# IfcOpenShell - IFC toolkit and geometry engine
# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
#
# This file is part of IfcOpenShell.
#
# IfcOpenShell 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.
#
# IfcOpenShell 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 IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.

import ifcopenshell


def add_metric(file: ifcopenshell.file, objective: ifcopenshell.entity_instance) -> ifcopenshell.entity_instance:
    """Add a new metric benchmark

    Qualitative constraints may have a series of quantitative benchmarks
    linked to it known as metrics. Metrics may be parametrically linked to
    computed model properties or quantities. Metrics need to be satisfied
    to meet the objective of the constraint.

    :param objective: The IfcObjective that this metric is a benchmark of.
    :return: The newly created IfcMetric entity

    Example:

    .. code:: python

        objective = ifcopenshell.api.constraint.add_objective(model)
        metric = ifcopenshell.api.constraint.add_metric(model,
            objective=objective)
    """
    metric = file.create_entity(
        "IfcMetric",
        **{
            "Name": "Unnamed",
            "ConstraintGrade": "NOTDEFINED",
            "Benchmark": "EQUALTO",
        },
    )
    if objective:
        benchmark_values: list[ifcopenshell.entity_instance]
        benchmark_values = list(objective.BenchmarkValues or [])
        benchmark_values.append(metric)
        objective.BenchmarkValues = benchmark_values
    return metric