#!python3
import random

"""generates a musical instrument by choosing at random a hornbostel-sachs category.

this version is uniformly distributed between the options at each level, but does not include suffxes."""


strip_dashes_and_dots = lambda x: x.replace("-", "").replace(".", "").replace(" ", "")
def generate_instrument(listing):
	""" listing contains a hornbostel-sachs dictionary; this steps through index-by-index
	picking numbers at random one by one until it's gotta stop, so this has even chances
	of every category, rather than an even chance to every listing."""

	nice_from_stripped = {strip_dashes_and_dots(x): x for x in listing.keys()}
	stripped_keys = [strip_dashes_and_dots(x) for x in listing.keys()]
	
	prefix = random.choice([x for x in stripped_keys if len(x) == 1])
	
	final_code = pick_code(prefix, [x for x in stripped_keys if x.startswith(prefix)])
	return nice_from_stripped[final_code]

# this defines a threshhold for quitting early dependent on the length of the code so far.
# so there's a 0% chance of stopping with a zero-length code, 0% with a 1-length code, 1% with 2-length...
chance_of_stopping = [0, 0, 0.01, 0.01, 0.01, 0.05, 0.05, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2]
def pick_code(prefix, keys):
	if random.random() < chance_of_stopping[len(prefix)]:
		return prefix 

	# only look at keys that are one longer than the current key
	next_keys = [x for x in keys if len(x) == len(prefix) + 1]
	if len(next_keys) == 0:
		return prefix # if we can't find any successors then stop

	next_prefix = random.choice(next_keys)

	return pick_code(next_prefix, [x for x in keys if x.startswith(next_prefix)])




if __name__ == "__main__":
	with open("Hornbostel-Sachs") as f:
		hornbostelsachs = {line.split(" ")[0]: " ".join(line.split(" ")[1:]) for line in f.readlines()}
		
		val = generate_instrument(hornbostelsachs)

		parents = [val[0:x+1] for x in range(len(val)) if val[x].isdigit()]
		
		for x in parents:
			print(x, " : ", hornbostelsachs[x].strip())