Source code for codegen.banner

import re
from dataclasses import dataclass
from importlib.metadata import version as _pkg_version
from typing import Literal

_BANNER_WIDTH = 76
MARKER_SENTINEL = "codegen:generated"
_MARKER_SCAN_LINES = 20
_MARKER_RE = re.compile(
    rf"{re.escape(MARKER_SENTINEL)}\s+target=(?P<target>\S+)\s+"
    r"version=(?P<version>\S+)"
)
_MARKER_VERSION_RE = re.compile(
    rf"({re.escape(MARKER_SENTINEL)}\s+target=\S+\s+version=)\S+"
)




@dataclass(frozen=True)
class CommentStyle:
    line: str | None = None
    block: tuple[str, str, str] | None = None
    fill: str = "#"

    def render(self, lines: list[str]) -> str:
        if self.line is not None:
            rule = self.fill * _BANNER_WIDTH
            body = [f"{self.line} {text}".rstrip() for text in lines]
            return "\n".join([rule, *body, rule])

        if self.block is not None:
            open_delim, cont, close_delim = self.block
            rule = f"{cont}{self.fill * (_BANNER_WIDTH - len(cont))}"
            body = [f"{cont}{text}".rstrip() for text in lines]
            return "\n".join([open_delim, rule, *body, rule, close_delim])

        msg = "CommentStyle has neither a line nor a block form"
        raise ValueError(msg)



_HASH = CommentStyle(line="#", fill="#")
_SLASH = CommentStyle(line="//", fill="/")
_CSS = CommentStyle(block=("/*", " * ", " */"), fill="*")
_HTML = CommentStyle(block=("<!--", "  ", "-->"), fill="=")


def _python_comment_styles() -> dict[str, CommentStyle]:
    return {
        "py": _HASH,
        "pyi": _HASH,
        "toml": _HASH,
        "ini": _HASH,
        "cfg": _HASH,
        "env": _HASH,
        ".env.example": _HASH,
        "gitignore": _HASH,
        "dockerignore": _HASH,
        "Dockerfile": _HASH,
        "justfile": _HASH,
        "just": _HASH,
    }


def _typescript_comment_styles() -> dict[str, CommentStyle]:
    return {
        "ts": _SLASH,
        "tsx": _SLASH,
        "js": _SLASH,
        "jsx": _SLASH,
        "mjs": _SLASH,
        "cjs": _SLASH,
        "jsonnet": _SLASH,
        "libsonnet": _SLASH,
        "css": _CSS,
        "scss": _CSS,
        "html": _HTML,
        "htm": _HTML,
        "gitignore": _HASH,
        "prettierignore": _HASH,
        "justfile": _HASH,
    }


def _rego_comment_styles() -> dict[str, CommentStyle]:
    return {"rego": _HASH, "yaml": _HASH, "yml": _HASH}


_COMMENT_STYLES: dict[str, CommentStyle] = {
    **_python_comment_styles(),
    **_typescript_comment_styles(),
    **_rego_comment_styles(),
}


def comment_style_for(path: str) -> CommentStyle | None:
    name = path.rsplit("/", 1)[-1]

    if name in _COMMENT_STYLES:
        return _COMMENT_STYLES[name]

    if "." in name:
        ext = name.rsplit(".", 1)[-1]
        return _COMMENT_STYLES.get(ext)

    return None


def render_banner(
    *,
    target_name: str,
    path: str,
    if_exists: Literal["overwrite", "skip"],
    version: str | None = None,
) -> str:
    style = comment_style_for(path)

    if style is None:
        return ""

    cmd = f"`codegen generate --target {target_name}`"

    if if_exists == "skip":
        lines = [
            f"AUTOGENERATED by {cmd}.",
            'One-shot scaffold (if_exists="skip"): your edits are preserved',
            "on re-run.  Pass --force-paths to regenerate it deliberately.",
        ]

    else:
        lines = [
            f"AUTOGENERATED by {cmd}.",
            (
                "─── DO NOT EDIT BY HAND "
                "──────────────────────────────────────────────────"
            ),
            "Overwritten on every run; edit the config or source, not here.",
        ]

    resolved = _pkg_version("codegen") if version is None else version
    lines.append(f"{MARKER_SENTINEL} target={target_name} version={resolved}")

    return style.render(lines)




@dataclass(frozen=True)
class ParsedMarker:
    target: str
    version: str



def parse_marker(content: str) -> ParsedMarker | None:
    for line in content.splitlines()[:_MARKER_SCAN_LINES]:
        match = _MARKER_RE.search(line)

        if match is not None:
            return ParsedMarker(
                target=match["target"], version=match["version"]
            )

    return None


def normalize_marker_version(content: str) -> str:
    return _MARKER_VERSION_RE.sub(r"\g<1>0", content)