"""Moteur Masquage (Masking Tape) — rectangles blancs."""

from pypdf import PdfReader, PdfWriter
from reportlab.pdfgen import canvas
from .pdf_utils import get_page_size
import io


def apply_masking(input_path, output_path, rectangles, apply_to="all"):
    """Appliquer des rectangles blancs de masquage.

    rectangles: liste de dicts {"x": pt, "y": pt, "width": pt, "height": pt}
    apply_to: "all", "even", "odd", ou un numero de page (1-based)
    """
    reader = PdfReader(input_path)
    writer = PdfWriter()

    for i, page in enumerate(reader.pages):
        page_num = i + 1

        should_apply = False
        if apply_to == "all":
            should_apply = True
        elif apply_to == "even":
            should_apply = page_num % 2 == 0
        elif apply_to == "odd":
            should_apply = page_num % 2 != 0
        elif isinstance(apply_to, int):
            should_apply = page_num == apply_to

        if should_apply and rectangles:
            w, h = get_page_size(page)
            packet = io.BytesIO()
            c = canvas.Canvas(packet, pagesize=(w, h))
            c.setFillColorRGB(1, 1, 1)
            c.setStrokeColorRGB(1, 1, 1)

            for rect in rectangles:
                c.rect(rect["x"], rect["y"], rect["width"], rect["height"],
                       fill=1, stroke=0)

            c.showPage()
            c.save()
            packet.seek(0)

            overlay_reader = PdfReader(packet)
            page.merge_page(overlay_reader.pages[0])

        writer.add_page(page)

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