import os
import sys
from typing import Optional, Any

IS_WINDOWS: bool = sys.platform == "win32"

if IS_WINDOWS:
    import win32pipe
    import win32file
    import pywintypes
else:
    import errno


class PipeOperator:
    """
    A Python implementation of the pipe operator similar to the C++ version.
    Uses win32pipe on Windows and os.mkfifo on POSIX systems.
    """

    pipe_handle: Optional[int]
    pipe_name: str

    def __init__(self, name: str):
        """
        Initialize the PipeOperator.
        
        :param name: Name of the pipe
        :param is_server: True if this instance should create the pipe (server), False if connecting to existing pipe (client)
        """
        self.pipe_handle = None

        if IS_WINDOWS:
            self.pipe_name = f"\\\\.\\pipe\\{name}"
            self.pipe_handle = win32pipe.CreateNamedPipe(
                self.pipe_name,
                win32pipe.PIPE_ACCESS_DUPLEX,
                win32pipe.PIPE_TYPE_BYTE | win32pipe.PIPE_READMODE_BYTE
                | win32pipe.PIPE_WAIT,
                1,  # Number of pipe instances
                65536,  # Output buffer size
                65536,  # Input buffer size
                0,  # Default timeout
                None  # Security attributes
            )
            if self.pipe_handle == win32file.INVALID_HANDLE_VALUE:
                raise RuntimeError("Failed to create named pipe.")

            # Wait for client to connect
            win32pipe.ConnectNamedPipe(self.pipe_handle, None)
        else:
            # POSIX implementation
            self.pipe_name = f"/tmp/{name}"
            try:
                os.mkfifo(self.pipe_name)
            except OSError as e:
                if e.errno != errno.EEXIST:
                    raise RuntimeError(f"Failed to create named pipe: {e}")

            # Open the FIFO for reading and writing (blocks until client connects)
            self.pipe_handle = os.open(self.pipe_name, os.O_RDWR)

    def __del__(self):
        """Cleanup resources when object is destroyed."""
        self.close()

    def close(self):
        """Close the pipe handle."""
        if self.pipe_handle is not None:
            if IS_WINDOWS:
                win32file.CloseHandle(self.pipe_handle)
            else:
                os.close(self.pipe_handle)
                # Remove the FIFO file if it is existing
                if os.path.exists(self.pipe_name):
                    os.unlink(self.pipe_name)

            self.pipe_handle = None

    def read(self, size: int) -> bytes:
        """
        Read data from the pipe. This is a blocking operation.
        
        :param size: Number of bytes to read
        :return: Bytes read from the pipe
        """
        if size <= 0:
            return b""

        if self.pipe_handle is None:
            raise RuntimeError("Pipe is not open")

        if IS_WINDOWS:
            try:
                # The result is a tuple of (hr, string/PyOVERLAPPEDReadBuffer).
                # You can convert this to a string (str(object)) [py2k] or (bytes(object)) [py3k] to obtain the data.
                # I can't visit PyOVERLAPPEDReadBuffer so I simply set it to Any
                data: Any
                (hr, data) = win32file.ReadFile(self.pipe_handle, size)
                if hr != 0:  # Error occurred
                    raise RuntimeError(
                        f"Failed to read from pipe, error code: {hr}")
                data = bytes(data)
                if len(data) != size:
                    raise RuntimeError(
                        f"Incomplete read from pipe: expected {size} bytes, got {len(data)} bytes"
                    )
                return data
            except pywintypes.error as e:
                raise RuntimeError(f"Failed to read from named pipe: {e}")
        else:
            # POSIX implementation
            data = b""
            while len(data) < size:
                try:
                    chunk = os.read(self.pipe_handle, size - len(data))
                    if not chunk:
                        raise RuntimeError("Named pipe closed during read")
                    data += chunk
                except OSError as e:
                    raise RuntimeError(f"Failed to read from named pipe: {e}")

            if len(data) != size:
                raise RuntimeError(
                    f"Incomplete read from pipe: expected {size} bytes, got {len(data)} bytes"
                )

            return data

    def write(self, data: bytes) -> None:
        """
        Write data to the pipe. This is a blocking operation.
        
        :param data: Data to write to the pipe
        """
        if len(data) == 0:
            return

        if self.pipe_handle is None:
            raise RuntimeError("Pipe is not open")

        if IS_WINDOWS:
            try:
                win32file.WriteFile(self.pipe_handle, data)
            except pywintypes.error as e:
                raise RuntimeError(f"Failed to write to named pipe: {e}")
        else:
            # POSIX implementation
            total_written = 0
            while total_written < len(data):
                try:
                    bytes_written = os.write(self.pipe_handle,
                                             data[total_written:])
                    total_written += bytes_written
                except OSError as e:
                    raise RuntimeError(f"Failed to write to named pipe: {e}")


# class PipeServer:
#     """
#     A convenience class for creating a pipe server that can handle connections in a separate thread.
#     """

#     def __init__(self, name: str):
#         self._name = name
#         self._pipe_operator: Optional[PipeOperator] = None
#         self._server_thread: Optional[threading.Thread] = None
#         self._stop_event = threading.Event()

#     def start_server(self, handler_func):
#         """
#         Start the pipe server in a separate thread.
        
#         :param handler_func: Function to handle the connected pipe (takes PipeOperator as parameter)
#         """
#         self._server_thread = threading.Thread(target=self._server_worker,
#                                                args=(handler_func, ))
#         self._server_thread.start()

#     def _server_worker(self, handler_func):
#         """Internal method to handle server operations."""
#         try:
#             # Create pipe server
#             pipe_op = PipeOperator(self._name, is_server=True)
#             self._pipe_operator = pipe_op

#             # Call the handler function with the connected pipe
#             handler_func(pipe_op)
#         except Exception as e:
#             print(f"Error in pipe server: {e}")
#         finally:
#             if self._pipe_operator:
#                 self._pipe_operator.close()

#     def stop_server(self):
#         """Stop the pipe server."""
#         self._stop_event.set()
#         if self._server_thread:
#             self._server_thread.join()

#     def get_pipe(self) -> Optional[PipeOperator]:
#         """Get the connected pipe operator (only valid after client connects)."""
#         return self._pipe_operator