import torch
from comfy_api.latest import Types


def pack_variable_mesh_batch(vertices, faces, colors=None):
    batch_size = len(vertices)
    max_vertices = max(v.shape[0] for v in vertices)
    max_faces = max(f.shape[0] for f in faces)

    packed_vertices = vertices[0].new_zeros((batch_size, max_vertices, vertices[0].shape[1]))
    packed_faces = faces[0].new_zeros((batch_size, max_faces, faces[0].shape[1]))
    vertex_counts = torch.tensor([v.shape[0] for v in vertices], device=vertices[0].device, dtype=torch.int64)
    face_counts = torch.tensor([f.shape[0] for f in faces], device=faces[0].device, dtype=torch.int64)

    for i, (v, f) in enumerate(zip(vertices, faces)):
        packed_vertices[i, :v.shape[0]] = v
        packed_faces[i, :f.shape[0]] = f

    mesh = Types.MESH(packed_vertices, packed_faces)
    mesh.vertex_counts = vertex_counts
    mesh.face_counts = face_counts

    if colors is not None:
        max_colors = max(c.shape[0] for c in colors)
        packed_colors = colors[0].new_zeros((batch_size, max_colors, colors[0].shape[1]))
        color_counts = torch.tensor([c.shape[0] for c in colors], device=colors[0].device, dtype=torch.int64)
        for i, c in enumerate(colors):
            packed_colors[i, :c.shape[0]] = c
        mesh.colors = packed_colors
        mesh.color_counts = color_counts

    return mesh


def get_mesh_batch_item(mesh, index):
    if hasattr(mesh, "vertex_counts"):
        vertex_count = int(mesh.vertex_counts[index].item())
        face_count = int(mesh.face_counts[index].item())
        vertices = mesh.vertices[index, :vertex_count]
        faces = mesh.faces[index, :face_count]
        colors = None
        if hasattr(mesh, "colors") and mesh.colors is not None:
            if hasattr(mesh, "color_counts"):
                color_count = int(mesh.color_counts[index].item())
                colors = mesh.colors[index, :color_count]
            else:
                colors = mesh.colors[index, :vertex_count]
        return vertices, faces, colors

    colors = None
    if hasattr(mesh, "colors") and mesh.colors is not None:
        colors = mesh.colors[index]
    return mesh.vertices[index], mesh.faces[index], colors