import argparse, os, sys
from pathlib import Path
# from aitextgen.TokenDataset import TokenDataset
# from aitextgen.tokenizers import train_tokenizer
# from aitextgen.utils import GPT2ConfigCPU
# from aitextgen.utils import build_gpt2_config
# from aitextgen import aitextgen

# import tokenise as tk
# import train as tr

def suffix(bs: int, ns: int, vs: int) -> str:
	return f"_bs={bs}_ns={ns}_vs={vs}"

def train(ouputdir: Path, blocksize: int, vocabsize: int, num_steps: int, gpu: bool = False) -> str:

	from aitextgen.TokenDataset import TokenDataset
	from aitextgen.utils import build_gpt2_config
	from aitextgen import aitextgen

	exts = ['.json', '.gz']
	files = [x for x in ouputdir.glob('*') if x.suffix in exts]
	if len(files) == 2:
		if files[0].suffix == '.json':
			tok = str(files[0])
			dat = str(files[1])
		else:
			tok = str(files[1])
			dat = str(files[0])

	config = build_gpt2_config(vocab_size=vocabsize, max_lenght=blocksize)

	ai = aitextgen(tokenizer_file=tok, config=config)

	data = TokenDataset(dat, tokenizer_file=tok, block_size=blocksize, from_cache=True)

	ai.train(data, output_dir=str(ouputdir), batch_size=16, num_steps=num_steps, generate_every=1000, save_every=1000, num_workers=4, to_gpu=gpu)

	return "Done!"


def encode(filepath: str, blocksize: int, vocabsize: int, ouputdir: Path, verbose: bool = False) -> str:

	f_path = Path(filepath)

	if f_path.is_dir():
		text = [x for x in f_path.glob('*') if x.is_file()]
	elif f_path.is_file():
		text = str(f_path)
	else:
		return "text input is not valid"		

	from aitextgen.TokenDataset import TokenDataset
	from aitextgen.tokenizers import train_tokenizer

	#NOTE: vocab_size is fixed since this is not yet in train_tokenizer
	#see https://github.com/minimaxir/aitextgen/blob/master/aitextgen/tokenizers.py

	fn = ouputdir / (f_path.name + f"_ns={vocabsize}")
	if type(text) is str:
		train_tokenizer(text, vocab_size=vocabsize, prefix=str(fn))
	else:
		train_tokenizer(files=[str(x) for x in text], vocab_size=vocabsize, prefix=str(fn))
	tok_fn = str(fn) + ".tokenizer.json"

	fnn = ouputdir / (f_path.name + f"_bs={blocksize}_ns={vocabsize}")
	dataset_fn = str(fnn) + ".tar.gz"

	print(tok_fn)
	print(dataset_fn)

	if type(text) is str:
		data = TokenDataset(file_path=text, tokenizer_file=tok_fn, block_size=blocksize)
	else:
		texts = [x.read_text() for x in text]
		data = TokenDataset(texts=texts, tokenizer_file=tok_fn, block_size=blocksize)
	data.save(cache_destination=dataset_fn)

	return "encode success"


def main() -> int:
	p = argparse.ArgumentParser()
	p.add_argument("text", type=str, help="text file path to be tokenised and encoded")
	p.add_argument("-b", "--blocksize", type=int, choices=[32, 64, 128, 256, 1024], default=64, help="block size, default=64 (corresponds to GPT-2 'max_lenght' config)")
	p.add_argument("-s", "--numsteps", type=int, default=10000)
	p.add_argument("-v", "--vocabsize", type=int, default=1000)
	p.add_argument("--ouputdir", type=str, default="data/tokens+models/")
	p.add_argument("--gpu", action="store_true")

	args = p.parse_args()

	text = Path(args.text)
	if not text.exists():
		return args.text + " doesn't exists"

	output_dir = Path(args.ouputdir + text.name + suffix(args.blocksize, args.numsteps, args.vocabsize))

	if output_dir.is_dir():
		exts = ['.json', '.gz', '.bin']
		files = [x for x in output_dir.glob('*') if x.suffix in exts]
		if len(files) == 4:
			print("Token + model already exists > " + output_dir.name)
			q = input("Continue? [y/n]")
			if q != 'y':
				return "Nothing to do..."
	else: 
		output_dir.mkdir()

	encode(filepath=args.text, blocksize=args.blocksize, vocabsize=args.vocabsize, ouputdir=output_dir)
	train(ouputdir=output_dir, blocksize=args.blocksize, vocabsize=args.vocabsize, num_steps=args.numsteps, gpu=args.gpu)


if __name__ == '__main__':
    sys.exit(main())