import torch
import numpy as np
from transformers import AutoTokenizer, AutoModelForSeq2SeqLM


def getScores(ids, scores, pad_token_id):
    """get sequence scores from model.generate output"""
    scores = torch.stack(scores, dim=1)
    log_probs = torch.log_softmax(scores, dim=2)
    # remove start token
    ids = ids[:,1:]
    # gather needed probs
    x = ids.unsqueeze(-1).expand(log_probs.shape)
    needed_logits = torch.gather(log_probs, 2, x)
    final_logits = needed_logits[:, :, 0]
    padded_mask = (ids == pad_token_id)
    final_logits[padded_mask] = 0
    final_scores = final_logits.sum(dim=-1)
    return final_scores.cpu().detach().numpy()

def topkSample(input, model, tokenizer, 
                num_samples=5,
                num_beams=1,
                max_output_length=30):
    tokenized = tokenizer(input, return_tensors="pt")
    out = model.generate(**tokenized,
                        do_sample=True,
                        num_return_sequences = num_samples,
                        num_beams = num_beams,
                        eos_token_id = tokenizer.eos_token_id,
                        pad_token_id = tokenizer.pad_token_id,
                        output_scores = True,
                        return_dict_in_generate=True,
                        max_length=max_output_length,)
    out_tokens = out.sequences
    out_str = tokenizer.batch_decode(out_tokens, skip_special_tokens=True)
    out_scores = getScores(out_tokens, out.scores, tokenizer.pad_token_id)
    
    pair_list = [(x[0], x[1]) for x in zip(out_str, out_scores)]
    sorted_pair_list = sorted(pair_list, key=lambda x:x[1], reverse=True)
    return sorted_pair_list

def greedyPredict(input, model, tokenizer):
    input_ids = tokenizer([input], return_tensors="pt").input_ids
    out_tokens = model.generate(input_ids)
    out_str = tokenizer.batch_decode(out_tokens, skip_special_tokens=True)
    return out_str[0]
    
def predict_tail(entity, relation):
    global model, tokenizer
    input = entity + "| " + relation
    out = topkSample(input, model, tokenizer, num_samples=5)
    out_dict = {}
    for k, v in out:
        out_dict[k] = np.exp(v).item()
    return out_dict

    
tokenizer = AutoTokenizer.from_pretrained("apoorvumang/kgt5-wikikg90mv2")
model = AutoModelForSeq2SeqLM.from_pretrained("apoorvumang/kgt5-base-wikikg90mv2")



ent_input = gradio.inputs.Textbox(lines=1, default="World War II")
rel_input = gradio.inputs.Textbox(lines=1, default="followed by")
output = gradio.outputs.Label()


iface = gr.Interface(fn=predict_tail, inputs=[ent_input, rel_input], outputs=output)
iface.launch()