import boto3
import collections
import datetime


# Set the global variables
globalVars  = {}
globalVars['Owner']                 = "Miztiik"
globalVars['Environment']           = "Test"
globalVars['REGION_NAME']           = "ap-south-1"
globalVars['tagName']               = "Valaxy-Serverless-Automated-Backup"
globalVars['findNeedle']            = "BackUp"
globalVars['RetentionTag']          = "DeleteOn"
globalVars['RetentionInDays']       = "70"

#Please mention your region name
ec = boto3.client('ec2', region_name='ap-south-1')

def backup_bot():

    snapsCreated = { 'Snapshots':[], }

    filters = [
        {'Name': 'tag-key', 'Values': [ globalVars['findNeedle'] ]},
        {'Name': 'tag-value', 'Values': ['Yes']},
    ]

    reservations = ec.describe_instances( Filters=filters ).get( 'Reservations', [] )

    instances = sum(
        [
            [i for i in r['Instances']]
            for r in reservations
        ], [])

    # print "Number of the Instances : %d" % len(instances)
    snapsCreated['InstanceCount']=len(instances)

    to_tag = collections.defaultdict(list)

    # Iterate for all Instances in the Region
    for instance in instances:
        try:
            retention_days = [
                int(t.get('Value')) for t in instance['Tags']
                if t['Key'] == 'Retention'][0]
        except IndexError:
            retention_days = int(globalVars['RetentionInDays'])

        # Get all the Block Device Mappings
        for dev in instance['BlockDeviceMappings']:
            if dev.get('Ebs', None) is None:
                continue
            vol_id = dev['Ebs']['VolumeId']

            # Iterate Tags to collect the instance name tag
            DescriptionTxt = ''
            for tag in instance['Tags']:
                if tag['Key'] == 'Name' :
                    DescriptionTxt = tag['Value']

            snap = ec.create_snapshot( VolumeId=vol_id, Description=DescriptionTxt )

            to_tag[retention_days].append(snap['SnapshotId'])

            # Tag all the snaps that were created today with Deletion Date
            # Processing "DeleteOn" here to allow for future case of each disk having its own Retention date
            for retention_days in to_tag.keys():
                delete_date = datetime.date.today() + datetime.timedelta(days=retention_days)
                # to mention the current date formet
                delete_fmt = delete_date.strftime('%Y-%m-%d')
                # below code is create the name and current date as instance name
                ec.create_tags(
                                Resources=to_tag[retention_days],
                                Tags=[
                                        {'Key': globalVars['RetentionTag'], 'Value': delete_fmt},
                                        {'Key': 'Name', 'Value': snap['Description'] },
                                    ]
                            )
                snapsCreated['Snapshots'].append({ 'SnapshotId':snap['SnapshotId'], 'VolumeId' : vol_id, 'InstanceId' : instance['InstanceId'], 'DeleteOn': delete_fmt })

        to_tag.clear()

    return snapsCreated


def lambda_handler(event, context):
    return backup_bot()

if __name__ == '__main__':
    lambda_handler(None, None)