import pika

# this is the physical conn
connection = pika.BlockingConnection(pika.ConnectionParameters("localhost"))
# a channel is a lightweight multiplexer over it
channel = connection.channel()

# first the exchanges

# this is A DECLARE, basically so can run multuple  times
# .x = exchange

# what does durable mean?
# when broke restarts
# even if I don't run this IaC like code to create the q
# the q will exist
# it basically commits the q defns to disk
# not the message
channel.exchange_declare(
    exchange="orders.x", exchange_type="direct", durable=True)
# .dlx = dead letter exchange for failed messages
channel.exchange_declare(exchange="orders.dlx",
                         exchange_type="direct", durable=True)
# the exchange_types are
# - direct: exact key match for routing
# - topic: pattern based
# - fanout: all
# - headers: defined in headers

# then the queues
# when changing settings, you might need to delete q from adming
# as it'll aready exist and this declare does not delete
channel.queue_declare(
    queue="orders.q",
    durable=True,
    arguments={
        #  what to do with "dead letters"
        # which can be when consumder signals issue
        # or q overflow
        # or ttl stuff
        "x-dead-letter-exchange": "orders.dlx",
        "x-dead-letter-routing-key": "order.dead",
    },
)
channel.queue_declare(queue="orders.processed.q", durable=True)
channel.queue_declare(queue="orders.failed.q", durable=True)
channel.queue_declare(queue="orders.dlq", durable=True)

# then the bindings
# these are rules on how exchange will route what message
# read as, on order.x, if key is order.created, push to orders.q
channel.queue_bind(exchange="orders.x", queue="orders.q",
                   routing_key="order.created")
channel.queue_bind(exchange="orders.x", queue="orders.processed.q",
                   routing_key="order.processed")
channel.queue_bind(exchange="orders.x", queue="orders.failed.q",
                   routing_key="order.failed")
channel.queue_bind(exchange="orders.dlx", queue="orders.dlq",
                   routing_key="order.dead")


connection.close()