#!/usr/bin/env -S uv run --script
# /// script
# requires-python = ">=3.11"
# dependencies = [
#   "reportlab>=4.0",
#   "python-barcode>=0.15",
# ]
# ///
"""Generate a Paperless-ngx separator page (PATCHT Code-128 barcode).

Run: ./generate_separator.py [out.pdf]
Default output: separator-patchT.pdf next to this script.

m prints the resulting PDF and lays one sheet between each document
in a multi-letter scan stack. Paperless-ngx (with
PAPERLESS_CONSUMER_ENABLE_BARCODES=true) detects the barcode and
splits the consumed PDF into separate documents.
"""

import sys
from pathlib import Path

from barcode import Code128
from barcode.writer import ImageWriter
from reportlab.lib.pagesizes import A4
from reportlab.lib.units import cm
from reportlab.pdfgen import canvas

SEPARATOR_STRING = "PATCHT"


def main(out_path: Path) -> None:
    page_w, page_h = A4

    # Render barcode to a temporary PNG (reportlab needs an image source).
    tmp_png = out_path.with_suffix(".tmp")
    barcode = Code128(SEPARATOR_STRING, writer=ImageWriter())
    barcode_path = barcode.save(
        str(tmp_png),
        options={
            "module_width": 0.6,   # mm per bar — bigger = easier OCR detection
            "module_height": 30.0, # mm tall
            "font_size": 14,
            "text_distance": 5,
            "quiet_zone": 8,
            "write_text": True,
        },
    )

    c = canvas.Canvas(str(out_path), pagesize=A4)

    # Header
    c.setFont("Helvetica-Bold", 36)
    c.drawCentredString(page_w / 2, page_h - 4 * cm, "SEPARATOR")
    c.setFont("Helvetica", 14)
    c.drawCentredString(page_w / 2, page_h - 5 * cm,
                        "Zwischen zwei Dokumente legen — Paperless splittet hier.")

    # Big crosshair for easy alignment when scanning
    c.setLineWidth(1)
    c.setStrokeGray(0.7)
    c.line(page_w / 2 - 4 * cm, page_h - 6 * cm, page_w / 2 + 4 * cm, page_h - 6 * cm)

    # Barcode — large, centred
    img_w, img_h = 14 * cm, 5 * cm
    c.drawImage(
        barcode_path,
        (page_w - img_w) / 2,
        (page_h - img_h) / 2 - 1 * cm,
        width=img_w,
        height=img_h,
        preserveAspectRatio=True,
        mask="auto",
    )

    # Footer
    c.setFont("Helvetica", 10)
    c.setFillGray(0.3)
    c.drawCentredString(page_w / 2, 4 * cm,
                        f"Code-128 · {SEPARATOR_STRING} · Paperless-ngx Barcode-Splitter")
    c.drawCentredString(page_w / 2, 3 * cm,
                        "Detection: PAPERLESS_CONSUMER_ENABLE_BARCODES=true")
    c.drawCentredString(page_w / 2, 2.4 * cm,
                        "Generator: infra/paperless/generate_separator.py (mDMS)")

    c.showPage()
    c.save()

    Path(barcode_path).unlink(missing_ok=True)
    print(f"wrote {out_path}")


if __name__ == "__main__":
    out = Path(sys.argv[1]) if len(sys.argv) > 1 else Path(__file__).parent / "separator-patchT.pdf"
    main(out)