# Copyright (c) 2013-2014, Rethink Robotics
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
#    this list of conditions and the following disclaimer.
# 2. 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.
# 3. Neither the name of the Rethink Robotics nor the names of its
#    contributors may be used to endorse or promote products derived from
#    this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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import errno

import rospy


def wait_for(test, timeout=1.0, raise_on_error=True, rate=100,
             timeout_msg="timeout expired", body=None):
    """
    Waits until some condition evaluates to true.

    @param test: zero param function to be evaluated
    @param timeout: max amount of time to wait. negative/inf for indefinitely
    @param raise_on_error: raise or just return False
    @param rate: the rate at which to check
    @param timout_msg: message to supply to the timeout exception
    @param body: optional function to execute while waiting
    """
    start = rospy.get_time()
    while start==0:
        rospy.sleep(0.1)
        start = rospy.get_time()
    end_time = start + timeout
    rate = rospy.Rate(rate)
    notimeout = (timeout < 0.0) or timeout == float("inf")
    while not test():
        if rospy.is_shutdown():
            if raise_on_error:
                raise OSError(errno.ESHUTDOWN, "ROS Shutdown")
            return False
        elif (not notimeout) and (rospy.get_time() >= end_time):
            if raise_on_error:
                raise OSError(errno.ETIMEDOUT, timeout_msg)
            return False
        if callable(body):
            body()
        rate.sleep()
    return True
