# Copyright (C) 2016-2023 RhodeCode GmbH
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License, version 3
# (only), as published by the Free Software Foundation.
#
# 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 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/>.
#
# This program is dual-licensed. If you wish to learn more about the
# RhodeCode Enterprise Edition, including its added features, Support services,
# and proprietary license terms, please see https://rhodecode.com/licenses/

import os
import fsspec  # noqa
import logging

from rhodecode.lib.ext_json import json

from rhodecode.apps.file_store.utils import sha256_safe, ShardFileReader, get_uid_filename
from rhodecode.apps.file_store.extensions import resolve_extensions
from rhodecode.apps.file_store.exceptions import FileNotAllowedException, FileOverSizeException  # noqa: F401

log = logging.getLogger(__name__)


class BaseShard:

    metadata_suffix: str = '.metadata'
    storage_type: str = ''
    fs = None

    @property
    def storage_medium(self):
        if not self.storage_type:
            raise ValueError('No storage type set for this shard storage_type=""')
        return getattr(self, self.storage_type)

    def __contains__(self, key):
        full_path = self.store_path(key)
        return self.fs.exists(full_path)

    def metadata_convert(self, uid_filename, metadata):
        return metadata

    def get_metadata_filename(self, uid_filename) -> tuple[str, str]:
        metadata_file: str = f'{uid_filename}{self.metadata_suffix}'
        return metadata_file, self.store_path(metadata_file)

    def get_metadata(self, uid_filename, ignore_missing=False) -> dict:
        _metadata_file, metadata_file_path = self.get_metadata_filename(uid_filename)
        if ignore_missing and not self.fs.exists(metadata_file_path):
            return {}

        with self.fs.open(metadata_file_path, 'rb') as f:
            metadata = json.loads(f.read())

        metadata = self.metadata_convert(uid_filename, metadata)
        return metadata

    def _store(self, key: str, uid_key: str, value_reader, max_filesize: int | None = None, metadata: dict | None = None, **kwargs):
        raise NotImplementedError

    def store(self, key: str, uid_key: str, value_reader, max_filesize: int | None = None, metadata: dict | None = None, **kwargs):
        return self._store(key, uid_key, value_reader, max_filesize, metadata, **kwargs)

    def _fetch(self, key, presigned_url_expires: int = 0):
        raise NotImplementedError

    def fetch(self, key, **kwargs) -> tuple[ShardFileReader, dict]:
        return self._fetch(key)

    def _delete(self, key):
        if key not in self:
            log.exception(f'requested key={key} not found in {self}')
            raise KeyError(key)

        metadata = self.get_metadata(key)
        _metadata_file, metadata_file_path = self.get_metadata_filename(key)
        artifact_file_path = metadata['filename_uid_path']
        self.fs.rm(artifact_file_path)
        self.fs.rm(metadata_file_path)

        return 1

    def delete(self, key):
        raise NotImplementedError

    def store_path(self, uid_filename):
        raise NotImplementedError


class BaseFileStoreBackend:
    _shards = tuple()
    _shard_cls = BaseShard
    _config: dict | None = None
    _storage_path: str = ''

    def __init__(self, settings, extension_groups=None):
        self._config = settings
        extension_groups = extension_groups or ['any']
        self.extensions = resolve_extensions([], groups=extension_groups)

    def __contains__(self, key):
        return self.filename_exists(key)

    def __repr__(self):
        return f'<{self.__class__.__name__}(storage={self.storage_path})>'

    @property
    def storage_path(self):
        return self._storage_path

    @classmethod
    def get_shard_index(cls, filename: str, num_shards) -> int:
        # Generate a hash value from the filename
        hash_value = sha256_safe(filename)

        # Convert the hash value to an integer
        hash_int = int(hash_value, 16)

        # Map the hash integer to a shard number between 1 and num_shards
        shard_number = (hash_int % num_shards)

        return shard_number

    @classmethod
    def apply_counter(cls, counter: int, filename: str) -> str:
        """
        Apply a counter to the filename.

        :param counter: The counter value to apply.
        :param filename: The original filename.
        :return: The modified filename with the counter.
        """
        name_counted = f'{counter:d}-{filename}'
        return name_counted

    def _get_shard(self, key) -> _shard_cls:
        index = self.get_shard_index(key, len(self._shards))
        shard = self._shards[index]
        return shard

    def get_conf(self, key, pop=False):
        if key not in self._config:
            raise ValueError(
                f"No configuration key '{key}', please make sure it exists in filestore config")
        val = self._config[key]
        if pop:
            del self._config[key]
        return val

    def filename_allowed(self, filename, extensions=None):
        """Checks if a filename has an allowed extension

        :param filename: base name of file
        :param extensions: iterable of extensions (or self.extensions)
        """
        _, ext = os.path.splitext(filename)
        return self.extension_allowed(ext, extensions)

    def extension_allowed(self, ext, extensions=None):
        """
        Checks if an extension is permitted. Both e.g. ".jpg" and
        "jpg" can be passed in. Extension lookup is case-insensitive.

        :param ext: extension to check
        :param extensions: iterable of extensions to validate against (or self.extensions)
        """
        def normalize_ext(_ext):
            if _ext.startswith('.'):
                _ext = _ext[1:]
            return _ext.lower()

        extensions = extensions or self.extensions
        if not extensions:
            return True

        ext = normalize_ext(ext)

        return ext in [normalize_ext(x) for x in extensions]

    def filename_exists(self, uid_filename):
        shard = self._get_shard(uid_filename)
        return uid_filename in shard

    def store_path(self, uid_filename):
        """
        Returns absolute file path of the uid_filename
        """
        shard = self._get_shard(uid_filename)
        return shard.store_path(uid_filename)

    def store_metadata(self, uid_filename):
        shard = self._get_shard(uid_filename)
        return shard.get_metadata_filename(uid_filename)

    def store(self, filename, value_reader, extensions=None, metadata=None, max_filesize=None, randomized_name=True, **kwargs):
        extensions = extensions or self.extensions

        if not self.filename_allowed(filename, extensions):
            msg = f'filename {filename} does not allow extensions {extensions}'
            raise FileNotAllowedException(msg)

        # # TODO: check why we need this setting ? it looks stupid...
        # no_body_seek is used in stream mode importer somehow
        # no_body_seek = kwargs.pop('no_body_seek', False)
        # if no_body_seek:
        #     pass
        # else:
        #     value_reader.seek(0)

        uid_filename = kwargs.pop('uid_filename', None)
        if uid_filename is None:
            uid_filename = get_uid_filename(filename, randomized=randomized_name)

        shard = self._get_shard(uid_filename)

        return shard.store(filename, uid_filename, value_reader, max_filesize, metadata, **kwargs)

    def import_to_store(self, value_reader, org_filename, uid_filename, metadata, **kwargs):
        shard = self._get_shard(uid_filename)
        max_filesize = None
        return shard.store(org_filename, uid_filename, value_reader, max_filesize, metadata, import_mode=True)

    def delete(self, uid_filename):
        shard = self._get_shard(uid_filename)
        return shard.delete(uid_filename)

    def fetch(self, uid_filename) -> tuple[ShardFileReader, dict]:
        shard = self._get_shard(uid_filename)
        return shard.fetch(uid_filename)

    def get_metadata(self, uid_filename, ignore_missing=False) -> dict:
        shard = self._get_shard(uid_filename)
        return shard.get_metadata(uid_filename, ignore_missing=ignore_missing)

    def iter_keys(self):
        for shard in self._shards:
            if shard.fs.exists(shard.storage_medium):
                for path, _dirs, _files in shard.fs.walk(shard.storage_medium):
                    for key_file_path in _files:
                        if key_file_path.endswith(shard.metadata_suffix):
                            yield shard, key_file_path

    def iter_artifacts(self):
        for shard, key_file in self.iter_keys():
            json_key = f"{shard.storage_medium}/{key_file}"
            with shard.fs.open(json_key, 'rb') as f:
                yield shard, json.loads(f.read())['filename_uid']

    def get_statistics(self):
        total_files = 0
        total_size = 0
        meta = {}

        for shard, key_file in self.iter_keys():
            json_key = f"{shard.storage_medium}/{key_file}"
            with shard.fs.open(json_key, 'rb') as f:
                total_files += 1
                metadata = json.loads(f.read())
                total_size += metadata['size']

        return total_files, total_size, meta