app.py

import os
import time
import streamlit as st
from PIL import Image
from io import BytesIO
from huggingface_hub import InferenceApi, login
from transformers import pipeline
from gtts import gTTS
import tempfile

# —––––––– Page Config —–––––––
st.set_page_config(page_title="Magic Story Generator (CPU)", layout="centered")
st.title("📖✨ Turn Images into Children's Stories (CPU)")

# —––––––– Clients (cached) —–––––––
@st.cache_resource(show_spinner=False)
def load_clients():
    hf_token = st.secrets["HF_TOKEN"]

    # Authenticate once so pipelines use your token automatically
    os.environ["HUGGINGFACEHUB_API_TOKEN"] = hf_token
    login(hf_token)

    # Pin cache locally to avoid re-downloads
    cache_dir = "./hf_cache"
    os.makedirs(cache_dir, exist_ok=True)
    os.environ["TRANSFORMERS_CACHE"] = cache_dir

    # 1) BLIP-based image captioning client
    caption_client = InferenceApi(
        repo_id="Salesforce/blip-image-captioning-base",
        token=hf_token
    )

    # 2) Text-generation pipeline forced onto CPU
    t0 = time.time()
    story_generator = pipeline(
        task="text-generation",
        model="deepseek-ai/DeepSeek-R1-Distill-Qwen-1.5B",
        tokenizer="deepseek-ai/DeepSeek-R1-Distill-Qwen-1.5B",
        device=-1,             # CPU only
        cache_dir=cache_dir
    )
    st.text(f"✅ Story model loaded in {time.time() - t0:.1f}s (cached thereafter)")

    return caption_client, story_generator

caption_client, story_generator = load_clients()


# —––––––– Helper: Generate Caption —–––––––
def generate_caption(img: Image.Image) -> str:
    buf = BytesIO()
    img.save(buf, format="JPEG")
    try:
        resp = caption_client(data=buf.getvalue())
        if isinstance(resp, list) and resp:
            return resp[0].get("generated_text", "").strip()
    except Exception as e:
        st.error(f"Caption generation error: {e}")
    return ""


# —––––––– Helper: Generate Story via pipeline —–––––––
def generate_story(caption: str) -> str:
    prompt = f"""
You are a creative children’s-story author.
Below is the description of an image:
“{caption}”

Write a coherent, 50 to 100-word story that:
1. Introduces the main character from the image.
2. Shows a simple problem or discovery.
3. Resolves it in a happy ending.
4. Uses clear language for ages 3–8.
5. Keeps each sentence under 20 words.
Story:
"""
    t0 = time.time()
    outputs = story_generator(
        prompt,
        max_new_tokens=120,
        temperature=0.7,
        top_p=0.9,
        repetition_penalty=1.1,
        no_repeat_ngram_size=3,
        do_sample=True
    )
    gen_time = time.time() - t0
    st.text(f"⏱ Generated in {gen_time:.1f}s on CPU")

    text = outputs[0]["generated_text"].strip()
    # Remove the echoed prompt portion
    if text.startswith(prompt):
        text = text[len(prompt):].strip()
    # Enforce max 100 words
    words = text.split()
    if len(words) > 100:
        text = " ".join(words[:100])
        if not text.endswith("."):
            text += "."
    return text


# —––––––– Main App Flow —–––––––
uploaded = st.file_uploader("Upload an image:", type=["jpg", "png", "jpeg"])
if uploaded:
    img = Image.open(uploaded).convert("RGB")
    if max(img.size) > 2048:
        img.thumbnail((2048, 2048))
    st.image(img, use_container_width=True)

    with st.spinner("🔍 Generating caption..."):
        caption = generate_caption(img)
    if not caption:
        st.error("😢 Couldn't understand this image. Try another one!")
        st.stop()
    st.success(f"**Caption:** {caption}")

    with st.spinner("📝 Writing magical story..."):
        story = generate_story(caption)

    st.subheader("📚 Your Magical Story")
    st.write(story)

    with st.spinner("🔊 Converting to audio..."):
        try:
            tts = gTTS(text=story, lang="en", slow=False)
            with tempfile.NamedTemporaryFile(delete=False, suffix=".mp3") as fp:
                tts.save(fp.name)
                st.audio(fp.name, format="audio/mp3")
        except Exception as e:
            st.warning(f"⚠️ TTS failed: {e}")

# Footer
st.markdown("---\n*Made with ❤️ by your friendly story wizard*")