from threading import Lock

from .io_buffer import IOBuffer

class WebIOBuffer(IOBuffer):
    """
    Thread-safe WebIOBuffer that maintains the synchronous IOBuffer interface.
    Uses threading primitives instead of asyncio for synchronization.
    """
    def __init__(self):
        self._stdin_buffer = ""
        self._stdout_buffer = ""
        self._lock = Lock()
        
    def append_stdin(self, content: str) -> None:
        """Thread-safe append to stdin buffer."""
        if not content:
            return
            
        with self._lock:
            self._stdin_buffer += content
    
    def read(self) -> str:
        """Thread-safe read from stdin buffer."""
        with self._lock:
            content = self._stdin_buffer
            self._stdin_buffer = ""
            return content
            
    def write(self, content: str) -> None:
        """Thread-safe write to stdout buffer."""
        if not content:
            return
            
        with self._lock:
            self._stdout_buffer += content
            
    def buffer_length(self) -> int:
        """
        Get the current length of the stdin buffer.
        
        Returns:
            int: Number of characters in the stdin buffer
        """
        return len(self._stdin_buffer)
        
    def append_stdin(self, content: str) -> None:
        """
        Append content to the stdin buffer.
        
        Args:
            content: String content to append to the stdin buffer
        """
        if content:
            self._stdin_buffer += content
            
    def get_stdout(self) -> str:
        """Thread-safe get stdout content."""
        with self._lock:
            return self._stdout_buffer
            
    def clear_stdout(self) -> None:
        """Thread-safe clear stdout buffer."""
        with self._lock:
            self._stdout_buffer = ""
            
    def buffer_length(self) -> int:
        """Thread-safe get stdin buffer length."""
        with self._lock:
            return len(self._stdin_buffer)