import os
import json
import faiss
from towhee.operator import PyOperator, SharedType

class Meta:
    def __init__(self, id=0, data=None):
        self._id = id
        self._data = data if data is not None else {}

    def add(self, data):
        self._id += 1
        self._data[self._id] = data
        return self._id

    def get(self, i):
        return self._data[i]

    @classmethod
    def load(cls, f_path):
        with open(f_path, 'r') as f:
            data = json.load(f)
            return cls(data['id'], data['data'])

    def save(self, f_path):
        with open(f_path, 'w') as f:
            json.dump({'id': self._id, 'data': self._data}, f)


class FaissSearch(PyOperator):
    """
    Search for embedding vectors in Faiss.
    Only support the data insert by ops.ann_insert.faiss_index()
    """
    def __init__(self, data_dir: str, top_k: int = 5):
        self._top_k = top_k
        self._index_file = os.path.join(data_dir, 'faiss.index')
        self._meta_file = os.path.join(data_dir, 'meta.bin')
        self._index = faiss.read_index(self._index_file)
        self._meta = Meta.load(self._meta_file)

    def __call__(self, query: 'ndarray'):
        np_data = query.reshape(1, -1)
        dist, ids = self._index.search(np_data, self._top_k)
        ids = [int(i) for i in ids[0]]
        meta_data = [self._meta.get(str(i)) for i in ids]
        return list(zip(ids, dist[0], meta_data))
    
    @property
    def shared_type(self):
        return SharedType.Shareable