"""Moteur ajout de contenu (texte, image) sur les pages."""

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


def add_text_to_pages(input_path, output_path, text, font_name="Helvetica",
                       font_size=12, color=(0, 0, 0), x=0, y=0,
                       apply_to="all", current_page=0):
    """Ajouter du texte sur les pages."""
    reader = PdfReader(input_path)
    writer = PdfWriter()

    for i, page in enumerate(reader.pages):
        if _should_apply(i, apply_to, current_page):
            w, h = get_page_size(page)
            packet = io.BytesIO()
            c = canvas.Canvas(packet, pagesize=(w, h))
            c.setFont(font_name, font_size)
            c.setFillColorRGB(*color)

            # Multi-ligne
            lines = text.split("\n")
            line_height = font_size * 1.3
            for j, line in enumerate(lines):
                c.drawString(x, y - j * line_height, line)

            c.showPage()
            c.save()
            packet.seek(0)
            overlay = PdfReader(packet)
            page.merge_page(overlay.pages[0])

        writer.add_page(page)

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


def add_image_to_pages(input_path, output_path, image_path, x=0, y=0,
                        width=100, height=None, apply_to="all", current_page=0):
    """Ajouter une image sur les pages."""
    reader = PdfReader(input_path)
    writer = PdfWriter()

    img = ImageReader(image_path)
    img_w, img_h = img.getSize()

    if height is None or height <= 0:
        height = width * (img_h / img_w)

    for i, page in enumerate(reader.pages):
        if _should_apply(i, apply_to, current_page):
            w, h = get_page_size(page)
            packet = io.BytesIO()
            c = canvas.Canvas(packet, pagesize=(w, h))
            c.drawImage(image_path, x, y, width=width, height=height,
                        preserveAspectRatio=True, mask='auto')
            c.showPage()
            c.save()
            packet.seek(0)
            overlay = PdfReader(packet)
            page.merge_page(overlay.pages[0])

        writer.add_page(page)

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


def _should_apply(page_index, apply_to, current_page):
    page_num = page_index + 1
    if apply_to == "all":
        return True
    elif apply_to == "current":
        return page_index == current_page
    elif apply_to == "even":
        return page_num % 2 == 0
    elif apply_to == "odd":
        return page_num % 2 != 0
    return False