"""Moteur Definition des fonds perdus (bleeds)."""

from pypdf import PdfReader, PdfWriter
from .pdf_utils import get_page_size, mm_to_pt


def define_bleeds(input_path, output_path, bleed_top=0, bleed_bottom=0,
                  bleed_left=0, bleed_right=0):
    """Definir les zones de fond perdu en etendant le TrimBox/BleedBox.

    Les valeurs sont en millimetres.
    """
    bt = mm_to_pt(bleed_top)
    bb = mm_to_pt(bleed_bottom)
    bl = mm_to_pt(bleed_left)
    br = mm_to_pt(bleed_right)

    reader = PdfReader(input_path)
    writer = PdfWriter()

    for page in reader.pages:
        w, h = get_page_size(page)

        # Le TrimBox definit la taille finale apres coupe
        page.trimbox.lower_left = (bl, bb)
        page.trimbox.upper_right = (w - br, h - bt)

        # Le BleedBox inclut le fond perdu
        page.bleedbox.lower_left = (0, 0)
        page.bleedbox.upper_right = (w, h)

        writer.add_page(page)

    with open(output_path, "wb") as f:
        writer.write(f)
    return output_path