"""Transformers-compatible wrapper for harpertoken/move.

The model classifies KTH actions from 16 frames with max-pooling over time,
not a transformer. This subclasses PreTrainedModel so the weights serialize
honestly as config.json plus model.safetensors and load through AutoModel.
Importing this module registers the architecture.
"""

import torch
import torch.nn as nn
from transformers import AutoConfig, AutoModel, PretrainedConfig, PreTrainedModel


class MoveConfig(PretrainedConfig):
    model_type = "move_temporal"

    def __init__(self, num_labels=6, dropout=0.25, **kwargs):
        super().__init__(**kwargs)
        self.num_labels = num_labels
        self.dropout = dropout


LABELS = ["walking", "jogging", "running", "boxing", "handwaving", "handclapping"]


class MoveTemporal(PreTrainedModel):
    config_class = MoveConfig
    base_model_prefix = "move"

    # Transformers 5 reads this mapping while finalising a load. Nothing here
    # is tied, but the attribute has to exist or from_pretrained raises
    # AttributeError before the weights are placed.
    all_tied_weights_keys = {}

    def __init__(self, config):
        super().__init__(config)
        self.cnn = nn.ModuleDict(
            {
                "conv1": nn.Conv2d(1, 32, 3, padding=1),
                "conv2": nn.Conv2d(32, 64, 3, padding=1),
                "fc1": nn.Linear(64 * 8 * 8, 128),
            }
        )
        self.pool = nn.MaxPool2d(2, 2)
        self.adapt = nn.AdaptiveAvgPool2d((8, 8))
        self.head = nn.Linear(128, config.num_labels)
        self.drop = nn.Dropout(config.dropout)

    def forward(self, clip):
        b, t, _, h, w = clip.shape
        x = clip.view(b * t, 1, h, w)
        x = self.pool(torch.relu(self.cnn["conv1"](x)))
        x = self.pool(torch.relu(self.cnn["conv2"](x)))
        x = self.adapt(x)
        feats = torch.relu(self.cnn["fc1"](x.view(b * t, -1))).view(b, t, -1)
        return self.head(self.drop(feats.amax(1)))

    def predict_label(self, clip):
        """clip: 16x64x64 float array in [0, 1]. Returns the action."""
        self.eval()
        x = torch.as_tensor(clip, dtype=torch.float32)
        if x.dim() == 3:
            x = x.unsqueeze(0).unsqueeze(0)
        elif x.dim() == 4:
            x = x.unsqueeze(0)
        with torch.no_grad():
            return LABELS[int(self.forward(x).argmax(1)[0])]


def register():
    AutoConfig.register(MoveConfig.model_type, MoveConfig, exist_ok=True)
    AutoModel.register(MoveConfig, MoveTemporal, exist_ok=True)


register()