app.py

# ======================================
# Package Import
# ======================================

import streamlit as st
from PIL import Image
import time
from transformers import pipeline
from typing import Tuple
from datasets import load_dataset
import soundfile as sf
import torch

# ======================================
# Basic Initialization
# ======================================

# Initialize image captioning pipeline with pretrained model
_image_caption_pipeline = pipeline(
    task="image-to-text",
    model="cnmoro/tiny-image-captioning"
)

# Global model configuration constants
_text_generation_pipeline = pipeline("text-generation", model="Qwen/Qwen1.5-0.5B",max_new_tokens=100)

# Initialize TTS components once to avoid reloading
_SPEECH_PIPELINE = pipeline("text-to-speech", model="microsoft/speecht5_tts")
_EMBEDDINGS_DATASET = load_dataset("Matthijs/cmu-arctic-xvectors", split="validation")
_DEFAULT_SPEAKER_EMBEDDING = torch.tensor(_EMBEDDINGS_DATASET[7306]["xvector"]).unsqueeze(0)

# ======================================
# Function settings
# ======================================

def generate_image_caption(input_image):
    """
    Generate a textual description for an input image using a pretrained model.
    
    Args:
        input_image (Union[PIL.Image.Image, str]): Image to process. Can be either:
            - A PIL Image object
            - A string containing a filesystem path to an image file
    
    Returns:
        str: Generated caption text in natural language
        
    Example:
        >>> from PIL import Image
        >>> img = Image.open("photo.jpg")
        >>> caption = generate_image_caption(img)
        >>> print(f"Caption: {caption}")
    """
    # Process image through the captioning pipeline
    inference_results = _image_caption_pipeline(input_image)
    
    # Extract text from the first (and only) result dictionary
    caption_text = inference_results[0]['generated_text']
    
    return caption_text

def generate_story_content(system_prompt: str, user_prompt: str) -> str:
    """
    Generates a children's story based on provided system and user prompts.
    
    Args:
        system_prompt: Defines the assistant's role and writing constraints
        user_prompt: Describes the story scenario and specific elements to include
        
    Returns:
        Generated story text without any thinking process metadata
        
    Raises:
        RuntimeError: If text generation fails at any stage
    
    Example:
        >>> story = generate_story_content(
        ...     "You are a helpful children's author...",
        ...     "Kids playing with dogs in a sunny meadow..."
        ... )
    """
    try:
        # Prepare chat message structure
        conversation_history = [
            {"role": "system", "content": system_prompt},
            {"role": "user", "content": user_prompt},
        ]

        # Generate the story
        story=_text_generation_pipeline(conversation_history)

        # Extract the stroy result
        stroy_result=story[0]["generated_text"][2]["content"]
        
        # Process and clean output
        return stroy_result
        
    except Exception as error:
        raise RuntimeError(f"Story generation failed: {str(error)}") from error

def generate_audio_from_story(story_text: str, output_path: str = "output.wav") -> str:
    """
    Convert text story to speech audio file using text-to-speech synthesis.
    
    Args:
        story_text: Input story text to synthesize
        output_path: Path to save generated audio (default: 'output.wav')
        
    Returns:
        Path to generated audio file
        
    Raises:
        ValueError: For empty/invalid input text
        RuntimeError: If audio generation fails
        
    Example:
        >>> generate_audio_from_story("Children playing in the park", "story_audio.wav")
        'story_audio.wav'
    """
    # Validate input text
    if not isinstance(story_text, str) or not story_text.strip():
        raise ValueError("Input story text must be a non-empty string")
    
    try:
        # Generate speech with default speaker profile
        speech_output = _SPEECH_PIPELINE(
            story_text,
            forward_params={"speaker_embeddings": _DEFAULT_SPEAKER_EMBEDDING}
        )
        
        # Save audio to WAV file
        sf.write(
            output_path,
            speech_output["audio"],
            samplerate=speech_output["sampling_rate"]
        )
        
        return output_path
        
    except Exception as error:
        raise RuntimeError(f"Audio synthesis failed: {str(error)}") from error


# ======================================
# Page Configuration & Custom Styling
# ======================================
st.set_page_config(
    page_title="Magic Story Generator",
    page_icon="🧚",
    layout="centered",
    initial_sidebar_state="collapsed"
)

# Custom CSS styling for child-friendly interface
st.markdown("""
<style>   
    /* Prompt buttons styling */
    .prompt-btn {
        background: #4CAF50 !important;
        border-radius: 15px !important;
        padding: 15px 30px !important;
        font-size: 1.1rem !important;
        margin: 10px;
    }
    
    /* Story container styling */
    .story-container {
        background: #FFF3E0;
        border-radius: 20px;
        padding: 25px;
        margin: 20px 0;
        box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    }
    /* Image caption styling */
    .image-caption {
        border-left: 4px solid #4CAF50;
        padding-left: 1rem;
        font-size: 1.1rem;
        color: #2c3e50;
        margin: 1.5rem 0;
    }
    
    /* Progress spinner styling */
    .stSpinner > div {
        font-size: 1.2rem !important;
        color: #9C27B0 !important;
    }
</style>
""", unsafe_allow_html=True)

# ======================================
# Main Application Interface
# ======================================
st.title("🧚 Welcome to Magic Story Maker!")

# File upload section
with st.container():
    st.subheader("Step 1: Upload Your Picture")
    uploaded_image = st.file_uploader("Choose an image...", 
                                    type=["png", "jpg", "jpeg"],
                                    label_visibility="collapsed")

# Initialize session state for confirmation status
if 'confirmed' not in st.session_state:
    st.session_state.confirmed = False

# Main processing flow
if uploaded_image is not None:
    # Display uploaded image
    with st.spinner("✨ Magical image processing..."):
        image = Image.open(uploaded_image)
        st.image(image, caption="Your Magical Image", use_column_width=True)

    # Prompt selection section
    with st.container():
        st.subheader("Step 2: Choose Story Style")
        
        # Create three columns for prompt buttons
        col1, col2, col3 = st.columns(3)
        with col1:
            if st.button("📚 Learning Story", 
                        help="Generate educational story with life lessons",
                        key="edu_btn"):
                st.session_state.selected_prompt = "educational"
                st.session_state.confirmed = False
        with col2:
            if st.button("🌠 Fantasy Adventure", 
                        help="Create magical adventure story",
                        key="fantasy_btn"):
                st.session_state.selected_prompt = "adventure"
                st.session_state.confirmed = False
        with col3:
            if st.button("🐻 Animal Friends", 
                        help="Make story about friendly animals",
                        key="animal_btn"):
                st.session_state.selected_prompt = "animal"
                st.session_state.confirmed = False

    # Add confirmation button
    with st.container():
        st.subheader("Step 3: Confirm Selection")
        if st.button("🔮 Start Magic Creation!", 
                   help="Click to generate story after choosing style",
                   type="primary"):
            st.session_state.confirmed = True

    # Only show generation when confirmed
    if st.session_state.get('confirmed', False):
        # Generate image caption with loading state
        with st.spinner("🔍 Analyzing image and generating description..."):
            image_caption = generate_image_caption(image)
            
            # Display caption results using CSS class
            st.subheader("📝 Image Understanding")
            st.markdown(f'<div class="story-container image-caption">{image_caption}</div>', 
                      unsafe_allow_html=True)
            st.write("")  # Add spacing

        # Define prompt templates
        PROMPT_TEMPLATES = {
            "educational": {
                "system": "You are a children's educator. Create a simple 100-word story that teaches basic life skills or moral lessons.",
                "icon": "📚"
            },
            "adventure": {
                "system": "You are a fantasy writer. Create a 100-word magical adventure story suitable for children.",
                "icon": "🌠"
            },
            "animal": {
                "system": "You are an animal expert. Create a 100-word story about friendly animals learning together.",
                "icon": "🐻"
            }
        }

        # Safe access with default fallback
        selected_prompt = st.session_state.get("selected_prompt", "educational")
        
        # Story generation section
        with st.spinner(f"{PROMPT_TEMPLATES[selected_prompt]['icon']} Creating your story..."):
            # Generate story content using the caption
            selected_template = PROMPT_TEMPLATES[selected_prompt]
            story_text = generate_story_content(
                system_prompt=selected_template["system"],
                user_prompt=image_caption
            )
            
            # Display formatted story
            st.subheader("✨ Your Magical Story")
            st.markdown(f'<div class="story-container">{story_text}</div>', 
                      unsafe_allow_html=True)

        # Audio generation section
        with st.spinner("🔮 Preparing story narration..."):
            audio_file = generate_audio_from_story(story_text, "story_audio.wav")
            st.subheader("🎧 Listen to Your Story")
            st.audio(audio_file)
    else:
        # Show waiting message
        st.info("ℹ️ Please select a story style and click the confirmation button to continue")

# Help section
st.markdown("---")
st.subheader("🌟 How to Use:")
st.info("""
1. Upload any picture (animals, nature, or people work best!)
2. Choose your favorite story style
3. Click the confirmation button
4. Wait for image analysis to complete
5. Enjoy your personalized story and audio!
""")