"""
NOTE: This vector database integration is community-supported and maintained on a best-effort basis.
"""

import re
import uuid
from typing import Any, Dict, List, Optional, Union

import weaviate
from rexpro_ai.config import (
    WEAVIATE_API_KEY,
    WEAVIATE_GRPC_HOST,
    WEAVIATE_GRPC_PORT,
    WEAVIATE_GRPC_SECURE,
    WEAVIATE_HTTP_HOST,
    WEAVIATE_HTTP_PORT,
    WEAVIATE_HTTP_SECURE,
    WEAVIATE_SKIP_INIT_CHECKS,
)
from rexpro_ai.retrieval.vector.main import (
    GetResult,
    SearchResult,
    VectorDBBase,
    VectorItem,
)
from rexpro_ai.retrieval.vector.utils import process_metadata


def _convert_uuids_to_strings(obj: Any) -> Any:
    """
    Recursively convert UUID objects to strings in nested data structures.

    This function handles:
    - UUID objects -> string
    - Dictionaries with UUID values
    - Lists/Tuples with UUID values
    - Nested combinations of the above

    Args:
        obj: Any object that might contain UUIDs

    Returns:
        The same object structure with UUIDs converted to strings
    """
    if isinstance(obj, uuid.UUID):
        return str(obj)
    elif isinstance(obj, dict):
        return {key: _convert_uuids_to_strings(value) for key, value in obj.items()}
    elif isinstance(obj, (list, tuple)):
        return type(obj)(_convert_uuids_to_strings(item) for item in obj)
    elif isinstance(obj, (str, int, float, bool, type(None))):
        return obj
    else:
        return obj


class WeaviateClient(VectorDBBase):
    def __init__(self):
        self.url = WEAVIATE_HTTP_HOST
        try:
            # Build connection parameters
            connection_params = {
                'http_host': WEAVIATE_HTTP_HOST,
                'http_port': WEAVIATE_HTTP_PORT,
                'http_secure': WEAVIATE_HTTP_SECURE,
                'grpc_host': WEAVIATE_GRPC_HOST,
                'grpc_port': WEAVIATE_GRPC_PORT,
                'grpc_secure': WEAVIATE_GRPC_SECURE,
                'skip_init_checks': WEAVIATE_SKIP_INIT_CHECKS,
            }

            # Only add auth_credentials if WEAVIATE_API_KEY exists and is not empty
            if WEAVIATE_API_KEY:
                connection_params['auth_credentials'] = weaviate.classes.init.Auth.api_key(WEAVIATE_API_KEY)

            self.client = weaviate.connect_to_custom(**connection_params)
            self.client.connect()
        except Exception as e:
            raise ConnectionError(f'Failed to connect to Weaviate: {e}') from e

    def _sanitize_collection_name(self, collection_name: str) -> str:
        """Sanitize collection name to be a valid Weaviate class name."""
        if not isinstance(collection_name, str) or not collection_name.strip():
            raise ValueError('Collection name must be a non-empty string')

        # Requirements for a valid Weaviate class name:
        # The collection name must begin with a capital letter.
        # The name can only contain letters, numbers, and the underscore (_) character. Spaces are not allowed.

        # Replace hyphens with underscores and keep only alphanumeric characters
        name = re.sub(r'[^a-zA-Z0-9_]', '', collection_name.replace('-', '_'))
        name = name.strip('_')

        if not name:
            raise ValueError('Could not sanitize collection name to be a valid Weaviate class name')

        # Ensure it starts with a letter and is capitalized
        if not name[0].isalpha():
            name = 'C' + name

        return name[0].upper() + name[1:]

    def has_collection(self, collection_name: str) -> bool:
        sane_collection_name = self._sanitize_collection_name(collection_name)
        return self.client.collections.exists(sane_collection_name)

    def delete_collection(self, collection_name: str) -> None:
        sane_collection_name = self._sanitize_collection_name(collection_name)
        if self.client.collections.exists(sane_collection_name):
            self.client.collections.delete(sane_collection_name)

    def _create_collection(self, collection_name: str) -> None:
        self.client.collections.create(
            name=collection_name,
            vector_config=weaviate.classes.config.Configure.Vectors.self_provided(),
            properties=[
                weaviate.classes.config.Property(name='text', data_type=weaviate.classes.config.DataType.TEXT),
            ],
        )

    def insert(self, collection_name: str, items: List[VectorItem]) -> None:
        sane_collection_name = self._sanitize_collection_name(collection_name)
        if not self.client.collections.exists(sane_collection_name):
            self._create_collection(sane_collection_name)

        collection = self.client.collections.get(sane_collection_name)

        with collection.batch.fixed_size(batch_size=100) as batch:
            for item in items:
                item_uuid = str(uuid.uuid4()) if not item['id'] else str(item['id'])

                properties = {'text': item['text']}
                if item['metadata']:
                    clean_metadata = _convert_uuids_to_strings(process_metadata(item['metadata']))
                    clean_metadata.pop('text', None)
                    properties.update(clean_metadata)

                batch.add_object(properties=properties, uuid=item_uuid, vector=item['vector'])

    def upsert(self, collection_name: str, items: List[VectorItem]) -> None:
        sane_collection_name = self._sanitize_collection_name(collection_name)
        if not self.client.collections.exists(sane_collection_name):
            self._create_collection(sane_collection_name)

        collection = self.client.collections.get(sane_collection_name)

        with collection.batch.fixed_size(batch_size=100) as batch:
            for item in items:
                item_uuid = str(item['id']) if item['id'] else None

                properties = {'text': item['text']}
                if item['metadata']:
                    clean_metadata = _convert_uuids_to_strings(process_metadata(item['metadata']))
                    clean_metadata.pop('text', None)
                    properties.update(clean_metadata)

                batch.add_object(properties=properties, uuid=item_uuid, vector=item['vector'])

    def search(
        self,
        collection_name: str,
        vectors: List[List[Union[float, int]]],
        filter: Optional[dict] = None,
        limit: int = 10,
    ) -> Optional[SearchResult]:
        sane_collection_name = self._sanitize_collection_name(collection_name)
        if not self.client.collections.exists(sane_collection_name):
            return None

        collection = self.client.collections.get(sane_collection_name)

        result_ids, result_documents, result_metadatas, result_distances = (
            [],
            [],
            [],
            [],
        )

        for vector_embedding in vectors:
            try:
                response = collection.query.near_vector(
                    near_vector=vector_embedding,
                    limit=limit,
                    return_metadata=weaviate.classes.query.MetadataQuery(distance=True),
                )

                ids = [str(obj.uuid) for obj in response.objects]
                documents = []
                metadatas = []
                distances = []

                for obj in response.objects:
                    properties = dict(obj.properties) if obj.properties else {}
                    documents.append(properties.pop('text', ''))
                    metadatas.append(_convert_uuids_to_strings(properties))

                # Weaviate has cosine distance, 2 (worst) -> 0 (best). Re-ordering to 0 -> 1
                raw_distances = [
                    (obj.metadata.distance if obj.metadata and obj.metadata.distance else 2.0)
                    for obj in response.objects
                ]
                distances = [(2 - dist) / 2 for dist in raw_distances]

                result_ids.append(ids)
                result_documents.append(documents)
                result_metadatas.append(metadatas)
                result_distances.append(distances)
            except Exception:
                result_ids.append([])
                result_documents.append([])
                result_metadatas.append([])
                result_distances.append([])

        return SearchResult(
            **{
                'ids': result_ids,
                'documents': result_documents,
                'metadatas': result_metadatas,
                'distances': result_distances,
            }
        )

    def query(self, collection_name: str, filter: Dict, limit: Optional[int] = None) -> Optional[GetResult]:
        sane_collection_name = self._sanitize_collection_name(collection_name)
        if not self.client.collections.exists(sane_collection_name):
            return None

        collection = self.client.collections.get(sane_collection_name)

        weaviate_filter = None
        if filter:
            for key, value in filter.items():
                prop_filter = weaviate.classes.query.Filter.by_property(name=key).equal(value)
                weaviate_filter = (
                    prop_filter
                    if weaviate_filter is None
                    else weaviate.classes.query.Filter.all_of([weaviate_filter, prop_filter])
                )

        try:
            response = collection.query.fetch_objects(filters=weaviate_filter, limit=limit)

            ids = [str(obj.uuid) for obj in response.objects]
            documents = []
            metadatas = []

            for obj in response.objects:
                properties = dict(obj.properties) if obj.properties else {}
                documents.append(properties.pop('text', ''))
                metadatas.append(_convert_uuids_to_strings(properties))

            return GetResult(
                **{
                    'ids': [ids],
                    'documents': [documents],
                    'metadatas': [metadatas],
                }
            )
        except Exception:
            return None

    def get(self, collection_name: str) -> Optional[GetResult]:
        sane_collection_name = self._sanitize_collection_name(collection_name)
        if not self.client.collections.exists(sane_collection_name):
            return None

        collection = self.client.collections.get(sane_collection_name)
        ids, documents, metadatas = [], [], []

        try:
            for item in collection.iterator():
                ids.append(str(item.uuid))
                properties = dict(item.properties) if item.properties else {}
                documents.append(properties.pop('text', ''))
                metadatas.append(_convert_uuids_to_strings(properties))

            if not ids:
                return None

            return GetResult(
                **{
                    'ids': [ids],
                    'documents': [documents],
                    'metadatas': [metadatas],
                }
            )
        except Exception:
            return None

    def delete(
        self,
        collection_name: str,
        ids: Optional[List[str]] = None,
        filter: Optional[Dict] = None,
    ) -> None:
        sane_collection_name = self._sanitize_collection_name(collection_name)
        if not self.client.collections.exists(sane_collection_name):
            return

        collection = self.client.collections.get(sane_collection_name)

        try:
            if ids:
                for item_id in ids:
                    collection.data.delete_by_id(uuid=item_id)
            elif filter:
                weaviate_filter = None
                for key, value in filter.items():
                    prop_filter = weaviate.classes.query.Filter.by_property(name=key).equal(value)
                    weaviate_filter = (
                        prop_filter
                        if weaviate_filter is None
                        else weaviate.classes.query.Filter.all_of([weaviate_filter, prop_filter])
                    )

                if weaviate_filter:
                    collection.data.delete_many(where=weaviate_filter)
        except Exception:
            pass

    def reset(self) -> None:
        try:
            for collection_name in self.client.collections.list_all().keys():
                self.client.collections.delete(collection_name)
        except Exception:
            pass