# (C) British Crown Copyright 2014, Met Office
#
# This file is part of Iris.
#
# Iris is free software: you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Iris is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Iris.  If not, see <http://www.gnu.org/licenses/>.
"""Unit tests for the `iris.fileformats.pp.load` function."""

from __future__ import (absolute_import, division, print_function)

# Import iris.tests first so that some things can be initialised before
# importing anything else.
import iris.tests as tests

import mock

import iris
from iris.fileformats.pp import _convert_constraints
from iris.fileformats.pp import STASH


class Test_convert_constraints(tests.IrisTest):
    def _single_stash(self):
        constraint = iris.AttributeConstraint(STASH='m01s03i236')
        return _convert_constraints(constraint)

    def test_single_stash(self):
        pp_filter = self._single_stash()
        stcube = mock.Mock(stash=STASH.from_msi('m01s03i236'))
        self.assertTrue(pp_filter(stcube))

    def test_stash_object(self):
        constraint = iris.AttributeConstraint(
            STASH=STASH.from_msi('m01s03i236'))
        pp_filter = _convert_constraints(constraint)
        stcube = mock.Mock(stash=STASH.from_msi('m01s03i236'))
        self.assertTrue(pp_filter(stcube))

    def test_surface_altitude(self):
        # Ensure that surface altitude fields are not filtered.
        pp_filter = self._single_stash()
        orography_cube = mock.Mock(stash=STASH.from_msi('m01s00i033'))
        self.assertTrue(pp_filter(orography_cube))

    def test_surface_pressure(self):
        # Ensure that surface pressure fields are not filtered.
        pp_filter = self._single_stash()
        pressure_cube = mock.Mock(stash=STASH.from_msi('m01s00i001'))
        self.assertTrue(pp_filter(pressure_cube))

    def test_double_stash(self):
        stcube236 = mock.Mock(stash=STASH.from_msi('m01s03i236'))
        stcube4 = mock.Mock(stash=STASH.from_msi('m01s00i004'))
        stcube7 = mock.Mock(stash=STASH.from_msi('m01s00i007'))
        constraints = [iris.AttributeConstraint(STASH='m01s03i236'),
                       iris.AttributeConstraint(STASH='m01s00i004')]
        pp_filter = _convert_constraints(constraints)
        self.assertTrue(pp_filter(stcube236))
        self.assertTrue(pp_filter(stcube4))
        self.assertFalse(pp_filter(stcube7))

    def test_multiple_with_stash(self):
        constraints = [iris.Constraint('air_potential_temperature'),
                       iris.AttributeConstraint(STASH='m01s00i004')]
        pp_filter = _convert_constraints(constraints)
        self.assertIsNone(pp_filter)

    def test_no_stash(self):
        constraints = [iris.Constraint('air_potential_temperature'),
                       iris.AttributeConstraint(source='asource')]
        pp_filter = _convert_constraints(constraints)
        self.assertIsNone(pp_filter)

    def test_no_constraint(self):
        constraints = []
        pp_filter = _convert_constraints(constraints)
        self.assertIsNone(pp_filter)


if __name__ == "__main__":
    tests.main()
