#########################################################################################
# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.                    #
# SPDX-License-Identifier: MIT-0                                                        #
#                                                                                       #
# Permission is hereby granted, free of charge, to any person obtaining a copy of this  #
# software and associated documentation files (the "Software"), to deal in the Software #
# without restriction, including without limitation the rights to use, copy, modify,    #
# merge, publish, distribute, sublicense, and/or sell copies of the Software, and to    #
# permit persons to whom the Software is furnished to do so.                            #
#                                                                                       #
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   #
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         #
# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT    #
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION     #
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import sys
if not sys.warnoptions:
    import warnings
with warnings.catch_warnings():
    warnings.simplefilter("ignore", category=Warning)
    import paramiko

def execute_cmd(host, username, key, cmd, using_key):
    output = ''
    error = ''
    ssh = None
    try:
        ssh = open_ssh(host, username, key, using_key)
        if ssh is None:
            error = "Not able to get the SSH connection for the host " + host
            print(error, flush = True)
        else:
            stdin, stdout, stderr = ssh.exec_command(cmd)
            for line in stdout.readlines():
                output = output + line
            for line in stderr.readlines():
                error = error + line
    except IOError as io_error:
        error = "Unable to execute the command " + cmd + " due to " + \
                str(io_error)
        print(error, flush = True)
    except paramiko.SSHException as ssh_exception:
        error = "Unable to execute the command " + cmd + " due to " + \
                str(ssh_exception)
        print(error, flush = True)
    finally:
        if ssh is not None:
            ssh.close()
    return output, error


def open_ssh(host, username, key_pwd, using_key):
    ssh = None
    try:
        if using_key:
            from io import StringIO
            private_key = paramiko.RSAKey.from_private_key_file(StringIO(key_pwd))
            ssh = paramiko.SSHClient()
            ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            ssh.connect(hostname=host, username=username, pkey=private_key)
        else:
            ssh = paramiko.SSHClient()
            ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            ssh.connect(hostname=host, username=username, password=key_pwd)
    except IOError as io_error:
        error = "Unable to connect to host " + host + " with username " + \
                username + " due to " + str(io_error)
        print(error)
    except paramiko.SSHException as ssh_exception:
        error = "Unable to connect to host " + host + " with username " + \
                username + " due to " + str(ssh_exception)
        print(error)
    return ssh


def find_distribution(host, username, key_pwd, using_key):
    distribution = "linux"
    output, error = execute_cmd(host, username, key_pwd, "cat /etc/*release",
                                using_key)
    if "ubuntu" in output:
        distribution = "ubuntu"
    elif "fedora" in output:
        distribution = "fedora"
    elif "suse" in output:
        distribution = "suse"
    return distribution


def install_wget(host, username, key_pwd, using_key):
    ssh = None
    try:
        # Find the distribution
        distribution = find_distribution(host, username, key_pwd, using_key)
        print("")
        print("***** Installing wget *****")
        ssh = open_ssh(host, username, key_pwd, using_key)
        if distribution == "ubuntu":
            ssh.exec_command("sudo apt-get update")
            stdin, stdout, stderr = ssh.exec_command(
                "sudo DEBIAN_FRONTEND=noninteractive apt-get install wget")
        elif distribution == "suse":
            stdin, stdout, stderr = ssh.exec_command("sudo zypper install wget")
            stdin.write('Y\n')
            stdin.flush()
        else:
            # This condition works with centos, fedora and RHEL distributions
            # ssh.exec_command("sudo yum update")
            stdin, stdout, stderr = ssh.exec_command("sudo yum install wget -y")
        # Check if there is any error while installing wget
        error = ''
        for line in stderr.readlines():
            error = error + line
        if not error:
            print("wget got installed successfully")
            # Execute the command wget and check if it got configured correctly
            stdin, stdout, stderr = ssh.exec_command("wget")
            error = ''
            for line in stderr.readlines():
                error = error + line
            if "not found" in error or "command-not-found" in error:
                print(
                    "wget is not recognized, unable to proceed! due to " + error)
        else:
            print("something went wrong while installing wget ", error)
    finally:
        if ssh is not None:
            ssh.close()


def check_python(host, username, key_pwd, using_key):
    output, error = execute_cmd(host, username, key_pwd, "python --version",
                                using_key)
    if error:
        if "Python 2" in error:
            return True
        else:
            return False
    else:
        return True


def check_python3(host, username, key_pwd, using_key):
    output, error = execute_cmd(host, username, key_pwd, "python3 --version",
                                using_key)
    if error:
        if "Python 3" in error:
            return True
        else:
            return False
    else:
        return True


def install_python3(host, username, key_pwd, using_key):
    ssh = None
    try:
        print("")
        print("***** Installing python3 *****")
        ssh = open_ssh(host, username, key_pwd, using_key)
        # Find the distribution
        distribution = find_distribution(host, username, key_pwd, using_key)
        if distribution == "ubuntu":
            ssh.exec_command("sudo apt-get update")
            command = "sudo DEBIAN_FRONTEND=noninteractive apt-get install " \
                      "python3"
            stdin, stdout, stderr = ssh.exec_command(command)
            stdin.write('Y\n')
            stdin.flush()
        elif distribution == 'suse':
            stdin, stdout, stderr = ssh.exec_command("sudo zypper install python3")
            stdin.write('Y\n')
            stdin.flush()
        elif distribution == "fedora":
            stdin, stdout, stderr = ssh.exec_command("sudo dnf install python3")
            stdin.write('Y\n')
            stdin.flush()
        else: #This installs on centos
            # ssh.exec_command("sudo yum update")
            ssh.exec_command("sudo yum install centos-release-scl")
            ssh.exec_command("sudo yum install rh-python36")
            ssh.exec_command("scl enable rh-python36 bash")
            stdin, stdout, stderr = ssh.exec_command("python --version")
        error = ''
        for line in stderr.readlines():
            error = error + line
        if not error:
            print("python got installed successfully")
        else:
            print(error)
    finally:
        if ssh is not None:
            ssh.close()


def install_mgn(agent_linux_download_url, region, s3_endpoint, host, username, key_pwd, using_key, AccessKeyId, SecretAccessKey):

    console_output = ""
    console_output = console_output + "\n" + "--------------------------------------------------------------------"
    console_output = console_output + "\n" + "- Installing Application Migration Service Agent for:  "+ host + " -"
    console_output = console_output + "\n" + "--------------------------------------------------------------------"
    output = None
    error = None
    try:
        command = "wget -O ./aws-replication-installer-init.py " + agent_linux_download_url
        output, error = execute_cmd(host=host, username=username, key=key_pwd,
                                cmd=command, using_key=using_key)
        console_output = console_output + "\n" + output
        if "not found" in error or "No such file or directory" in error:
            install_wget(host, username, key_pwd, using_key)
            output, error = execute_cmd(host=host, username=username, key=key_pwd,
                                    cmd=command, using_key=using_key)
            console_output = console_output + "\n" +output
        # Check if python is already installed if not install python3
        python_str = "python"
        if not check_python(host, username, key_pwd, using_key):
            if not check_python3(host, username, key_pwd, using_key):
                install_python3(host, username, key_pwd, using_key)
                python_str = "python3"
            else:
                python_str = "python3"
        # Step 2 - execute linux installer
        command = "sudo " + python_str + " ./aws-replication-installer-init.py --region " + \
              region + " --aws-access-key-id " + AccessKeyId + " --aws-secret-access-key " + SecretAccessKey + " --no-prompt" + " --s3-endpoint " + s3_endpoint 
        display_command = "sudo " + python_str + " ./aws-replication-installer-init.py --region " + \
              region + " --aws-access-key-id " + AccessKeyId + " --aws-secret-access-key ************* --no-prompt" + " --s3-endpoint " + s3_endpoint
        console_output = console_output + "\n" + "Executing " + display_command

        output, error = execute_cmd(host=host, username=username, key=key_pwd,
                                cmd=command, using_key=using_key)
        console_output = console_output + "\n" +output
    except Exception as e:
        error = 'Got exception! ' + str(e)
    if not error and 'Error: Installation failed' not in output:
        console_output = console_output + "\n" + "***** Agent installation completed successfully on "+host+ "*****"
        return host,console_output
    else:
        console_output = console_output + "\n" + "--------------------------------------------"
        console_output = console_output + "\n" + "Error: Installation Failed. Unable to install Agent on "+host+" due to: "
        console_output = console_output + "\n" + ""
        if output:
            console_output = console_output + "\n" + output
        console_output = console_output + "\n" + error
        console_output = console_output + "\n" + "--------------------------------------------"
        return host,console_output