#!/usr/bin/env python3
from __future__ import annotations

import argparse
import os
import sys
from pathlib import Path
from typing import Any

import numpy as np

# Necessary to load the local gguf package
if "NO_LOCAL_GGUF" not in os.environ and (Path(__file__).parent.parent.parent / 'gguf-py').exists():
    sys.path.insert(0, str(Path(__file__).parent.parent))

from gguf import GGUFReader, GGUFValueType  # noqa: E402


def get_file_host_endian(reader: GGUFReader) -> tuple[str, str]:
    host_endian = 'LITTLE' if np.uint32(1) == np.uint32(1).newbyteorder("<") else 'BIG'
    if reader.byte_order == 'S':
        file_endian = 'BIG' if host_endian == 'LITTLE' else 'LITTLE'
    else:
        file_endian = host_endian
    return (host_endian, file_endian)


# For more information about what field.parts and field.data represent,
# please see the comments in the modify_gguf.py example.
def dump_metadata(reader: GGUFReader, args: argparse.Namespace) -> None:
    host_endian, file_endian = get_file_host_endian(reader)
    print(f'* File is {file_endian} endian, script is running on a {host_endian} endian host.')
    print(f'\n* Dumping {len(reader.fields)} key/value pair(s)')
    for n, field in enumerate(reader.fields.values(), 1):
        if not field.types:
            pretty_type = 'N/A'
        elif field.types[0] == GGUFValueType.ARRAY:
            nest_count = len(field.types) - 1
            pretty_type = '[' * nest_count + str(field.types[-1].name) + ']' * nest_count
        else:
            pretty_type = str(field.types[-1].name)
        print(f'  {n:5}: {pretty_type:10} | {len(field.data):8} | {field.name}', end = '')
        if len(field.types) == 1:
            curr_type = field.types[0]
            if curr_type == GGUFValueType.STRING:
                print(' = {0}'.format(repr(str(bytes(field.parts[-1]), encoding='utf8')[:60])), end = '')
            elif field.types[0] in reader.gguf_scalar_to_np:
                print(' = {0}'.format(field.parts[-1][0]), end = '')
        print()
    if args.no_tensors:
        return
    print(f'\n* Dumping {len(reader.tensors)} tensor(s)')
    for n, tensor in enumerate(reader.tensors, 1):
        prettydims = ', '.join('{0:5}'.format(d) for d in list(tensor.shape) + [1] * (4 - len(tensor.shape)))
        print(f'  {n:5}: {tensor.n_elements:10} | {prettydims} | {tensor.tensor_type.name:7} | {tensor.name}')


def dump_metadata_json(reader: GGUFReader, args: argparse.Namespace) -> None:
    import json
    host_endian, file_endian = get_file_host_endian(reader)
    metadata: dict[str, Any] = {}
    tensors: dict[str, Any] = {}
    result = {
        "filename": args.model,
        "endian": file_endian,
        "metadata": metadata,
        "tensors": tensors,
    }
    for idx, field in enumerate(reader.fields.values()):
        curr: dict[str, Any] = {
            "index": idx,
            "type": field.types[0].name if field.types else 'UNKNOWN',
            "offset": field.offset,
        }
        metadata[field.name] = curr
        if field.types[:1] == [GGUFValueType.ARRAY]:
            curr["array_types"] = [t.name for t in field.types][1:]
            if not args.json_array:
                continue
            itype = field.types[-1]
            if itype == GGUFValueType.STRING:
                curr["value"] = [str(bytes(field.parts[idx]), encoding="utf-8") for idx in field.data]
            else:
                curr["value"] = [pv for idx in field.data for pv in field.parts[idx].tolist()]
        elif field.types[0] == GGUFValueType.STRING:
            curr["value"] = str(bytes(field.parts[-1]), encoding="utf-8")
        else:
            curr["value"] = field.parts[-1].tolist()[0]
    if not args.no_tensors:
        for idx, tensor in enumerate(reader.tensors):
            tensors[tensor.name] = {
                "index": idx,
                "shape": tensor.shape.tolist(),
                "type": tensor.tensor_type.name,
                "offset": tensor.field.offset,
            }
    json.dump(result, sys.stdout)


def main() -> None:
    parser = argparse.ArgumentParser(description="Dump GGUF file metadata")
    parser.add_argument("model",           type=str,            help="GGUF format model filename")
    parser.add_argument("--no-tensors", action="store_true", help="Don't dump tensor metadata")
    parser.add_argument("--json",       action="store_true", help="Produce JSON output")
    parser.add_argument("--json-array", action="store_true", help="Include full array values in JSON output (long)")
    args = parser.parse_args(None if len(sys.argv) > 1 else ["--help"])
    if not args.json:
        print(f'* Loading: {args.model}')
    reader = GGUFReader(args.model, 'r')
    if args.json:
        dump_metadata_json(reader, args)
    else:
        dump_metadata(reader, args)


if __name__ == '__main__':
    main()