#
# The internetarchive module is a Python/CLI interface to Archive.org.
#
# Copyright (C) 2012-2024 Internet Archive
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""
internetarchive.utils
~~~~~~~~~~~~~~~~~~~~~

This module provides utility functions for the internetarchive library.

:copyright: (C) 2012-2024 by Internet Archive.
:license: AGPL 3, see LICENSE for more details.
"""
from __future__ import annotations

import hashlib
import os
import platform
import re
import sys
import warnings
from collections.abc import Mapping
from typing import Iterable
from xml.dom.minidom import parseString

# Make preferred JSON package available via `from internetarchive.utils import json`
try:
    import ujson as json

    # ujson lacks a JSONDecodeError: https://github.com/ultrajson/ultrajson/issues/497
    JSONDecodeError = ValueError
except ImportError:
    import json  # type: ignore
    JSONDecodeError = json.JSONDecodeError  # type: ignore


def deep_update(d: dict, u: Mapping) -> dict:
    for k, v in u.items():
        if isinstance(v, Mapping):
            r = deep_update(d.get(k, {}), v)
            d[k] = r
        else:
            d[k] = u[k]
    return d


class InvalidIdentifierException(Exception):
    pass


def validate_s3_identifier(string: str) -> bool:
    legal_chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789._-'
    # periods, underscores, and dashes are legal, but may not be the first
    # character!
    if any(string.startswith(c) is True for c in ['.', '_', '-']):
        raise InvalidIdentifierException('Identifier cannot begin with periods ".", underscores '
                                        '"_", or dashes "-".')

    if len(string) > 100 or len(string) < 3:
        raise InvalidIdentifierException('Identifier should be between 3 and 80 characters in '
                                        'length.')

    # Support for uploading to user items, e.g. first character can be `@`.
    if string.startswith('@'):
        string = string[1:]

    if any(c not in legal_chars for c in string):
        raise InvalidIdentifierException('Identifier can only contain alphanumeric characters, '
                                        'periods ".", underscores "_", or dashes "-". However, '
                                        'identifier cannot begin with periods, underscores, or '
                                        'dashes.')

    return True


def needs_quote(s: str) -> bool:
    try:
        s.encode('ascii')
    except (UnicodeDecodeError, UnicodeEncodeError):
        return True
    return re.search(r'\s', s) is not None


def norm_filepath(fp: bytes | str) -> str:
    if isinstance(fp, bytes):
        fp = fp.decode('utf-8')
    fp = fp.replace(os.path.sep, '/')
    if not fp.startswith('/'):
        fp = f'/{fp}'
    return fp


def get_md5(file_object) -> str:
    m = hashlib.md5()
    while True:
        data = file_object.read(8192)
        if not data:
            break
        m.update(data)
    file_object.seek(0, os.SEEK_SET)
    return m.hexdigest()


def chunk_generator(fp, chunk_size: int):
    while True:
        chunk = fp.read(chunk_size)
        if not chunk:
            break
        yield chunk


def suppress_keyboard_interrupt_message() -> None:
    """Register a new excepthook to suppress KeyboardInterrupt
    exception messages, and exit with status code 130.

    """
    old_excepthook = sys.excepthook

    def new_hook(type, value, traceback):
        if type is KeyboardInterrupt:
            sys.exit(130)
        old_excepthook(type, value, traceback)

    sys.excepthook = new_hook


class IterableToFileAdapter:
    def __init__(self, iterable, size: int, pre_encode: bool = False):
        self.iterator = iter(iterable)
        self.length = size
        # pre_encode is needed because http doesn't know that it
        # needs to encode a TextIO object when it's wrapped
        # in the Iterator from tqdm.
        # So, this FileAdapter provides pre-encoded output
        self.pre_encode = pre_encode

    def read(self, size: int = -1):  # TBD: add buffer for `len(data) > size` case
        if self.pre_encode:
            # this adapter is intended to emulate the encoding that is usually
            # done by the http lib.
            # As of 2022, iso-8859-1 encoding is used to meet the HTTP standard,
            # see in the cpython repo (https://github.com/python/cpython
            # Lib/http/client.py lines 246; 1340; or grep 'iso-8859-1'
            return next(self.iterator, '').encode("iso-8859-1")
        return next(self.iterator, b'')

    def __len__(self) -> int:
        return self.length


class IdentifierListAsItems:
    """This class is a lazily-loaded list of Items, accessible by index or identifier.
    """

    def __init__(self, id_list_or_single_id, session):
        self.ids = (id_list_or_single_id
                    if isinstance(id_list_or_single_id, list)
                    else [id_list_or_single_id])
        self._items = [None] * len(self.ids)
        self.session = session

    def __len__(self) -> int:
        return len(self.ids)

    def __getitem__(self, idx):
        for i in (range(*idx.indices(len(self))) if isinstance(idx, slice) else [idx]):
            if self._items[i] is None:
                self._items[i] = self.session.get_item(self.ids[i])
        return self._items[idx]

    def __getattr__(self, name):
        try:
            return self[self.ids.index(name)]
        except ValueError:
            raise AttributeError

    def __repr__(self) -> str:
        return f'{self.__class__.__name__}({self.ids!r})'


def get_s3_xml_text(xml_str: str) -> str:
    def _get_tag_text(tag_name, xml_obj):
        text = ''
        elements = xml_obj.getElementsByTagName(tag_name)
        for e in elements:
            for node in e.childNodes:
                if node.nodeType == node.TEXT_NODE:
                    text += node.data
        return text

    tag_names = ['Message', 'Resource']
    try:
        p = parseString(xml_str)
        _msg = _get_tag_text('Message', p)
        _resource = _get_tag_text('Resource', p)
        # Avoid weird Resource text that contains PUT method.
        if _resource and "'PUT" not in _resource:
            return f'{_msg} - {_resource.strip()}'
        else:
            return _msg
    except Exception:
        return str(xml_str)


def get_file_size(file_obj) -> int | None:
    if is_filelike_obj(file_obj):
        try:
            file_obj.seek(0, os.SEEK_END)
            size = file_obj.tell()
            # Avoid OverflowError.
            if size > sys.maxsize:
                size = None
            file_obj.seek(0, os.SEEK_SET)
        except OSError:
            size = None
    else:
        st = os.stat(file_obj)
        size = st.st_size
    return size


def iter_directory(directory: str):
    """Given a directory, yield all files recursively as a two-tuple (filepath, s3key)"""
    for path, _dir, files in os.walk(directory):
        for f in files:
            filepath = os.path.join(path, f)
            key = os.path.relpath(filepath, directory)
            yield (filepath, key)


def recursive_file_count_and_size(files, item=None, checksum=False):
    """Given a filepath or list of filepaths, return the total number and size of files.
    If `checksum` is `True`, skip over files whose MD5 hash matches any file in the `item`.
    """
    if not isinstance(files, (list, set)):
        files = [files]
    total_files = 0
    total_size = 0
    if checksum is True:
        md5s = [f.get('md5') for f in item.files]
    else:
        md5s = []
    if isinstance(files, dict):
        # make sure to use local filenames.
        _files = files.values()
    else:
        if isinstance(files[0], tuple):
            _files = dict(files).values()
        else:
            _files = files
    for f in _files:
        try:
            is_dir = os.path.isdir(f)
        except TypeError:
            try:
                f = f[0]
                is_dir = os.path.isdir(f)
            except (AttributeError, TypeError):
                is_dir = False
        if is_dir:
            it = iter_directory(f)
        else:
            it = [(f, None)]
        for x, _ in it:
            if checksum is True:
                try:
                    with open(x, 'rb') as fh:
                        lmd5 = get_md5(fh)
                except TypeError:
                    # Support file-like objects.
                    lmd5 = get_md5(x)
                if lmd5 in md5s:
                    continue
            total_size += get_file_size(x)
            total_files += 1
    return total_files, total_size


def recursive_file_count(*args, **kwargs):
    """Like `recursive_file_count_and_size`, but returns only the file count."""
    total_files, _ = recursive_file_count_and_size(*args, **kwargs)
    return total_files


def is_dir(obj) -> bool:
    """Special is_dir function to handle file-like object cases that
    cannot be stat'd"""
    try:
        return os.path.isdir(obj)
    except TypeError as exc:
        return False


def is_filelike_obj(obj) -> bool:
    """Distinguish file-like from path-like objects"""
    try:
        os.fspath(obj)
    except TypeError:
        return True
    else:
        return False


def reraise_modify(
    caught_exc: Exception,
    append_msg: str,
    prepend: bool = False,
) -> None:
    """Append message to exception while preserving attributes.

    Preserves exception class, and exception traceback.

    Note:
        This function needs to be called inside an except because an exception
        must be active in the current scope.

    Args:
        caught_exc(Exception): The caught exception object
        append_msg(str): The message to append to the caught exception
        prepend(bool): If True prepend the message to args instead of appending

    Returns:
        None

    Side Effects:
        Re-raises the exception with the preserved data / trace but
        modified message
    """
    if not caught_exc.args:
        # If no args, create our own tuple
        arg_list = [append_msg]
    else:
        # Take the last arg
        # If it is a string
        # append your message.
        # Otherwise append it to the
        # arg list(Not as pretty)
        arg_list = list(caught_exc.args[:-1])
        last_arg = caught_exc.args[-1]
        if isinstance(last_arg, str):
            if prepend:
                arg_list.append(append_msg + last_arg)
            else:
                arg_list.append(last_arg + append_msg)
        else:
            arg_list += [last_arg, append_msg]
    caught_exc.args = tuple(arg_list)
    raise  # noqa: PLE0704


def remove_none(obj):
    if isinstance(obj, (list, tuple, set)):
        lst = type(obj)(remove_none(x) for x in obj if x)
        try:
            return [dict(t) for t in {tuple(sorted(d.items())) for d in lst}]
        except (AttributeError, TypeError):
            return lst
    elif isinstance(obj, dict):
        return type(obj)((remove_none(k), remove_none(v))
                         for k, v in obj.items() if k is not None and v is not None)
    else:
        return obj


def delete_items_from_dict(d: dict | list, to_delete):
    """Recursively deletes items from a dict,
    if the item's value(s) is in ``to_delete``.
    """
    if not isinstance(to_delete, list):
        to_delete = [to_delete]
    if isinstance(d, dict):
        for single_to_delete in set(to_delete):
            if single_to_delete in d.values():
                for k, v in d.copy().items():
                    if v == single_to_delete:
                        del d[k]
        for v in d.values():
            delete_items_from_dict(v, to_delete)
    elif isinstance(d, list):
        for i in d:
            delete_items_from_dict(i, to_delete)
    return remove_none(d)


def is_valid_metadata_key(name: str) -> bool:
    # According to the documentation a metadata key
    # has to be a valid XML tag name.
    #
    # The actual allowed tag names (at least as tested with the metadata API),
    # are way more restrictive and only allow ".-A-Za-z_", possibly followed
    # by an index in square brackets e. g. [0].
    # On the other hand the Archive allows tags starting with the string "xml".
    return bool(re.fullmatch(r'[A-Za-z][.\-0-9A-Za-z_]+(?:\[[0-9]+\])?', name))


def merge_dictionaries(
    dict0: dict | None,
    dict1: dict | None,
    keys_to_drop: Iterable | None = None,
) -> dict:
    """Merge two dictionaries.

       Items in `dict0` can optionally be dropped before the merge.

       If equal keys exist in both dictionaries,
       entries in`dict0` are overwritten.

       :param dict0: A base dictionary with the bulk of the items.

       :param dict1: Additional items which overwrite the items in `dict0`.

       :param keys_to_drop: An iterable of keys to drop from `dict0` before the merge.

       :returns: A merged dictionary.
       """
    if dict0 is not None:
        new_dict = dict0.copy()
    else:
        new_dict = {}

    if keys_to_drop is not None:
        for key in keys_to_drop:
            new_dict.pop(key, None)

    # Items from `dict1` take precedence over items from `dict0`.
    if dict1 is not None:
        new_dict.update(dict1)

    return new_dict


def parse_dict_cookies(value: str) -> dict[str, str | None]:
    result: dict[str, str | None] = {}
    for item in value.split(';'):
        item = item.strip()
        if not item:
            continue
        if '=' not in item:
            result[item] = None
            continue
        name, value = item.split('=', 1)
        result[name] = value
    if 'domain' not in result:
        result['domain'] = '.archive.org'
    if 'path' not in result:
        result['path'] = '/'
    return result


def is_valid_email(email):
    # Regular expression pattern for a valid email address
    # Ensures the TLD has at least 2 characters
    pattern = r'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z]{2,}$'
    return re.match(pattern, email) is not None


def is_windows() -> bool:
    return (
        platform.system().lower() == "windows"
        or sys.platform.startswith("win")
    )


def sanitize_filepath(filepath: str, avoid_colon: bool = False) -> str:
    """
    Sanitizes only the filename part of a full file path, leaving the directory path intact.

    This is useful when you need to ensure the filename is safe for filesystem use
    without modifying the directory structure. Typically used before creating files
    or directories to prevent invalid filename characters.

    Args:
        filepath (str): The full file path to sanitize.
        avoid_colon (bool): If True, colon ':' in the filename will be percent-encoded
            for macOS compatibility. Defaults to False.

    Returns:
        str: The sanitized file path with the filename portion percent-encoded as needed.
    """
    parent_dir = os.path.dirname(filepath)
    filename = os.path.basename(filepath)
    sanitized_filename = sanitize_filename(filename, avoid_colon)
    return os.path.join(parent_dir, sanitized_filename)


def sanitize_filename(name: str, avoid_colon: bool = False) -> str:
    """
    Sanitizes a filename by replacing invalid characters with percent-encoded values.
    This function is designed to be compatible with both Windows and POSIX systems.

    Args:
        name (str): The original string to sanitize.
        avoid_colon (bool): If True, colon ':' will be percent-encoded.

    Returns:
        str: A sanitized version of the filename.
    """
    original = name
    if is_windows():
        sanitized = sanitize_filename_windows(name)
    else:
        sanitized = sanitize_filename_posix(name, avoid_colon)

    if sanitized != original:
        warnings.warn(
            f"Filename sanitized: original='{original}' sanitized='{sanitized}'",
            UserWarning,
            stacklevel=2
        )

    return sanitized


def unsanitize_filename(name: str) -> str:
    """
    Reverses percent-encoding of the form %XX back to original characters.
    Works for filenames sanitized by sanitize_filename (Windows or POSIX).

    Args:
        name (str): Sanitized filename string with %XX encodings.

    Returns:
        str: Original filename with all %XX sequences decoded.
    """
    if '%' in name:
        if re.search(r'%[0-9A-Fa-f]{2}', name):
            warnings.warn(
                "Filename contains percent-encoded sequences that will be decoded.",
                UserWarning,
                stacklevel=2
            )
    def decode_match(match):
        hex_value = match.group(1)
        return chr(int(hex_value, 16))

    return re.sub(r'%([0-9A-Fa-f]{2})', decode_match, name)


def sanitize_filename_windows(name: str) -> str:
    r"""
    Replaces Windows-invalid filename characters with percent-encoded values.
    Characters replaced: < > : " / \ | ? * %

    Args:
        name (str): The original string.

    Returns:
        str: A sanitized version safe for filesystem use.
    """
    # Encode `%` so that it's possible to round-trip (i.e. via `unsanitize_filename`)
    invalid_chars = r'[<>:"/\\|?*\x00-\x1F%]'

    def encode(char):
        return f'%{ord(char.group()):02X}'

    # Replace invalid characters
    name = re.sub(invalid_chars, encode, name)

    # Remove trailing dots or spaces (not allowed in Windows filenames)
    return name.rstrip(' .')


def sanitize_filename_posix(name: str, avoid_colon: bool = False) -> str:
    """
    Sanitizes filenames for Linux, BSD, and Unix-like systems.

    - Percent-encodes forward slash '/' (always)
    - Optionally percent-encodes colon ':' for macOS compatibility

    Args:
        name (str): Original filename string.
        avoid_colon (bool): If True, colon ':' will be encoded.

    Returns:
        str: Sanitized filename safe for POSIX systems.
    """
    # Build regex pattern dynamically
    chars_to_encode = r'/'
    if avoid_colon:
        chars_to_encode += ':'

    pattern = f'[{re.escape(chars_to_encode)}]'

    def encode_char(match):
        return f'%{ord(match.group()):02X}'

    return re.sub(pattern, encode_char, name)
