# Copyright 2018, The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""
Utility functions for metrics.
"""

import os
import platform
import sys
import time
import traceback

from . import metrics
from . import metrics_base


def static_var(varname, value):
    """Decorator to cache static variable."""
    def fun_var_decorate(func):
        """Set the static variable in a function."""
        setattr(func, varname, value)
        return func
    return fun_var_decorate


@static_var("start_time", [])
def get_start_time():
    """Get start time.

    Return:
        start_time: Start time in seconds. Return cached start_time if exists,
        time.time() otherwise.
    """
    if not get_start_time.start_time:
        get_start_time.start_time = time.time()
    return get_start_time.start_time


def convert_duration(diff_time_sec):
    """Compute duration from time difference.

    A Duration represents a signed, fixed-length span of time represented
    as a count of seconds and fractions of seconds at nanosecond
    resolution.

    Args:
        dur_time_sec: The time in seconds as a floating point number.

    Returns:
        A dict of Duration.
    """
    seconds = int(diff_time_sec)
    nanos = int((diff_time_sec - seconds)*10**9)
    return {'seconds': seconds, 'nanos': nanos}


# pylint: disable=broad-except
def handle_exc_and_send_exit_event(exit_code):
    """handle exceptions and send exit event.

    Args:
        exit_code: An integer of exit code.
    """
    stacktrace = logs = ''
    try:
        exc_type, exc_msg, _ = sys.exc_info()
        stacktrace = traceback.format_exc()
        if exc_type:
            logs = '{etype}: {value}'.format(etype=exc_type.__name__,
                                             value=exc_msg)
    except Exception:
        pass
    send_exit_event(exit_code, stacktrace=stacktrace, logs=logs)


def send_exit_event(exit_code, stacktrace='', logs=''):
    """Log exit event and flush all events to clearcut.

    Args:
        exit_code: An integer of exit code.
        stacktrace: A string of stacktrace.
        logs: A string of logs.
    """
    clearcut = metrics.AtestExitEvent(
        duration=convert_duration(time.time()-get_start_time()),
        exit_code=exit_code,
        stacktrace=stacktrace,
        logs=logs)
    # pylint: disable=no-member
    if clearcut:
        clearcut.flush_events()


def send_start_event(tool_name, command_line='', test_references='',
                     cwd=None, operating_system=None):
    """Log start event of clearcut.

    Args:
        tool_name: A string of the asuite product name.
        command_line: A string of the user input command.
        test_references: A string of the input tests.
        cwd: A string of current path.
        operating_system: A string of user's operating system.
    """
    if not cwd:
        cwd = os.getcwd()
    if not operating_system:
        operating_system = platform.platform()
    # Without tool_name information, asuite's clearcut client will not send
    # event to server.
    metrics_base.MetricsBase.tool_name = tool_name
    get_start_time()
    metrics.AtestStartEvent(command_line=command_line,
                            test_references=test_references,
                            cwd=cwd,
                            os=operating_system)