import { useState, useCallback } from 'react';
import Cropper from 'react-easy-crop';
import type { Area, Point } from 'react-easy-crop';
import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter } from '@/components/ui/dialog';
import { Button } from '@/components/ui/button';
import { Slider } from '@/components/ui/slider';
import { ZoomIn, ZoomOut, RotateCcw } from 'lucide-react';

interface ImageCropDialogProps {
  open: boolean;
  imageSrc: string;
  aspect: number;
  title?: string;
  onCancel: () => void;
  onCrop: (croppedBlob: Blob) => void;
}

async function getCroppedBlob(imageSrc: string, pixelCrop: Area): Promise<Blob> {
  const image = await createImageBitmap(await (await fetch(imageSrc)).blob());
  const canvas = document.createElement('canvas');
  canvas.width = pixelCrop.width;
  canvas.height = pixelCrop.height;
  const ctx = canvas.getContext('2d');
  if (!ctx) throw new Error('Canvas context unavailable');
  ctx.drawImage(
    image,
    pixelCrop.x,
    pixelCrop.y,
    pixelCrop.width,
    pixelCrop.height,
    0,
    0,
    pixelCrop.width,
    pixelCrop.height,
  );
  return new Promise<Blob>((resolve, reject) => {
    canvas.toBlob((blob) => {
      if (blob) resolve(blob);
      else reject(new Error('Failed to create blob'));
    }, 'image/jpeg', 0.92);
  });
}

export function ImageCropDialog({ open, imageSrc, aspect, title = 'Crop Image', onCancel, onCrop }: ImageCropDialogProps) {
  const [crop, setCrop] = useState<Point>({ x: 0, y: 0 });
  const [zoom, setZoom] = useState(1);
  const [croppedAreaPixels, setCroppedAreaPixels] = useState<Area | null>(null);
  const [isProcessing, setIsProcessing] = useState(false);

  const onCropComplete = useCallback((_: Area, areaPixels: Area) => {
    setCroppedAreaPixels(areaPixels);
  }, []);

  const handleReset = () => {
    setCrop({ x: 0, y: 0 });
    setZoom(1);
  };

  const handleConfirm = async () => {
    if (!croppedAreaPixels) return;
    setIsProcessing(true);
    try {
      const blob = await getCroppedBlob(imageSrc, croppedAreaPixels);
      onCrop(blob);
    } finally {
      setIsProcessing(false);
    }
  };

  return (
    <Dialog open={open} onOpenChange={(v) => { if (!v) onCancel(); }}>
      <DialogContent className="sm:max-w-lg p-0 gap-0 overflow-hidden">
        <DialogHeader className="px-5 pt-5 pb-3">
          <DialogTitle className="text-base">{title}</DialogTitle>
        </DialogHeader>

        {/* Cropper area */}
        <div className="relative bg-black" style={{ height: 320 }}>
          <Cropper
            image={imageSrc}
            crop={crop}
            zoom={zoom}
            aspect={aspect}
            onCropChange={setCrop}
            onZoomChange={setZoom}
            onCropComplete={onCropComplete}
            style={{
              containerStyle: { borderRadius: 0 },
              cropAreaStyle: { border: '2px solid hsl(var(--primary))' },
            }}
          />
        </div>

        {/* Controls */}
        <div className="px-5 py-4 space-y-3 border-t">
          <div className="flex items-center gap-3">
            <ZoomOut className="size-4 text-muted-foreground shrink-0" />
            <Slider
              min={1}
              max={3}
              step={0.01}
              value={[zoom]}
              onValueChange={([v]) => setZoom(v)}
              className="flex-1"
            />
            <ZoomIn className="size-4 text-muted-foreground shrink-0" />
          </div>
          <div className="flex justify-between items-center">
            <Button variant="ghost" size="sm" onClick={handleReset} className="text-xs gap-1.5 h-8">
              <RotateCcw className="size-3" />
              Reset
            </Button>
            <p className="text-xs text-muted-foreground">Drag to reposition · Pinch or scroll to zoom</p>
          </div>
        </div>

        <DialogFooter className="px-5 pb-5 gap-2 flex-row justify-end">
          <Button variant="outline" onClick={onCancel} disabled={isProcessing} size="sm">
            Cancel
          </Button>
          <Button onClick={handleConfirm} disabled={isProcessing} size="sm">
            {isProcessing ? 'Processing…' : 'Apply Crop'}
          </Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  );
}