#!/usr/bin/env python3

# sortashuffle.py
# Shuffles shows but keeps episodes in order.

# USAGE
# 0. Copy this script to the playlist folder
# 1. Modify the TARGET variable below
# 2. Modify the SOURCES variable below
# 3. Run the script as administrator
#
# To add/remove shows or regenerate playlist,
# delete everything in TARGET (except this script)
# and re-run the script.

import os
import random

# Must be in format "C://Dir1//Dir2"
TARGET  =  "<TARGET DIR>"
SOURCES = ["<SOURCE DIR>",
           "<SOURCE DIR>"]

def collect_showlist(sources):
    """Returns a list of lists.
    Each sub-list represents a show, and elements represent episodes."""
    return [[f for f in os.listdir(source)] for source in sources]

def calculate_weights(showlist):
    """Calculate the weights for each show; # of remaining episodes"""
    return [len(show) for show in showlist]

def select_show(showlist, weightlist):
    """Select a show, accounting weight."""
    return random.choices(range(len(showlist)),
                          weights=weightlist,
                          k=1)[0]

def shuffle(showlist, weightlist):
    """Shuffle the playlist."""
    shuffled = []
    while any(showlist):
        selection = select_show(showlist, weightlist, previous)
        shuffled.append(SOURCES[selection] + "//" + showlist[selection].pop(0))
        weightlist[selection] = len(showlist[selection])
    return shuffled

def deploy_symlinks(shuffled):
    """Deploy episode symlinks."""
    count = 0
    for episode in shuffled:
        os.symlink(episode, TARGET + "//" + str(count))
        count += 1
    return count

def deploy_index(shuffled):
    """Deploy playlist index."""
    index = open(TARGET + "//" + "_PLAYLIST_INDEX.txt", 'w', encoding='utf-8')
    index.write("\n".join(shuffled))
    index.close()
    return INDEX

def main():
    SHOWLIST = collect_showlist(SOURCES)
    WEIGHTLIST = calculate_weights(SHOWLIST)
    SHUFFLED = shuffle(SHOWLIST, WEIGHTLIST)
    deploy_symlinks(SHUFFLED)
    deploy_index(SHUFFLED)
    return 0

if __name__=="__main__":
    main()