semibold text-muted-foreground">
          {t('emptyHeading')}
        </h2>
        <p className="text-sm text-muted-foreground">
          {t('emptyBody')}
        </p>
      </div>
    );
  }

  return (
    <div ref={containerRef}>
      <Responsive
        width={width}
        breakpoints={BREAKPOINTS}
        cols={COLS}
        layouts={layouts as ResponsiveLayouts}
        rowHeight={20}
        margin={[8, 8] as [number, number]}
        // containerPadding bewusst nicht gesetzt: react-grid-layout 2.2.3 nimmt
        // dann das margin (gemessen: effectiveContainerPadding = containerPadding ?? margin).
        dragConfig={{
          enabled: isEditMode,
          handle: '.widget-drag-handle',
        }}
        resizeConfig={{
          enabled: isEditMode,
        }}
        compactor={noCompactor}
        onLayoutChange={(_currentLayout, allLayouts) => onLayoutChange(allLayouts)}
      >
        {widgets.map((widget) => {
          const constraints = WIDGET_CONSTRAINTS[widget.widgetType as WidgetType];
          return (
            <div
              key={widget.id}
              data-grid={{
                ...(layouts.lg?.find((l) => l.i === widget.id) ?? {
                  x: 0,
                  y: 0,
                  w: constraints?.defaultW ?? 4,
                  h: constraints?.defaultH ?? 4,
                }),
                minW: constraints?.minW ?? 4,
                minH: constraints?.minH ?? 4,
              }}
            >
              <WidgetWrapper
                widget={widget}
                isEditMode={isEditMode}
                onRemove={onRemoveWidget}
              />
            </div>
          );
        })}
      </Responsive>
    </div>
  );
}