import streamlit as st
from PIL import Image
import io
import os

# Set page config
st.set_page_config(
    page_title="Image Compressor",
    page_icon="🗜️",
    layout="wide"
)

def get_file_size(image_bytes):
    """Get file size in bytes"""
    return len(image_bytes)

def format_size(size_bytes):
    """Format bytes to human readable format"""
    if size_bytes < 1024:
        return f"{size_bytes} B"
    elif size_bytes < 1024 * 1024:
        return f"{size_bytes / 1024:.1f} KB"
    else:
        return f"{size_bytes / (1024 * 1024):.1f} MB"

def compress_image(image, quality):
    """Compress image with specified quality"""
    # Convert to RGB if necessary
    if image.mode != 'RGB':
        image = image.convert('RGB')
    
    # Save to bytes with specified quality
    output = io.BytesIO()
    image.save(output, format='JPEG', quality=quality, optimize=True)
    compressed_bytes = output.getvalue()
    
    return compressed_bytes

def main():
    st.title("🗜️ Image Compressor")
    st.markdown("Upload an image and adjust the compression quality to reduce file size.")
    
    # File uploader
    uploaded_file = st.file_uploader(
        "Choose an image file",
        type=['png', 'jpg', 'jpeg', 'gif', 'bmp', 'webp'],
        help="Upload an image to compress"
    )
    
    if uploaded_file is not None:
        # Display original image
        col1, col2 = st.columns(2)
        
        with col1:
            st.subheader("Original Image")
            original_image = Image.open(uploaded_file)
            st.image(original_image, caption="Original", use_column_width=True)
            
            # Get original file size
            original_bytes = uploaded_file.getvalue()
            original_size = get_file_size(original_bytes)
            st.metric("Original Size", format_size(original_size))
        
        with col2:
            st.subheader("Compressed Image")
            
            # Quality slider
            quality = st.slider(
                "Compression Quality",
                min_value=1,
                max_value=100,
                value=85,
                help="Lower values = smaller file size, higher compression"
            )
            
            # Compress image
            compressed_bytes = compress_image(original_image, quality)
            compressed_size = get_file_size(compressed_bytes)
            
            # Calculate savings
            savings = original_size - compressed_size
            savings_percent = (savings / original_size) * 100 if original_size > 0 else 0
            
            # Display compressed image
            compressed_image = Image.open(io.BytesIO(compressed_bytes))
            st.image(compressed_image, caption=f"Compressed (Quality: {quality})", use_column_width=True)
            
            # Display metrics
            col_metric1, col_metric2, col_metric3 = st.columns(3)
            with col_metric1:
                st.metric("Compressed Size", format_size(compressed_size))
            with col_metric2:
                st.metric("Size Reduction", format_size(savings))
            with col_metric3:
                st.metric("Compression Ratio", f"{savings_percent:.1f}%")
        
        # Download button
        st.subheader("Download Compressed Image")
        
        # Get file extension
        file_extension = os.path.splitext(uploaded_file.name)[1].lower()
        if file_extension in ['.png', '.gif', '.bmp']:
            output_format = 'JPEG'
        else:
            output_format = 'JPEG'
        
        # Create download filename
        base_name = os.path.splitext(uploaded_file.name)[0]
        download_filename = f"{base_name}_compressed.jpg"
        
        st.download_button(
            label="Download Compressed Image",
            data=compressed_bytes,
            file_name=download_filename,
            mime="image/jpeg"
        )
        
        # Additional info
        with st.expander("Compression Details"):
            st.write(f"**Original format:** {original_image.format}")
            st.write(f"**Original mode:** {original_image.mode}")
            st.write(f"**Original dimensions:** {original_image.size[0]} x {original_image.size[1]}")
            st.write(f"**Compressed format:** JPEG")
            st.write(f"**Quality setting:** {quality}")
            st.write(f"**Size reduction:** {format_size(savings)} ({savings_percent:.1f}%)")
    
    else:
        st.info("👆 Please upload an image file to get started!")
        
        # Show example
        st.markdown("### How to use:")
        st.markdown("1. **Upload an image** using the file uploader above")
        st.markdown("2. **Adjust the quality slider** to control compression")
        st.markdown("3. **Compare** the original and compressed images")
        st.markdown("4. **Download** the compressed image")

if __name__ == "__main__":
    main()