// src/components/CarouselDemo.tsx
import * as React from "react";
import Autoplay from "embla-carousel-autoplay";//实现轮播图的自动播放功能

import { Card, CardContent } from "@/ui/card";
import {
  Carousel,//主体
  CarouselContent,//内容容器
  CarouselItem,//单个轮播项
  CarouselNext,
  CarouselPrevious,
  type CarouselApi,
} from "@/ui/carousel";


export function CarouselDemo() {
  const [api, setApi] = React.useState<CarouselApi>();
  const [current, setCurrent] = React.useState(0);
  const [count, setCount] = React.useState(0);

  const totalSlides = 6; 

  React.useEffect(() => {
    if (!api) return;

    setCount(api.scrollSnapList().length);
    setCurrent(api.selectedScrollSnap());//获取当前选中的轮播项的索引
    api.on("select", () => {
      setCurrent(api.selectedScrollSnap());
    });
  }, [api]);//当api改变时，执行此函数 水平居中 循环 自动播放 回传状态

  return (
    <div className="relative w-full max-w-4xl mx-auto">
      <Carousel
        opts={{
          loop: true,
        }}
        plugins={[
          Autoplay({
            delay: 3000,
            stopOnInteraction: false, 
          }),
        ]}
        setApi={setApi}
      >
        <CarouselContent className="h-full w-full">
          {Array.from({ length: totalSlides }).map((_, index) => (
            <CarouselItem key={index} className="w-full h-full">
              <div className="p-1">
                <Card>
                  <CardContent className="flex aspect-square items-center justify-center ">
                    <div 
                    className="w-full h-full"
                    style={{
                      backgroundImage: "url('/app/images/header.png')",//背景图片可修改
                      backgroundSize: '100% 100%',
                    }}
                    >
                    </div>
                  </CardContent>
                </Card>
              </div>
            </CarouselItem>
          ))}
        </CarouselContent>
        <CarouselPrevious className="absolute left-2 top-1/2 -translate-y-1/2 z-10" />
        <CarouselNext className="absolute right-2 top-1/2 -translate-y-1/2 z-10" />
      </Carousel>

      {/* 分页指示器 - 右下角 */}
      <div className="absolute bottom-4 right-4 flex gap-2 z-10">
        {Array.from({ length: count }).map((_, index) => (
          <button
            key={index}
            onClick={() => api?.scrollTo(index)}
            className={`h-2 w-2 rounded-full transition-colors ${
              index === current ? "bg-black" : "bg-black/50"
            }`}
          />
        ))}
      </div>
    </div>
  );
}