#!/usr/bin/env python3

# Copyright (c) 2021 PickNik, Inc.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
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#    * Redistributions of source code must retain the above copyright
#      notice, this list of conditions and the following disclaimer.
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#    * Redistributions in binary form must reproduce the above copyright
#      notice, this list of conditions and the following disclaimer in the
#      documentation and/or other materials provided with the distribution.
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#    * Neither the name of the {copyright_holder} nor the names of its
#      contributors may be used to endorse or promote products derived from
#      this software without specific prior written permission.
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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# POSSIBILITY OF SUCH DAMAGE.

#
# Author: Lovro Ivanov

import math
import os
import yaml

from ament_index_python.packages import get_package_share_directory


def construct_angle_radians(loader, node):
    """Utility function to construct radian values from yaml."""
    value = loader.construct_scalar(node)
    try:
        return float(value)
    except SyntaxError:
        raise Exception("invalid expression: %s" % value)


def construct_angle_degrees(loader, node):
    """Utility function for converting degrees into radians from yaml."""
    return math.radians(construct_angle_radians(loader, node))


def load_yaml(package_name, file_path):
    package_path = get_package_share_directory(package_name)
    absolute_file_path = os.path.join(package_path, file_path)

    try:
        yaml.SafeLoader.add_constructor("!radians", construct_angle_radians)
        yaml.SafeLoader.add_constructor("!degrees", construct_angle_degrees)
    except Exception:
        raise Exception("yaml support not available; install python-yaml")

    try:
        with open(absolute_file_path) as file:
            return yaml.safe_load(file)
    except OSError:  # parent of IOError, OSError *and* WindowsError where available
        return None


def load_yaml_abs(absolute_file_path):

    try:
        yaml.SafeLoader.add_constructor("!radians", construct_angle_radians)
        yaml.SafeLoader.add_constructor("!degrees", construct_angle_degrees)
    except Exception:
        raise Exception("yaml support not available; install python-yaml")

    try:
        with open(absolute_file_path) as file:
            return yaml.safe_load(file)
    except OSError:  # parent of IOError, OSError *and* WindowsError where available
        return None