#!/usr/bin/env python
import pytest
numpy = pytest.importorskip('numpy')
scipy = pytest.importorskip('scipy')

import networkx as nx
from networkx.algorithms import node_classification


class TestHarmonicFunction:

    def test_path_graph(self):
        G = nx.path_graph(4)
        label_name = 'label'
        G.nodes[0][label_name] = 'A'
        G.nodes[3][label_name] = 'B'
        predicted = node_classification.harmonic_function(
            G, label_name=label_name)
        assert predicted[0] == 'A'
        assert predicted[1] == 'A'
        assert predicted[2] == 'B'
        assert predicted[3] == 'B'

    @pytest.mark.xfail(nx.NetworkXError)
    def test_no_labels(self):
        G = nx.path_graph(4)
        node_classification.harmonic_function(G)

    @pytest.mark.xfail(nx.NetworkXError)
    def test_no_nodes(self):
        G = nx.Graph()
        node_classification.harmonic_function(G)

    @pytest.mark.xfail(nx.NetworkXError)
    def test_no_edges(self):
        G = nx.Graph()
        G.add_node(1)
        G.add_node(2)
        node_classification.harmonic_function(G)

    @pytest.mark.xfail(nx.NetworkXNotImplemented)
    def test_digraph(self):
        G = nx.DiGraph()
        G.add_edge(0, 1)
        G.add_edge(1, 2)
        G.add_edge(2, 3)
        label_name = 'label'
        G.nodes[0][label_name] = 'A'
        G.nodes[3][label_name] = 'B'
        node_classification.harmonic_function(G)

    def test_one_labeled_node(self):
        G = nx.path_graph(4)
        label_name = 'label'
        G.nodes[0][label_name] = 'A'
        predicted = node_classification.harmonic_function(
            G, label_name=label_name)
        assert predicted[0] == 'A'
        assert predicted[1] == 'A'
        assert predicted[2] == 'A'
        assert predicted[3] == 'A'

    def test_nodes_all_labeled(self):
        G = nx.karate_club_graph()
        label_name = 'club'
        predicted = node_classification.harmonic_function(
            G, label_name=label_name)
        for i in range(len(G)):
            assert predicted[i] == G.nodes[i][label_name]

    def test_labeled_nodes_are_not_changed(self):
        G = nx.karate_club_graph()
        label_name = 'club'
        label_removed = set([0, 1, 2, 3, 4, 5, 6, 7])
        for i in label_removed:
            del G.nodes[i][label_name]
        predicted = node_classification.harmonic_function(
            G, label_name=label_name)
        label_not_removed = set(list(range(len(G)))) - label_removed
        for i in label_not_removed:
            assert predicted[i] == G.nodes[i][label_name]