"""Local Git subprocess interface."""

import abc
import subprocess
from pathlib import Path
from typing import Any


class GitOperations(abc.ABC):
    """Local Git subprocess interface.

    This abstraction is separate from :class:`~app.git.provider.GitProvider`,
    which handles remote provider API operations.
    """

    @abc.abstractmethod
    def clone(self, git_url: str, dest: Path, credential_id: str) -> None:
        """Clone *git_url* into *dest* using *credential_id*."""

    @abc.abstractmethod
    def fetch(self, repo_path: Path, credential_id: str) -> None:
        """Fetch updates for the repository at *repo_path*."""

    @abc.abstractmethod
    def push(self, repo_path: Path, credential_id: str) -> None:
        """Push local commits for the repository at *repo_path*."""

    @abc.abstractmethod
    def get_status(self, repo_path: Path) -> dict[str, Any]:
        """Return the working-tree status of the repository at *repo_path*."""


class LocalGitOperations(GitOperations):
    """Git operations backed by the local ``git`` CLI."""

    def clone(self, git_url: str, dest: Path, credential_id: str) -> None:
        raise NotImplementedError(
            "Credential-aware subprocess invocation will be implemented in a follow-up task"
        )

    def fetch(self, repo_path: Path, credential_id: str) -> None:
        raise NotImplementedError(
            "Credential-aware subprocess invocation will be implemented in a follow-up task"
        )

    def push(self, repo_path: Path, credential_id: str) -> None:
        raise NotImplementedError(
            "Credential-aware subprocess invocation will be implemented in a follow-up task"
        )

    def get_status(self, repo_path: Path) -> dict[str, Any]:
        if not repo_path.exists() or not (repo_path / ".git").is_dir():
            raise RuntimeError("Not a git repository")

        try:
            branch_result = subprocess.run(
                ["git", "-C", str(repo_path), "branch", "--show-current"],
                capture_output=True,
                text=True,
                encoding="utf-8",
                check=True,
            )
            branch = branch_result.stdout.strip()

            status_result = subprocess.run(
                ["git", "-C", str(repo_path), "status", "--porcelain"],
                capture_output=True,
                text=True,
                encoding="utf-8",
                check=True,
            )
        except subprocess.CalledProcessError as exc:
            raise RuntimeError("Git command failed") from exc

        untracked: list[str] = []
        modified: list[str] = []
        staged: list[str] = []
        deleted: list[str] = []

        for line in status_result.stdout.splitlines():
            if len(line) < 3:
                continue
            index_status = line[0]
            worktree_status = line[1]
            filename = line[3:]

            if index_status == "?" and worktree_status == "?":
                untracked.append(filename)
            elif index_status in ("M", "A"):
                staged.append(filename)

            if index_status == "D" or worktree_status == "D":
                deleted.append(filename)

            if worktree_status == "M":
                modified.append(filename)

        clean = not (untracked or modified or staged or deleted)

        return {
            "branch": branch,
            "clean": clean,
            "untracked": untracked,
            "modified": modified,
            "staged": staged,
            "deleted": deleted,
        }