dataroom/components/documents/preview-viewers/preview-pages-viewer.tsx

import { useCallback, useEffect, useState } from "react";

import { ChevronLeftIcon, ChevronRightIcon } from "lucide-react";

import { DocumentPreviewData } from "@/lib/types/document-preview";
import { cn } from "@/lib/utils";

import { Button } from "@/components/ui/button";

interface PreviewPagesViewerProps {
  documentData: DocumentPreviewData;
  onClose: () => void;
}

export function PreviewPagesViewer({
  documentData,
  onClose,
}: PreviewPagesViewerProps) {
  const [currentPage, setCurrentPage] = useState(1);
  const [imageCache, setImageCache] = useState<{ [key: number]: boolean }>({});
  const [imageLoaded, setImageLoaded] = useState(imageCache[1] || false);

  const { pages, numPages, documentName, isVertical } = documentData;

  const goToNextPage = useCallback(() => {
    if (currentPage < numPages) {
      setCurrentPage(currentPage + 1);
      setImageLoaded(imageCache[currentPage + 1] || false);
    }
  }, [currentPage, numPages, imageCache]);

  const goToPreviousPage = useCallback(() => {
    if (currentPage > 1) {
      setCurrentPage(currentPage - 1);
      setImageLoaded(imageCache[currentPage - 1] || false);
    }
  }, [currentPage, numPages, imageCache]);

  useEffect(() => {
    const handleKeyDown = (e: KeyboardEvent) => {
      switch (e.key) {
        case "ArrowLeft":
          goToPreviousPage();
          break;
        case "ArrowRight":
          goToNextPage();
          break;
        case "Escape":
          onClose();
          break;
      }
    };

    document.addEventListener("keydown", handleKeyDown);
    return () => document.removeEventListener("keydown", handleKeyDown);
  }, [goToPreviousPage, goToNextPage, onClose]);

  if (!pages || pages.length === 0) {
    return (
      <div className="flex h-full w-full items-center justify-center">
        <p className="text-gray-400">No pages available for preview</p>
      </div>
    );
  }

  const currentPageData = pages[currentPage - 1];

  const handleImageLoad = () => {
    setImageLoaded(true);
    setImageCache((prev) => ({ ...prev, [currentPage]: true }));
  };

  if (!currentPageData) {
    return (
      <div className="flex h-full w-full items-center justify-center">
        <p className="text-gray-400">Page not found</p>
      </div>
    );
  }

  return (
    <div className="relative h-full w-full overflow-hidden">
      {/* Navigation Controls */}
      <div className="absolute left-4 top-4 z-50">
        <div className="flex items-center gap-2 rounded-lg bg-black/20 px-3 py-2 text-white">
          <span className="text-sm">
            Page {currentPage} of {numPages}
          </span>
        </div>
      </div>

      {/* Document Title */}
      <div className="absolute left-1/2 top-4 z-50 -translate-x-1/2">
        <div className="rounded-lg bg-black/20 px-3 py-2 text-white">
          <span className="text-sm font-medium">{documentName}</span>
        </div>
      </div>

      {/* Previous Page Button */}
      <Button
        variant="ghost"
        size="icon"
        onClick={goToPreviousPage}
        disabled={currentPage <= 1}
        className={cn(
          "absolute left-4 top-1/2 z-40 h-12 w-12 -translate-y-1/2 rounded-full bg-black/20 text-white hover:bg-black/40",
          currentPage <= 1 && "cursor-not-allowed opacity-50",
        )}
      >
        <ChevronLeftIcon className="h-6 w-6" />
      </Button>

      {/* Next Page Button */}
      <Button
        variant="ghost"
        size="icon"
        onClick={goToNextPage}
        disabled={currentPage >= numPages}
        className={cn(
          "absolute right-4 top-1/2 z-40 h-12 w-12 -translate-y-1/2 rounded-full bg-black/20 text-white hover:bg-black/40",
          currentPage >= numPages && "cursor-not-allowed opacity-50",
        )}
      >
        <ChevronRightIcon className="h-6 w-6" />
      </Button>

      {/* Page Content */}
      <div className="flex h-full w-full items-center justify-center p-4">
        <div className="relative max-h-full max-w-full">
          {!imageLoaded && (
            <div className="absolute inset-0 flex items-center justify-center">
              <div className="h-8 w-8 animate-spin rounded-full border-2 border-white border-t-transparent"></div>
            </div>
          )}

          <img
            src={currentPageData.file}
            alt={`Page ${currentPage}`}
            className={cn(
              "max-h-[calc(100vh-120px)] max-w-full object-contain transition-opacity duration-200",
              imageLoaded ? "opacity-100" : "opacity-0",
            )}
            onLoad={handleImageLoad}
            onError={() => {
              setImageLoaded(true);
              setImageCache((prev) => ({ ...prev, [currentPage]: true }));
            }}
            draggable={false}
            onContextMenu={(e) => e.preventDefault()}
          />
        </div>
      </div>

      {/* Bottom Navigation */}
      <div className="absolute bottom-4 left-1/2 z-50 -translate-x-1/2">
        <div className="flex items-center gap-2 rounded-lg bg-black/20 px-4 py-2">
          <Button
            variant="ghost"
            size="sm"
            onClick={goToPreviousPage}
            disabled={currentPage <= 1}
            className="h-8 px-3 text-white hover:bg-white/10"
          >
            Previous
          </Button>

          <span className="text-sm text-white">
            {currentPage} / {numPages}
          </span>

          <Button
            variant="ghost"
            size="sm"
            onClick={goToNextPage}
            disabled={currentPage >= numPages}
            className="h-8 px-3 text-white hover:bg-white/10"
          >
            Next
          </Button>
        </div>
      </div>
    </div>
  );
}