#!/usr/bin/env python3
# infer.py
# ============================================================
# HF inference (CausalLM) en base-2
# - Encode le --prompt en bits (MSB->LSB) comme llmTalk
# - Prompt = [BOS] + bits + [EOS] + [BOS]  (reset latent)
# - Boucle manuelle token-par-token (pas model.generate)
# - Décodage FINAL via decode_base2_digits_strict
# - indentation AVEC TABULATIONS (comme ton fichier actuel)
# ============================================================

import sys
import os
import argparse
import random
import codecs
from typing import List, Dict
from collections import Counter

import torch
from transformers import AutoModelForCausalLM


def decode_base2_digits_strict(digits: List[int], *, encoding: str = "utf-8", errors: str = "replace") -> str:
	# Filtre minimal: ne garder que 0/1 (au cas où)
	bits: List[int] = []
	for d in digits:
		di = int(d)
		if di == 0 or di == 1:
			bits.append(di)

	n_full_bytes = len(bits) // 8
	if n_full_bytes <= 0:
		return ""

	out = bytearray(n_full_bytes)

	j = 0
	for i in range(n_full_bytes):
		# MSB -> LSB (bits[j] est le bit de poids fort)
		b = 0
		b = (b << 1) | bits[j + 0]
		b = (b << 1) | bits[j + 1]
		b = (b << 1) | bits[j + 2]
		b = (b << 1) | bits[j + 3]
		b = (b << 1) | bits[j + 4]
		b = (b << 1) | bits[j + 5]
		b = (b << 1) | bits[j + 6]
		b = (b << 1) | bits[j + 7]
		out[i] = b
		j += 8

	bb = bytes(out)

	# Décodage robuste UTF-8 (gère proprement les séquences multi-octets)
	if encoding.lower() == "utf-8":
		inc = codecs.getincrementaldecoder("utf-8")(errors=errors)
		s = inc.decode(bb, final=False)
		s += inc.decode(b"", final=True)
		return s

	return bb.decode(encoding, errors=errors)


def bytes_to_base2_digits_bytesafe(data: bytes) -> List[int]:
	digits: List[int] = []
	for b in data:
		for i in range(7, -1, -1):
			digits.append((b >> i) & 1)
	return digits


def text_to_base2_digits(text: str) -> List[int]:
	# Même logique que llmTalk: UTF-8 -> bits MSB->LSB
	return bytes_to_base2_digits_bytesafe(text.encode("utf-8"))


def wrap_base2_sequence_2(ids: List[int], bos_id: int, eos_id: int) -> List[int]:
	return [int(bos_id), *ids, int(eos_id)]


def apply_repetition_penalty_(logits: torch.Tensor, token_ids: List[int], penalty: float) -> None:
	if penalty is None or penalty == 1.0 or penalty <= 0:
		return
	for t in set(token_ids):
		val = logits[0, t]
		logits[0, t] = val * penalty if val < 0 else val / penalty


def apply_presence_frequency_penalties_(logits: torch.Tensor, token_ids: List[int], presence_penalty: float, frequency_penalty: float) -> None:
	counts = Counter(token_ids)
	if presence_penalty:
		for t in counts:
			logits[0, t] -= presence_penalty
	if frequency_penalty:
		for t, c in counts.items():
			logits[0, t] -= frequency_penalty * c


def get_banned_tokens_no_repeat_ngram(seq: List[int], n: int) -> set:
	if n <= 0 or len(seq) < n - 1:
		return set()

	prefix_len = n - 1
	ngrams: Dict[tuple, set] = {}
	for i in range(len(seq) - n + 1):
		prefix = tuple(seq[i:i + prefix_len])
		nxt = seq[i + prefix_len]
		ngrams.setdefault(prefix, set()).add(nxt)

	return ngrams.get(tuple(seq[-prefix_len:]), set())


def mask_banned_tokens_(logits: torch.Tensor, banned: set) -> None:
	if banned:
		logits[0, list(banned)] = float("-inf")


def _maybe_hf_token() -> str:
	tok = os.environ.get("HF_TOKEN")
	if tok:
		return tok
	tok = os.environ.get("HUGGINGFACE_HUB_TOKEN")
	if tok:
		return tok
	return ""


def main() -> None:
	parser = argparse.ArgumentParser()

	parser.add_argument("--repo", type=str, required=True, help="chemin dossier HF local (./hf_binaryllm_repo) ou repo_id")
	parser.add_argument("--device", type=str, default="cuda", choices=["cpu", "cuda"])
	parser.add_argument("--seed", type=int, default=-1)

	# Base-2 avec 2 spéciaux => vocab_size=4 attendu: 0,1 + BOS=2 + EOS=3
	parser.add_argument("--bos", type=int, default=2, help="BOS id (base2: BOS=2)")
	parser.add_argument("--eos", type=int, default=3, help="EOS id (base2: EOS=3)")
	parser.add_argument("--prompt", type=str, required=True, help="texte à encoder en base2 (UTF-8 -> bits MSB->LSB)")

	parser.add_argument("--max_new_tokens", type=int, default=800)
	parser.add_argument("--temperature", type=float, default=0.7)
	parser.add_argument("--top_k", type=int, default=50)

	parser.add_argument("--repetition_penalty", type=float, default=1.0)
	parser.add_argument("--presence_penalty", type=float, default=0.0)
	parser.add_argument("--frequency_penalty", type=float, default=0.0)
	parser.add_argument("--no_repeat_ngram_size", type=int, default=0)

	parser.add_argument("--decode_encoding", type=str, default="utf-8")
	parser.add_argument("--decode_errors", type=str, default="replace")
	parser.add_argument("--print_ids", action="store_true")
	parser.add_argument("--stream", action="store_true", help="stream strict (réaffiche decode strict à chaque step)")

	args = parser.parse_args()

	seed = args.seed if args.seed >= 0 else random.randint(0, 2**31 - 1)
	print(f"[Seed] {seed}")
	torch.manual_seed(seed)
	if torch.cuda.is_available():
		torch.cuda.manual_seed_all(seed)

	device = torch.device("cuda" if (args.device == "cuda" and torch.cuda.is_available()) else "cpu")
	print(f"[Device] {device}")

	# --------- Load HF model ---------
	hf_token = _maybe_hf_token()
	if hf_token:
		m = AutoModelForCausalLM.from_pretrained(args.repo, trust_remote_code=True, token=hf_token)
	else:
		m = AutoModelForCausalLM.from_pretrained(args.repo, trust_remote_code=True)

	m.to(device)
	m.eval()

	# IMPORTANT: pas de KV-cache (train-like)
	if hasattr(m, "config") and m.config is not None:
		m.config.use_cache = True

	# --------- Encode prompt EXACTEMENT comme llmTalk (base=2) ---------
	def encode_prompt(text: str) -> List[int]:
		ids = text_to_base2_digits(text)                      # 0/1 bits (MSB->LSB)
		ids = wrap_base2_sequence_2(ids, args.bos, args.eos) # [BOS] bits [EOS]
		ids = ids + [int(args.bos)]                          # reset latent: ...[EOS][BOS]
		print("[+] PROMPT IDS = ", ids)                             
		return ids

	prompt_ids = encode_prompt(args.prompt)

	tokens = torch.tensor([prompt_ids], dtype=torch.long, device=device)
	generated: List[int] = []
	last_text_len = 0

	print("\n[Prompt]\n", args.prompt)
	print(f"\n[Prompt IDs] len={len(prompt_ids)} | BOS={args.bos} EOS={args.eos}")
	print("\n[Stream]" if args.stream else "\n[Output]")

	with torch.no_grad():
		for _ in range(int(args.max_new_tokens)):
			# full forward sur toute la séquence, sans cache
			out = m(input_ids=tokens, use_cache=True)
			logits = out.logits[:, -1, :]

			full_seq = tokens[0].tolist()

			apply_repetition_penalty_(logits, full_seq, float(args.repetition_penalty))
			apply_presence_frequency_penalties_(logits, full_seq, float(args.presence_penalty), float(args.frequency_penalty))

			if int(args.no_repeat_ngram_size) > 0:
				banned = get_banned_tokens_no_repeat_ngram(full_seq, int(args.no_repeat_ngram_size))
				mask_banned_tokens_(logits, banned)

			logits = logits / max(float(args.temperature), 1e-6)

			if 0 < int(args.top_k) < logits.size(-1):
				v, _ = torch.topk(logits, int(args.top_k))
				logits[logits < v[:, [-1]]] = float("-inf")

			probs = torch.softmax(logits, dim=-1)
			next_token = torch.multinomial(probs, 1)
			tok_id = int(next_token.item())

			if tok_id == int(args.eos):
				break

			tokens = torch.cat([tokens, next_token], dim=1)
			generated.append(tok_id)

			if args.stream:
				text = decode_base2_digits_strict(generated, encoding=args.decode_encoding, errors=args.decode_errors)
				if len(text) > last_text_len:
					sys.stdout.write(text[last_text_len:])
					sys.stdout.flush()
					last_text_len = len(text)

	if args.stream:
		print()

	print("\n[Final Output]\n")
	print(decode_base2_digits_strict(generated, encoding=args.decode_encoding, errors=args.decode_errors))

	if args.print_ids:
		print("\n[Generated IDs]\n")
		print(generated)


if __name__ == "__main__":
	main()