#
# Copyright 2012 Quantopian, Inc.
#
# 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.


import logbook
from contextlib import contextmanager


log = logbook.Logger("LogUtils")


class redirector(object):
    def __init__(self, logger, name):
        self.logger = logger
        self.buffer = bytes()
        self.name = name

    def write(self, line):
        self.buffer += ''.join(['>>> ', line.strip('\n'), '\n'])

    def flush(self, final=False):
        if not self.buffer:
            return
        out_form = """ [{pipe_name}] \n{buffer}""".format(
            pipe_name=self.name,
            buffer=self.buffer
        )
        self.logger.error(out_form)
        self.buffer = bytes()


class log_redirector(object):
    def __init__(self, logger):
        self.logger = logger

    def write(self, line):
        #Absorb blank lines from print statements.
        if line == '\n':
            return

        else:
            #TODO: add logic to guarantee we made this
            self.logger.info(line.strip('\n'))

    def flush(self, final=False):
        pass


@contextmanager
def stdout_pipe(logger, pipe_name):
    """
    Pipe stdout and stderr into a python logger interface
    """
    import sys
    orig_fds = sys.stdout, sys.stderr

    sys.stderr = redirector(logger, pipe_name)
    sys.stdout = redirector(logger, pipe_name)

    yield
    sys.stderr.flush()
    sys.stdout.flush()
    sys.stdout, sys.stderr = orig_fds


@contextmanager
def stdout_only_pipe(logger, pipe_name):
    """
    Pipes just stdout into a python logger interface
    """
    import sys
    orig_fd = sys.stdout
    sys.stdout = log_redirector(logger)

    yield
    sys.stdout.flush()
    sys.stdout = orig_fd