#!/usr/bin/python
DOCUMENTATION = '''
---
module: ec2_eip
short_decription: associate an EC2 elastic IP with an instance.
description:
    - This module associates AWS EC2 elastic IP addresses with instances
options:
  instance_id:
    description:
      - The EC2 instance id
    required: true
  public_ip:
    description:
      - The elastic IP address to associate with the instance
    required: true
  state:
    description:
      - If present, associate the IP with the instance.
      - If absent, disassociate the IP with the instance.
    required: false
    choices: ['present', 'absent']
    default: present
  ec2_url:
    description:
      - URL to use to connect to EC2-compatible cloud (by default the module will use EC2 endpoints)
    required: false
    default: null
    aliases: [ EC2_URL ]
  ec2_access_key:
    description:
      - EC2 access key. If not specified then the EC2_ACCESS_KEY environment variable is used.
    required: false
    default: null
    aliases: [ EC2_ACCESS_KEY ]
  ec2_secret_key:
    description:
      - EC2 secret key. If not specified then the EC2_SECRET_KEY environment variable is used.
    required: false
    default: null
    aliases: [ EC2_SECRET_KEY ]
  region:
    description:
      - the EC2 region to use
    required: false
    default: null
    aliases: [ ec2_region ]
requirements: [ "boto" ]
author: Lorin Hochstein <lorin@nimbisservices.com>
'''

EXAMPLES = '''
- ec2_eip: instance_id=i-1212f003 ip=93.184.216.119

- ec2_eip: instance_id=i-1212f003 ip=93.184.216.119 state=absent
'''

try:
    import boto.ec2
except ImportError:
    boto_found = False
else:
    boto_found = True


def connect(ec2_url, ec2_secret_key, ec2_access_key, region):
    """ Return an ec2 connection"""
    # allow environment variables to be used if ansible vars aren't set
    if not ec2_url and 'EC2_URL' in os.environ:
        ec2_url = os.environ['EC2_URL']
    if not ec2_secret_key and 'EC2_SECRET_KEY' in os.environ:
        ec2_secret_key = os.environ['EC2_SECRET_KEY']
    if not ec2_access_key and 'EC2_ACCESS_KEY' in os.environ:
        ec2_access_key = os.environ['EC2_ACCESS_KEY']

    # If we have a region specified, connect to its endpoint.
    if region:
        try:
            ec2 = boto.ec2.connect_to_region(region,
                                        aws_access_key_id=ec2_access_key,
                                        aws_secret_access_key=ec2_secret_key)
        except boto.exception.NoAuthHandlerFound, e:
            module.fail_json(msg = str(" %s %s %s " % (region, ec2_access_key,
                                                       ec2_secret_key)))
    # Otherwise, no region so we fallback to the old connection method
    else:
        try:
            if ec2_url: # if we have an URL set, connect to the specified endpoint
                ec2 = boto.connect_ec2_endpoint(ec2_url, ec2_access_key, ec2_secret_key)
            else: # otherwise it's Amazon.
                ec2 = boto.connect_ec2(ec2_access_key, ec2_secret_key)
        except boto.exception.NoAuthHandlerFound, e:
            module.fail_json(msg = str(e))
    return ec2


def associate_ip_and_instance(ec2, public_ip, instance_id, module):
    if ip_is_associated_with_instance(ec2, public_ip, instance_id):
        module.exit_json(changed=False)

    # If we're in check mode, nothing else to do
    if module.check_mode:
        module.exit_json(changed=True)

    res = ec2.associate_address(instance_id, public_ip)
    if res:
        module.exit_json(changed=True)
    else:
        module.fail_json(msg="association failed")


def disassociate_ip_and_instance(ec2, public_ip, instance_id, module):
    if not ip_is_associated_with_instance(ec2, public_ip, instance_id):
        module.exit_json(changed=False)

    # If we're in check mode, nothing else to do
    if module.check_mode:
        module.exit_json(changed=True)

    res = ec2.disassociate_address(public_ip)
    if res:
        module.exit_json(changed=True)
    else:
        module.fail_json(msg="disassociation failed")


def ip_is_associated_with_instance(ec2, public_ip, instance_id):
    """ Check if the elastic IP is currently associated with the instance """
    addresses = ec2.get_all_addresses([public_ip])
    if addresses:
        return addresses[0].instance_id == instance_id
    else:
        return False

def main():
    module = AnsibleModule(
        argument_spec = dict(
            instance_id = dict(required=True),
            public_ip = dict(required=True, alises= ['ip'] ),
            state = dict(required=False, default='present',
                         choices=['present', 'absent']),
            ec2_url = dict(required=False, aliases=['EC2_URL']),
            ec2_secret_key = dict(required=False, aliases=['EC2_SECRET_KEY'], no_log=True),
            ec2_access_key = dict(required=False, aliases=['EC2_ACCESS_KEY']),
            region = dict(required=False, aliases=['ec2_region'])
        ),
        supports_check_mode=True
    )

    if not boto_found:
        module.fail_json(msg="boto is required")

    ec2 = connect(ec2_url=module.params.get('ec2_url'),
                  ec2_secret_key=module.params.get('ec2_secret_key'),
                  ec2_access_key=module.params.get('ec2_access_key'),
                  region=module.params.get('region'))

    instance_id = module.params.get('instance_id')
    public_ip = module.params.get('public_ip')
    state = module.params.get('state')

    if state == 'present':
        associate_ip_and_instance(ec2, public_ip, instance_id, module)
    else:
        disassociate_ip_and_instance(ec2, public_ip, instance_id, module)



# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>

if __name__ == '__main__':
    main()