"""
    Unit tests for degree centrality.
"""

import pytest

import networkx as nx


class TestDegreeCentrality:
    def setup_method(self):

        self.K = nx.krackhardt_kite_graph()
        self.P3 = nx.path_graph(3)
        self.K5 = nx.complete_graph(5)

        F = nx.Graph()  # Florentine families
        F.add_edge("Acciaiuoli", "Medici")
        F.add_edge("Castellani", "Peruzzi")
        F.add_edge("Castellani", "Strozzi")
        F.add_edge("Castellani", "Barbadori")
        F.add_edge("Medici", "Barbadori")
        F.add_edge("Medici", "Ridolfi")
        F.add_edge("Medici", "Tornabuoni")
        F.add_edge("Medici", "Albizzi")
        F.add_edge("Medici", "Salviati")
        F.add_edge("Salviati", "Pazzi")
        F.add_edge("Peruzzi", "Strozzi")
        F.add_edge("Peruzzi", "Bischeri")
        F.add_edge("Strozzi", "Ridolfi")
        F.add_edge("Strozzi", "Bischeri")
        F.add_edge("Ridolfi", "Tornabuoni")
        F.add_edge("Tornabuoni", "Guadagni")
        F.add_edge("Albizzi", "Ginori")
        F.add_edge("Albizzi", "Guadagni")
        F.add_edge("Bischeri", "Guadagni")
        F.add_edge("Guadagni", "Lamberteschi")
        self.F = F

        G = nx.DiGraph()
        G.add_edge(0, 5)
        G.add_edge(1, 5)
        G.add_edge(2, 5)
        G.add_edge(3, 5)
        G.add_edge(4, 5)
        G.add_edge(5, 6)
        G.add_edge(5, 7)
        G.add_edge(5, 8)
        self.G = G

    def test_degree_centrality_1(self):
        d = nx.degree_centrality(self.K5)
        exact = dict(zip(range(5), [1] * 5))
        for n, dc in d.items():
            assert exact[n] == pytest.approx(dc, abs=1e-7)

    def test_degree_centrality_2(self):
        d = nx.degree_centrality(self.P3)
        exact = {0: 0.5, 1: 1, 2: 0.5}
        for n, dc in d.items():
            assert exact[n] == pytest.approx(dc, abs=1e-7)

    def test_degree_centrality_3(self):
        d = nx.degree_centrality(self.K)
        exact = {
            0: 0.444,
            1: 0.444,
            2: 0.333,
            3: 0.667,
            4: 0.333,
            5: 0.556,
            6: 0.556,
            7: 0.333,
            8: 0.222,
            9: 0.111,
        }
        for n, dc in d.items():
            assert exact[n] == pytest.approx(float(f"{dc:.3f}"), abs=1e-7)

    def test_degree_centrality_4(self):
        d = nx.degree_centrality(self.F)
        names = sorted(self.F.nodes())
        dcs = [
            0.071,
            0.214,
            0.143,
            0.214,
            0.214,
            0.071,
            0.286,
            0.071,
            0.429,
            0.071,
            0.214,
            0.214,
            0.143,
            0.286,
            0.214,
        ]
        exact = dict(zip(names, dcs))
        for n, dc in d.items():
            assert exact[n] == pytest.approx(float(f"{dc:.3f}"), abs=1e-7)

    def test_indegree_centrality(self):
        d = nx.in_degree_centrality(self.G)
        exact = {
            0: 0.0,
            1: 0.0,
            2: 0.0,
            3: 0.0,
            4: 0.0,
            5: 0.625,
            6: 0.125,
            7: 0.125,
            8: 0.125,
        }
        for n, dc in d.items():
            assert exact[n] == pytest.approx(dc, abs=1e-7)

    def test_outdegree_centrality(self):
        d = nx.out_degree_centrality(self.G)
        exact = {
            0: 0.125,
            1: 0.125,
            2: 0.125,
            3: 0.125,
            4: 0.125,
            5: 0.375,
            6: 0.0,
            7: 0.0,
            8: 0.0,
        }
        for n, dc in d.items():
            assert exact[n] == pytest.approx(dc, abs=1e-7)

    def test_small_graph_centrality(self):
        G = nx.empty_graph(create_using=nx.DiGraph)
        assert {} == nx.degree_centrality(G)
        assert {} == nx.out_degree_centrality(G)
        assert {} == nx.in_degree_centrality(G)

        G = nx.empty_graph(1, create_using=nx.DiGraph)
        assert {0: 1} == nx.degree_centrality(G)
        assert {0: 1} == nx.out_degree_centrality(G)
        assert {0: 1} == nx.in_degree_centrality(G)
