import json
import os
import subprocess
import uuid

DEFAULT_AWS_CUSTOMER_ID = "unknown_customer_id"
DEFAULT_REQUEST_ID = "unknown_request_id"


def extract_custom_attributes(custom_attributes_string):
    """
    Extract session information from the header
    """
    session_info = dict()
    session_info['requestId'] = DEFAULT_REQUEST_ID
    session_info['awsAccountId'] = DEFAULT_AWS_CUSTOMER_ID
    session_info['traceId'] = str(uuid.uuid4())
    session_info['processId'] = os.getpid()

    if custom_attributes_string:
        custom_attributes = json.loads(custom_attributes_string)
        if 'requestId' in custom_attributes:
            session_info['requestId'] = custom_attributes['requestId']

        if 'awsAccountId' in custom_attributes:
            session_info['awsAccountId'] = custom_attributes['awsAccountId']

    return session_info


def run_cmd(cmd_args, change_working_directory="./", shell=False,
            stdout=subprocess.PIPE, stderr=subprocess.PIPE,
            env=None):
    """
    Function used to execute the shell commands

    Arguments:
        cmd_args (list): This is the list of commands to be appended in case
                         of shell=True, else executed as pipes.
        change_working_directory (string): This is to execute the command in different
                                           directory
        shell (bool): This is to say if the command to be executed as shell or not
        stdout (int): stdout stream target
        stderr (int): stderr stream target
        env (dict): environment variables
    Returns:
        (returncode, stdout, stderr) - tuples of returncode, stdout, and stderr
    """
    cmd = " ".join(map(str, cmd_args))
    process = subprocess.Popen(
        cmd if shell else cmd_args,
        cwd=change_working_directory,
        shell=shell,
        stdout=stdout,
        stderr=stderr,
        env=env
    )
    stdout, stderr = process.communicate()
    return process.returncode, stdout, stderr