import time
from typing import Optional, Tuple
import tempfile
from queue import Queue, Empty
from threading import Thread
import wave
import os

SAMPLE_RATE = 44100
MICROPHONE = 'default'
DEST_FOLDER = "/dev/shm/"


class SlicedPlayer(Thread):
    BYTES_PER_SAMPLE = 2  # 16bit

    def __init__(self, slice_size: float, sample_rate=SAMPLE_RATE, microphone=MICROPHONE, dest_folder=DEST_FOLDER):
        super().__init__()
        self._output_queue = Queue()
        self._active = True
        self._wavefile = wave.open(microphone, "rb")
        self._sample_rate = self._wavefile.getframerate()
        self._dest_folder = dest_folder
        self._samples_per_slice = int(self._sample_rate * slice_size)
        self._slice_size = slice_size  # length in seconds

    def _request_new_file(self) -> Tuple[str, wave.Wave_write]:
        file_handle, record_path = tempfile.mkstemp(prefix="rec", suffix=".wav", dir=self._dest_folder)
        wavefile = wave.open(open(file_handle, 'wb'), 'wb')
        wavefile.setnchannels(self._wavefile.getnchannels())
        wavefile.setframerate(self._sample_rate)
        wavefile.setsampwidth(self.BYTES_PER_SAMPLE)  # 16bit
        return record_path, wavefile

    def run(self):

        while self._active:
            time_started = time.time()
            current_working_file_name, current_working_file = self._request_new_file()

            sound_data = bytes()
            while True:
                sound_data += self._wavefile.readframes(self._samples_per_slice - len(sound_data))

                if len(sound_data) < self._samples_per_slice:
                    self._wavefile.rewind()
                else:
                    break

            current_working_file.writeframes(sound_data)
            current_working_file.close()
            self._output_queue.put(current_working_file_name)

            time.sleep(self._slice_size - (time.time() - time_started))  # Emulate recording time

    def get_recording(self, blocking: bool) -> Optional[str]:
        try:
            return self._output_queue.get(block=blocking)
        except Empty:
            return None

    def get_queue_length(self) -> int:
        return self._output_queue.qsize()

    def stop(self):
        self._active = False


class BirbnetesIoTPlatformRecordDriver:
    sliced_recorder = None

    @classmethod
    def init(cls, sample_length_sec: float, sample_rate=SAMPLE_RATE, microphone=MICROPHONE, dest_folder=DEST_FOLDER):
        cls.sliced_recorder = SlicedPlayer(sample_length_sec, sample_rate, microphone, dest_folder)
        cls.sliced_recorder.start()

    @classmethod
    def get_recording(cls, blocking: bool = False) -> Optional[str]:
        return cls.sliced_recorder.get_recording(blocking)

    @classmethod
    def get_queue_length(cls) -> int:
        return cls.sliced_recorder.get_queue_length()

    @classmethod
    def cleanup(cls):
        cls.sliced_recorder.stop()

        while True:
            fname = cls.sliced_recorder.get_recording(False)
            if fname:
                os.unlink(fname)
            else:
                break