import React, { useState, useEffect } from "react";
import { Button } from "@/components/ui/button";
import { 
  Download, 
  X, 
  Maximize, 
  Minimize,
  AlertCircle,
  Loader2,
  Info
} from "lucide-react";
import { toast } from "sonner";
import { Attachment, attachmentApi } from '@/services/attachmentApi';
import { cn } from '@/lib/utils';
import CustomDialog from '@/components/CustomDialog';

interface AttachmentViewerDialogProps {
  isOpen: boolean;
  onClose: () => void;
  attachment: Attachment | null;
  onDownload: (attachment: Attachment) => void;
}

const AttachmentViewerDialog: React.FC<AttachmentViewerDialogProps> = ({
  isOpen,
  onClose,
  attachment,
  onDownload
}) => {
  const [fileUrl, setFileUrl] = useState<string | null>(null);
  const [isLoading, setIsLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [isFullscreen, setIsFullscreen] = useState(false);

  useEffect(() => {
    const loadFile = async () => {
      if (!attachment || !isOpen) return;
      
      setIsLoading(true);
      setError(null);
      
      try {
        // Use the attachmentApi directly to download the file
        const result = await attachmentApi.download(attachment.attachmentId);
        const objectUrl = URL.createObjectURL(result.blob);
        setFileUrl(objectUrl);
      } catch (err) {
        console.error('Error loading file:', err);
        setError('Failed to load the file for preview. Please try downloading instead.');
      } finally {
        setIsLoading(false);
      }
    };

    loadFile();

    // Cleanup function to revoke the object URL when component unmounts or dialog closes
    return () => {
      if (fileUrl) {
        URL.revokeObjectURL(fileUrl);
        setFileUrl(null);
      }
    };
  }, [attachment, isOpen]);

  const toggleFullscreen = () => {
    setIsFullscreen(!isFullscreen);
  };

  const handleDownload = () => {
    if (attachment) {
      onDownload(attachment);
    }
  };

  const isImage = attachment?.fileType?.startsWith('image/') || attachment?.fileName?.match(/\.(jpg|jpeg|png|gif|bmp|webp)$/i);
  const isPdf = attachment?.fileType === 'application/pdf' || attachment?.fileName?.endsWith('.pdf');
  const isText = attachment?.fileType?.startsWith('text/') || attachment?.fileName?.match(/\.(txt|md|rtf|json|xml|html|css|js|ts)$/i);

  return (
    <CustomDialog
      isOpen={isOpen}
      onClose={onClose}
      title={attachment?.fileName || 'File Preview'}
      description={attachment?.fileType || ''}
      allowClose={true}
    >
      <div className={cn("flex flex-col", isFullscreen && "w-full h-full")}>
        <div className="flex flex-col mb-3">
          <div className="flex justify-between items-center">
            <div className="text-xs text-muted-foreground">
              {attachment?.createdBy && <span>Added by {attachment.createdBy}</span>}
              {attachment?.createdAt && attachment?.createdBy && <span> · </span>}
              {attachment?.createdAt && 
                <span>
                  {new Date(attachment.createdAt).toLocaleDateString(undefined, {
                    year: 'numeric',
                    month: 'short',
                    day: 'numeric',
                    hour: '2-digit',
                    minute: '2-digit'
                  })}
                </span>
              }
            </div>
            <Button 
              variant="outline" 
              size="icon" 
              onClick={toggleFullscreen}
              className="h-8 w-8"
            >
              {isFullscreen ? <Minimize className="h-4 w-4" /> : <Maximize className="h-4 w-4" />}
            </Button>
          </div>
          
          {/* File description */}
          {attachment?.description && (
            <div className="mt-2 text-sm flex items-start gap-2 bg-accent/50 p-2 rounded-md">
              <Info className="h-4 w-4 text-muted-foreground mt-0.5 flex-shrink-0" />
              <p className="text-sm text-muted-foreground">{attachment.description}</p>
            </div>
          )}
        </div>

        <div className={cn(
          "flex-1 overflow-auto flex items-center justify-center rounded-md border bg-muted",
          isFullscreen ? "w-full h-[85vh]" : "h-[70vh]"
        )}>
          {isLoading ? (
            <div className="flex flex-col items-center justify-center p-8 text-center">
              <Loader2 className="h-8 w-8 animate-spin text-primary mb-4" />
              <p className="text-sm text-muted-foreground">Loading preview...</p>
            </div>
          ) : error ? (
            <div className="flex flex-col items-center justify-center p-8 text-center">
              <AlertCircle className="h-8 w-8 text-destructive mb-4" />
              <p className="text-sm text-destructive">{error}</p>
            </div>
          ) : fileUrl && isImage ? (
            <img 
              src={fileUrl} 
              alt={attachment?.fileName || 'Image preview'} 
              className="max-w-full max-h-full object-contain"
            />
          ) : fileUrl && isPdf ? (
            <iframe 
              src={fileUrl} 
              title={attachment?.fileName || 'PDF preview'} 
              className="w-full h-full"
              style={{ minHeight: isFullscreen ? '85vh' : '70vh' }}
            />
          ) : fileUrl && isText ? (
            <iframe 
              src={fileUrl} 
              title={attachment?.fileName || 'Text preview'} 
              className="w-full h-full bg-white"
            />
          ) : (
            <div className="flex flex-col items-center justify-center p-8 text-center">
              <AlertCircle className="h-8 w-8 text-amber-500 mb-4" />
              <p className="text-sm text-muted-foreground">Preview not available for this file type</p>
              <Button 
                onClick={handleDownload} 
                variant="outline" 
                className="mt-4 flex items-center gap-2"
              >
                <Download className="h-4 w-4" />
                Download to view
              </Button>
            </div>
          )}
        </div>

        <div className="flex justify-end gap-2 mt-4">
          <Button 
            onClick={handleDownload} 
            className="flex items-center gap-2"
          >
            <Download className="h-4 w-4" />
            Download
          </Button>
          <Button 
            variant="outline" 
            onClick={onClose}
          >
            Close
          </Button>
        </div>
      </div>
    </CustomDialog>
  );
};

export default AttachmentViewerDialog;