import base64
import logging
from typing import Any

from github3 import exceptions as github_exceptions, login as github_login
from github3.exceptions import ForbiddenError, NotFoundError
from github3.repos.contents import Contents

logger = logging.getLogger(__name__)

# List of common code file extensions to target
CODE_EXTENSIONS = {
    ".py",
    ".js",
    ".jsx",
    ".ts",
    ".tsx",
    ".java",
    ".c",
    ".cpp",
    ".h",
    ".hpp",
    ".cs",
    ".go",
    ".rb",
    ".php",
    ".swift",
    ".kt",
    ".scala",
    ".rs",
    ".m",
    ".sh",
    ".bash",
    ".ps1",
    ".lua",
    ".pl",
    ".pm",
    ".r",
    ".dart",
    ".sql",
}

# List of common documentation/text file extensions
DOC_EXTENSIONS = {
    ".md",
    ".txt",
    ".rst",
    ".adoc",
    ".html",
    ".htm",
    ".xml",
    ".json",
    ".yaml",
    ".yml",
    ".toml",
}

# Maximum file size in bytes (e.g., 1MB)
MAX_FILE_SIZE = 1 * 1024 * 1024


class GitHubConnector:
    """Connector for interacting with the GitHub API."""

    # Directories to skip during file traversal
    SKIPPED_DIRS = {
        # Version control
        ".git",
        # Dependencies
        "node_modules",
        "vendor",
        # Build artifacts / Caches
        "build",
        "dist",
        "target",
        "__pycache__",
        # Virtual environments
        "venv",
        ".venv",
        "env",
        # IDE/Editor config
        ".vscode",
        ".idea",
        ".project",
        ".settings",
        # Temporary / Logs
        "tmp",
        "logs",
        # Add other project-specific irrelevant directories if needed
    }

    def __init__(self, token: str):
        """
        Initializes the GitHub connector.

        Args:
            token: GitHub Personal Access Token (PAT).
        """
        if not token:
            raise ValueError("GitHub token cannot be empty.")
        try:
            self.gh = github_login(token=token)
            # Try a simple authenticated call to check token validity
            self.gh.me()
            logger.info("Successfully authenticated with GitHub API.")
        except (github_exceptions.AuthenticationFailed, ForbiddenError) as e:
            logger.error(f"GitHub authentication failed: {e}")
            raise ValueError("Invalid GitHub token or insufficient permissions.") from e
        except Exception as e:
            logger.error(f"Failed to initialize GitHub client: {e}")
            raise e

    def get_user_repositories(self) -> list[dict[str, Any]]:
        """Fetches repositories accessible by the authenticated user."""
        repos_data = []
        try:
            # type='owner' fetches repos owned by the user
            # type='member' fetches repos the user is a collaborator on (including orgs)
            # type='all' fetches both
            for repo in self.gh.repositories(type="all", sort="updated"):
                repos_data.append(
                    {
                        "id": repo.id,
                        "name": repo.name,
                        "full_name": repo.full_name,
                        "private": repo.private,
                        "url": repo.html_url,
                        "description": repo.description or "",
                        "last_updated": repo.updated_at if repo.updated_at else None,
                    }
                )
            logger.info(f"Fetched {len(repos_data)} repositories.")
            return repos_data
        except Exception as e:
            logger.error(f"Failed to fetch GitHub repositories: {e}")
            return []  # Return empty list on error

    def get_repository_files(
        self, repo_full_name: str, path: str = ""
    ) -> list[dict[str, Any]]:
        """
        Recursively fetches details of relevant files (code, docs) within a repository path.

        Args:
            repo_full_name: The full name of the repository (e.g., 'owner/repo').
            path: The starting path within the repository (default is root).

        Returns:
            A list of dictionaries, each containing file details (path, sha, url, size).
            Returns an empty list if the repository or path is not found or on error.
        """
        files_list = []
        try:
            owner, repo_name = repo_full_name.split("/")
            repo = self.gh.repository(owner, repo_name)
            if not repo:
                logger.warning(f"Repository '{repo_full_name}' not found.")
                return []
            contents = repo.directory_contents(
                directory_path=path
            )  # Use directory_contents for clarity

            # contents returns a list of tuples (name, content_obj)
            for _item_name, content_item in contents:
                if not isinstance(content_item, Contents):
                    continue

                if content_item.type == "dir":
                    # Check if the directory name is in the skipped list
                    if content_item.name in self.SKIPPED_DIRS:
                        logger.debug(f"Skipping directory: {content_item.path}")
                        continue  # Skip recursion for this directory

                    # Recursively fetch contents of subdirectory
                    files_list.extend(
                        self.get_repository_files(
                            repo_full_name, path=content_item.path
                        )
                    )
                elif content_item.type == "file":
                    # Check if the file extension is relevant and size is within limits
                    file_extension = (
                        "." + content_item.name.split(".")[-1].lower()
                        if "." in content_item.name
                        else ""
                    )
                    is_code = file_extension in CODE_EXTENSIONS
                    is_doc = file_extension in DOC_EXTENSIONS

                    if (is_code or is_doc) and content_item.size <= MAX_FILE_SIZE:
                        files_list.append(
                            {
                                "path": content_item.path,
                                "sha": content_item.sha,
                                "url": content_item.html_url,
                                "size": content_item.size,
                                "type": "code" if is_code else "doc",
                            }
                        )
                    elif content_item.size > MAX_FILE_SIZE:
                        logger.debug(
                            f"Skipping large file: {content_item.path} ({content_item.size} bytes)"
                        )
                    else:
                        logger.debug(
                            f"Skipping irrelevant file type: {content_item.path}"
                        )

        except (NotFoundError, ForbiddenError) as e:
            logger.warning(f"Cannot access path '{path}' in '{repo_full_name}': {e}")
        except Exception as e:
            logger.error(
                f"Failed to get files for {repo_full_name} at path '{path}': {e}"
            )
            # Return what we have collected so far in case of partial failure

        return files_list

    def get_file_content(self, repo_full_name: str, file_path: str) -> str | None:
        """
        Fetches the decoded content of a specific file.

        Args:
            repo_full_name: The full name of the repository (e.g., 'owner/repo').
            file_path: The path to the file within the repository.

        Returns:
            The decoded file content as a string, or None if fetching fails or file is too large.
        """
        try:
            owner, repo_name = repo_full_name.split("/")
            repo = self.gh.repository(owner, repo_name)
            if not repo:
                logger.warning(
                    f"Repository '{repo_full_name}' not found when fetching file '{file_path}'."
                )
                return None

            content_item = repo.file_contents(
                path=file_path
            )  # Use file_contents for clarity

            if (
                not content_item
                or not isinstance(content_item, Contents)
                or content_item.type != "file"
            ):
                logger.warning(
                    f"File '{file_path}' not found or is not a file in '{repo_full_name}'."
                )
                return None

            if content_item.size > MAX_FILE_SIZE:
                logger.warning(
                    f"File '{file_path}' in '{repo_full_name}' exceeds max size ({content_item.size} > {MAX_FILE_SIZE}). Skipping content fetch."
                )
                return None

            # Content is base64 encoded
            if content_item.content:
                try:
                    decoded_content = base64.b64decode(content_item.content).decode(
                        "utf-8"
                    )
                    return decoded_content
                except UnicodeDecodeError:
                    logger.warning(
                        f"Could not decode file '{file_path}' in '{repo_full_name}' as UTF-8. Trying with 'latin-1'."
                    )
                    try:
                        # Try a fallback encoding
                        decoded_content = base64.b64decode(content_item.content).decode(
                            "latin-1"
                        )
                        return decoded_content
                    except Exception as decode_err:
                        logger.error(
                            f"Failed to decode file '{file_path}' with fallback encoding: {decode_err}"
                        )
                        return None  # Give up if fallback fails
            else:
                logger.warning(
                    f"No content returned for file '{file_path}' in '{repo_full_name}'. It might be empty."
                )
                return ""  # Return empty string for empty files

        except (NotFoundError, ForbiddenError) as e:
            logger.warning(
                f"Cannot access file '{file_path}' in '{repo_full_name}': {e}"
            )
            return None
        except Exception as e:
            logger.error(
                f"Failed to get content for file '{file_path}' in '{repo_full_name}': {e}"
            )
            return None