app.py

import os
import qrcode
from PIL import Image, ImageDraw, ImageFont, ImageOps
import streamlit as st
import io

st.set_page_config(page_title="QR Code Generator", layout="centered")

# 1. Custom CSS Injector to create the Application Border Frame Layout
st.markdown("""
    <style>
    /* Wraps the entire content block inside a structured business card frame */
    .block-container {
        border: 2px solid #E0E4EC;
        border-radius: 12px;
        padding: 40px !important;
        background-color: #FFFFFF;
        box-shadow: 0px 4px 12px rgba(0, 0, 0, 0.03);
        margin-top: 30px;
        margin-bottom: 30px;
    }
    /* Adds a clean layout border block styling around the main container */
    .main .block-container {
        max-width: 700px !important;
    }
    </style>
""", unsafe_allow_html=True)

# 2. Application Header
st.title("📊 QR Generator")
st.write("Generate high-resolution, branded QR codes.")

# 3. Streamlit Interactive Inputs with Guide Instructions Placed Below
target_url = st.text_input("👉 ENTER URL:")
st.caption("💡 *Example to enter: https://github.com or your live deployed app link*")

display_name = st.text_input("👤 ENTER YOUR NAME:")
st.caption("💡 *Example to enter: Appala Srinivas Tanakala*")

display_title = st.text_input("💼 ENTER YOUR TITLE:")
st.caption("💡 *Example to enter: Data Scientist & AI / Fintech Leader*")

# 4. Linux System Font Routing Fix
font_path = None
possible_paths = [
    "/usr/share/fonts/truetype/liberation/LiberationSans-Bold.ttf",
    "/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf",
    "/usr/share/fonts/truetype/ubuntu/Ubuntu-B.ttf"
]

for path in possible_paths:
    if os.path.exists(path):
        font_path = path
        break

# 5. Action button validation sequence
if st.button("Generate QR Code") or target_url:
    if target_url.strip():
        # Configure high-resolution QR matrix
        qr = qrcode.QRCode(
            version=4,  
            error_correction=qrcode.constants.ERROR_CORRECT_M, 
            box_size=14,  
            border=4,
        )
        qr.add_data(target_url.strip())
        qr.make(fit=True)

        # Convert to RGB color canvas
        qr_img = qr.make_image(fill_color="black", back_color="white").convert('RGB')
        qr_width, qr_height = qr_img.size

        # Set up dynamic white canvas buffer space for clear text spacing
        extra_bottom_space = 110
        new_width = qr_width
        new_height = qr_height + extra_bottom_space

        final_img = Image.new("RGB", (new_width, new_height), "white")
        final_img.paste(qr_img, (0, 0))
        draw = ImageDraw.Draw(final_img)

        # Initialize the explicit sharp fonts with clean system fallback structures
        if font_path:
            name_font = ImageFont.truetype(font_path, 26)  # Bold and readable
            title_font = ImageFont.truetype(font_path, 18)  # Clean secondary text
        else:
            name_font = title_font = ImageFont.load_default()

        # Helper function to auto-center text layers accurately
        def draw_centered_text(text_to_print, y_position, font_style, text_color="black"):
            bbox = draw.textbbox((0, 0), text_to_print, font=font_style)
            text_w = bbox[2] - bbox[0]
            x_position = (new_width - text_w) // 2
            draw.text((x_position, y_position), text_to_print, fill=text_color, font=font_style)

        # Print typography fields on bottom white canvas
        print_name = display_name.strip() if display_name.strip() else "Appala Srinivas Tanakala"
        print_title = display_title.strip() if display_title.strip() else "Data Scientist"

        draw_centered_text(print_name, qr_height + 15, name_font, text_color="black")
        draw_centered_text(print_title, qr_height + 55, title_font, text_color="#555555")

        # Add an inner frame border around the image asset file itself
        final_img = ImageOps.expand(final_img, border=3, fill="#333333")

        # 6. Display the image inside your new app frame layout
        st.write("---")
        st.image(final_img, caption="Preview of your framed QR badge", use_container_width=False, width=350)

        # Convert the framed PIL image array into downloadable bytes stream
        img_buffer = io.BytesIO()
        final_img.save(img_buffer, format="PNG")
        byte_data = img_buffer.getvalue()

        # Download button forcing filename explicitly to generated_qr
        st.download_button(
            label="⬇️ Download Framed QR Code",
            data=byte_data,
            file_name="generated_qr.png",
            mime="image/png"
        )
    else:
        st.error("❌ Error: The URL input field cannot be left blank.")