import os
import sys
import json
import ffmpeg

if sys.argv[1] == 'grid' or sys.argv[1] == 'file':
  mode = sys.argv[1]

  if (mode == 'grid'):
    cols = sys.argv[2]
    rows = sys.argv[3]
    inputpath = os.path.abspath(sys.argv[4])
    outputdir = os.path.abspath(sys.argv[5])
  if (mode == 'file'):
    layoutpath = os.path.abspath(sys.argv[2])
    inputpath = os.path.abspath(sys.argv[3])
    outputdir = os.path.abspath(sys.argv[4])
else:
  print('Videoshredder splits a video into multiple tiles')
  print('There are two layout input modes available: grid and file')
  print('')
  print('Examples:')
  print('')
  print('./video-shredder.py grid 4 3 path/to/inputfile.mp4 output_dirctory')
  print('  ... splits the video into 4x3 equally distributed tiles')
  print('')
  print('./video-shredder.py file layout.json path/to/inputfile.mp4 output_dirctory')
  print('  ... splits into tiles defined in the layout file')
  print('')
  exit()

try:
  os.stat(outputdir)
except:
  print('Creating new directory', outputdir)
  os.mkdir(outputdir)

def generateGrid (source, h_tiles, v_tiles):
  probe = ffmpeg.probe(source)
  video = next((stream for stream in probe['streams'] if stream['codec_type'] == 'video'), None)
  width = int(video['width'])
  height = int(video['height'])

  layout = []

  tile_width = width/int(h_tiles)
  tile_height = height/int(v_tiles)

  for row in range(int(v_tiles)):
    for col in range(int(h_tiles)):
      print('row col', row, col)
      layout.append(
      {
        "name": str(row+1) + "-" + str(col+1),
        "geomentry": {
          "x": str(tile_width*col).split('.')[0],
          "y": str(tile_height*row).split('.')[0],
          "width": str(tile_width).split('.')[0],
          "height": str(tile_height).split('.')[0]
        }
      })
  return layout

def processLayout (layout):
  print(layout)
  for item in layout:
    outputpath = os.path.join(outputdir, item["name"] + '.mp4')
    print('processing: ' +item["name"])
    print('   input path:  ' + inputpath)
    print('   output path: ' + outputpath)
    stream = (
      ffmpeg
      .input(inputpath)
      .crop(**item['geomentry'])
      .output(outputpath, pix_fmt='yuv420p')
      .run()
    )
  print('Finished processing all tiles!')
  print('Output directory: ' + str(outputdir))

if (mode == 'file'):
  with open(layoutpath, "r") as read_file:
    processLayout(json.load(read_file))
if (mode == 'grid'):
  layout = generateGrid(inputpath, cols, rows)
  processLayout(layout)