"""Git operations handler for Git Commit AI."""

import os
from pathlib import Path
from typing import Optional

from git import Repo
from git.exc import GitCommandError, InvalidGitRepositoryError


class GitHandler:
    """Handler for Git operations."""

    def __init__(self, repo_path: Optional[str] = None):
        if repo_path is None:
            repo_path = os.getcwd()
        self.repo_path = Path(repo_path)
        self._repo: Optional[Repo] = None

    @property
    def repo(self) -> Repo:
        if self._repo is None:
            self._repo = Repo(str(self.repo_path))
        return self._repo

    def is_repository(self) -> bool:
        try:
            self.repo.git.status()
            return True
        except (InvalidGitRepositoryError, GitCommandError):
            return False

    def ensure_repository(self) -> bool:
        return self.is_repository()

    def get_staged_changes(self) -> str:
        try:
            if not self.is_staged():
                return ""

            diff = self.repo.git.diff("--cached")
            return diff
        except GitCommandError as e:
            raise GitError(f"Failed to get staged changes: {e}") from e

    def get_staged_files(self) -> list[str]:
        try:
            staged = self.repo.index.diff("HEAD")
            return [s.a_path for s in staged]
        except GitCommandError:
            return []

    def is_staged(self) -> bool:
        try:
            return bool(self.repo.index.diff("HEAD"))
        except GitCommandError:
            return False

    def get_commit_history(self, max_commits: int = 5, conventional_only: bool = False) -> list[dict[str, str]]:
        try:
            commits = []
            for commit in self.repo.iter_commits(max_count=max_commits):
                message = commit.message.strip()
                if conventional_only:
                    if not self._is_conventional(message):
                        continue

                commits.append({"hash": commit.hexsha[:7], "message": message, "type": self._extract_type(message)})
            return commits
        except GitCommandError as e:
            raise GitError(f"Failed to get commit history: {e}") from e

    def _is_conventional(self, message: str) -> bool:
        conventional_types = ["feat", "fix", "docs", "style", "refactor", "perf", "test", "build", "ci", "chore", "revert"]
        return any(message.startswith(f"{t}:") for t in conventional_types)

    def _extract_type(self, message: str) -> str:
        conventional_types = ["feat", "fix", "docs", "style", "refactor", "perf", "test", "build", "ci", "chore", "revert"]
        for t in conventional_types:
            if message.startswith(f"{t}:"):
                return t
        return "unknown"

    def get_changed_languages(self) -> list[str]:
        staged_files = self.get_staged_files()
        languages = set()

        extension_map = {
            ".py": "Python", ".js": "JavaScript", ".ts": "TypeScript", ".jsx": "React", ".tsx": "TypeScript React",
            ".java": "Java", ".go": "Go", ".rs": "Rust", ".rb": "Ruby", ".php": "PHP", ".swift": "Swift",
            ".c": "C", ".cpp": "C++", ".h": "C Header", ".cs": "C#", ".scala": "Scala", ".kt": "Kotlin",
            ".lua": "Lua", ".r": "R", ".sql": "SQL", ".html": "HTML", ".css": "CSS", ".scss": "SCSS",
            ".json": "JSON", ".yaml": "YAML", ".yml": "YAML", ".xml": "XML", ".md": "Markdown",
            ".sh": "Shell", ".bash": "Bash", ".zsh": "Zsh", ".dockerfile": "Docker", ".tf": "Terraform",
        }

        for file_path in staged_files:
            ext = Path(file_path).suffix.lower()
            if ext in extension_map:
                languages.add(extension_map[ext])

        return sorted(list(languages))

    def get_diff_summary(self) -> str:
        diff = self.get_staged_changes()
        if not diff:
            return "No staged changes"

        files = self.get_staged_files()
        languages = self.get_changed_languages()

        summary = f"Files changed: {len(files)}\n"
        if languages:
            summary += f"Languages: {', '.join(languages)}\n"
        summary += f"\nDiff length: {len(diff)} characters"

        return summary


class GitError(Exception):
    """Exception raised for Git-related errors."""
    pass


def get_git_handler(repo_path: Optional[str] = None) -> GitHandler:
    return GitHandler(repo_path)