#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Name: Video2X Upscaler
Author: K4YT3X
Date Created: December 10, 2018
Last Modified: August 15, 2019

Dev: SAT3LL

Licensed under the GNU General Public License Version 3 (GNU GPL v3),
    available at: https://www.gnu.org/licenses/gpl-3.0.txt

(C) 2018-2019 K4YT3X
"""

# local imports
from anime4k import Anime4k
from exceptions import *
from ffmpeg import Ffmpeg
from image_cleaner import ImageCleaner
from waifu2x_caffe import Waifu2xCaffe
from waifu2x_converter import Waifu2xConverter
from waifu2x_ncnn_vulkan import Waifu2xNcnnVulkan

# built-in imports
from fractions import Fraction
import copy
import pathlib
import re
import shutil
import tempfile
import threading
import time
import traceback

# third-party imports
from avalon_framework import Avalon
from tqdm import tqdm

AVAILABLE_DRIVERS = ['waifu2x_caffe', 'waifu2x_converter', 'waifu2x_ncnn_vulkan', 'anime4k']


class Upscaler:
    """ An instance of this class is a upscaler that will
    upscale all images in the given directory.

    Raises:
        Exception -- all exceptions
        ArgumentError -- if argument is not valid
    """

    def __init__(self, input_video, output_video, method, waifu2x_settings, ffmpeg_settings):
        # mandatory arguments
        self.input_video = input_video
        self.output_video = output_video
        self.method = method
        self.waifu2x_settings = waifu2x_settings
        self.ffmpeg_settings = ffmpeg_settings

        # optional arguments
        self.waifu2x_driver = 'waifu2x_caffe'
        self.scale_width = None
        self.scale_height = None
        self.scale_ratio = None
        self.model_dir = None
        self.threads = 5
        self.video2x_cache_directory = pathlib.Path(tempfile.gettempdir()) / 'video2x'
        self.image_format = 'png'
        self.preserve_frames = False

    def create_temp_directories(self):
        """create temporary directory
        """
        self.extracted_frames = pathlib.Path(tempfile.mkdtemp(dir=self.video2x_cache_directory))
        Avalon.debug_info(f'Extracted frames are being saved to: {self.extracted_frames}')
        self.upscaled_frames = pathlib.Path(tempfile.mkdtemp(dir=self.video2x_cache_directory))
        Avalon.debug_info(f'Upscaled frames are being saved to: {self.upscaled_frames}')

    def cleanup_temp_directories(self):
        """delete temp directories when done
        """
        if not self.preserve_frames:
            for directory in [self.extracted_frames, self.upscaled_frames]:
                try:
                    # avalon framework cannot be used if python is shutting down
                    # therefore, plain print is used
                    print(f'Cleaning up cache directory: {directory}')
                    shutil.rmtree(directory)
                except (OSError, FileNotFoundError):
                    print(f'Unable to delete: {directory}')
                    traceback.print_exc()

    def _check_arguments(self):
        # check if arguments are valid / all necessary argument
        # values are specified
        if not self.input_video:
            raise ArgumentError('You need to specify the video to process')
        elif (not self.scale_width or not self.scale_height) and not self.scale_ratio:
            raise ArgumentError('You must specify output video width and height or upscale factor')
        elif not self.output_video:
            raise ArgumentError('You need to specify the output video name')
        elif not self.method:
            raise ArgumentError('You need to specify the enlarging processing unit')

    def _progress_bar(self, extracted_frames_directories):
        """ This method prints a progress bar

        This method prints a progress bar by keeping track
        of the amount of frames in the input directory
        and the output directory. This is originally
        suggested by @ArmandBernard.
        """

        # get number of extracted frames
        self.total_frames = 0
        for directory in extracted_frames_directories:
            self.total_frames += len([f for f in directory.iterdir() if str(f)[-4:] == f'.{self.image_format}'])

        with tqdm(total=self.total_frames, ascii=True, desc='Upscaling Progress') as progress_bar:

            # tqdm update method adds the value to the progress
            # bar instead of setting the value. Therefore, a delta
            # needs to be calculated.
            previous_cycle_frames = 0
            while not self.progress_bar_exit_signal:

                try:
                    self.total_frames_upscaled = len([f for f in self.upscaled_frames.iterdir() if str(f)[-4:] == f'.{self.image_format}'])
                    delta = self.total_frames_upscaled - previous_cycle_frames
                    previous_cycle_frames = self.total_frames_upscaled

                    # if upscaling is finished
                    if self.total_frames_upscaled >= self.total_frames:
                        return

                    # adds the delta into the progress bar
                    progress_bar.update(delta)
                except FileNotFoundError:
                    pass

                time.sleep(1)

    def _upscale_frames(self):
        """ Upscale video frames with waifu2x-caffe

        This function upscales all the frames extracted
        by ffmpeg using the waifu2x-caffe binary.

        Arguments:
            w2 {Waifu2x Object} -- initialized waifu2x object
        """

        # progress bar thread exit signal
        self.progress_bar_exit_signal = False

        # create a container for exceptions in threads
        # if this thread is not empty, then an exception has occured
        self.upscaler_exceptions = []

        # initialize waifu2x driver
        drivers = AVAILABLE_DRIVERS
        if self.waifu2x_driver not in drivers:
            raise UnrecognizedDriverError(f'Unrecognized waifu2x driver: {self.waifu2x_driver}')

        # it's easier to do multi-threading with waifu2x_converter
        # the number of threads can be passed directly to waifu2x_converter
        if self.waifu2x_driver == 'waifu2x_converter':
            w2 = Waifu2xConverter(self.waifu2x_settings, self.model_dir)

            progress_bar = threading.Thread(target=self._progress_bar, args=([self.extracted_frames],))
            progress_bar.start()

            w2.upscale(self.extracted_frames, self.upscaled_frames, self.scale_ratio, self.threads, self.image_format, self.upscaler_exceptions)
            for image in [f for f in self.upscaled_frames.iterdir() if f.is_file()]:
                renamed = re.sub(f'_\[.*-.*\]\[x(\d+(\.\d+)?)\]\.{self.image_format}', f'.{self.image_format}', str(image))
                (self.upscaled_frames / image).rename(self.upscaled_frames / renamed)

            self.progress_bar_exit_signal = True
            progress_bar.join()
            return

        # drivers that are to be multi-threaded by video2x
        else:
            # create a container for all upscaler threads
            upscaler_threads = []

            # list all images in the extracted frames
            frames = [(self.extracted_frames / f) for f in self.extracted_frames.iterdir() if f.is_file]

            # if we have less images than threads,
            # create only the threads necessary
            if len(frames) < self.threads:
                self.threads = len(frames)

            # create a directory for each thread and append directory
            # name into a list

            thread_pool = []
            thread_directories = []
            for thread_id in range(self.threads):
                thread_directory = self.extracted_frames / str(thread_id)
                thread_directories.append(thread_directory)

                # delete old directories and create new directories
                if thread_directory.is_dir():
                    shutil.rmtree(thread_directory)
                thread_directory.mkdir(parents=True, exist_ok=True)

                # append directory path into list
                thread_pool.append((thread_directory, thread_id))

            # evenly distribute images into each directory
            # until there is none left in the directory
            for image in frames:
                # move image
                image.rename(thread_pool[0][0] / image.name)
                # rotate list
                thread_pool = thread_pool[-1:] + thread_pool[:-1]

            # create threads and start them
            for thread_info in thread_pool:

                # create a separate w2 instance for each thread
                if self.waifu2x_driver == 'waifu2x_caffe':
                    w2 = Waifu2xCaffe(copy.deepcopy(self.waifu2x_settings), self.method, self.model_dir, self.bit_depth)
                    if self.scale_ratio:
                        thread = threading.Thread(target=w2.upscale,
                                                  args=(thread_info[0],
                                                        self.upscaled_frames,
                                                        self.scale_ratio,
                                                        False,
                                                        False,
                                                        self.image_format,
                                                        self.upscaler_exceptions))
                    else:
                        thread = threading.Thread(target=w2.upscale,
                                                  args=(thread_info[0],
                                                        self.upscaled_frames,
                                                        False,
                                                        self.scale_width,
                                                        self.scale_height,
                                                        self.image_format,
                                                        self.upscaler_exceptions))

                # if the driver being used is waifu2x_ncnn_vulkan
                elif self.waifu2x_driver == 'waifu2x_ncnn_vulkan':
                    w2 = Waifu2xNcnnVulkan(copy.deepcopy(self.waifu2x_settings))
                    thread = threading.Thread(target=w2.upscale,
                                              args=(thread_info[0],
                                                    self.upscaled_frames,
                                                    self.scale_ratio,
                                                    self.upscaler_exceptions))

                # if the driver being used is anime4k
                elif self.waifu2x_driver == 'anime4k':
                    w2 = Anime4k(copy.deepcopy(self.waifu2x_settings))
                    thread = threading.Thread(target=w2.upscale,
                                              args=(thread_info[0],
                                                    self.upscaled_frames,
                                                    self.scale_ratio,
                                                    self.upscaler_exceptions))

                # create thread
                thread.name = thread_info[1]

                # add threads into the pool
                upscaler_threads.append(thread)

            # start progress bar in a different thread
            progress_bar = threading.Thread(target=self._progress_bar, args=(thread_directories,))
            progress_bar.start()

            # create the clearer and start it
            Avalon.debug_info('Starting upscaled image cleaner')
            image_cleaner = ImageCleaner(self.extracted_frames, self.upscaled_frames, len(upscaler_threads))
            image_cleaner.start()

            # start all threads
            for thread in upscaler_threads:
                thread.start()

            # wait for threads to finish
            for thread in upscaler_threads:
                thread.join()

            # upscaling done, kill the clearer
            Avalon.debug_info('Killing upscaled image cleaner')
            image_cleaner.stop()

            self.progress_bar_exit_signal = True

            if len(self.upscaler_exceptions) != 0:
                raise(self.upscaler_exceptions[0])

    def run(self):
        """Main controller for Video2X

        This function controls the flow of video conversion
        and handles all necessary functions.
        """

        # parse arguments for waifu2x
        # check argument sanity
        self._check_arguments()

        # convert paths to absolute paths
        self.input_video = self.input_video.absolute()
        self.output_video = self.output_video.absolute()

        # initialize objects for ffmpeg and waifu2x-caffe
        fm = Ffmpeg(self.ffmpeg_settings, self.image_format)

        # extract frames from video
        fm.extract_frames(self.input_video, self.extracted_frames)

        Avalon.info('Reading video information')
        video_info = fm.get_video_info(self.input_video)
        # analyze original video with ffprobe and retrieve framerate
        # width, height = info['streams'][0]['width'], info['streams'][0]['height']

        # find index of video stream
        video_stream_index = None
        for stream in video_info['streams']:
            if stream['codec_type'] == 'video':
                video_stream_index = stream['index']
                break

        # exit if no video stream found
        if video_stream_index is None:
            Avalon.error('Aborting: No video stream found')
            raise StreamNotFoundError('no video stream found')

        # get average frame rate of video stream
        framerate = float(Fraction(video_info['streams'][video_stream_index]['avg_frame_rate']))
        fm.pixel_format = video_info['streams'][video_stream_index]['pix_fmt']

        # get a dict of all pixel formats and corresponding bit depth
        pixel_formats = fm.get_pixel_formats()

        try:
            self.bit_depth = pixel_formats[fm.pixel_format]
        except KeyError:
            Avalon.error(f'Unsupported pixel format: {fm.pixel_format}')
            raise UnsupportedPixelError(f'unsupported pixel format {fm.pixel_format}')

        Avalon.info(f'Framerate: {framerate}')

        # width/height will be coded width/height x upscale factor
        if self.scale_ratio:
            original_width = video_info['streams'][video_stream_index]['width']
            original_height = video_info['streams'][video_stream_index]['height']
            self.scale_width = int(self.scale_ratio * original_width)
            self.scale_height = int(self.scale_ratio * original_height)

        # upscale images one by one using waifu2x
        Avalon.info('Starting to upscale extracted images')
        self._upscale_frames()
        Avalon.info('Upscaling completed')

        # frames to Video
        Avalon.info('Converting extracted frames into video')

        # use user defined output size
        fm.convert_video(framerate, f'{self.scale_width}x{self.scale_height}', self.upscaled_frames)
        Avalon.info('Conversion completed')

        # migrate audio tracks and subtitles
        Avalon.info('Migrating audio tracks and subtitles to upscaled video')
        fm.migrate_audio_tracks_subtitles(self.input_video, self.output_video, self.upscaled_frames)