"""
Git operations wrapper using GitPython.

Provides high-level git operations with proper error handling,
async compatibility, and structured results.
"""

import asyncio
import logging
import os
import re
from concurrent.futures import ThreadPoolExecutor
from datetime import UTC, datetime
from functools import partial
from pathlib import Path
from typing import Any

from git import GitCommandError, InvalidGitRepositoryError, NoSuchPathError
from git import Repo as GitRepo

from config import Settings, get_settings
from exceptions import (
    BranchExistsError,
    BranchNotFoundError,
    CheckoutError,
    CloneError,
    CommitError,
    DirtyWorkspaceError,
    GitError,
    MergeConflictError,
    PullError,
    PushError,
)
from models import (
    BranchInfo,
    BranchResult,
    CheckoutResult,
    CloneResult,
    CommitInfo,
    CommitResult,
    DiffHunk,
    DiffResult,
    FileChange,
    FileChangeType,
    FileDiff,
    ListBranchesResult,
    LogResult,
    PullResult,
    PushResult,
    StatusResult,
)

logger = logging.getLogger(__name__)


def sanitize_url_for_logging(url: str) -> str:
    """
    Remove any credentials from a URL before logging.

    Handles URLs like:
    - https://token@github.com/owner/repo.git
    - https://user:password@github.com/owner/repo.git
    - git@github.com:owner/repo.git (unchanged, no credentials)
    """
    # Pattern to match https://[credentials@]host/path
    sanitized = re.sub(r"(https?://)([^@]+@)", r"\1***@", url)
    return sanitized


# Thread pool for blocking git operations
_executor: ThreadPoolExecutor | None = None


def get_executor() -> ThreadPoolExecutor:
    """Get the shared thread pool executor."""
    global _executor
    if _executor is None:
        _executor = ThreadPoolExecutor(max_workers=4, thread_name_prefix="git-ops-")
    return _executor


async def run_in_executor(func: Any, *args: Any, **kwargs: Any) -> Any:
    """Run a blocking function in the thread pool."""
    loop = asyncio.get_event_loop()
    executor = get_executor()
    partial_func = partial(func, *args, **kwargs)
    return await loop.run_in_executor(executor, partial_func)


class GitWrapper:
    """
    Wrapper for git operations using GitPython.

    Provides async-compatible git operations with proper error handling.
    """

    def __init__(
        self,
        workspace_path: Path | str,
        settings: Settings | None = None,
    ) -> None:
        """
        Initialize GitWrapper.

        Args:
            workspace_path: Path to the git workspace
            settings: Optional settings override
        """
        self.workspace_path = (
            Path(workspace_path) if isinstance(workspace_path, str) else workspace_path
        )
        self.settings = settings or get_settings()
        self._repo: GitRepo | None = None

    @property
    def repo(self) -> GitRepo:
        """Get the GitPython Repo instance."""
        if self._repo is None:
            try:
                self._repo = GitRepo(self.workspace_path)
            except InvalidGitRepositoryError:
                raise GitError(f"Not a git repository: {self.workspace_path}")
            except NoSuchPathError:
                raise GitError(f"Path does not exist: {self.workspace_path}")
        return self._repo

    def _refresh_repo(self) -> None:
        """Refresh the repo instance after operations that change it."""
        self._repo = None

    # Clone operations

    async def clone(
        self,
        repo_url: str,
        branch: str | None = None,
        depth: int | None = None,
        auth_token: str | None = None,
    ) -> CloneResult:
        """
        Clone a repository.

        Args:
            repo_url: Repository URL to clone
            branch: Branch to checkout after clone
            depth: Shallow clone depth (None for full)
            auth_token: Optional auth token for HTTPS

        Returns:
            CloneResult with clone status
        """

        def _do_clone() -> CloneResult:
            try:
                # Build clone URL with auth if provided
                clone_url = repo_url
                if auth_token and repo_url.startswith("https://"):
                    # Insert token in URL: https://token@host/path
                    clone_url = re.sub(
                        r"^(https://)(.+)$",
                        rf"\1{auth_token}@\2",
                        repo_url,
                    )

                # Build clone arguments
                kwargs: dict[str, Any] = {
                    "url": clone_url,
                    "to_path": str(self.workspace_path),
                }

                if branch:
                    kwargs["branch"] = branch

                if depth:
                    kwargs["depth"] = depth

                # Set environment for auth
                env = os.environ.copy()
                env["GIT_TERMINAL_PROMPT"] = "0"

                logger.info(f"Cloning repository: {repo_url} -> {self.workspace_path}")

                repo = GitRepo.clone_from(**kwargs)
                self._repo = repo

                return CloneResult(
                    success=True,
                    project_id="",  # Set by caller
                    workspace_path=str(self.workspace_path),
                    branch=repo.active_branch.name,
                    commit_sha=repo.head.commit.hexsha,
                )

            except GitCommandError as e:
                # Sanitize URLs in error messages to prevent credential leakage
                error_msg = sanitize_url_for_logging(str(e))
                logger.error(f"Clone failed: {error_msg}")
                raise CloneError(sanitize_url_for_logging(repo_url), error_msg)

        return await run_in_executor(_do_clone)

    # Status operations

    async def status(self, include_untracked: bool = True) -> StatusResult:
        """
        Get git status.

        Args:
            include_untracked: Include untracked files

        Returns:
            StatusResult with working tree status
        """

        def _get_status() -> StatusResult:
            repo = self.repo

            # Get staged changes
            staged = []
            for diff in repo.index.diff("HEAD"):
                change_type = self._diff_to_change_type(diff.change_type)
                path = diff.b_path or diff.a_path or ""
                staged.append(
                    FileChange(
                        path=path,
                        change_type=change_type,
                        old_path=diff.a_path if diff.renamed else None,
                    ).to_dict()
                )

            # Get unstaged changes
            unstaged = []
            for diff in repo.index.diff(None):
                change_type = self._diff_to_change_type(diff.change_type)
                path = diff.b_path or diff.a_path or ""
                unstaged.append(
                    FileChange(
                        path=path,
                        change_type=change_type,
                    ).to_dict()
                )

            # Get untracked files
            untracked = list(repo.untracked_files) if include_untracked else []

            # Get tracking info
            ahead = behind = 0
            try:
                tracking = repo.active_branch.tracking_branch()
                if tracking:
                    ahead = len(
                        list(
                            repo.iter_commits(
                                f"{tracking.name}..{repo.active_branch.name}"
                            )
                        )
                    )
                    behind = len(
                        list(
                            repo.iter_commits(
                                f"{repo.active_branch.name}..{tracking.name}"
                            )
                        )
                    )
            except Exception:
                pass  # No tracking branch

            is_clean = len(staged) == 0 and len(unstaged) == 0 and len(untracked) == 0

            return StatusResult(
                project_id="",  # Set by caller
                branch=repo.active_branch.name,
                commit_sha=repo.head.commit.hexsha,
                is_clean=is_clean,
                staged=staged,
                unstaged=unstaged,
                untracked=untracked,
                ahead=ahead,
                behind=behind,
            )

        return await run_in_executor(_get_status)

    # Branch operations

    async def create_branch(
        self,
        branch_name: str,
        from_ref: str | None = None,
        checkout: bool = True,
    ) -> BranchResult:
        """
        Create a new branch.

        Args:
            branch_name: Name for the new branch
            from_ref: Reference to create from (default: HEAD)
            checkout: Whether to checkout after creation

        Returns:
            BranchResult with creation status
        """

        def _create_branch() -> BranchResult:
            repo = self.repo

            # Check if branch already exists
            if branch_name in [b.name for b in repo.branches]:
                raise BranchExistsError(branch_name)

            try:
                # Get the starting point
                if from_ref:
                    start_point = repo.commit(from_ref)
                else:
                    start_point = repo.head.commit

                # Create branch
                new_branch = repo.create_head(branch_name, start_point)

                # Checkout if requested
                if checkout:
                    new_branch.checkout()

                return BranchResult(
                    success=True,
                    branch=branch_name,
                    commit_sha=new_branch.commit.hexsha,
                    is_current=checkout,
                )

            except GitCommandError as e:
                logger.error(f"Failed to create branch {branch_name}: {e}")
                raise GitError(f"Failed to create branch: {e}")

        return await run_in_executor(_create_branch)

    async def delete_branch(
        self,
        branch_name: str,
        force: bool = False,
    ) -> BranchResult:
        """
        Delete a branch.

        Args:
            branch_name: Branch to delete
            force: Force delete even if not merged

        Returns:
            BranchResult with deletion status
        """

        def _delete_branch() -> BranchResult:
            repo = self.repo

            if branch_name not in [b.name for b in repo.branches]:
                raise BranchNotFoundError(branch_name)

            if repo.active_branch.name == branch_name:
                raise GitError(f"Cannot delete current branch: {branch_name}")

            try:
                repo.delete_head(branch_name, force=force)
                return BranchResult(
                    success=True,
                    branch=branch_name,
                    is_current=False,
                )
            except GitCommandError as e:
                logger.error(f"Failed to delete branch {branch_name}: {e}")
                raise GitError(f"Failed to delete branch: {e}")

        return await run_in_executor(_delete_branch)

    async def list_branches(self, include_remote: bool = False) -> ListBranchesResult:
        """
        List branches.

        Args:
            include_remote: Include remote tracking branches

        Returns:
            ListBranchesResult with branch lists
        """

        def _list_branches() -> ListBranchesResult:
            repo = self.repo

            local_branches = []
            for branch in repo.branches:
                tracking = branch.tracking_branch()
                msg = branch.commit.message
                commit_msg = (
                    msg.decode("utf-8", errors="replace")
                    if isinstance(msg, bytes)
                    else msg
                ).split("\n")[0]
                local_branches.append(
                    BranchInfo(
                        name=branch.name,
                        is_current=branch == repo.active_branch,
                        is_remote=False,
                        tracking_branch=tracking.name if tracking else None,
                        commit_sha=branch.commit.hexsha,
                        commit_message=commit_msg,
                    ).to_dict()
                )

            remote_branches = []
            if include_remote:
                for remote in repo.remotes:
                    for ref in remote.refs:
                        # Skip HEAD refs
                        if ref.name.endswith("/HEAD"):
                            continue
                        msg = ref.commit.message
                        commit_msg = (
                            msg.decode("utf-8", errors="replace")
                            if isinstance(msg, bytes)
                            else msg
                        ).split("\n")[0]
                        remote_branches.append(
                            BranchInfo(
                                name=ref.name,
                                is_current=False,
                                is_remote=True,
                                commit_sha=ref.commit.hexsha,
                                commit_message=commit_msg,
                            ).to_dict()
                        )

            return ListBranchesResult(
                project_id="",  # Set by caller
                current_branch=repo.active_branch.name,
                local_branches=local_branches,
                remote_branches=remote_branches,
            )

        return await run_in_executor(_list_branches)

    async def checkout(
        self,
        ref: str,
        create_branch: bool = False,
        force: bool = False,
    ) -> CheckoutResult:
        """
        Checkout a branch or ref.

        Args:
            ref: Branch, tag, or commit to checkout
            create_branch: Create new branch with this name
            force: Force checkout (discard local changes)

        Returns:
            CheckoutResult with checkout status
        """

        def _checkout() -> CheckoutResult:
            repo = self.repo

            try:
                if create_branch:
                    # Create and checkout new branch
                    if ref in [b.name for b in repo.branches]:
                        raise BranchExistsError(ref)
                    new_branch = repo.create_head(ref)
                    new_branch.checkout(force=force)
                else:
                    # Checkout existing ref
                    if ref in [b.name for b in repo.branches]:
                        # Local branch
                        repo.heads[ref].checkout(force=force)
                    else:
                        # Try as a commit/tag
                        repo.git.checkout(ref, force=force)

                return CheckoutResult(
                    success=True,
                    ref=ref,
                    commit_sha=repo.head.commit.hexsha,
                )

            except GitCommandError as e:
                error_msg = str(e)
                if "would be overwritten" in error_msg:
                    raise DirtyWorkspaceError([])
                raise CheckoutError(ref, error_msg)

        return await run_in_executor(_checkout)

    # Commit operations

    async def commit(
        self,
        message: str,
        files: list[str] | None = None,
        author_name: str | None = None,
        author_email: str | None = None,
        allow_empty: bool = False,
    ) -> CommitResult:
        """
        Create a commit.

        Args:
            message: Commit message
            files: Specific files to commit (None = all staged)
            author_name: Author name override
            author_email: Author email override
            allow_empty: Allow empty commits

        Returns:
            CommitResult with commit info
        """

        def _commit() -> CommitResult:
            repo = self.repo

            try:
                # Stage files if specified
                if files:
                    repo.index.add(files)
                elif not allow_empty:
                    # Stage all modified/deleted
                    repo.git.add("-A")

                # Check if there's anything to commit
                if (
                    not allow_empty
                    and not repo.index.diff("HEAD")
                    and not repo.untracked_files
                ):
                    raise CommitError("Nothing to commit")

                # Build author
                author = None
                if author_name and author_email:
                    from git import Actor

                    author = Actor(author_name, author_email)
                elif author_name or author_email:
                    from git import Actor

                    author = Actor(
                        author_name or self.settings.git_author_name,
                        author_email or self.settings.git_author_email,
                    )

                # Create commit
                commit = repo.index.commit(
                    message,
                    author=author,
                    committer=author,
                )

                # Get stats
                stats = commit.stats.total
                files_changed = stats.get("files", 0)
                insertions = stats.get("insertions", 0)
                deletions = stats.get("deletions", 0)

                return CommitResult(
                    success=True,
                    commit_sha=commit.hexsha,
                    short_sha=commit.hexsha[:7],
                    message=message,
                    files_changed=files_changed,
                    insertions=insertions,
                    deletions=deletions,
                )

            except GitCommandError as e:
                logger.error(f"Commit failed: {e}")
                raise CommitError(str(e))

        return await run_in_executor(_commit)

    async def stage(self, files: list[str] | None = None) -> int:
        """
        Stage files for commit.

        Args:
            files: Files to stage (None = all)

        Returns:
            Number of files staged
        """

        def _stage() -> int:
            repo = self.repo
            if files:
                repo.index.add(files)
                return len(files)
            else:
                repo.git.add("-A")
                return len(repo.index.diff("HEAD")) + len(repo.untracked_files)

        return await run_in_executor(_stage)

    async def unstage(self, files: list[str] | None = None) -> int:
        """
        Unstage files.

        Args:
            files: Files to unstage (None = all)

        Returns:
            Number of files unstaged
        """

        def _unstage() -> int:
            repo = self.repo
            staged = list(repo.index.diff("HEAD"))

            if files:
                repo.index.remove(files, working_tree=False)
                return len(files)
            else:
                # Unstage all
                if staged:
                    repo.git.reset("HEAD")
                return len(staged)

        return await run_in_executor(_unstage)

    # Push/Pull operations

    async def push(
        self,
        branch: str | None = None,
        remote: str = "origin",
        force: bool = False,
        set_upstream: bool = True,
        auth_token: str | None = None,
    ) -> PushResult:
        """
        Push to remote.

        Args:
            branch: Branch to push (None = current)
            remote: Remote name
            force: Force push
            set_upstream: Set upstream tracking
            auth_token: Auth token for HTTPS

        Returns:
            PushResult with push status
        """

        def _push() -> PushResult:
            repo = self.repo
            push_branch = branch or repo.active_branch.name

            # Check force push policy
            if force and not self.settings.enable_force_push:
                raise PushError(push_branch, "Force push is disabled")

            try:
                # Build push info
                push_info_list: list[Any] = []

                if remote not in [r.name for r in repo.remotes]:
                    raise PushError(push_branch, f"Remote not found: {remote}")

                remote_obj = repo.remote(remote)

                # Configure auth if provided
                if auth_token:
                    # Set credential helper temporarily
                    pass  # TODO: Implement token-based auth

                # Build refspec
                refspec = f"{push_branch}:{push_branch}"
                if set_upstream:
                    push_info_list = remote_obj.push(
                        refspec=refspec,
                        force=force,
                        set_upstream=True,
                    )
                else:
                    push_info_list = remote_obj.push(
                        refspec=refspec,
                        force=force,
                    )

                # Check for errors
                for info in push_info_list:
                    if info.flags & info.ERROR:
                        raise PushError(push_branch, info.summary)

                # Count commits pushed (approximate)
                commits_pushed = 0
                try:
                    tracking = repo.active_branch.tracking_branch()
                    if tracking:
                        commits_pushed = len(
                            list(repo.iter_commits(f"{tracking.name}..{push_branch}"))
                        )
                except Exception:
                    pass

                return PushResult(
                    success=True,
                    branch=push_branch,
                    remote=remote,
                    commits_pushed=commits_pushed,
                )

            except GitCommandError as e:
                error_msg = str(e)
                if "rejected" in error_msg:
                    raise PushError(
                        push_branch,
                        "Push rejected - pull and merge first or force push",
                    )
                raise PushError(push_branch, error_msg)

        return await run_in_executor(_push)

    async def pull(
        self,
        branch: str | None = None,
        remote: str = "origin",
        rebase: bool = False,
        auth_token: str | None = None,
    ) -> PullResult:
        """
        Pull from remote.

        Args:
            branch: Branch to pull (None = current)
            remote: Remote name
            rebase: Rebase instead of merge
            auth_token: Auth token for HTTPS

        Returns:
            PullResult with pull status
        """

        def _pull() -> PullResult:
            repo = self.repo
            pull_branch = branch or repo.active_branch.name

            try:
                if remote not in [r.name for r in repo.remotes]:
                    raise PullError(pull_branch, f"Remote not found: {remote}")

                remote_obj = repo.remote(remote)

                # Fetch first to check for conflicts
                remote_obj.fetch()

                # Get commits before pull
                head_before = repo.head.commit.hexsha

                # Perform pull
                if rebase:
                    repo.git.pull("--rebase", remote, pull_branch)
                else:
                    repo.git.pull(remote, pull_branch)

                # Count new commits
                commits_received = len(list(repo.iter_commits(f"{head_before}..HEAD")))

                # Check if fast-forward
                fast_forward = commits_received > 0 and not repo.head.commit.parents

                return PullResult(
                    success=True,
                    branch=pull_branch,
                    commits_received=commits_received,
                    fast_forward=fast_forward,
                )

            except GitCommandError as e:
                error_msg = str(e)
                if "conflict" in error_msg.lower():
                    # Get conflicting files - keys are paths directly
                    conflicts = [
                        str(path) for path in repo.index.unmerged_blobs().keys()
                    ]
                    raise MergeConflictError(conflicts)
                raise PullError(pull_branch, error_msg)

        return await run_in_executor(_pull)

    async def fetch(
        self,
        remote: str = "origin",
        prune: bool = False,
    ) -> bool:
        """
        Fetch from remote.

        Args:
            remote: Remote name
            prune: Prune deleted remote branches

        Returns:
            True if successful
        """

        def _fetch() -> bool:
            repo = self.repo
            try:
                if remote not in [r.name for r in repo.remotes]:
                    raise GitError(f"Remote not found: {remote}")

                remote_obj = repo.remote(remote)
                remote_obj.fetch(prune=prune)
                return True
            except GitCommandError as e:
                logger.error(f"Fetch failed: {e}")
                raise GitError(f"Fetch failed: {e}")

        return await run_in_executor(_fetch)

    # Diff operations

    async def diff(
        self,
        base: str | None = None,
        head: str | None = None,
        files: list[str] | None = None,
        context_lines: int = 3,
    ) -> DiffResult:
        """
        Get diff between refs.

        Args:
            base: Base reference (None = working tree)
            head: Head reference (None = HEAD)
            files: Specific files to diff
            context_lines: Context lines to include

        Returns:
            DiffResult with diff info
        """

        def _diff() -> DiffResult:
            repo = self.repo
            file_diffs = []
            total_additions = 0
            total_deletions = 0

            try:
                # Determine what to diff
                if base is None and head is None:
                    # Working tree vs staged
                    diffs = repo.index.diff(None, create_patch=True)
                elif base is None:
                    # Working tree vs specified ref
                    diffs = repo.commit(head).diff(None, create_patch=True)
                elif head is None:
                    # Specified ref vs HEAD
                    diffs = repo.commit(base).diff("HEAD", create_patch=True)
                else:
                    # Between two refs
                    diffs = repo.commit(base).diff(head, create_patch=True)

                for diff in diffs:
                    # Filter by files if specified
                    if files and diff.a_path not in files and diff.b_path not in files:
                        continue

                    change_type = self._diff_to_change_type(diff.change_type)
                    path = diff.b_path or diff.a_path or ""

                    # Parse hunks from patch
                    hunks = []
                    additions = 0
                    deletions = 0

                    if diff.diff:
                        # Handle both bytes and str
                        raw_diff = diff.diff
                        patch_text = (
                            raw_diff.decode("utf-8", errors="replace")
                            if isinstance(raw_diff, bytes)
                            else raw_diff
                        )
                        # Parse hunks (simplified)
                        for line in patch_text.split("\n"):
                            if line.startswith("+") and not line.startswith("+++"):
                                additions += 1
                            elif line.startswith("-") and not line.startswith("---"):
                                deletions += 1

                        # Add as single hunk for now
                        hunks.append(
                            DiffHunk(
                                old_start=1,
                                old_lines=deletions,
                                new_start=1,
                                new_lines=additions,
                                content=patch_text[: self.settings.git_max_diff_lines],
                            )
                        )

                    file_diffs.append(
                        FileDiff(
                            path=path,
                            change_type=change_type,
                            old_path=diff.a_path if diff.renamed else None,
                            hunks=hunks,
                            additions=additions,
                            deletions=deletions,
                            is_binary=diff.diff is None and not diff.deleted_file,
                        ).to_dict()
                    )

                    total_additions += additions
                    total_deletions += deletions

                return DiffResult(
                    project_id="",  # Set by caller
                    base=base,
                    head=head,
                    files=file_diffs,
                    total_additions=total_additions,
                    total_deletions=total_deletions,
                    files_changed=len(file_diffs),
                )

            except GitCommandError as e:
                raise GitError(f"Diff failed: {e}")

        return await run_in_executor(_diff)

    # Log operations

    async def log(
        self,
        ref: str | None = None,
        limit: int = 20,
        skip: int = 0,
        path: str | None = None,
    ) -> LogResult:
        """
        Get commit log.

        Args:
            ref: Reference to start from
            limit: Max commits to return
            skip: Commits to skip
            path: Filter by path

        Returns:
            LogResult with commit history
        """

        def _log() -> LogResult:
            repo = self.repo
            commits = []

            try:
                kwargs: dict[str, Any] = {
                    "max_count": limit,
                    "skip": skip,
                }

                if path:
                    kwargs["paths"] = path

                if ref:
                    iterator = repo.iter_commits(ref, **kwargs)
                else:
                    iterator = repo.iter_commits(**kwargs)

                for commit in iterator:
                    # Handle message that can be bytes
                    msg = commit.message
                    message_str = (
                        msg.decode("utf-8", errors="replace")
                        if isinstance(msg, bytes)
                        else msg
                    )
                    commits.append(
                        CommitInfo(
                            sha=commit.hexsha,
                            short_sha=commit.hexsha[:7],
                            message=message_str,
                            author_name=commit.author.name or "Unknown",
                            author_email=commit.author.email or "",
                            authored_date=datetime.fromtimestamp(
                                commit.authored_date, tz=UTC
                            ),
                            committer_name=commit.committer.name or "Unknown",
                            committer_email=commit.committer.email or "",
                            committed_date=datetime.fromtimestamp(
                                commit.committed_date, tz=UTC
                            ),
                            parents=[p.hexsha for p in commit.parents],
                        ).to_dict()
                    )

                return LogResult(
                    project_id="",  # Set by caller
                    commits=commits,
                    total_commits=len(commits),
                )

            except GitCommandError as e:
                raise GitError(f"Log failed: {e}")

        return await run_in_executor(_log)

    # Reset operations

    async def reset(
        self,
        ref: str = "HEAD",
        mode: str = "mixed",
        files: list[str] | None = None,
    ) -> bool:
        """
        Reset to a ref.

        Args:
            ref: Reference to reset to
            mode: Reset mode (soft, mixed, hard)
            files: Specific files to reset

        Returns:
            True if successful
        """

        def _reset() -> bool:
            repo = self.repo
            try:
                if files:
                    # Reset specific files
                    repo.index.reset(commit=ref, paths=files)
                else:
                    # Full reset
                    if mode == "soft":
                        repo.head.reset(ref, index=False, working_tree=False)
                    elif mode == "mixed":
                        repo.head.reset(ref, index=True, working_tree=False)
                    elif mode == "hard":
                        repo.head.reset(ref, index=True, working_tree=True)
                    else:
                        raise GitError(f"Invalid reset mode: {mode}")

                return True
            except GitCommandError as e:
                raise GitError(f"Reset failed: {e}")

        return await run_in_executor(_reset)

    # Stash operations

    async def stash(self, message: str | None = None) -> str | None:
        """
        Stash changes.

        Args:
            message: Optional stash message

        Returns:
            Stash reference or None if nothing to stash
        """

        def _stash() -> str | None:
            repo = self.repo
            try:
                if message:
                    result = repo.git.stash("push", "-m", message)
                else:
                    result = repo.git.stash("push")

                if "No local changes to save" in result:
                    return None

                return repo.git.stash("list").split("\n")[0].split(":")[0]
            except GitCommandError as e:
                raise GitError(f"Stash failed: {e}")

        return await run_in_executor(_stash)

    async def stash_pop(self, stash_ref: str | None = None) -> bool:
        """
        Pop stashed changes.

        Args:
            stash_ref: Specific stash to pop

        Returns:
            True if successful
        """

        def _stash_pop() -> bool:
            repo = self.repo
            try:
                if stash_ref:
                    repo.git.stash("pop", stash_ref)
                else:
                    repo.git.stash("pop")
                return True
            except GitCommandError as e:
                if "conflict" in str(e).lower():
                    raise MergeConflictError([])
                raise GitError(f"Stash pop failed: {e}")

        return await run_in_executor(_stash_pop)

    # Utility methods

    def _diff_to_change_type(self, change_type: str | None) -> FileChangeType:
        """Convert GitPython change type to our enum."""
        if change_type is None:
            return FileChangeType.MODIFIED
        mapping = {
            "A": FileChangeType.ADDED,
            "M": FileChangeType.MODIFIED,
            "D": FileChangeType.DELETED,
            "R": FileChangeType.RENAMED,
            "C": FileChangeType.COPIED,
        }
        return mapping.get(change_type, FileChangeType.MODIFIED)

    async def is_valid_ref(self, ref: str) -> bool:
        """Check if a reference is valid."""

        def _check() -> bool:
            try:
                self.repo.commit(ref)
                return True
            except Exception:
                return False

        return await run_in_executor(_check)

    async def get_remote_url(self, remote: str = "origin") -> str | None:
        """Get the URL for a remote."""

        def _get_url() -> str | None:
            repo = self.repo
            if remote in [r.name for r in repo.remotes]:
                return repo.remote(remote).url
            return None

        return await run_in_executor(_get_url)

    async def set_config(self, key: str, value: str, global_: bool = False) -> None:
        """Set a git config value."""

        def _set_config() -> None:
            repo = self.repo
            with repo.config_writer("global" if global_ else "repository") as cw:
                section, option = key.rsplit(".", 1)
                cw.set_value(section, option, value)

        await run_in_executor(_set_config)

    async def get_config(self, key: str) -> str | None:
        """Get a git config value."""

        def _get_config() -> str | None:
            repo = self.repo
            try:
                cr = repo.config_reader()
                section, option = key.rsplit(".", 1)
                value = cr.get_value(section, option)
                return str(value) if value is not None else None
            except Exception:
                return None

        return await run_in_executor(_get_config)