# HF gptneox--> gguf conversion

import gguf
import os
import sys
import struct
import json
import numpy as np
import torch

from typing import Any, List
from pathlib import Path
from transformers import AutoTokenizer

# ref: https://github.com/openai/gpt-2/blob/master/src/encoder.py
def bytes_to_unicode():
    """
    Returns list of utf-8 byte and a corresponding list of unicode strings.
    The reversible bpe codes work on unicode strings.
    This means you need a large # of unicode characters in your vocab if you want to avoid UNKs.
    When you're at something like a 10B token dataset you end up needing around 5K for decent coverage.
    This is a significant percentage of your normal, say, 32K bpe vocab.
    To avoid that, we want lookup tables between utf-8 bytes and unicode strings.
    And avoids mapping to whitespace/control characters the bpe code barfs on.
    """
    bs = list(range(ord("!"), ord("~")+1))+list(range(ord("¡"), ord("¬")+1))+list(range(ord("®"), ord("ÿ")+1))
    cs = bs[:]
    n = 0
    for b in range(2**8):
        if b not in bs:
            bs.append(b)
            cs.append(2**8+n)
            n += 1
    cs = [chr(n) for n in cs]
    return dict(zip(bs, cs))

def count_model_parts(dir_model: str) -> int:
    num_parts = 0
    for filename in os.listdir(dir_model):
        if filename.startswith("pytorch_model-"):
            num_parts += 1

    if num_parts > 0:
        print("gguf: found " + str(num_parts) + " model parts")
    return num_parts

if len(sys.argv) < 3:
    print("Usage: convert-h5-to-ggml.py dir-model ftype\n")
    print("  ftype == 0 -> float32")
    print("  ftype == 1 -> float16")
    sys.exit(1)


# output in the same directory as the model
dir_model = sys.argv[1]
last_dir = os.path.basename(os.path.normpath(dir_model))

# possible tensor data types
#   ftype == 0 -> float32
#   ftype == 1 -> float16
#
# map from ftype to string
ftype_str = ["f32", "f16"]

ftype = 1
if len(sys.argv) > 2:
    ftype = int(sys.argv[2])
    if ftype < 0 or ftype > 1:
        print("Invalid ftype: " + str(ftype))
        sys.exit(1)

fname_out = sys.argv[1] + "/ggml-model-" + ftype_str[ftype] + ".gguf"

print("gguf: loading model "+last_dir)

with open(dir_model + "/config.json", "r", encoding="utf-8") as f:
    hparams = json.load(f)

if hparams["architectures"][0] != "GPTNeoXForCausalLM":
    print("Model architecture not supported: " + hparams["architectures"][0] )
    sys.exit()

# get number of model parts
num_parts = count_model_parts(dir_model)

gguf_writer = gguf.GGUFWriter.open(fname_out)

print("gguf: get model metadata")

llm_arch    = "gptneox"
block_count = hparams["num_hidden_layers"]

gguf_writer.add_architecture(llm_arch)
gguf_writer.add_name(last_dir)
gguf_writer.add_file_type( "All tensors F32" if ftype == 0 else "Most tensors F16, some F32")
gguf_writer.add_context_length(llm_arch, hparams["max_position_embeddings"])
gguf_writer.add_embedding_length(llm_arch, hparams["hidden_size"])
gguf_writer.add_block_count(llm_arch, block_count)
gguf_writer.add_feed_forward_length(llm_arch, hparams["intermediate_size"])
gguf_writer.add_rope_dimension_count(llm_arch, int( hparams["rotary_pct"]*(hparams["hidden_size"]//hparams["num_attention_heads"])) )
gguf_writer.add_head_count(llm_arch, hparams["num_attention_heads"])
gguf_writer.add_parallel_residual(llm_arch, hparams["use_parallel_residual"] if "use_parallel_residual" in hparams else True)
gguf_writer.add_layer_norm_eps(llm_arch, hparams["layer_norm_eps"])

# TOKENIZATION

print("gguf: get tokenizer metadata")

tokens: List[str] = []
merges: List[str] = []


if Path(dir_model + "/tokenizer.json").is_file():
    # gpt2 tokenizer
    gguf_writer.add_tokenizer_model("gpt2")

    print("gguf: get gpt2 tokenizer merges")

    with open(dir_model + "/tokenizer.json", "r", encoding="utf-8") as f:
        tokenizer_json = json.load(f)
    merges = tokenizer_json["model"]["merges"]

    gguf_writer.add_token_merges(merges)

    print("gguf: get gpt2 tokenizer vocab")

    vocab_size = len( tokenizer_json["model"]["vocab"] )

    # ref: https://github.com/cmp-nct/ggllm.cpp/blob/master/falcon_convert.py
    tokenizer = AutoTokenizer.from_pretrained(dir_model)

    reverse_vocab = {id: encoded_tok for encoded_tok, id in tokenizer.vocab.items()}
    byte_encoder = bytes_to_unicode()
    byte_decoder = {v:k for k, v in byte_encoder.items()}

    for i in range(vocab_size):
        if i in reverse_vocab:
            try:
                text = bytearray([byte_decoder[c] for c in reverse_vocab[i]])
            except KeyError:
                text = bytearray()
                for c in reverse_vocab[i]:
                    if ord(c) < 256:  # single byte character
                        text.append(byte_decoder[ord(c)])
                    else:  # multibyte special token character
                        text.extend(c.encode('utf-8'))
        else:
            print(f"Key {i} not in tokenizer vocabulary. Padding with an arbitrary token.")
            padding_token = f"[PAD{i}]".encode("utf8")
            text = bytearray(padding_token)
        tokens.append(text)

    gguf_writer.add_token_list(tokens)

    if "added_tokens" in tokenizer_json and Path(dir_model + "/tokenizer_config.json").is_file():
        print("gguf: get special token ids")

        with open(dir_model + "/tokenizer_config.json", "r", encoding="utf-8") as f:
            tokenizer_config = json.load(f)

        # find special token ids

        if "bos_token" in tokenizer_config:
            for key in tokenizer_json["added_tokens"]:
                if key["content"] == tokenizer_config["bos_token"]:
                    gguf_writer.add_bos_token_id(key["id"])

        if "eos_token" in tokenizer_config:
            for key in tokenizer_json["added_tokens"]:
                if key["content"] == tokenizer_config["eos_token"]:
                    gguf_writer.add_eos_token_id(key["id"])

        if "unk_token" in tokenizer_config:
            for key in tokenizer_json["added_tokens"]:
                if key["content"] == tokenizer_config["unk_token"]:
                    gguf_writer.add_unk_token_id(key["id"])

        if "sep_token" in tokenizer_config:
            for key in tokenizer_json["added_tokens"]:
                if key["content"] == tokenizer_config["sep_token"]:
                    gguf_writer.add_sep_token_id(key["id"])

        if "pad_token" in tokenizer_config:
            for key in tokenizer_json["added_tokens"]:
                if key["content"] == tokenizer_config["pad_token"]:
                    gguf_writer.add_pad_token_id(key["id"])


# TENSORS

tensor_map = gguf.get_tensor_name_map(block_count)

# tensor info
print("gguf: get tensor metadata")

if num_parts == 0:
    part_names = ("pytorch_model.bin",)
else:
    part_names = (
        f"pytorch_model-{n:05}-of-{num_parts:05}.bin" for n in range(1, num_parts + 1)
    )

for part_name in part_names:
    print("gguf: loading model part '"+ part_name + "'")
    model_part = torch.load(f"{dir_model}/{part_name}", map_location="cpu")

    for name in model_part.keys():
        data = model_part[name]

        # we don't need these
        if name.endswith(".attention.masked_bias") or name.endswith(".attention.bias") or name.endswith(".attention.rotary_emb.inv_freq"):
            continue

        # convert any unsupported data types to float32
        if data.dtype != torch.float16 and data.dtype != torch.float32:
            data = data.to(torch.float32)

        data = data.squeeze().numpy()

        # map tensor names
        if name.endswith(".weight") and name[:-7] in tensor_map:
            name = tensor_map[name[:-7]] + ".weight"
        elif name.endswith(".bias") and name[:-5] in tensor_map:
            name = tensor_map[name[:-5]] + ".bias"
        else:
            print( "Can not map tensor '" + name + "'" )
            sys.exit()

        n_dims = len(data.shape)
        data_dtype = data.dtype

        # if f32 desired, convert any float16 to float32
        if ftype == 0 and data.dtype == np.float16:
            data_dtype = np.float32

        # TODO: Why cant we use these float16 as-is? There should be not reason to store float16 as float32
        if ftype == 1 and data.dtype == np.float16 and n_dims == 1:
            data_dtype = np.float32

        # if f16 desired, convert any float32 2-dim weight tensors to float16
        if ftype == 1 and data.dtype == np.float32 and name.endswith(".weight") and n_dims == 2:
            data_dtype = np.float16

        data_nbytes = data.size * 2 if data_dtype == np.float16 else data.size * 4

        gguf_writer.add_tensor_info(name, data.shape, data_dtype, data_nbytes)


print("gguf: write header")
gguf_writer.write_header_to_file()
print("gguf: write metadata")
gguf_writer.write_kv_data_to_file()
print("gguf: write tensor metadata")
gguf_writer.write_ti_data_to_file()

# tensor data
print("gguf: convert and write tensor data")

if num_parts == 0:
    part_names = ("pytorch_model.bin",)
else:
    part_names = (
        f"pytorch_model-{n:05}-of-{num_parts:05}.bin" for n in range(1, num_parts + 1)
    )

for part_name in part_names:
    print("gguf: loading model part '"+ part_name + "'")
    model_part = torch.load(f"{dir_model}/{part_name}", map_location="cpu")

    for name in model_part.keys():
        data = model_part[name]

        old_dtype = data.dtype

        # we don't need these
        if name.endswith(".attention.masked_bias") or name.endswith(".attention.bias") or name.endswith(".attention.rotary_emb.inv_freq"):
            continue

        # convert any unsupported data types to float32
        if data.dtype != torch.float16 and data.dtype != torch.float32:
            data = data.to(torch.float32)

        data = data.squeeze().numpy()

        # map tensor names
        if name.endswith(".weight") and name[:-7] in tensor_map:
            name = tensor_map[name[:-7]] + ".weight"
        elif name.endswith(".bias") and name[:-5] in tensor_map:
            name = tensor_map[name[:-5]] + ".bias"
        else:
            print( "Can not map tensor '" + name + "'" )
            sys.exit()

        n_dims = len(data.shape)
        data_dtype = data.dtype

        # if f32 desired, convert any float16 to float32
        if ftype == 0 and data.dtype == np.float16:
            data = data.astype(np.float32)

        # TODO: Why cant we use these float16 as-is? There should be not reason to store float16 as float32
        if ftype == 1 and data_dtype == np.float16 and n_dims == 1:
            data = data.astype(np.float32)

        # if f16 desired, convert any float32 2-dim weight tensors to float16
        if ftype == 1 and data_dtype == np.float32 and name.endswith(".weight") and n_dims == 2:
            data = data.astype(np.float16)

        print( name + ", shape " + str(len(data.shape)) + ", " + str(old_dtype) + " --> " + str(data.dtype))

        gguf_writer.write_tensor_to_file(data)

gguf_writer.close()


print("gguf: model successfully exported to '" + fname_out + "'" )
print("")