#!/usr/bin/python
#
# Copyright (c) 2020 Haiyuan Zhang, <haiyzhan@microsoft.com>
#
# 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
import datetime

__metaclass__ = type


DOCUMENTATION = '''
---
module: azure_rm_adpassword

version_added: "0.2.0"

short_description: Manage application password

description:
    - Manage application password.

options:
    app_id:
        description:
            - The application ID.
        type: str
    service_principal_object_id:
        description:
            - The service principal object ID.
        type: str
    key_id:
        description:
            - The password key ID.
        type: str
    tenant:
        description:
            - The tenant ID.
        type: str
        required: True
    end_date:
        description:
            - Date or datemtime after which credentials expire.
            - Default value is one year after current time.
        type: str
    value:
        description:
            - The application password value.
            - Length greater than 18 characters.
        type: str
    app_object_id:
        description:
            - The application object ID.
        type: str
    state:
        description:
            - Assert the state of Active Dirctory Password.
            - Use C(present) to create or update a Password and use C(absent) to delete.
            - Update is not supported, if I(state=absent) and I(key_id=None), then all passwords of the application will be deleted.
        default: present
        choices:
            - absent
            - present
        type: str

extends_documentation_fragment:
    - azure.azcollection.azure
    - azure.azcollection.azure_tags

author:
    haiyuan_zhang (@haiyuazhang)
    Fred-sun (@Fred-sun)

'''

EXAMPLES = '''
    - name: create ad password
      azure_rm_adpassword:
        app_id: "{{ app_id }}"
        state: present
        value: "$abc12345678"
        tenant: "{{ tenant_id }}"
'''

RETURN = '''
end_date:
    description:
        - Date or datemtime after which credentials expire.
        - Default value is one year after current time.
    type: str
    returned: always
    sample: 2021-06-28T06:00:32.637070+00:00
key_id:
    description:
        - The password key ID
    type: str
    returned: always
    sample: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
start_date:
    description:
        - Date or datetime at which credentials become valid.
        - Default value is current time.
    type: str
    returned: always
    sample: 2020-06-28T06:00:32.637070+00:00

'''

from ansible_collections.azure.azcollection.plugins.module_utils.azure_rm_common import AzureRMModuleBase
import uuid

try:
    from msrestazure.azure_exceptions import CloudError
    from azure.graphrbac.models import GraphErrorException
    from azure.graphrbac.models import PasswordCredential
    from azure.graphrbac.models import ApplicationUpdateParameters
    from dateutil.relativedelta import relativedelta
except ImportError:
    # This is handled in azure_rm_common
    pass


class AzureRMADPassword(AzureRMModuleBase):
    def __init__(self):

        self.module_arg_spec = dict(
            app_id=dict(type='str'),
            service_principal_object_id=dict(type='str'),
            app_object_id=dict(type='str'),
            key_id=dict(type='str'),
            tenant=dict(type='str', required=True),
            value=dict(type='str'),
            end_date=dict(type='str'),
            state=dict(type='str', default='present', choices=['present', 'absent']),
        )

        self.state = None
        self.tenant = None
        self.app_id = None
        self.service_principal_object_id = None
        self.app_object_id = None
        self.key_id = None
        self.value = None
        self.end_date = None
        self.results = dict(changed=False)

        self.client = None

        super(AzureRMADPassword, self).__init__(derived_arg_spec=self.module_arg_spec,
                                                supports_check_mode=False,
                                                supports_tags=False,
                                                is_ad_resource=True)

    def exec_module(self, **kwargs):
        for key in list(self.module_arg_spec.keys()):
            setattr(self, key, kwargs[key])

        self.client = self.get_graphrbac_client(self.tenant)
        self.resolve_app_obj_id()
        passwords = self.get_all_passwords()

        if self.state == 'present':
            if self.key_id and self.key_exists(passwords):
                self.update(passwords)
            else:
                self.create_password(passwords)
        else:
            if self.key_id is None:
                self.delete_all_passwords(passwords)
            else:
                self.delete_password(passwords)

        return self.results

    def key_exists(self, old_passwords):
        for pd in old_passwords:
            if pd.key_id == self.key_id:
                return True
        return False

    def resolve_app_obj_id(self):
        try:
            if self.app_object_id is not None:
                return
            elif self.app_id or self.service_principal_object_id:
                if not self.app_id:
                    sp = self.client.service_principals.get(self.service_principal_object_id)
                    self.app_id = sp.app_id
                if not self.app_id:
                    self.fail("can't resolve app via service principal object id {0}".format(self.service_principal_object_id))

                result = list(self.client.applications.list(filter="appId eq '{0}'".format(self.app_id)))
                if result:
                    self.app_object_id = result[0].object_id
                else:
                    self.fail("can't resolve app via app id {0}".format(self.app_id))
            else:
                self.fail("one of the [app_id, app_object_id, service_principal_id] must be set")

        except GraphErrorException as ge:
            self.fail("error in resolve app_object_id {0}".format(str(ge)))

    def get_all_passwords(self):

        try:
            return list(self.client.applications.list_password_credentials(self.app_object_id))
        except GraphErrorException as ge:
            self.fail("failed to fetch passwords for app {0}: {1}".format(self.app_object_id, str(ge)))

    def delete_all_passwords(self, old_passwords):

        if len(old_passwords) == 0:
            self.results['changed'] = False
            return
        try:
            self.client.applications.patch(self.app_object_id, ApplicationUpdateParameters(password_credentials=[]))
            self.results['changed'] = True
        except GraphErrorException as ge:
            self.fail("fail to purge all passwords for app: {0} - {1}".format(self.app_object_id, str(ge)))

    def delete_password(self, old_passwords):
        if not self.key_exists(old_passwords):
            self.results['changed'] = False
            return

        num_of_passwords_before_delete = len(old_passwords)

        for pd in old_passwords:
            if pd.key_id == self.key_id:
                old_passwords.remove(pd)
                break
        try:
            self.client.applications.patch(self.app_object_id, ApplicationUpdateParameters(password_credentials=old_passwords))
            num_of_passwords_after_delete = len(self.get_all_passwords())
            if num_of_passwords_after_delete != num_of_passwords_before_delete:
                self.results['changed'] = True

        except GraphErrorException as ge:
            self.fail("failed to delete password with key id {0} - {1}".format(self.app_id, str(ge)))

    def create_password(self, old_passwords):

        def gen_guid():
            return uuid.uuid4()

        if self.value is None:
            self.fail("when creating a new password, module parameter value can't be None")

        start_date = datetime.datetime.now(datetime.timezone.utc)
        end_date = self.end_date or start_date + relativedelta(years=1)
        value = self.value
        key_id = self.key_id or str(gen_guid())

        new_password = PasswordCredential(start_date=start_date, end_date=end_date, key_id=key_id,
                                          value=value, custom_key_identifier=None)
        old_passwords.append(new_password)

        try:
            client = self.get_graphrbac_client(self.tenant)
            app_patch_parameters = ApplicationUpdateParameters(password_credentials=old_passwords)
            client.applications.patch(self.app_object_id, app_patch_parameters)

            new_passwords = self.get_all_passwords()
            for pd in new_passwords:
                if pd.key_id == key_id:
                    self.results['changed'] = True
                    self.results.update(self.to_dict(pd))
        except GraphErrorException as ge:
            self.fail("failed to create new password: {0}".format(str(ge)))

    def update_password(self, old_passwords):
        self.fail("update existing password is not supported")

    def to_dict(self, pd):
        return dict(
            end_date=pd.end_date,
            start_date=pd.start_date,
            key_id=pd.key_id
        )


def main():
    AzureRMADPassword()


if __name__ == '__main__':
    main()