import boto3, datetime


def lambda_handler(event, context):
    hours_duration_for_trainers = 12
    hours_duration_for_defaults = 2
    region = "ap-southeast-1"
    cloudformation = boto3.client("cloudformation", region_name=region)
    print("lab control housekeeper started.")
    except_list = ["lab-control", "lab-control-v2", "lab-tidb-training"]
    # Reserved for course 303 trainers
    long_hours_list = [
        "guanglei-bao",
        "dongfei",
        "chenhao-huang",
        "sean-bogaard",
        "todongfei-gmail-com",
    ]
    stacks = []
    response = cloudformation.list_stacks(
        StackStatusFilter=["CREATE_FAILED", "CREATE_COMPLETE"],
    )
    stacks += response["StackSummaries"]
    while "NextToken" in response and response["NextToken"] != None:
        nt = response["NextToken"]
        response = cloudformation.list_stacks(
            NextToken=nt,
            StackStatusFilter=["CREATE_FAILED", "CREATE_COMPLETE"],
        )
        stacks += response["StackSummaries"]
    for s in stacks:
        stack_name = s["StackName"]
        if (
            stack_name.replace("-class-env", "").replace("-demo-env", "")
            not in except_list
        ):
            stack_creation_time = s["CreationTime"]
            now = datetime.datetime.utcnow()
            stack_creation_time = stack_creation_time.replace(tzinfo=None)
            delta = now - stack_creation_time
            if (
                # More than 4 hours, and not belongs to trainers
                delta > datetime.timedelta(hours=hours_duration_for_defaults)
                and stack_name.replace("-class-env", "").replace("-demo-env", "")
                not in long_hours_list
            ) or (
                # More than 8 hours, and belongs to trainers
                delta > datetime.timedelta(hours=hours_duration_for_trainers)
                and stack_name.replace("-class-env", "").replace("-demo-env", "")
                in long_hours_list
            ):
                print("Stack creation time (utc truncated):", stack_creation_time)
                print(
                    "Destroying",
                    stack_name,
                    "which was created at",
                    stack_creation_time,
                )
                cloudformation.delete_stack(StackName=stack_name)
    print("lab control housekeeper ended.")
    return "ap-southeast-1 lab-control housekeeper invoked."