#!/usr/bin/env python
# encoding: utf-8
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#  to you under the Apache License, Version 2.0 (the
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"""This module provides functions to generate an ec2stack configuration file.
"""

import os
import argparse

from ConfigParser import SafeConfigParser


def main():
    """
    Entry point into the configuration application.

    """
    config_folder = _create_config_folder()
    _create_config_file(config_folder)


def _create_config_folder():
    """
    Creates a folder to hold the user's configuration files.

    @return: Path of the configuration folder.
    """
    config_folder = os.path.join(os.path.expanduser('~'), '.ec2stack')
    if not os.path.exists(config_folder):
        os.makedirs(config_folder)
    os.chmod(config_folder, 0700)
    return config_folder


def _create_config_file(config_folder):
    """
    Reads in configuration items and writes them out to the configuration file.

    @param config_folder: Path of the configuration folder.
    """
    args = _generate_args()
    profile = args.pop('profile')
    advanced_network_enabled = args.pop('advanced')
    config_file_path = config_folder + '/ec2stack.conf'
    config = _modify_config_profile(
        config_file_path, profile, advanced_network_enabled)
    config_file = open(config_file_path, 'w+')
    config.write(config_file)


def _generate_args():
    """
    Generate command line arguments for ec2stack-configure.

    @return: args.
    """
    parser = argparse.ArgumentParser(
        'Command line utility for configuring ec2stack'
    )

    parser.add_argument(
        '-p',
        '--profile',
        required=False,
        help='The profile to configure, default is initial',
        default='initial'
    )

    parser.add_argument(
        '-a',
        '--advanced',
        required=False,
        help='Turn advanced network config on for application',
        default=False
    )

    args = parser.parse_args()

    return vars(args)


def _modify_config_profile(config_file, profile, advanced_network_enabled):
    """
    Modify configuration profile.

    @param config_file: current config file configuration.
    @param profile: the profile to set the attribute in.
    @return: configparser configuration.
    """
    config = SafeConfigParser()
    config.read(config_file)

    if not config.has_section(profile):
        config.add_section(profile)

    config = _set_mandatory_attributes_of_profile(config, profile)

    if advanced_network_enabled:
        config = _set_advanced_network_attributes_of_profile(config, profile)

    config = _set_optional_attributes_of_profile(config, profile)

    return config


def _set_mandatory_attributes_of_profile(config, profile):
    """
    Modify mandatory attributes of profile.

    @param config: current configparser configuration.
    @param profile: the profile to set the attribute in.
    @return: configparser configuration.
    """
    config = _set_attribute_of_profile(
        config, profile, 'ec2stack_bind_address', 'EC2Stack bind address', 'localhost'
    )
    config = _set_attribute_of_profile(
        config, profile, 'ec2stack_port', 'EC2Stack bind port', '5000'
    )
    config = _set_attribute_of_profile(
        config, profile, 'cloudstack_host', 'Cloudstack host', 'localhost'
    )
    config = _set_attribute_of_profile(
        config, profile, 'cloudstack_port', 'Cloudstack port', '8080'
    )
    config = _set_attribute_of_profile(
        config, profile, 'cloudstack_protocol', 'Cloudstack protocol', 'http'
    )
    config = _set_attribute_of_profile(
        config, profile, 'cloudstack_path', 'Cloudstack path', '/client/api'
    )
    config = _set_attribute_of_profile(
        config, profile, 'cloudstack_custom_disk_offering', 'Cloudstack custom disk offering name', 'Custom'
    )

    while True:
        config = _set_attribute_of_profile(
            config, profile, 'cloudstack_default_zone', 'Cloudstack default zone name', ''
        )
        if config.get(profile, 'cloudstack_default_zone') is not '':
            break

    return config


def _set_advanced_network_attributes_of_profile(config, profile):
    """
    Modify advanced network attributes of profile.

    @param config: current configparser configuration.
    @param profile: the profile to set the attribute in.
    @return: configparser configuration.
    """
    config = _set_attribute_of_profile(
        config, profile, 'vpc_offering_id', 'VPC offering id', ''
    )

    return config


def _set_optional_attributes_of_profile(config, profile):
    """
    Modify optional attributes of profile.

    @param config: current configparser configuration.
    @param profile: the profile to set the attribute in.
    @return: configparser configuration.
    """
    configure_instance_type_mapings = raw_input(
        'Do you wish to input instance type mappings? (Yes/No): '
    )

    if configure_instance_type_mapings.lower() in ['yes', 'y']:
        config = _read_user_instance_mappings(config, profile)

    configure_resource_type_mapings = raw_input(
        'Do you wish to input resource type to resource id mappings' +
        ' for tag support? (Yes/No): '
    )

    if configure_resource_type_mapings.lower() in ['yes', 'y']:
        config = _read_user_resource_type_mappings(config, profile)

    return config


def _read_user_instance_mappings(config, profile):
    """
    Add instance type mappings to profile.

    @param config: current configparser configuration.
    @param profile: the profile to set the attribute in.
    @return: configparser configuration.
    """
    instance_section = profile + "instancemap"
    if not config.has_section(instance_section):
        config.add_section(instance_section)

    while True:
        key = raw_input(
            'Insert the AWS EC2 instance type you wish to map: '
        )

        value = raw_input(
            'Insert the name of the instance type you wish to map this to: '
        )

        config.set(instance_section, key, value)

        add_more = raw_input(
            'Do you wish to add more mappings? (Yes/No): ')
        if add_more.lower() in ['no', 'n']:
            break

    return config


def _read_user_resource_type_mappings(config, profile):
    """
    Add resource type mappings to profile.

    @param config: current configparser configuration.
    @param profile: the profile to set the attribute in.
    @return: configparser configuration.
    """
    resource_section = profile + "resourcemap"
    if not config.has_section(resource_section):
        config.add_section(resource_section)

    while True:
        key = raw_input(
            'Insert the cloudstack resource id you wish to map: '
        )

        value = raw_input(
            'Insert the cloudstack resource type you wish to map this to: '
        )

        config.set(resource_section, key, value)

        add_more = raw_input(
            'Do you wish to add more mappings? (Yes/No): ')
        if add_more.lower() in ['no', 'n']:
            break

    return config


def _set_attribute_of_profile(config, profile, attribute, message, default):
    """
    Set attribute of profile

    @param config: current configparser configuration.
    @param profile: the profile to set the attribute in.
    @param attribute: the attribute to set.
    @param message: the message to prompt the user with.
    @param default: the default value to use if none is entered.
    @return: configparser configuration.
    """
    if config.has_option(profile, attribute):
        default = config.get(profile, attribute)

    attribute_value = _read_in_config_attribute_or_use_default(
        message, default)

    config.set(profile, attribute, attribute_value)
    return config


def _read_in_config_attribute_or_use_default(message, default):
    """
    Add resource type mappings to profile.

    @param message: the message to prompt the user with.
    @param default: the default value to use if none is entered.
    @return: configparser configuration.
    """
    attribute = raw_input(message + ' [' + default + ']: ')
    if attribute == '':
        attribute = default

    return attribute