#!/usr/bin/env python3

import sys
from pathlib import Path
from PIL import Image
from reportlab.lib.pagesizes import A4
from reportlab.pdfgen import canvas
from reportlab.lib.units import mm

def image_to_pdf(image_path, output_pdf=None):
    image_path = Path(image_path)

    if not image_path.exists():
        raise FileNotFoundError(f"File not found: {image_path}")

    if output_pdf is None:
        output_pdf = image_path.with_suffix(".pdf")

    img = Image.open(image_path)
    img_width, img_height = img.size

    # A4 page size (points)
    page_width, page_height = A4

    # Convert pixels to points assuming 300 DPI
    dpi = img.info.get("dpi", (300, 300))[0]
    img_width_pt = img_width * 72 / dpi
    img_height_pt = img_height * 72 / dpi

    # Scale to fit page while preserving aspect ratio
    scale = min(page_width / img_width_pt, page_height / img_height_pt)
    draw_width = img_width_pt * scale
    draw_height = img_height_pt * scale

    x = (page_width - draw_width) / 2
    y = (page_height - draw_height) / 2

    c = canvas.Canvas(str(output_pdf), pagesize=A4)
    c.drawImage(str(image_path), x, y, draw_width, draw_height)
    c.showPage()
    c.save()

    print(f"✔ PDF created: {output_pdf}")

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: cover_to_pdf.py <image.jpg/png> [output.pdf]")
        sys.exit(1)

    image = sys.argv[1]
    output = sys.argv[2] if len(sys.argv) > 2 else None
    image_to_pdf(image, output)