from dataclasses import dataclass, field

import yaml


@dataclass
class Article:
    metadata: dict = field(default_factory=dict)
    content: str = ""


def load(file_name) -> Article:
    content = ""
    with open(file=file_name, mode="r", encoding="utf8") as file:
        content = file.read()

    return loads(content)


def loads(content: str) -> Article:
    lines = content.splitlines()

    start = -1
    end = -1

    for index, line in enumerate(lines):
        if line.startswith("---"):
            if start == -1:
                start = index
            elif end == -1:
                end = index
                break

    if start == -1 or end == -1:
        raise ValueError("Missing frontmatter delimiters")

    metadata = lines[start + 1 : end]
    content = lines[end + 1 :]

    metadata = yaml.safe_load("\n".join(metadata))
    if not metadata:
        metadata = {}
    return Article(
        metadata=metadata,
        content="\n".join(content),
    )


def dumps(article: Article) -> str:
    return f"""---\n{yaml.dump(article.metadata)}---\n{article.content}\n"""