import streamlit as st
from transformers import VisionEncoderDecoderModel, AutoFeatureExtractor, AutoTokenizer
import requests
from PIL import Image
import torch


CHECKPOINT = "g8a9/vit-geppetto-captioning"

@st.cache
def get_model():
    model = VisionEncoderDecoderModel.from_pretrained(CHECKPOINT)
    return model


feature_extractor = AutoFeatureExtractor.from_pretrained(CHECKPOINT)
tokenizer = AutoTokenizer.from_pretrained(CHECKPOINT)

st.title("Image Captioning with ViT & GePpeTto 🇮🇹")

st.sidebar.markdown("## Generation parameters")
max_length = st.sidebar.number_input("Max length", value=20, min_value=1)
no_repeat_ngram_size = st.sidebar.number_input("no repeat ngrams size", value=2, min_value=1)
num_return_sequences = st.sidebar.number_input("Generated sequences", value=3, min_value=1)

gen_mode = st.sidebar.selectbox("Generation mode", ["beam search", "sampling"])
if gen_mode == "beam search": 
    num_beams = st.sidebar.number_input("Beam size", value=5, min_value=1)
    early_stopping = st.sidebar.checkbox("Early stopping", value=True)
    gen_params = {
        "num_beams": num_beams,
        "early_stopping": early_stopping
    }
elif gen_mode == "sampling":
    do_sample = True
    top_k = st.sidebar.number_input("top_k", value=30, min_value=0)
    top_p = st.sidebar.number_input("top_p", value=0, min_value=0)  
    temperature = st.sidebar.number_input("temperature", value=0.7, min_value=0.0)
    gen_params = {
        "do_sample": do_sample,
        "top_k": top_k,
        "top_p": top_p,
        "temperature": temperature
    }

def generate_caption(url):
    image = Image.open(requests.get(url, stream=True).raw).convert("RGB")
    inputs = feature_extractor(image, return_tensors="pt")
    model = get_model()
    model.eval()
    generated_ids = model.generate(
        inputs["pixel_values"],
        max_length=20,
        no_repeat_ngram_size=2,
        num_return_sequences=3,
        **gen_params
    )
    captions = tokenizer.batch_decode(
        generated_ids,
        skip_special_tokens=True,
    )
    return captions[0]


url = st.text_input(
    "Insert your URL", "https://iheartcats.com/wp-content/uploads/2015/08/c84.jpg"
)

st.image(url)

if st.button("Run captioning"):
    with st.spinner("Processing image..."):
        caption = generate_caption(url)
        st.text(caption)