test_viewers.py

import base64
import re
import sys
from io import StringIO
from pathlib import Path

import ase
import numpy as np
import pytest
import traitlets as tl
from aiida import orm

from aiidalab_widgets_base import viewers


@pytest.mark.usefixtures("aiida_profile_clean")
def test_pbc_structure_data_viewer(structure_data_object):
    """Test the periodicity of the structure viewer widget."""
    # Prepare a structure with periodicity xy
    ase_input = ase.Atoms(
        symbols="Li2",
        positions=[(0.0, 0.0, 0.0), (1.5, 1.5, 1.5)],
        pbc=[True, True, False],
        cell=[3.5, 3.5, 3.5],
    )
    viewer = viewers.StructureDataViewer()
    viewer.structure = ase_input
    assert viewer.periodicity.value == "Periodicity: xy"
    assert viewer.cell_volume.value == "Cell area: 12.2500 (Ų)"


@pytest.mark.usefixtures("aiida_profile_clean")
def test_several_data_viewers(generate_calc_job_node):
    v = viewers.viewer(orm.Int(1))

    # No viewer for Int, so it should return the input
    assert isinstance(v, orm.Int)

    # DictViewer
    v = viewers.viewer(orm.Dict(dict={"a": 1}))
    assert isinstance(v, viewers.DictViewer)

    # ProcessNodeViewer
    process = generate_calc_job_node(
        inputs={
            "parameters": orm.Int(1),
            "nested": {
                "inner": orm.Int(2),
            },
        }
    )
    v = viewers.viewer(process)
    assert isinstance(v, viewers.ProcessNodeViewerWidget)


@pytest.mark.usefixtures("aiida_profile_clean")
def test_dict_viewer_renders_table_and_csv_payload():
    long_value = "0123456789" * 5
    escaped_value = "<tag> & value"
    parameter = orm.Dict(
        dict={
            "z-key": escaped_value,
            "a-key": long_value,
        }
    ).store()

    viewer = viewers.DictViewer(parameter, downloadable=True)

    assert "<table" in viewer.value
    assert "<th>Key</th>" in viewer.value
    assert "<th>Value</th>" in viewer.value
    assert viewer.value.index("a-key") < viewer.value.index("z-key")
    assert long_value in viewer.value
    assert "&lt;tag&gt; &amp; value" in viewer.value
    assert escaped_value not in viewer.value
    assert f'download="{parameter.pk}.csv"' in viewer.value

    match = re.search(r'data:text/csv;base64,([^"]+)', viewer.value)
    assert match is not None

    decoded_payload = base64.b64decode(match.group(1)).decode()
    assert decoded_payload == (
        f"Key,Value\na-key,{long_value}\nz-key,{escaped_value}\n"
    )


@pytest.mark.usefixtures("aiida_profile_clean")
def test_dict_viewer_skips_download_link_when_disabled():
    parameter = orm.Dict(dict={"a": 1}).store()

    viewer = viewers.DictViewer(parameter, downloadable=False)

    assert "Download table in csv format" not in viewer.value
    assert "data:text/csv;base64," not in viewer.value


@pytest.mark.usefixtures("aiida_profile_clean")
def test_folder_data_viewer(folder_data_object):
    v = viewers.viewer(folder_data_object)
    assert isinstance(v, viewers.FolderDataViewer)

    v.files.value = "test1.txt"
    assert v.text.value == "content of test1.txt"

    v.files.value = "test2.txt"
    assert v.text.value == "content of test2.txt"
    v.download_btn.click()
    # NOTE: We're testing the download() method directly as well,
    # since triggering it via self.download_btn.click() callback
    # seems to swallow all exceptions.
    v.download()

    v.files.value = "test.bin"
    assert v.text.value == "[Binary file, preview not available]"
    v.download()


@pytest.mark.usefixtures("aiida_profile_clean")
def test_structure_data_viewer_storage(monkeypatch, tmp_path, structure_data_object):
    v = viewers.viewer(structure_data_object)
    assert isinstance(v, viewers.StructureDataViewer)

    # Check the `_prepare_payload` function used for downloading.
    format_cases = {
        "Extended xyz": """MgpMYXR0aWNlPSIzLjg0NzM3IDAuMCAwLjAgMS45MjM2ODUgMy4zMzE5MiAwLjAgMS45MjM2ODUgMS4xMTA2NCAzLjE0MTM2NCIgUHJvcGVydGllcz1zcGVjaWVzOlM6MTpwb3M6UjozOm1hc3NlczpSOjE6X2FpaWRhbGFiX3ZpZXdlcl9yZXByZXNlbnRhdGlvbl9kZWZhdWx0Okk6MSBwYmM9IlQgVCBUIgpTaSAgICAgICAwLjAwMDAwMDAwICAgICAgIDAuMDAwMDAwMDAgICAgICAgMC4wMDAwMDAwMCAgICAgIDI4LjA4NTUwMDAwICAgICAgICAwClNpICAgICAgIDEuOTIzNjg1MDAgICAgICAgMS4xMTA2NDAwMCAgICAgICAwLjc4NTM0MTAwICAgICAgMjguMDg1NTAwMDAgICAgICAgIDAK""",
        "xsf": """Q1JZU1RBTApQUklNVkVDCiAzLjg0NzM3MDAwMDAwMDAwIDAuMDAwMDAwMDAwMDAwMDAgMC4wMDAwMDAwMDAwMDAwMAogMS45MjM2ODUwMDAwMDAwMCAzLjMzMTkyMDAwMDAwMDAwIDAuMDAwMDAwMDAwMDAwMDAKIDEuOTIzNjg1MDAwMDAwMDAgMS4xMTA2NDAwMDAwMDAwMCAzLjE0MTM2NDAwMDAwMDAwClBSSU1DT09SRAogMiAxCiAxNCAgICAgMC4wMDAwMDAwMDAwMDAwMCAgICAgMC4wMDAwMDAwMDAwMDAwMCAgICAgMC4wMDAwMDAwMDAwMDAwMAogMTQgICAgIDEuOTIzNjg1MDAwMDAwMDAgICAgIDEuMTEwNjQwMDAwMDAwMDAgICAgIDAuNzg1MzQxMDAwMDAwMDAK""",
        "cif": """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""",
    }

    # Compatibility with old ASE versions <3.23
    old_ase = format_cases.copy()
    old_ase["cif"] = (
        """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"""
    )

    for fmt in format_cases:  # noqa: PLC0206
        v.file_format.label = fmt
        b64_payload = v._prepare_payload()
        try:
            assert b64_payload == format_cases[fmt], (
                f"{fmt} structure payload does not match"
            )
        except AssertionError:
            assert b64_payload == old_ase[fmt], (
                f"{fmt} structure payload does not match"
            )

    # Monkey patch the viewer to avoid the need for a running X server.
    # fmt: off
    v._viewer._camera_orientation = [
        16.619212980943573, 0, 0, 0,
        0, 16.619212980943573, 0, 0,
        0, 0, 16.619212980943573, 0,
        -1.6859999895095825, -1.6859999895095825, -0.6669999957084656, 1,
    ]
    # fmt: on
    # Avoid producing temporary files from povray in the repo
    monkeypatch.chdir(tmp_path)
    v._render_structure()

    # Make sure we don't polute current working dir with tempfiles
    assert not Path("__temp__.pov").exists()
    assert not Path("Si2.png").exists()


@pytest.mark.usefixtures("aiida_profile_clean")
def test_structure_data_viewer_selection(structure_data_object):
    v = viewers.viewer(structure_data_object)

    # Direct selection.
    v._selected_atoms.value = "1..2"
    v.apply_displayed_selection()
    assert v.selection == [0, 1]
    assert v.displayed_selection == [0, 1]
    assert "Distance" in v.selection_info.value

    # The x coordinate lower than 0.5.
    v._selected_atoms.value = "x<0.5"
    v.apply_displayed_selection()
    assert v.selection == [0]
    assert v.displayed_selection == [0]

    # The id of the second atom
    v._selected_atoms.value = "id > 1"
    v.apply_displayed_selection()
    assert v.selection == [1]

    # or of the two selections.
    v._selected_atoms.value = "x>=0.5 or x<0.5"
    v.apply_displayed_selection()
    assert v.selection == [0, 1]

    # Display 2*2*2 supercell
    v.supercell = [2, 2, 2]
    assert len(v.structure) == 2
    assert len(v.displayed_structure) == 16

    # Test intersection of the selection with the supercell.
    v._selected_atoms.value = "z>0 and z<2.5"
    v.apply_displayed_selection()
    assert v.selection == [1]
    assert v.displayed_selection == [1, 5, 9, 13]

    v._selected_atoms.value = "x<=2.0 and z<3"
    v.apply_displayed_selection()
    assert v.selection == [0, 1]
    assert v.displayed_selection == [4, 0, 1]
    assert "Angle" in v.selection_info.value

    # Convert to boron nitride.
    new_structure = v.structure.copy()
    new_structure.symbols = ["B", "N"]
    v.structure = None
    v.structure = new_structure

    # Use "name" and "not" operators.
    v._selected_atoms.value = "z<2 and name B"
    v.apply_displayed_selection()
    assert v.selection == [0]
    assert v.displayed_selection == [0, 4, 8, 12]

    v._selected_atoms.value = "z<2 and name not B"
    v.apply_displayed_selection()
    assert v.selection == [1]
    assert v.displayed_selection == [1, 5, 9, 13]

    v._selected_atoms.value = "z<2 and name not [B, O]"
    v.apply_displayed_selection()
    assert v.selection == [1]
    assert v.displayed_selection == [1, 5, 9, 13]

    # Use "id" operator.
    v._selected_atoms.value = "id == 1 or id == 8"
    v.apply_displayed_selection()
    assert v.selection == [0, 1]
    assert v.displayed_selection == [0, 7]

    # Use the d_from operator.
    v._selected_atoms.value = "d_from[0,0,0] < 4"
    v.apply_displayed_selection()
    assert v.selection == [0, 1]
    assert v.displayed_selection == [4, 8, 0, 1, 2]

    # Use the != operator.
    v._selected_atoms.value = "id != 5"
    v.apply_displayed_selection()
    assert v.selection == [0, 1]
    assert v.displayed_selection == [0, 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

    # Use ^ and - operators.
    v._selected_atoms.value = "(x-4)^2 + (y-2)^2 < 4"
    v.apply_displayed_selection()
    assert v.selection == [1, 0]
    assert v.displayed_selection == [3, 9, 10]

    # Division and multiplication.
    v._selected_atoms.value = "x/2 < 1"
    v.apply_displayed_selection()
    assert v.selection == [0, 1]
    assert v.displayed_selection == [4, 0, 1, 2]

    v._selected_atoms.value = "x*1.5 < y + z"
    v.apply_displayed_selection()
    assert v.selection == [0, 1]
    assert v.displayed_selection == [2, 3, 4, 6, 7]

    # Test wrong syntax.
    assert v.wrong_syntax.layout.visibility == "hidden"
    v._selected_atoms.value = "x--x"
    v.apply_displayed_selection()
    assert v.wrong_syntax.layout.visibility == "visible"


@pytest.mark.usefixtures("aiida_profile_clean")
def test_structure_data_viewer_representation(structure_data_object):
    v = viewers.viewer(structure_data_object)

    # By default, there should be one "default" representation.
    assert len(v._all_representations) == 1
    assert (
        v._all_representations[0].style_id == "_aiidalab_viewer_representation_default"
    )
    assert v._all_representations[0].selection.value == "1..2"

    # Display only one atom.
    v._all_representations[0].selection.value = "1"
    v._apply_representations()
    assert "2" in v.atoms_not_represented.value

    # Add a new representation.
    v._add_representation()
    assert "2" in v.atoms_not_represented.value
    v._all_representations[1].selection.value = "2"
    v._all_representations[0].type.value = "ball+stick"
    v._all_representations[1].type.value = "spacefill"
    v._apply_representations()
    assert v.atoms_not_represented.value == ""

    # Add an atom to the structure.
    new_structure = v.structure.copy()
    new_structure.append(ase.Atom("C", (0.5, 0.5, 0.5)))
    v.structure = None
    v.structure = new_structure

    # The new atom should appear in the default representation.
    assert v._all_representations[0].selection.value == "1 3"
    assert "3" not in v.atoms_not_represented.value

    # Delete the second representation.
    assert v._all_representations[0].delete_button.layout.visibility == "hidden"
    assert v._all_representations[1].delete_button.layout.visibility == "visible"
    v._all_representations[1].delete_button.click()
    assert len(v._all_representations) == 1
    assert "2" in v.atoms_not_represented.value

    # Try to provide different object type than the viewer accepts.
    with pytest.raises(tl.TraitError):
        v.structure = 2

    with pytest.raises(tl.TraitError):
        v.structure = orm.Int(1)


def test_structure_data_viewer_imports_unknown_representation_array():
    structure = ase.Atoms(
        symbols=["C", "H"],
        positions=[(0.0, 0.0, 0.0), (0.0, 0.0, 1.1)],
    )
    style_id = f"{viewers.StructureDataViewer.REPRESENTATION_PREFIX}custom"
    structure.set_array(style_id, np.array([1, -1], dtype=int))

    viewer = viewers.StructureDataViewer()
    viewer.structure = structure

    representation_ids = [rep.style_id for rep in viewer._all_representations]
    assert style_id in representation_ids
    representation = viewer._all_representations[representation_ids.index(style_id)]
    assert representation.selection.value == "1"
    assert representation.type.value == "ball+stick"
    assert representation.size.value == 3
    assert representation.color.value == "element"


def test_structure_data_viewer_imports_encoded_representation_array():
    structure = ase.Atoms(
        symbols=["C", "H"],
        positions=[(0.0, 0.0, 0.0), (0.0, 0.0, 1.1)],
    )
    style_id = viewers.encode_representation_style_id(
        viewers.StructureDataViewer.REPRESENTATION_PREFIX,
        representation_type="spacefill",
        size=4,
        color="red",
        token="surface",
    )
    structure.set_array(style_id, np.array([1, -1], dtype=int))

    viewer = viewers.StructureDataViewer()
    viewer.structure = structure

    representation_ids = [rep.style_id for rep in viewer._all_representations]
    assert style_id in representation_ids
    representation = viewer._all_representations[representation_ids.index(style_id)]
    assert representation.selection.value == "1"
    assert representation.type.value == "spacefill"
    assert representation.size.value == 4
    assert representation.color.value == "red"


@pytest.mark.usefixtures("aiida_profile_clean")
def test_structure_data_viewer_restores_representation_arrays_from_extras():
    structure = ase.Atoms(
        symbols=["C", "H"],
        positions=[(0.0, 0.0, 0.0), (0.0, 0.0, 1.1)],
    )
    style_id = viewers.encode_representation_style_id(
        viewers.StructureDataViewer.REPRESENTATION_PREFIX,
        representation_type="spacefill",
        size=2,
        color="red",
        token="stored",
    )
    node = orm.StructureData(ase=structure)
    node.base.extras.set(viewers.VIEWER_REPRESENTATIONS_EXTRA, {style_id: [1, -1]})

    viewer = viewers.StructureDataViewer(node)

    representation_ids = [rep.style_id for rep in viewer._all_representations]
    assert style_id in representation_ids
    representation = viewer._all_representations[representation_ids.index(style_id)]
    assert representation.selection.value == "1"
    assert representation.type.value == "spacefill"
    assert representation.size.value == 2
    assert representation.color.value == "red"


def test_structure_data_viewer_imports_multiple_encoded_representation_arrays():
    structure = ase.Atoms(
        symbols=["C", "H", "H"],
        positions=[(0.0, 0.0, 0.0), (0.0, 0.0, 1.1), (0.0, 1.0, 0.0)],
    )
    style_id_1 = viewers.encode_representation_style_id(
        viewers.StructureDataViewer.REPRESENTATION_PREFIX,
        representation_type="spacefill",
        size=2,
        color="element",
        token="surface",
    )
    style_id_2 = viewers.encode_representation_style_id(
        viewers.StructureDataViewer.REPRESENTATION_PREFIX,
        representation_type="ball+stick",
        size=4,
        color="red",
        token="molecule",
    )
    structure.set_array(style_id_1, np.array([1, -1, -1], dtype=int))
    structure.set_array(style_id_2, np.array([-1, 1, 1], dtype=int))

    viewer = viewers.StructureDataViewer()
    viewer.structure = structure

    representation_ids = [rep.style_id for rep in viewer._all_representations]
    assert style_id_1 in representation_ids
    assert style_id_2 in representation_ids
    representation_1 = viewer._all_representations[representation_ids.index(style_id_1)]
    representation_2 = viewer._all_representations[representation_ids.index(style_id_2)]
    assert representation_1.selection.value == "1"
    assert representation_1.type.value == "spacefill"
    assert representation_1.size.value == 2
    assert representation_2.selection.value == "2..3"
    assert representation_2.type.value == "ball+stick"
    assert representation_2.size.value == 4
    assert representation_2.color.value == "red"


def test_structure_data_viewer_drops_stale_representations_on_structure_change():
    structure = ase.Atoms(
        symbols=["C", "H"],
        positions=[(0.0, 0.0, 0.0), (0.0, 0.0, 1.1)],
    )
    style_id = viewers.encode_representation_style_id(
        viewers.StructureDataViewer.REPRESENTATION_PREFIX,
        representation_type="spacefill",
        size=2,
        color="red",
        token="old",
    )
    structure.set_array(style_id, np.array([1, -1], dtype=int))
    viewer = viewers.StructureDataViewer()
    viewer.structure = structure
    assert style_id in [rep.style_id for rep in viewer._all_representations]

    viewer.structure = ase.Atoms(
        symbols=["C", "H", "H"],
        positions=[(0.0, 0.0, 0.0), (0.0, 0.0, 1.1), (0.0, 1.0, 0.0)],
    )

    assert [rep.style_id for rep in viewer._all_representations] == [
        viewers.DEFAULT_REPRESENTATION
    ]
    assert viewer._all_representations[0].selection.value == "1..3"


def test_structure_data_viewer_updates_encoded_representation_array_name():
    structure = ase.Atoms(
        symbols=["C", "H"],
        positions=[(0.0, 0.0, 0.0), (0.0, 0.0, 1.1)],
    )
    viewer = viewers.StructureDataViewer()
    viewer.structure = structure

    viewer._add_representation()
    representation = viewer._all_representations[-1]
    old_style_id = representation.style_id
    representation.selection.value = "2"
    representation.type.value = "spacefill"
    representation.size.value = 4
    representation.color.value = "red"

    viewer._apply_representations()

    assert old_style_id not in viewer.structure.arrays
    assert representation.style_id in viewer.structure.arrays
    assert representation.style_id.startswith(
        f"{viewer.REPRESENTATION_PREFIX}spacefill_r4_red_"
    )
    assert viewer.structure.arrays[representation.style_id].tolist() == [-1, 1]


def test_structure_data_viewer_clears_bond_shape_components():
    water = ase.Atoms(
        symbols=["O", "H", "H"],
        positions=[
            (0.0, 0.0, 0.119262),
            (0.0, 0.763239, -0.477047),
            (0.0, -0.763239, -0.477047),
        ],
    )
    viewer = viewers.StructureDataViewer()

    viewer.structure = water
    assert len(viewer._viewer._ngl_component_ids) == 2

    viewer.structure = None

    assert viewer.displayed_structure is None
    assert viewer._viewer._ngl_component_ids == []
    assert viewer._viewer._ngl_component_names == []


@pytest.mark.usefixtures("aiida_profile_clean")
def test_compute_bonds_in_structure_data_viewer():
    # Check the function to compute bonds.
    water = ase.Atoms(
        symbols=["O", "H", "H"],
        positions=[
            (0.0, 0.0, 0.119262),
            (0.0, 0.763239, -0.477047),
            (0.0, -0.763239, -0.477047),
        ],
    )
    viewer = viewers.StructureDataViewer()
    bonds = viewer._compute_bonds(water)
    assert len(bonds) == 4


@pytest.mark.usefixtures("aiida_profile_clean")
def test_loading_viewer_using_process_type(generate_calc_job_node):
    """Test loading a viewer widget based on the process type of the process node."""
    from aiidalab_widgets_base import register_viewer_widget

    # Define and register a viewer widget for the calculation type identified by "aiida.calculations:abc".
    @register_viewer_widget("aiida.calculations:abc")
    class AbcViewer:
        def __init__(self, node=None):
            self.node = node

    # Generate a calc job node with the specific entry point "abc".
    process = generate_calc_job_node(entry_point_name="abc")
    # Load the viewer widget for the generated process node.
    viewer = viewers.viewer(process)
    # Verify that the loaded viewer is the correct type and is associated with the intended node.
    assert isinstance(viewer, AbcViewer), (
        "Viewer is not an instance of the expected viewer class."
    )
    assert viewer.node == process, "Viewer's node does not match the test process node."


def test_node_view_for_non_widget_viewer():
    """Test that a node with no registered viewer is displayed in an output widget"""

    # Intercepting stdout because `ipw.Output` does not
    # store outputs in non-interactive environments.
    captured = StringIO()
    sys.stdout = captured

    node_view = viewers.AiidaNodeViewWidget()
    node = orm.Int(1)
    node_view.node = node
    assert node_view.children[0] is node_view._output
    assert str(node) in sys.stdout.getvalue()


def test_node_view_caching():
    """Test that providing a given node a second time returns the cached viewer."""
    node_view = viewers.AiidaNodeViewWidget()
    node = orm.Dict()
    node_view.node = node
    viewer = node_view.children[0]
    assert len(node_view.node_views) == 1

    # orm.Int doesn't have a dedicated viewer
    # so it will not be cached.
    stdout = sys.stdout
    with StringIO() as captured:
        sys.stdout = captured
        node_view.node = orm.Int(2)
    sys.stdout = stdout

    assert len(node_view.node_views) == 1

    node_view.node = None
    assert not node_view.children

    node_view.node = node
    assert node_view.children[0] is viewer
    assert len(node_view.node_views) == 1