from typing import Any, Optional, Type

from crewai.tools import BaseTool
from pydantic import BaseModel, Field


class FileReadToolSchema(BaseModel):
    """Input for FileReadTool."""

    file_path: str = Field(..., description="Mandatory file full path to read the file")


class FileReadTool(BaseTool):
    """A tool for reading file contents.

    This tool inherits its schema handling from BaseTool to avoid recursive schema
    definition issues. The args_schema is set to FileReadToolSchema which defines
    the required file_path parameter. The schema should not be overridden in the
    constructor as it would break the inheritance chain and cause infinite loops.

    The tool supports two ways of specifying the file path:
    1. At construction time via the file_path parameter
    2. At runtime via the file_path parameter in the tool's input

    Args:
        file_path (Optional[str]): Path to the file to be read. If provided,
            this becomes the default file path for the tool.
        **kwargs: Additional keyword arguments passed to BaseTool.

    Example:
        >>> tool = FileReadTool(file_path="/path/to/file.txt")
        >>> content = tool.run()  # Reads /path/to/file.txt
        >>> content = tool.run(file_path="/path/to/other.txt")  # Reads other.txt
    """
    name: str = "Read a file's content"
    description: str = "A tool that reads the content of a file. To use this tool, provide a 'file_path' parameter with the path to the file you want to read."
    args_schema: Type[BaseModel] = FileReadToolSchema
    file_path: Optional[str] = None

    def __init__(self, file_path: Optional[str] = None, **kwargs: Any) -> None:
        """Initialize the FileReadTool.

        Args:
            file_path (Optional[str]): Path to the file to be read. If provided,
                this becomes the default file path for the tool.
            **kwargs: Additional keyword arguments passed to BaseTool.
        """
        super().__init__(**kwargs)
        if file_path is not None:
            self.file_path = file_path
            self.description = f"A tool that reads file content. The default file is {file_path}, but you can provide a different 'file_path' parameter to read another file."

    def _run(
        self,
        **kwargs: Any,
    ) -> str:
        file_path = kwargs.get("file_path", self.file_path)
        if file_path is None:
            return "Error: No file path provided. Please provide a file path either in the constructor or as an argument."
        
        try:
            with open(file_path, "r") as file:
                return file.read()
        except FileNotFoundError:
            return f"Error: File not found at path: {file_path}"
        except PermissionError:
            return f"Error: Permission denied when trying to read file: {file_path}"
        except Exception as e:
            return f"Error: Failed to read file {file_path}. {str(e)}"

    def _generate_description(self) -> None:
        """Generate the tool description based on file path.

        This method updates the tool's description to include information about
        the default file path while maintaining the ability to specify a different
        file at runtime.

        Returns:
            None
        """
        self.description = f"A tool that can be used to read {self.file_path}'s content."
