import re
from pathlib import Path


class CopybookPreprocessor:
    def __init__(self, search_paths: list[str] | None = None):
        self.search_paths = search_paths or ["./copybooks"]

    def expand(self, source_text: str) -> str:
        pattern = re.compile(
            r'^       COPY\s+(\w+(?:-\w+)?)\s*(?:\.|$.|$)',
            re.MULTILINE)
        return pattern.sub(self._replace_copy, source_text)

    def _replace_copy(self, match):
        name = match.group(1).strip()
        for path in self.search_paths:
            for ext in ["", ".cpy", ".cbl", ".copy"]:
                p = Path(path) / f"{name}{ext}"
                if p.exists():
                    content = p.read_text()
                    return f"      *> COPY {name}\n{content}\n      *> END COPY {name}"
        return f"      *> COPY {name} NOT FOUND"