#!/usr/bin/env python

"""Video Thumbnail Generator

Usage:
  ./generator <video> <interval> <width> <height> <columns> <output>
  ./generator (-h | --help)
  ./generator --version

Options:
  -h --help     Show this screen.
  --version     Show version.
  <video>         Video filepath.
  <interval>      Interval em seconds between frames.
  <width>         Width of each thumbnail.
  <height>        Height of each thumbnail.
  <columns>       Total number of thumbnails per line.
  <output>        Output.
"""

from docopt import docopt
from moviepy.editor import VideoFileClip
from PIL import Image
from click import progressbar
import glob, os, random, shutil, math, tempfile


TMP_FRAMES_PATH = tempfile.mkdtemp()

def generate_video_thumbnail(args):
    videoFileClip = VideoFileClip(args['<video>'])
    interval = int(args['<interval>'])
    size = (int(args['<width>']), int(args['<height>']))
    outputPrefix = get_output_prefix()
    generate_frames(videoFileClip, interval, outputPrefix, size)

    columns = int(args['<columns>'])
    output = args['<output>']
    generate_sprite_from_frames(outputPrefix, columns, size, output)

def generate_frames(videoFileClip, interval, outputPrefix, size):
    print("Extracting", int(videoFileClip.duration / interval), "frames")
    frameCount = 0
    with progressbar(range(0, int(videoFileClip.duration), interval)) as items:
        for i in items:
            extract_frame(videoFileClip, i, outputPrefix, size, frameCount)
            frameCount += 1
    print("Frames extracted.")

def extract_frame(videoFileClip, moment, outputPrefix, size, frameCount):
    output = outputPrefix + ("%05d.png" % frameCount)
    videoFileClip.save_frame(output, t=int(moment))
    resize_frame(output, size)

def resize_frame(filename, size):
    image = Image.open(filename)
    image = image.resize(size, Image.ANTIALIAS)
    image.save(filename)

def generate_sprite_from_frames(framesPath, columns, size, output):
    framesMap = sorted(glob.glob(framesPath + "*.png"))

    masterWidth = size[0] * columns
    masterHeight = size[1] * int(math.ceil(float(len(framesMap)) / columns))

    line, column, mode = 0, 0, 'RGBA'

    try:
        finalImage = Image.new(mode=mode, size=(masterWidth, masterHeight), color=(0,0,0,0))
        finalImage.save(output)
    except IOError:
        mode = 'RGB'
        finalImage = Image.new(mode=mode, size=(masterWidth, masterHeight))

    for filename in framesMap:
        with Image.open(filename) as image:              

            locationX = size[0] * column
            locationY = size[1] * line

            finalImage.paste(image, (locationX, locationY))

            column += 1
            
            if column == columns:
                line += 1
                column = 0

    finalImage.save(output)
    shutil.rmtree(TMP_FRAMES_PATH, ignore_errors=True)
    print("Saved!")

def get_output_prefix():
    if not os.path.exists(TMP_FRAMES_PATH):
        os.makedirs(TMP_FRAMES_PATH)
    return TMP_FRAMES_PATH + os.sep + ("%032x_" % random.getrandbits(128))

if __name__ == "__main__":
    arguments = docopt(__doc__, version='0.0.2')
    generate_video_thumbnail(arguments)