# Converts a TeX file into a PNG/SVG file.
template = r"""
\documentclass[utf8,preview,varwidth]{{standalone}}
    \usepackage{{amsmath}}
    \usepackage[active]{{preview}}
    \usepackage[utf8]{{inputenc}}
    \usepackage{{tikz}}
    % TODO: Add user packages here.
    {packages}
\begin{{document}}
    % The user content goes here.
    {content}

\end{{document}}
"""


def render(user: str, source: str, png: bool = True) -> str:
    import tempfile
    import subprocess
    import utils
    import os

    # Put the user's packages in the format too.
    directory = utils.create_user_dir(user)
    pkgs = ""

    for f in os.listdir(directory):
        if f.endswith(".sty"):
            base = os.path.join(directory, f[:-4])
            pkgs += "\\usepackage{{{base}}}\n    ".format(base=base)

    fmt = template.format(content=source, packages=pkgs)

    tmp = tempfile.NamedTemporaryFile(delete=False)
    tmp.write(bytes(fmt, encoding="utf8"))
    tmp.close()

    # Parse our templated file thru' LaTeX and dvipng.
    # TODO: Allow arbitrary DPI and foreground color.
    ret = subprocess.run(["latex", "-halt-on-error", tmp.name],
                         cwd="/tmp", capture_output=True)
    if ret.returncode != 0:
        raise FileNotFoundError(ret.stdout.decode())

    if png:
        subprocess.run(["dvipng", "-D", "5000", tmp.name + ".dvi", "-bg", "Transparent",
                       "-fg", "rgb 1 1 1", "-o", tmp.name + ".png"], cwd="/tmp")

        return tmp.name + ".png"

    # TODO:
    raise NotImplementedError("SVG support is not currently implemented")