"""Shows what an evaluation copy looks like: a document written with no licence key,
which the library stamps with a watermark on every page.

The Python twin of the `write_eval_watermark` example in Rust. A licensed document
is what most examples show; this one is the opposite. No key is set, so the library
writes an evaluation copy and marks every page as one. Set a licence key and the
mark is gone.

The page under the mark is held in `Words`, once per language, and `HQF_PDF_LANG`
picks which set is drawn. The watermark itself is the library's, not the page's, and
does not follow the page's language.

Usage: python examples/write_eval_watermark.py [out.pdf] [font.ttf]
       HQF_PDF_LANG=fr python examples/write_eval_watermark.py
"""

from __future__ import annotations

from dataclasses import dataclass
from pathlib import Path

import _language
import _out

import hqf_pdf

# The size each line is set at, and the baseline it sits on, in the order they are laid
# down.
PLACES = (
    (20.0, 760.0),
    (11.0, 730.0),
    (11.0, 700.0),
    (11.0, 684.0),
    (10.0, 120.0),
    (10.0, 106.0),
)


@dataclass(frozen=True)
class Words:
    """Every word the page draws, in one language.

    The watermark is not here: the library writes it, and it says the same thing
    whatever language the page under it is in.
    """

    # A short document laid under the watermark, and under it a note that says what the
    # watermark is, in the order the lines are laid down.
    lines: tuple[str, str, str, str, str, str]


# The page in English.
ENGLISH = Words(
    lines=(
        "Quarterly report",
        "Prepared for HQF Development",
        "Revenue held steady across the three months, and costs fell as the new",
        "rendering pipeline replaced the tools it was built to retire.",
        "This is an evaluation copy: the library stamps every page with the",
        "watermark above until a licence key is set. Set one and it is gone.",
    ),
)

# The page in French.
FRENCH = Words(
    lines=(
        "Rapport trimestriel",
        "Établi pour HQF Development",
        "Le chiffre d'affaires est resté stable sur les trois mois, et les",
        "coûts ont baissé quand la nouvelle chaîne de rendu a pris la suite.",
        "Ceci est une copie d'évaluation : la bibliothèque marque chaque page",
        "du filigrane ci-dessus tant qu'aucune clé n'est posée. Posez-en une.",
    ),
)


# Every language the example is written in. A language is added by writing its own set
# of words and naming it here.
WORDS = {_language.ENGLISH: ENGLISH, _language.FRENCH: FRENCH}


def main() -> None:
    language = _language.from_environment()
    words = _language.words_of(WORDS, language)

    # A named file is written as named; the default one carries the language, so the two
    # languages do not overwrite each other in `tmp/`.
    out = _out.output_path(Path(_language.file_name("eval.pdf", language)).stem)

    document = hqf_pdf.Document()
    # No key is set: the document is an evaluation copy, and the library marks every
    # page of it with a watermark.
    document.set_license(hqf_pdf.License.evaluation())
    font = document.add_font(hqf_pdf.Font.from_path(_out.font_path()))

    content = hqf_pdf.Content()
    for line, (size, top) in zip(words.lines, PLACES):
        content.draw_text(font, size, 72.0, top, line)

    page = hqf_pdf.Page.a4()
    page.set_content(content)
    document.add_page(page)

    written = document.write(out)
    print(f"wrote {out}: {written} bytes")


if __name__ == "__main__":
    main()