#!/usr/bin/python
# Copyright: Ansible Project
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

from __future__ import absolute_import, division, print_function

__metaclass__ = type


DOCUMENTATION = '''
---
module: cloudwatchlogs_log_group
version_added: 5.0.0
short_description: create or delete log_group in CloudWatchLogs
description:
  - Create or delete log_group in CloudWatchLogs.
  - This module was originally added to C(community.aws) in release 1.0.0.
notes:
  - For details of the parameters and returns see U(http://boto3.readthedocs.io/en/latest/reference/services/logs.html).
  - Support for I(purge_tags) was added in release 4.0.0.
author:
  - Willian Ricardo (@willricardo) <willricardo@gmail.com>
options:
  state:
    description:
      - Whether the rule is present or absent.
    choices: ["present", "absent"]
    default: present
    required: false
    type: str
  log_group_name:
    description:
      - The name of the log group.
    required: true
    type: str
  kms_key_id:
    description:
      - The Amazon Resource Name (ARN) of the CMK to use when encrypting log data.
    required: false
    type: str
  retention:
    description:
      - The number of days to retain the log events in the specified log group.
      - "Valid values are: [1, 3, 5, 7, 14, 30, 60, 90, 120, 150, 180, 365, 400, 545, 731, 1827, 3653]"
      - Mutually exclusive with I(purge_retention_policy).
    required: false
    type: int
  purge_retention_policy:
    description:
      - "Whether to purge the retention policy or not."
      - "Mutually exclusive with I(retention) and I(overwrite)."
    default: false
    required: false
    type: bool
  overwrite:
    description:
      - Whether an existing log group should be overwritten on create.
      - Mutually exclusive with I(purge_retention_policy).
    default: false
    required: false
    type: bool
extends_documentation_fragment:
  - amazon.aws.aws
  - amazon.aws.ec2
  - amazon.aws.tags
  - amazon.aws.boto3

'''

EXAMPLES = '''
# Note: These examples do not set authentication details, see the AWS Guide for details.

- amazon.aws.cloudwatchlogs_log_group:
    log_group_name: test-log-group

- amazon.aws.cloudwatchlogs_log_group:
    state: present
    log_group_name: test-log-group
    tags: { "Name": "test-log-group", "Env" : "QA" }

- amazon.aws.cloudwatchlogs_log_group:
    state: present
    log_group_name: test-log-group
    tags: { "Name": "test-log-group", "Env" : "QA" }
    kms_key_id: arn:aws:kms:region:account-id:key/key-id

- amazon.aws.cloudwatchlogs_log_group:
    state: absent
    log_group_name: test-log-group

'''

RETURN = '''
log_groups:
    description: Return the list of complex objects representing log groups
    returned: success
    type: complex
    version_added: 4.0.0
    version_added_collection: community.aws
    contains:
        log_group_name:
            description: The name of the log group.
            returned: always
            type: str
        creation_time:
            description: The creation time of the log group.
            returned: always
            type: int
        retention_in_days:
            description: The number of days to retain the log events in the specified log group.
            returned: always
            type: int
        metric_filter_count:
            description: The number of metric filters.
            returned: always
            type: int
        arn:
            description: The Amazon Resource Name (ARN) of the log group.
            returned: always
            type: str
        stored_bytes:
            description: The number of bytes stored.
            returned: always
            type: str
        kms_key_id:
            description: The Amazon Resource Name (ARN) of the CMK to use when encrypting log data.
            returned: always
            type: str
        tags:
            description: A dictionary representing the tags on the log group.
            returned: always
            type: dict
'''

try:
    import botocore
except ImportError:
    pass  # Handled by AnsibleAWSModule

from ansible.module_utils.common.dict_transformations import camel_dict_to_snake_dict

from ansible_collections.amazon.aws.plugins.module_utils.core import AnsibleAWSModule
from ansible_collections.amazon.aws.plugins.module_utils.core import is_boto3_error_code
from ansible_collections.amazon.aws.plugins.module_utils.tagging import compare_aws_tags


def create_log_group(client, log_group_name, kms_key_id, tags, retention, module):
    request = {'logGroupName': log_group_name}
    if kms_key_id:
        request['kmsKeyId'] = kms_key_id
    if tags:
        request['tags'] = tags

    if module.check_mode:
        module.exit_json(changed=True, msg="Would have created log group if not in check_mode.")

    try:
        client.create_log_group(**request)
    except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
        module.fail_json_aws(e, msg="Unable to create log group")

    if retention:
        input_retention_policy(client=client,
                               log_group_name=log_group_name,
                               retention=retention, module=module)

    found_log_group = describe_log_group(client=client, log_group_name=log_group_name, module=module)

    if not found_log_group:
        module.fail_json(msg="The aws CloudWatchLogs log group was not created. \n please try again!")
    return found_log_group


def input_retention_policy(client, log_group_name, retention, module):
    try:
        permited_values = [1, 3, 5, 7, 14, 30, 60, 90, 120, 150, 180, 365, 400, 545, 731, 1827, 3653]

        if retention in permited_values:
            response = client.put_retention_policy(logGroupName=log_group_name,
                                                   retentionInDays=retention)
        else:
            delete_log_group(client=client, log_group_name=log_group_name, module=module)
            module.fail_json(msg="Invalid retention value. Valid values are: [1, 3, 5, 7, 14, 30, 60, 90, 120, 150, 180, 365, 400, 545, 731, 1827, 3653]")
    except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
        module.fail_json_aws(e, msg="Unable to put retention policy for log group {0}".format(log_group_name))


def delete_retention_policy(client, log_group_name, module):
    if module.check_mode:
        return True

    try:
        client.delete_retention_policy(logGroupName=log_group_name)
    except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
        module.fail_json_aws(e, msg="Unable to delete retention policy for log group {0}".format(log_group_name))


def delete_log_group(client, log_group_name, module):
    if module.check_mode:
        module.exit_json(changed=True, msg="Would have deleted log group if not in check_mode.")

    try:
        client.delete_log_group(logGroupName=log_group_name)
    except is_boto3_error_code('ResourceNotFoundException'):
        return {}
    except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:  # pylint: disable=duplicate-except
        module.fail_json_aws(e, msg="Unable to delete log group {0}".format(log_group_name))


def describe_log_group(client, log_group_name, module):
    try:
        desc_log_group = client.describe_log_groups(logGroupNamePrefix=log_group_name)
    except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
        module.fail_json_aws(e, msg="Unable to describe log group {0}".format(log_group_name))

    matching_logs = [log for log in desc_log_group.get('logGroups', []) if log['logGroupName'] == log_group_name]

    if not matching_logs:
        return {}

    found_log_group = matching_logs[0]

    try:
        tags = client.list_tags_log_group(logGroupName=log_group_name)
    except is_boto3_error_code('AccessDeniedException'):
        tags = {}
        module.warn('Permission denied listing tags for log group {0}'.format(log_group_name))
    except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:  # pylint: disable=duplicate-except
        module.fail_json_aws(e, msg="Unable to describe tags for log group {0}".format(log_group_name))

    found_log_group['tags'] = tags.get('tags', {})
    return found_log_group


def format_result(found_log_group):
    # Prior to 4.0.0 we documented returning log_groups=[log_group], but returned **log_group
    # Return both to avoid a breaking change.
    log_group = camel_dict_to_snake_dict(found_log_group, ignore_list=['tags'])
    return dict(log_groups=[log_group], **log_group)


def ensure_tags(client, found_log_group, desired_tags, purge_tags, module):
    if desired_tags is None:
        return False

    group_name = module.params.get('log_group_name')
    current_tags = found_log_group.get('tags', {})
    tags_to_add, tags_to_remove = compare_aws_tags(current_tags, desired_tags, purge_tags)

    if not tags_to_add and not tags_to_remove:
        return False
    if module.check_mode:
        return True

    try:
        if tags_to_remove:
            client.untag_log_group(logGroupName=group_name, tags=tags_to_remove)
        if tags_to_add:
            client.tag_log_group(logGroupName=group_name, tags=tags_to_add)
    except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
        module.fail_json_aws(e, msg='Failed to update tags')

    return True


def main():
    argument_spec = dict(
        log_group_name=dict(required=True, type='str'),
        state=dict(choices=['present', 'absent'],
                   default='present'),
        kms_key_id=dict(required=False, type='str'),
        tags=dict(required=False, type='dict', aliases=['resource_tags']),
        purge_tags=dict(required=False, type='bool', default=True),
        retention=dict(required=False, type='int'),
        purge_retention_policy=dict(required=False, type='bool', default=False),
        overwrite=dict(required=False, type='bool', default=False),
    )

    mutually_exclusive = [['retention', 'purge_retention_policy'], ['purge_retention_policy', 'overwrite']]
    module = AnsibleAWSModule(supports_check_mode=True, argument_spec=argument_spec, mutually_exclusive=mutually_exclusive)

    try:
        logs = module.client('logs')
    except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
        module.fail_json_aws(e, msg='Failed to connect to AWS')

    state = module.params.get('state')
    changed = False

    # Determine if the log group exists
    found_log_group = describe_log_group(client=logs, log_group_name=module.params['log_group_name'], module=module)

    if state == 'present':
        if found_log_group:
            if module.params['overwrite'] is True:
                changed = True
                delete_log_group(client=logs, log_group_name=module.params['log_group_name'], module=module)
                found_log_group = create_log_group(client=logs,
                                                   log_group_name=module.params['log_group_name'],
                                                   kms_key_id=module.params['kms_key_id'],
                                                   tags=module.params['tags'],
                                                   retention=module.params['retention'],
                                                   module=module)
            else:
                changed |= ensure_tags(client=logs,
                                       found_log_group=found_log_group,
                                       desired_tags=module.params['tags'],
                                       purge_tags=module.params['purge_tags'],
                                       module=module)
                if module.params['purge_retention_policy']:
                    if found_log_group.get('retentionInDays'):
                        changed = True
                        delete_retention_policy(client=logs,
                                                log_group_name=module.params['log_group_name'],
                                                module=module)
                elif module.params['retention'] != found_log_group.get('retentionInDays'):
                    if module.params['retention'] is not None:
                        changed = True
                        input_retention_policy(client=logs,
                                               log_group_name=module.params['log_group_name'],
                                               retention=module.params['retention'],
                                               module=module)
                if changed:
                    found_log_group = describe_log_group(client=logs,
                                                         log_group_name=module.params['log_group_name'],
                                                         module=module)

        elif not found_log_group:
            changed = True
            found_log_group = create_log_group(client=logs,
                                               log_group_name=module.params['log_group_name'],
                                               kms_key_id=module.params['kms_key_id'],
                                               tags=module.params['tags'],
                                               retention=module.params['retention'],
                                               module=module)

        result = format_result(found_log_group)
        module.exit_json(changed=changed, **result)

    elif state == 'absent':
        if found_log_group:
            changed = True
            delete_log_group(client=logs,
                             log_group_name=module.params['log_group_name'],
                             module=module)

    module.exit_json(changed=changed)


if __name__ == '__main__':
    main()
