from abc import ABCMeta, abstractmethod


class CXGDriver(metaclass=ABCMeta):
    def __init__(self, data, schema=None, graph_method=None, diffexp_method=None):
        self.data = self._load_data(data)

    @staticmethod
    @abstractmethod
    def _load_data(data):
        pass

    @abstractmethod
    def _load_or_infer_schema(data):
        pass

    @abstractmethod
    def cells(self):
        pass

    @abstractmethod
    def genes(self):
        pass

    @abstractmethod
    def filter_cells(self, filter):
        """
        Filter cells from data and return a subset of the data
        A filter is a dictionary where the key is a metadatata category
        Value is dictionary
            value_type: int, float, string
            variable_type: continuous, categorical
            query: filter value, for categorical [val1, val2], for continuous {min: x, max:y}
        Filters are combined with the and operator
        :param filter:
        :return: filtered dataframe
        """
        pass

    @abstractmethod
    def metadata(self, df, fields=None):
        """
         Gets metadata key:value for each cells

        :param df: from filter_cells, dataframe
        :param fields: list of keys for metadata to return, returns all metadata values if not set.
        :return: list of metadata values
        """
        pass

    @abstractmethod
    def create_graph(self, df):
        """
        Computes a n-d layout for cells through dimensionality reduction.
        :param df: from filter_cells, dataframe
        :return:  [cellid, x, y]
        """
        pass

    @abstractmethod
    def diffexp(self, df1, df2):
        """
        Computes the top differentially expressed genes between two clusters
        :param df1: from filter_cells, dataframe containing first set of cells
        :param df2: from filter_cells, dataframe containing second set of cells
        :return: top genes, stats and expression values for top genes
        """
        pass

    @abstractmethod
    def expression(self, df):
        """
        Retrieves expression for each gene for cells in data frame
        :param df:
        :return: {
            "genes": list of genes,
            "cells": list of cells and expression list,
            "nonzero_gene_count": number of nonzero genes
        }
        """
        pass