# app.py (streamlined and modularized for clarity and maintainability)
import streamlit as st
import os
import glob
import base64
import pandas as pd
import fitz
from PIL import Image
from io import BytesIO
from datetime import datetime
from reportlab.pdfgen import canvas
from reportlab.lib.utils import ImageReader
from markdown2 import markdown

# --- Config ---
st.set_page_config(
    page_title="Vision & Layout Titans 🚀",
    page_icon="🤖",
    layout="wide"
)

# --- Helper Functions ---
def get_files(exts):
    files = []
    for ext in exts:
        files.extend(glob.glob(f'*.{ext}'))
    return sorted([f for f in files if f.lower() != "readme.md"])

def image_to_pdf(images, md_files):
    buffer = BytesIO()
    c = canvas.Canvas(buffer)
    
    for img_path in images:
        img = Image.open(img_path)
        width, height = img.size
        c.setPageSize((width, height))
        c.drawImage(ImageReader(img), 0, 0, width, height)
        c.showPage()

    for md_path in md_files:
        with open(md_path, 'r', encoding='utf-8') as f:
            md_content = f.read()
            html = markdown(md_content)
        c.setPageSize((595, 842))  # A4 size
        c.setFont("Helvetica", 10)
        c.drawString(50, 800, md_content[:1000])  # Simplified render
        c.showPage()

    c.save()
    buffer.seek(0)
    return buffer

def render_pdf_gallery(pdf_files):
    for pdf_file in pdf_files:
        doc = fitz.open(pdf_file)
        page = doc.load_page(0)
        pix = page.get_pixmap(matrix=fitz.Matrix(0.5, 0.5))
        img = Image.frombytes("RGB", [pix.width, pix.height], pix.samples)
        st.image(img, caption=os.path.basename(pdf_file))

# --- Sidebar Management ---
st.sidebar.header("Content Management")

image_files = get_files(['png', 'jpg', 'jpeg'])
pdf_files = get_files(['pdf'])
md_files = get_files(['md'])

selected_images = st.sidebar.multiselect("Select Images", image_files)
selected_md_files = st.sidebar.multiselect("Select Markdown Files", md_files)

# PDF Gallery
if st.sidebar.checkbox("Show PDF Gallery"):
    render_pdf_gallery(pdf_files)

# PDF Generation with rearrangement
st.sidebar.subheader("Reorder Content for PDF")
content_df = pd.DataFrame({
    "Content": selected_images + selected_md_files,
    "Type": ["Image"] * len(selected_images) + ["Markdown"] * len(selected_md_files),
    "Order": range(len(selected_images) + len(selected_md_files))
})

edited_df = st.sidebar.data_editor(content_df, use_container_width=True)
sorted_contents = edited_df.sort_values('Order')['Content'].tolist()

if st.sidebar.button("Generate PDF"):
    sorted_images = [item for item in sorted_contents if item in selected_images]
    sorted_md_files = [item for item in sorted_contents if item in selected_md_files]
    pdf_buffer = image_to_pdf(sorted_images, sorted_md_files)
    st.sidebar.download_button("Download PDF", pdf_buffer, "output.pdf")

# Deletion
st.sidebar.subheader("Delete Files")
file_to_delete = st.sidebar.selectbox("Select file to delete", image_files + pdf_files + md_files)
if st.sidebar.button("Delete Selected File"):
    os.remove(file_to_delete)
    st.sidebar.success(f"Deleted {file_to_delete}")
    st.rerun()

# --- Main Page ---
st.title("Vision & Layout Titans 🚀")
st.markdown("### Manage, View, and Export Your Files Easily!")

# Display selected images
st.subheader("Selected Images")
for img_path in selected_images:
    img = Image.open(img_path)
    st.image(img, caption=os.path.basename(img_path))

# Display selected markdown
st.subheader("Selected Markdown")
for md_path in selected_md_files:
    with open(md_path, 'r', encoding='utf-8') as f:
        md_content = f.read()
    st.markdown(md_content[:500] + '...')