#
# Pyserini: Reproducible IR research with sparse and dense representations
#
# 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 logging
from typing import List, Dict

from pyserini.pyclass import autoclass

logger = logging.getLogger(__name__)

JLuceneIndexer = autoclass('io.anserini.index.SimpleIndexer')
JsonCollectionDocument = autoclass('io.anserini.collection.JsonCollection$Document')
JacksonObjectMapper = autoclass('com.fasterxml.jackson.databind.ObjectMapper')
JacksonJsonNode = autoclass('com.fasterxml.jackson.databind.JsonNode')


class LuceneIndexer:
    """Wrapper class for ``SimpleIndexer`` in Anserini. Provides basic functionality for on-the-fly indexing via a
    programmatic API, i.e., indexing in-process objects as opposed to on-file documents.

    Parameters
    ----------
    index_dir : str
        Path to Lucene index directory.
    args : List[str]
        List of arguments to pass to ``SimpleIndexer``.
    append : bool
        Append to existing index.
    threads : int
        Number of indexing threads.
    """
    def __init__(self, index_dir: str = None, args: List[str] = None, append: bool = False, threads: int = 8):
        self.index_dir = index_dir
        self.args = args
        if args:
            args.extend(['-input', '', '-collection', 'JsonCollection', '-threads', str(threads)])
            if append:
                args.extend(['-append'])
            self.object = JLuceneIndexer(args)
        else:
            self.object = JLuceneIndexer(index_dir, append, int(threads))

        self.mapper = JacksonObjectMapper()

    def add_doc_raw(self, doc: str):
        """Add a raw document (in the form of a JSON string) to the index.

        Parameters
        ----------
        doc : str
            Document to add.
        """
        self.object.addRawDocument(doc)

    def add_doc_dict(self, doc: Dict[str, str]):
        """Add a document (in the form of a Python dictionary) to the index.

        Parameters
        ----------
        doc : Dict[str, str]
            Document to add.
        """
        self.object.addJsonDocument(JsonCollectionDocument.fromFields(doc['id'], doc['contents']))

    def add_doc_json(self, node: JacksonJsonNode):
        """Add a document (in the form of a Jackson JSON node object) to the index.

        Parameters
        ----------
        node : JacksonJsonNode
            Document to add.
        """
        self.object.addJsonNode(node)

    def add_batch_raw(self, docs: List[str]):
        """Add a batch of raw documents (in the form of JSON strings) to the index.

        Parameters
        ----------
        docs : List[str]
            Documents to add.
        """
        self.object.addRawDocuments(docs)

    def add_batch_dict(self, docs: List[Dict[str, str]]):
        """Add a batch of documents (in the form of Python dictionaries) to the index.

        Parameters
        ----------
        docs : List[Dict[str, str]]
            Documents to add.
        """
        docs = list(map(lambda d: JsonCollectionDocument.fromFields(d['id'], d['contents']), docs))
        self.object.addJsonDocuments(docs)

    def add_batch_json(self, nodes: List[JacksonJsonNode]):
        """Add a batch of documents (in the form of Jackson JSON node objects) to the index.

        Parameters
        ----------
        nodes : List[JacksonJsonNode]
            Documents to add.
        """
        self.object.addJsonNodes(nodes)

    def close(self):
        """Close this indexer, committing all in-memory data to disk."""
        self.object.close()