# Copyright (c) 2023 - present, Anton Anikin <anton@anikin.xyz>
# All rights reserved.

import numpy as np
import platform
import struct
import sys

from typing import Optional

is_windows = (platform.system() == "Windows")
if is_windows:
    import win32file
    import win32pipe
    from time import sleep


class Ipc:
    def __init__(self, name: str, is_server: bool, verbose: int = 0):
        self.verbose = verbose

        if is_windows:
            full_name = f"\\\\.\\pipe\\{name}"

            if is_server:
                # https://mhammond.github.io/pywin32/win32pipe__CreateNamedPipe_meth.html
                self.pipe = win32pipe.CreateNamedPipe(
                    full_name, # pipeName : PyUnicode
                    win32pipe.PIPE_ACCESS_DUPLEX, # openMode : int
                    win32pipe.PIPE_TYPE_BYTE, # pipeMode : int
                    1, # nMaxInstances : int
                    0, # nOutBufferSize : int
                    0, # nInBufferSize : int
                    0, # nDefaultTimeOut : int
                    None # sa : PySECURITY_ATTRIBUTES
                )

                # https://mhammond.github.io/pywin32/win32pipe__ConnectNamedPipe_meth.html
                win32pipe.ConnectNamedPipe(self.pipe)

            else:
                time_step = 0.5
                time_current = 0
                while time_current < 10:
                    try:
                        # https://mhammond.github.io/pywin32/win32file__CreateFile_meth.html
                        self.pipe = win32file.CreateFile(
                            full_name, # fileName : PyUnicode
                            win32file.GENERIC_READ |
                            win32file.GENERIC_WRITE, # desiredAccess : int
                            0, # shareMode : int
                            None, # attributes : PySECURITY_ATTRIBUTES
                            win32file.OPEN_EXISTING, # CreationDisposition : int
                            win32file.FILE_ATTRIBUTE_NORMAL, # flagsAndAttributes : int
                            None # hTemplateFile : PyHANDLE
                        )
                        break

                    except Exception:
                        time_current += time_step
                        sleep(time_step)

        else: # unix-like systems ------------------------------------------------
            if is_server:
                self._reader = open(name + "_c", "rb")
                self._writer = open(name + "_s", "wb")
            else:
                self._writer = open(name + "_c", "wb")
                self._reader = open(name + "_s", "rb")

    def _write(self, data):
        if is_windows:
            # https://mhammond.github.io/pywin32/win32file__WriteFile_meth.html
            errCode, nBytesWritten = win32file.WriteFile(self.pipe, data)

        else:
            self._writer.write(data)
            self._writer.flush()

    def _read(self, len):
        if is_windows:
            try:
                # https://mhammond.github.io/pywin32/win32file__ReadFile_meth.html
                errCode, data = win32file.ReadFile(self.pipe, len)
            except Exception:
                data = None

            return data

        else:
            return self._reader.read(len)

    def write_int(self, value: int):
        data = struct.pack("i", value)
        self._write(data)

    def write_double(self, value: float):
        data = struct.pack("d", value)
        self._write(data)

    def write_array(self, array: np.ndarray):
        data = array.tobytes(order="C")
        self._write(data)

    def read_int(self) -> int:
        data = self._read(4)
        return struct.unpack("i", data)[0]

    def read_int_opt(self) -> Optional[int]:
        data = self._read(4)
        if data:
            return struct.unpack("i", data)[0]
        else:
            return None

    def read_double(self) -> float:
        data = self._read(8)
        return struct.unpack("d", data)[0]

    def read_array(self, size: int, dtype: np.dtype) -> np.ndarray:
        data = self._read(size * dtype(0).itemsize)
        array = np.frombuffer(data, dtype=dtype)

        # fix for 'ValueError: assignment destination is read-only' on windows OS
        array = np.copy(array)

        return array

    def read_str(self) -> str:
        len = self.read_int()
        data = self._read(len)
        return data.decode(sys.getdefaultencoding())

    def read_str_opt(self) -> Optional[str]:
        len = self.read_int_opt()
        if len:
            data = self._read(len)
            return data.decode(sys.getdefaultencoding())
        else:
            return None