"""Utilities for the Docker integration tests under tests/."""

from __future__ import annotations

import os
import pathlib
from typing import Annotated

import jinja2
import typer

app = typer.Typer(help="Utilities for the tests/ Docker integration tests")

TESTS_DIR = pathlib.Path(__file__).resolve().parent.parent / "tests"


def _env(name: str) -> str:
    """Jinja2 filter: `'NAME' | env` -> the environment variable NAME."""
    return os.environ[name]


def _file(relative: str) -> str:
    """Jinja2 filter: `'relative/path' | file` -> content of tests/relative/path."""
    path = (TESTS_DIR / relative).resolve()
    if path != TESTS_DIR and TESTS_DIR not in path.parents:
        raise ValueError(f"refusing to read a file outside of {TESTS_DIR}: {relative}")
    return path.read_text(encoding="utf-8")


def render_template(text: str) -> str:
    """Render a tests/configs/*.yaml.j2 fixture as a Jinja2 template.

    Custom filters: `| env` reads an environment variable, `| file` reads a
    file relative to tests/. Combine with Jinja2's built-in `indent` filter
    to fit multi-line content (e.g. a PEM certificate) into a YAML
    block-literal field, e.g.:

        content: |
          {{ 'certs/test-ca.crt.pem' | file | indent(6, first=true) }}
    """
    # Autoescaping is for HTML output; these templates render YAML, so escaping
    # would corrupt them (e.g. turning "&" into "&" inside a PEM/URL).
    environment = jinja2.Environment(undefined=jinja2.StrictUndefined)  # nosec B701
    environment.filters["env"] = _env
    environment.filters["file"] = _file
    return environment.from_string(text).render()


@app.command(
    name="render-config",
    help="Render a tests/configs/*.yaml.j2 fixture into a ready-to-use configuration.",
)
def render_config(
    template: Annotated[pathlib.Path, typer.Argument(exists=True, dir_okay=False)],
    output: pathlib.Path,
) -> None:
    """Renders `template` as a Jinja2 template (see `render_template`) and
    writes the result to `output`, creating its parent directories as
    needed."""
    content = render_template(template.read_text(encoding="utf-8"))
    output.parent.mkdir(parents=True, exist_ok=True)
    output.write_text(content, encoding="utf-8")


if __name__ == "__main__":
    app()