#
# Copyright (C) 2016 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.
#

from __future__ import print_function

import datetime
import logging
import os
import re
import sys

from vts.runners.host import utils

log_line_format = "%(asctime)s.%(msecs).03d %(levelname)s %(message)s"
# The micro seconds are added by the format string above,
# so the time format does not include ms.
log_line_time_format = "%m-%d %H:%M:%S"
log_line_timestamp_len = 18

logline_timestamp_re = re.compile("\d\d-\d\d \d\d:\d\d:\d\d.\d\d\d")

log_severity_map = {
    "ERROR": logging.ERROR,
    "WARNING": logging.WARNING,
    "INFO": logging.INFO,
    "DEBUG": logging.DEBUG,
}

# Directory name in the log path in which files will be included in TradeFed output
PYTHON_CUSTOM_OUTPUT = 'custom_output_files'

def _parse_logline_timestamp(t):
    """Parses a logline timestamp into a tuple.

    Args:
        t: Timestamp in logline format.

    Returns:
        An iterable of date and time elements in the order of month, day, hour,
        minute, second, microsecond.
    """
    date, time = t.split(' ')
    month, day = date.split('-')
    h, m, s = time.split(':')
    s, ms = s.split('.')
    return (month, day, h, m, s, ms)


def isValidLogLineTimestamp(timestamp):
    if len(timestamp) == log_line_timestamp_len:
        if logline_timestamp_re.match(timestamp):
            return True
    return False


def logLineTimestampComparator(t1, t2):
    """Comparator for timestamps in logline format.

    Args:
        t1: Timestamp in logline format.
        t2: Timestamp in logline format.

    Returns:
        -1 if t1 < t2; 1 if t1 > t2; 0 if t1 == t2.
    """
    dt1 = _parse_logline_timestamp(t1)
    dt2 = _parse_logline_timestamp(t2)
    for u1, u2 in zip(dt1, dt2):
        if u1 < u2:
            return -1
        elif u1 > u2:
            return 1
    return 0


def _get_timestamp(time_format, delta=None):
    t = datetime.datetime.now()
    if delta:
        t = t + datetime.timedelta(seconds=delta)
    return t.strftime(time_format)[:-3]


def epochToLogLineTimestamp(epoch_time):
    d = datetime.datetime.fromtimestamp(epoch_time / 1000)
    return d.strftime("%m-%d %H:%M:%S.%f")[:-3]


def getLogLineTimestamp(delta=None):
    """Returns a timestamp in the format used by log lines.

    Default is current time. If a delta is set, the return value will be
    the current time offset by delta seconds.

    Args:
        delta: Number of seconds to offset from current time; can be negative.

    Returns:
        A timestamp in log line format with an offset.
    """
    return _get_timestamp("%m-%d %H:%M:%S.%f", delta)


def getLogFileTimestamp(delta=None):
    """Returns a timestamp in the format used for log file names.

    Default is current time. If a delta is set, the return value will be
    the current time offset by delta seconds.

    Args:
        delta: Number of seconds to offset from current time; can be negative.

    Returns:
        A timestamp in log filen name format with an offset.
    """
    return _get_timestamp("%m-%d-%Y_%H-%M-%S-%f", delta)


def _initiateTestLogger(log_path, prefix=None, filename=None, log_severity="INFO"):
    """Customizes the root logger for a test run.

    The logger object has a stream handler and a file handler. Both handler logs data
    according to the log severty level.

    Args:
        log_path: Location of the log file.
        prefix: A prefix for each log line in terminal.
        filename: Name of the log file. The default is the time the logger
                  is requested.
        log_severity: string, set the log severity level, default is INFO.
                      This value affects console stream log handler and the python runner
                      part of TradeFed host_log.
    """
    log = logging.getLogger()
    # Clean up any remaining handlers.
    killTestLogger(log)
    log.propagate = False

    log.setLevel(logging.DEBUG)

    # Log into stream
    terminal_format = log_line_format
    if prefix:
        terminal_format = "[{}] {}".format(prefix, log_line_format)
    c_formatter = logging.Formatter(terminal_format, log_line_time_format)
    ch = logging.StreamHandler(sys.stdout)
    ch.setFormatter(c_formatter)
    ch.setLevel(log_severity_map.get(log_severity, logging.INFO))
    log.addHandler(ch)

    # Log everything to file
    f_formatter = logging.Formatter(log_line_format, log_line_time_format)

    # All the logs of this test class go into one directory
    if filename is None:
        filename = getLogFileTimestamp()
        utils.create_dir(log_path)

    default_log_levels = ('ERROR', 'INFO', 'DEBUG')
    for level in default_log_levels:
        idx = filename.rfind('.')
        if idx < 0:
            idx = len(filename)
        addLogFile(log_path=log_path,
                   filename=filename[:idx] + '_' + level + filename[idx:],
                   log_severity=level)

    log.log_path = log_path
    logging.log_path = log_path


def killTestLogger(logger):
    """Cleans up the handlers attached to a test logger object.

    Args:
        logger: The logging object to clean up.
    """
    for h in list(logger.handlers):
        if isinstance(h, logging.FileHandler):
            h.close()
        logger.removeHandler(h)


def isSymlinkSupported():
    """Checks whether the OS supports symbolic link.

    Returns:
        A boolean representing whether the OS supports symbolic link.
    """
    return hasattr(os, "symlink")


def createLatestLogAlias(actual_path):
    """Creates a symlink to the latest test run logs.

    Args:
        actual_path: The source directory where the latest test run's logs are.
    """
    link_path = os.path.join(os.path.dirname(actual_path), "latest")
    if os.path.islink(link_path):
        os.remove(link_path)
    os.symlink(actual_path, link_path)


def setupTestLogger(log_path,
                    prefix=None,
                    filename=None,
                    log_severity="INFO",
                    create_symlink=True):
    """Customizes the root logger for a test run.

    Args:
        log_path: Location of the report file.
        prefix: A prefix for each log line in terminal.
        filename: Name of the files. The default is the time the objects
                  are requested.
        create_symlink: bool. determines whether to create the symlink or not.
                        set to True as default.

    Returns:
        A string, abs path to the created log file.
    """
    if filename is None:
        filename = getLogFileTimestamp()
    utils.create_dir(log_path)
    logger = _initiateTestLogger(log_path, prefix, filename, log_severity)
    if create_symlink and isSymlinkSupported():
        createLatestLogAlias(log_path)
    return os.path.join(log_path, filename)


def addLogFile(log_path, filename=None, log_severity="INFO"):
    """Creates a log file and adds the handler to the root logger.

    Args:
        log_path: Location of the report file.
        filename: Name of the log file. The default is the time the logger
                  is requested.

    Returns:
        A string, abs path to the created log file.
        logging.FileHandler instance which is added to the logger.
    """
    if filename is None:
        filename = getLogFileTimestamp()
    f_formatter = logging.Formatter(log_line_format, log_line_time_format)
    fh = logging.FileHandler(os.path.join(log_path, filename))
    fh.setFormatter(f_formatter)
    fh.setLevel(log_severity_map.get(log_severity, logging.INFO))
    logging.getLogger().addHandler(fh)
    return os.path.join(log_path, filename), fh


def normalizeLogLineTimestamp(log_line_timestamp):
    """Replace special characters in log line timestamp with normal characters.

    Args:
        log_line_timestamp: A string in the log line timestamp format. Obtained
            with getLogLineTimestamp.

    Returns:
        A string representing the same time as input timestamp, but without
        special characters.
    """
    norm_tp = log_line_timestamp.replace(' ', '_')
    norm_tp = norm_tp.replace(':', '-')
    return norm_tp


class LoggerProxy(object):
    """This class is for situations where a logger may or may not exist.

    e.g. In controller classes, sometimes we don't have a logger to pass in,
    like during a quick try in python console. In these cases, we don't want to
    crash on the log lines because logger is None, so we should set self.log to
    an object of this class in the controller classes, instead of the actual
    logger object.
    """

    def __init__(self, logger=None):
        self.log = logger

    @property
    def log_path(self):
        if self.log:
            return self.log.log_path
        return "/tmp/logs"

    def __getattr__(self, name):
        def log_call(*args):
            if self.log:
                return getattr(self.log, name)(*args)
            print(*args)

        return log_call