"""
Testing
=======

General guidelines for writing good tests:

- doctests always assume ``import networkx as nx`` so don't add that
- prefer pytest fixtures over classes with setup methods.
- use the ``@pytest.mark.parametrize``  decorator
- use ``pytest.importorskip`` for numpy, scipy, pandas, and matplotlib b/c of PyPy.
  and add the module to the relevant entries below.

"""
import os
import sys
import warnings
from importlib.metadata import entry_points

import pytest

import networkx


def pytest_addoption(parser):
    parser.addoption(
        "--runslow", action="store_true", default=False, help="run slow tests"
    )
    parser.addoption(
        "--backend",
        action="store",
        default=None,
        help="Run tests with a backend by auto-converting nx graphs to backend graphs",
    )
    parser.addoption(
        "--fallback-to-nx",
        action="store_true",
        default=False,
        help="Run nx function if a backend doesn't implement a dispatchable function"
        " (use with --backend)",
    )


def pytest_configure(config):
    config.addinivalue_line("markers", "slow: mark test as slow to run")
    backend = config.getoption("--backend")
    if backend is None:
        backend = os.environ.get("NETWORKX_TEST_BACKEND")
    if backend:
        networkx.utils.backends._dispatch._automatic_backends = [backend]
        fallback_to_nx = config.getoption("--fallback-to-nx")
        if not fallback_to_nx:
            fallback_to_nx = os.environ.get("NETWORKX_FALLBACK_TO_NX")
        networkx.utils.backends._dispatch._fallback_to_nx = bool(fallback_to_nx)
    # nx-loopback backend is only available when testing
    if sys.version_info < (3, 10):
        backends = (
            ep for ep in entry_points()["networkx.backends"] if ep.name == "nx-loopback"
        )
    else:
        backends = entry_points(name="nx-loopback", group="networkx.backends")
    networkx.utils.backends.backends["nx-loopback"] = next(iter(backends))


def pytest_collection_modifyitems(config, items):
    # Setting this to True here allows tests to be set up before dispatching
    # any function call to a backend.
    networkx.utils.backends._dispatch._is_testing = True
    if automatic_backends := networkx.utils.backends._dispatch._automatic_backends:
        # Allow pluggable backends to add markers to tests (such as skip or xfail)
        # when running in auto-conversion test mode
        backend = networkx.utils.backends.backends[automatic_backends[0]].load()
        if hasattr(backend, "on_start_tests"):
            getattr(backend, "on_start_tests")(items)

    if config.getoption("--runslow"):
        # --runslow given in cli: do not skip slow tests
        return
    skip_slow = pytest.mark.skip(reason="need --runslow option to run")
    for item in items:
        if "slow" in item.keywords:
            item.add_marker(skip_slow)


# TODO: The warnings below need to be dealt with, but for now we silence them.
@pytest.fixture(autouse=True)
def set_warnings():
    warnings.filterwarnings(
        "ignore", category=DeprecationWarning, message="nx.nx_pydot"
    )
    warnings.filterwarnings(
        "ignore",
        category=DeprecationWarning,
        message="single_target_shortest_path_length will",
    )
    warnings.filterwarnings(
        "ignore",
        category=DeprecationWarning,
        message="shortest_path for all_pairs",
    )
    warnings.filterwarnings(
        "ignore", category=DeprecationWarning, message="\nforest_str is deprecated"
    )
    warnings.filterwarnings(
        "ignore", category=DeprecationWarning, message="\n\nrandom_tree"
    )
    warnings.filterwarnings(
        "ignore", category=DeprecationWarning, message="Edmonds has been deprecated"
    )
    warnings.filterwarnings(
        "ignore",
        category=DeprecationWarning,
        message="MultiDiGraph_EdgeKey has been deprecated",
    )
    warnings.filterwarnings(
        "ignore", category=DeprecationWarning, message="\n\nThe `normalized`"
    )
    warnings.filterwarnings(
        "ignore", category=DeprecationWarning, message="function `join` is deprecated"
    )
    warnings.filterwarnings(
        "ignore",
        category=DeprecationWarning,
        message="\n\nstrongly_connected_components_recursive",
    )


@pytest.fixture(autouse=True)
def add_nx(doctest_namespace):
    doctest_namespace["nx"] = networkx
    # TODO: remove the try-except block when we require numpy >= 2
    try:
        import numpy as np

        np.set_printoptions(legacy="1.21")
    except ImportError:
        pass


# What dependencies are installed?

try:
    import numpy

    has_numpy = True
except ImportError:
    has_numpy = False

try:
    import scipy

    has_scipy = True
except ImportError:
    has_scipy = False

try:
    import matplotlib

    has_matplotlib = True
except ImportError:
    has_matplotlib = False

try:
    import pandas

    has_pandas = True
except ImportError:
    has_pandas = False

try:
    import pygraphviz

    has_pygraphviz = True
except ImportError:
    has_pygraphviz = False

try:
    import pydot

    has_pydot = True
except ImportError:
    has_pydot = False

try:
    import sympy

    has_sympy = True
except ImportError:
    has_sympy = False


# List of files that pytest should ignore

collect_ignore = []

needs_numpy = [
    "algorithms/approximation/traveling_salesman.py",
    "algorithms/centrality/current_flow_closeness.py",
    "algorithms/node_classification.py",
    "algorithms/non_randomness.py",
    "algorithms/shortest_paths/dense.py",
    "linalg/bethehessianmatrix.py",
    "linalg/laplacianmatrix.py",
    "utils/misc.py",
    "algorithms/centrality/laplacian.py",
]
needs_scipy = [
    "algorithms/approximation/traveling_salesman.py",
    "algorithms/assortativity/correlation.py",
    "algorithms/assortativity/mixing.py",
    "algorithms/assortativity/pairs.py",
    "algorithms/bipartite/matrix.py",
    "algorithms/bipartite/spectral.py",
    "algorithms/centrality/current_flow_betweenness.py",
    "algorithms/centrality/current_flow_betweenness_subset.py",
    "algorithms/centrality/eigenvector.py",
    "algorithms/centrality/katz.py",
    "algorithms/centrality/second_order.py",
    "algorithms/centrality/subgraph_alg.py",
    "algorithms/communicability_alg.py",
    "algorithms/link_analysis/hits_alg.py",
    "algorithms/link_analysis/pagerank_alg.py",
    "algorithms/node_classification.py",
    "algorithms/similarity.py",
    "convert_matrix.py",
    "drawing/layout.py",
    "generators/spectral_graph_forge.py",
    "linalg/algebraicconnectivity.py",
    "linalg/attrmatrix.py",
    "linalg/bethehessianmatrix.py",
    "linalg/graphmatrix.py",
    "linalg/modularitymatrix.py",
    "linalg/spectrum.py",
    "utils/rcm.py",
    "algorithms/centrality/laplacian.py",
]
needs_matplotlib = ["drawing/nx_pylab.py"]
needs_pandas = ["convert_matrix.py"]
needs_pygraphviz = ["drawing/nx_agraph.py"]
needs_pydot = ["drawing/nx_pydot.py"]
needs_sympy = ["algorithms/polynomials.py"]

if not has_numpy:
    collect_ignore += needs_numpy
if not has_scipy:
    collect_ignore += needs_scipy
if not has_matplotlib:
    collect_ignore += needs_matplotlib
if not has_pandas:
    collect_ignore += needs_pandas
if not has_pygraphviz:
    collect_ignore += needs_pygraphviz
if not has_pydot:
    collect_ignore += needs_pydot
if not has_sympy:
    collect_ignore += needs_sympy