import subprocess
from pathlib import Path

from app.repository.security import SKIPPED_PARTS, safe_repository_member


class RepositoryTools:
    """Git-backed read tools. A partial clone fetches a blob only when read_file needs it."""

    def __init__(self, root: Path, max_file_bytes: int):
        self.root, self.max_file_bytes = root.resolve(), max_file_bytes

    def _run(self, args: list[str], timeout: int = 15) -> str:
        result = subprocess.run(
            args, cwd=self.root, text=True, capture_output=True, timeout=timeout, check=False
        )
        if result.returncode != 0:
            raise RuntimeError(result.stderr.strip() or "Repository command failed")
        return result.stdout

    def tree(self, limit: int = 300) -> str:
        output = self._run(["git", "ls-tree", "-r", "--name-only", "HEAD"])
        paths: list[str] = []
        for path in output.splitlines():
            if any(part in SKIPPED_PARTS for part in Path(path).parts):
                continue
            try:
                safe_repository_member(path)
            except ValueError:
                continue
            paths.append(path)
        return "\n".join(paths[:limit])

    def find_files(self, query: str) -> str:
        if not query or len(query) > 100:
            raise ValueError("Invalid search query")
        return "\n".join(
            line for line in self.tree(2_000).splitlines() if query.lower() in line.lower()
        )[:12_000]

    def search_text(self, query: str) -> str:
        if not query or len(query) > 300:
            raise ValueError("Invalid search query")
        return "Text search would fetch too many blobs; use find_files then read_file."

    def read_file(self, path: str, start_line: int = 1, end_line: int = 200) -> str:
        member = safe_repository_member(path)
        if start_line < 1 or end_line < start_line or end_line - start_line > 500:
            raise ValueError("Invalid line range")
        size = int(self._run(["git", "cat-file", "-s", f"HEAD:{member.as_posix()}"]).strip())
        if size > self.max_file_bytes:
            raise ValueError("File is unavailable or too large")
        content = self._run(["git", "show", f"HEAD:{member.as_posix()}"], timeout=30)
        lines = content.splitlines()
        return "\n".join(
            f"{i}: {line}" for i, line in enumerate(lines[start_line - 1 : end_line], start_line)
        )

    def current_commit(self) -> str:
        return self._run(["git", "rev-parse", "HEAD"]).strip()

    def recent_commits(self) -> str:
        return self._run(["git", "log", "--oneline", "-10"])

    def recent_diff(self) -> str:
        return self._run(["git", "diff", "HEAD~1", "HEAD", "--stat"])[:12_000]

    def file_info(self, path: str) -> str:
        member = safe_repository_member(path)
        size = self._run(["git", "cat-file", "-s", f"HEAD:{member.as_posix()}"]).strip()
        return f"{path}: {size} bytes, extension={member.suffix or 'none'}"