# ComfyUI Custom Node: Remove (Exclude) Image @ Index from a Batch
# Save as:
#   ComfyUI/custom_nodes/batch_remove_index/__init__.py
# Restart ComfyUI, then find it under category: "Batch/Index"

import torch


def _clamp_index(index: int, batch_size: int) -> int:
    """Clamp index into [0, batch_size-1]."""
    if batch_size <= 0:
        raise ValueError("Input batch is empty (batch_size <= 0).")
    if index < 0 or index >= batch_size:
        print(
            f"[BatchRemoveIndex] index {index} out of range for batch_size {batch_size}; "
            f"clamping to valid range."
        )
        index = max(0, min(index, batch_size - 1))
    return index


class BatchRemoveImageAtIndex:
    """
    Takes an IMAGE batch and an integer index (0-based),
    outputs the batch WITHOUT the image at that index.

    Example:
      images = [img0,img1,img2,img3], index=2
      output = [img0,img1,img3]
    """

    @classmethod
    def INPUT_TYPES(cls):
        return {
            "required": {
                "images": ("IMAGE",),
                "index": ("INT", {"default": 0, "min": 0, "max": 10**9}),
            }
        }

    RETURN_TYPES = ("IMAGE",)
    RETURN_NAMES = ("images",)
    FUNCTION = "remove"
    CATEGORY = "Batch/Index"

    def remove(self, images, index):
        if not torch.is_tensor(images):
            raise TypeError("Expected 'images' to be a torch Tensor (ComfyUI IMAGE type).")
        if images.ndim != 4:
            raise ValueError(f"Expected 'images' with shape [B,H,W,C], got ndim={images.ndim}.")

        b = images.shape[0]
        if b <= 1:
            # Producing an empty IMAGE batch often breaks downstream nodes.
            raise ValueError(
                f"Cannot remove an item from a batch of size {b} (would produce an empty batch)."
            )

        idx = _clamp_index(int(index), b)

        # Concatenate everything except the excluded index
        out = torch.cat([images[:idx], images[idx + 1 :]], dim=0)
        return (out,)


NODE_CLASS_MAPPINGS = {
    "BatchRemoveImageAtIndex": BatchRemoveImageAtIndex,
}

NODE_DISPLAY_NAME_MAPPINGS = {
    "BatchRemoveImageAtIndex": "Batch: Remove Image @ Index",
}