deer-flow/frontend/src/components/ai-elements/inline-citation.tsx

"use client";

import { Badge } from "@/components/ui/badge";
import {
  Carousel,
  type CarouselApi,
  CarouselContent,
  CarouselItem,
} from "@/components/ui/carousel";
import {
  HoverCard,
  HoverCardContent,
  HoverCardTrigger,
} from "@/components/ui/hover-card";
import { cn } from "@/lib/utils";
import { ExternalLinkIcon, ArrowLeftIcon, ArrowRightIcon } from "lucide-react";
import {
  type ComponentProps,
  createContext,
  useCallback,
  useContext,
  useEffect,
  useState,
} from "react";
import type { Citation } from "@/core/citations";
import { extractDomainFromUrl } from "@/core/citations";
import { Shimmer } from "./shimmer";
import { useI18n } from "@/core/i18n/hooks";

export type InlineCitationProps = ComponentProps<"span">;

export const InlineCitation = ({
  className,
  ...props
}: InlineCitationProps) => (
  <span
    className={cn("group inline items-center gap-1", className)}
    {...props}
  />
);

export type InlineCitationTextProps = ComponentProps<"span">;

export const InlineCitationText = ({
  className,
  ...props
}: InlineCitationTextProps) => (
  <span
    className={cn("transition-colors group-hover:bg-accent", className)}
    {...props}
  />
);

export type InlineCitationCardProps = ComponentProps<typeof HoverCard>;

export const InlineCitationCard = (props: InlineCitationCardProps) => (
  <HoverCard closeDelay={0} openDelay={0} {...props} />
);

export type InlineCitationCardTriggerProps = ComponentProps<typeof Badge> & {
  sources: string[];
};

export const InlineCitationCardTrigger = ({
  sources,
  className,
  ...props
}: InlineCitationCardTriggerProps) => (
  <HoverCardTrigger asChild>
    <Badge
      className={cn("ml-1 rounded-full", className)}
      variant="secondary"
      {...props}
    >
      {sources[0] ? (
        <>
          {new URL(sources[0]).hostname}{" "}
          {sources.length > 1 && `+${sources.length - 1}`}
        </>
      ) : (
        "unknown"
      )}
    </Badge>
  </HoverCardTrigger>
);

export type InlineCitationCardBodyProps = ComponentProps<"div">;

export const InlineCitationCardBody = ({
  className,
  ...props
}: InlineCitationCardBodyProps) => (
  <HoverCardContent className={cn("relative w-80 p-0", className)} {...props} />
);

const CarouselApiContext = createContext<CarouselApi | undefined>(undefined);

const useCarouselApi = () => {
  const context = useContext(CarouselApiContext);
  return context;
};

export type InlineCitationCarouselProps = ComponentProps<typeof Carousel>;

export const InlineCitationCarousel = ({
  className,
  children,
  ...props
}: InlineCitationCarouselProps) => {
  const [api, setApi] = useState<CarouselApi>();

  return (
    <CarouselApiContext.Provider value={api}>
      <Carousel className={cn("w-full", className)} setApi={setApi} {...props}>
        {children}
      </Carousel>
    </CarouselApiContext.Provider>
  );
};

export type InlineCitationCarouselContentProps = ComponentProps<"div">;

export const InlineCitationCarouselContent = (
  props: InlineCitationCarouselContentProps
) => <CarouselContent {...props} />;

export type InlineCitationCarouselItemProps = ComponentProps<"div">;

export const InlineCitationCarouselItem = ({
  className,
  ...props
}: InlineCitationCarouselItemProps) => (
  <CarouselItem
    className={cn("w-full space-y-2 p-4 pl-8", className)}
    {...props}
  />
);

export type InlineCitationCarouselHeaderProps = ComponentProps<"div">;

export const InlineCitationCarouselHeader = ({
  className,
  ...props
}: InlineCitationCarouselHeaderProps) => (
  <div
    className={cn(
      "flex items-center justify-between gap-2 rounded-t-md bg-secondary p-2",
      className
    )}
    {...props}
  />
);

export type InlineCitationCarouselIndexProps = ComponentProps<"div">;

export const InlineCitationCarouselIndex = ({
  children,
  className,
  ...props
}: InlineCitationCarouselIndexProps) => {
  const api = useCarouselApi();
  const [current, setCurrent] = useState(0);
  const [count, setCount] = useState(0);

  useEffect(() => {
    if (!api) {
      return;
    }

    setCount(api.scrollSnapList().length);
    setCurrent(api.selectedScrollSnap() + 1);

    api.on("select", () => {
      setCurrent(api.selectedScrollSnap() + 1);
    });
  }, [api]);

  return (
    <div
      className={cn(
        "flex flex-1 items-center justify-end px-3 py-1 text-muted-foreground text-xs",
        className
      )}
      {...props}
    >
      {children ?? `${current}/${count}`}
    </div>
  );
};

export type InlineCitationCarouselPrevProps = ComponentProps<"button">;

export const InlineCitationCarouselPrev = ({
  className,
  ...props
}: InlineCitationCarouselPrevProps) => {
  const api = useCarouselApi();

  const handleClick = useCallback(() => {
    if (api) {
      api.scrollPrev();
    }
  }, [api]);

  return (
    <button
      aria-label="Previous"
      className={cn("shrink-0", className)}
      onClick={handleClick}
      type="button"
      {...props}
    >
      <ArrowLeftIcon className="size-4 text-muted-foreground" />
    </button>
  );
};

export type InlineCitationCarouselNextProps = ComponentProps<"button">;

export const InlineCitationCarouselNext = ({
  className,
  ...props
}: InlineCitationCarouselNextProps) => {
  const api = useCarouselApi();

  const handleClick = useCallback(() => {
    if (api) {
      api.scrollNext();
    }
  }, [api]);

  return (
    <button
      aria-label="Next"
      className={cn("shrink-0", className)}
      onClick={handleClick}
      type="button"
      {...props}
    >
      <ArrowRightIcon className="size-4 text-muted-foreground" />
    </button>
  );
};

export type InlineCitationSourceProps = ComponentProps<"div"> & {
  title?: string;
  url?: string;
  description?: string;
};

export const InlineCitationSource = ({
  title,
  url,
  description,
  className,
  children,
  ...props
}: InlineCitationSourceProps) => (
  <div className={cn("space-y-1", className)} {...props}>
    {title && (
      <h4 className="truncate font-medium text-sm leading-tight">{title}</h4>
    )}
    {url && (
      <p className="truncate break-all text-muted-foreground text-xs">{url}</p>
    )}
    {description && (
      <p className="line-clamp-3 text-muted-foreground text-sm leading-relaxed">
        {description}
      </p>
    )}
    {children}
  </div>
);

export type InlineCitationQuoteProps = ComponentProps<"blockquote">;

export const InlineCitationQuote = ({
  children,
  className,
  ...props
}: InlineCitationQuoteProps) => (
  <blockquote
    className={cn(
      "border-muted border-l-2 pl-3 text-muted-foreground text-sm italic",
      className
    )}
    {...props}
  >
    {children}
  </blockquote>
);

/**
 * Shared CitationLink component that renders a citation as a hover card badge
 * Used across message-list-item, artifact-file-detail, and message-group
 * 
 * When citation is provided, displays title and snippet from the citation.
 * When citation is omitted, falls back to displaying the domain name extracted from href.
 */
export type CitationLinkProps = {
  citation?: Citation;
  href: string;
  children: React.ReactNode;
};

export const CitationLink = ({
  citation,
  href,
  children,
}: CitationLinkProps) => {
  const domain = extractDomainFromUrl(href);
  
  // Priority: citation.title > children (if meaningful) > domain
  // - citation.title: from parsed <citations> block, most accurate
  // - children: from markdown link text [Text](url), used when no citation data
  // - domain: fallback when both above are unavailable
  // Skip children if it's a generic placeholder like "Source"
  const childrenText = typeof children === "string" ? children : null;
  const isGenericText = childrenText === "Source" || childrenText === "来源";
  const displayText = citation?.title || (!isGenericText && childrenText) || domain;

  return (
    <InlineCitationCard>
      <HoverCardTrigger asChild>
        <a
          href={href}
          target="_blank"
          rel="noopener noreferrer"
          className="inline-flex items-center"
          onClick={(e) => e.stopPropagation()}
        >
          <Badge
            variant="secondary"
            className="hover:bg-secondary/80 mx-0.5 cursor-pointer gap-1 rounded-full px-2 py-0.5 text-xs font-normal"
          >
            {displayText}
            <ExternalLinkIcon className="size-3" />
          </Badge>
        </a>
      </HoverCardTrigger>
      <InlineCitationCardBody>
        <div className="p-3">
          <InlineCitationSource
            title={citation?.title || domain}
            url={href}
            description={citation?.snippet}
          />
          <a
            href={href}
            target="_blank"
            rel="noopener noreferrer"
            className="text-primary mt-2 inline-flex items-center gap-1 text-xs hover:underline"
          >
            Visit source
            <ExternalLinkIcon className="size-3" />
          </a>
        </div>
      </InlineCitationCardBody>
    </InlineCitationCard>
  );
};

/**
 * Shared CitationsLoadingIndicator component
 * Used across message-list-item and message-group to show loading citations
 */
export type CitationsLoadingIndicatorProps = {
  citations: Citation[];
  className?: string;
};

export const CitationsLoadingIndicator = ({
  citations,
  className,
}: CitationsLoadingIndicatorProps) => {
  const { t } = useI18n();

  return (
    <div className={cn("flex flex-col gap-2", className)}>
      <Shimmer duration={2.5} className="text-sm">
        {citations.length > 0
          ? t.citations.loadingCitationsWithCount(citations.length)
          : t.citations.loadingCitations}
      </Shimmer>
      {citations.length > 0 && (
        <div className="flex flex-wrap gap-2">
          {citations.map((citation) => (
            <Badge
              key={citation.id}
              variant="secondary"
              className="animate-fade-in gap-1 rounded-full px-2.5 py-1 text-xs font-normal"
            >
              <Shimmer duration={2} as="span">
                {citation.title || extractDomainFromUrl(citation.url)}
              </Shimmer>
            </Badge>
          ))}
        </div>
      )}
    </div>
  );
};