model.py

import streamlit as st
from huggingface_hub import hf_hub_url, cached_download
from PIL import Image
import os
import json
import glob
import random
from typing import Any, Dict, List
import torch
import torchvision

import wordsegment as ws

from virtex.config import Config
from virtex.factories import TokenizerFactory, PretrainingModelFactory, ImageTransformsFactory
from virtex.utils.checkpointing import CheckpointManager

CONFIG_PATH = "config.yaml"
MODEL_PATH = "checkpoint_last5.pth"
VALID_SUBREDDITS_PATH = "subreddit_list.json"
SAMPLES_PATH = "./samples/*.jpg"

class ImageLoader():
    def __init__(self):
        self.image_transform = torchvision.transforms.Compose([
                               torchvision.transforms.ToTensor(),
                               torchvision.transforms.Resize(256),
                               torchvision.transforms.CenterCrop(224),
                               torchvision.transforms.Normalize((.485, .456, .406), (.229, .224, .225))])
        self.show_size=500
        
    def load(self, im_path):
        im = torch.FloatTensor(self.image_transform(Image.open(im_path))).unsqueeze(0)
        return {"image": im}
    
    def raw_load(self, im_path):
        im = torch.FloatTensor(Image.open(im_path))
        return {"image": im}
    
    def transform(self, image):
        im = torch.FloatTensor(self.image_transform(image)).unsqueeze(0)
        return {"image": im}
    
    def text_transform(self, text):
        # at present just lowercasing:
        return text.lower()
    
    def show_resize(self, image):
        # ugh we need to do this manually cuz this is pytorch==0.8 not 1.9 lol
        image = torchvision.transforms.functional.to_tensor(image)
        x,y = image.shape[-2:]
        ratio = float(self.show_size/max((x,y)))
        image = torchvision.transforms.functional.resize(image, [int(x * ratio), int(y * ratio)])
        return torchvision.transforms.functional.to_pil_image(image)
    

class VirTexModel():
    def __init__(self):
        self.config = Config(CONFIG_PATH)
        ws.load()
        self.device = 'cpu'
        self.tokenizer = TokenizerFactory.from_config(self.config)
        self.model = PretrainingModelFactory.from_config(self.config).to(self.device)
        CheckpointManager(model=self.model).load(MODEL_PATH)
        self.model.eval()
        self.valid_subs = json.load(open(VALID_SUBREDDITS_PATH))
        
    def predict(self, image_dict, sub_prompt = None, prompt = ""):
        if sub_prompt is None:
            subreddit_tokens = torch.tensor([self.model.sos_index], device=self.device).long()
        else:
            subreddit_tokens = " ".join(ws.segment(ws.clean(sub_prompt)))
            subreddit_tokens = (
                [self.model.sos_index] + 
                self.tokenizer.encode(subreddit_tokens) +
                [self.tokenizer.token_to_id("[SEP]")]
                               )
            subreddit_tokens = torch.tensor(subreddit_tokens, device=self.device).long()
            
        if prompt is not "":
            # at present prompts without subreddits will break without this change
            # TODO FIX
            cap_tokens = self.tokenizer.encode(prompt)
            cap_tokens = torch.tensor(cap_tokens, device=self.device).long()
            subreddit_tokens = subreddit_tokens if sub_prompt is not None else torch.tensor(
                (
                    [self.model.sos_index] + 
                    self.tokenizer.encode("pics") + 
                    [self.tokenizer.token_to_id("[SEP]")]
                ), device = self.device).long()

            subreddit_tokens = torch.cat(
                [
                    subreddit_tokens,
                    torch.tensor([self.tokenizer.token_to_id("[SEP]")], device=self.device).long(),
                    cap_tokens
                ])
            
            
        predictions: List[Dict[str, Any]] = []
        
        is_valid_subreddit = False
        subreddit, rest_of_caption = "", ""
        image_dict["decode_prompt"] = subreddit_tokens
        while not is_valid_subreddit:
            
            with torch.no_grad():
                caption = self.model(image_dict)["predictions"][0].tolist()
                
            if self.tokenizer.token_to_id("[SEP]") in caption:
                sep_index = caption.index(self.tokenizer.token_to_id("[SEP]"))
                caption[sep_index] = self.tokenizer.token_to_id("://")
            
            caption = self.tokenizer.decode(caption)
            
            if "://" in caption:
                subreddit, rest_of_caption = caption.split("://")
                subreddit = "".join(subreddit.split())
                rest_of_caption = rest_of_caption.strip()
            else:
                subreddit, rest_of_caption = "", caption
            
            is_valid_subreddit = subreddit in self.valid_subs
            
            
        return subreddit, rest_of_caption

def download_files():
    #download model files
    download_files = [CONFIG_PATH, MODEL_PATH, VALID_SUBREDDITS_PATH]
    for f in download_files:
        fp = cached_download(hf_hub_url("zamborg/redcaps", filename=f))
        os.system(f"cp {fp} ./{f}")

def get_samples():
    return glob.glob(SAMPLES_PATH)

def get_rand_idx(samples):
    return random.randint(0,len(samples)-1)

@st.cache(allow_output_mutation=True) # allow mutation to update nucleus size
def create_objects():
    sample_images = get_samples()
    virtexModel = VirTexModel()
    imageLoader = ImageLoader()
    valid_subs = json.load(open(VALID_SUBREDDITS_PATH))
    valid_subs.insert(0, None)
    return virtexModel, imageLoader, sample_images, valid_subs