# Copyright (c) 2025 SandAI. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import hashlib
import os
from functools import reduce
from typing import Any, List, Union

HASH_LENGTH = 10


def _fn_hash_key(fn) -> str:
    sha256_hash = hashlib.sha256()
    sha256_hash.update(fn.__qualname__.encode())
    sha256_hash.update(str(fn.__code__.co_firstlineno).encode())
    return sha256_hash.hexdigest()[:HASH_LENGTH]


def compute_hash(obj: Union[Any, List[Any]]) -> str:
    if isinstance(obj, list):
        return reduce(lambda x, y: compute_hash(x + y), [compute_hash(_item) for _item in obj], "")

    elif isinstance(obj, dict):
        return reduce(lambda x, y: compute_hash(x + y), [compute_hash(_k) + compute_hash(_v) for _k, _v in obj.items()], "")

    elif callable(obj):
        return _fn_hash_key(obj)

    return hashlib.md5(str(obj).encode(), usedforsecurity=False).hexdigest()[:HASH_LENGTH]


def compute_code_hash_with_content(file_contents: dict[str, str]) -> str:
    items = list(sorted(file_contents.items(), key=lambda x: x[0]))
    hash_content = []
    for filepath, content in items:
        hash_content.append(filepath)
        if filepath == "<string>":
            # This means the function was dynamically generated, with e.g. exec(). We can't actually check these.
            continue
        hash_content.append(content)
    return compute_hash("\n".join(hash_content))


def compute_code_hash(files: set[str]) -> str:
    file_contents = {}
    for filepath in files:
        # Skip files that don't exist (e.g., <string>, <frozen modules>, etc.)
        if not os.path.isfile(filepath):
            file_contents[filepath] = ""
        else:
            with open(filepath) as f:
                file_contents[filepath] = f.read()
    return compute_code_hash_with_content(file_contents)