Query Customers

This action can be split into three separate functions within business.js: send_message, price_messaging, movement_messaging.

Let’s start with send_message. Send_message() will add messages to state.messages with a neighbor agent_id, position, item_price, and rgb. Add this function to business.js. (Rgb is sent so we can visually see which business a customer chooses to shop at)

const behavior = (state, context) => {
    const send_message = (agent_id, position, price) => {
        state.addMessage(agent_id, "business_movement", {
           position,
           price,
           rgb: state.rgb
        });
    }
}

The next step is to create the price_messaging() function. This function will receive the neighbor agent_id and position change, iterate through the possible item_price values, and call send_message to notify all possible neighbors.

const price_messaging = (agent_id, position) => {
    const item_price = state.item_price;
    send_message(agent_id, position, item_price);
    send_message(agent_id, position, item_price + 1);
    if (item_price > 1) {
        send_message(agent_id, position, item_price - 1);
    }
}

Notice here how we check if the item_price is greater than 1. This is important as we don’t want the item_price to drop below 0.

The final function we are going to create for querying Customers is movement messaging; however, since this will be our top level function we are going to name it query_customers(). In this function, business agents are going to iterate through their Customer neighbors and send them all possible position and item_price change combinations.

const query_customers = (neighbors, state_position) => {
    const possible_movement = [[-1, 0], [0, 0], [1, 0], [0, -1], [0, 1]];
    neighbors.filter((neighbor) => neighbor.behaviors.includes("customer.js"))
        .forEach((neighbor) => {
            possible_movement.forEach((movement) => {
                const new_position = [state_position[0] + movement[0], state_position[1] + movement[1], 0];
                price_messaging(neighbor.agent_id, new_position);
            })
        })
}

You can test your new code by placing the following snippet underneath your function declarations (at line 30) and looking at the Raw Output view tab.

query_customers(context.neighbors(), state.position);

Find the messages field for a Business agent and it should be filled with “business_movement” type messages.

const behavior = (state, context) => {
 const send_message = (agent_id, position, price) => {
   state.addMessage(agent_id, "business_movement", {
     position,
     price,
     rgb: state.rgb
   });
 }
 
 const price_messaging = (agent_id, position) => {
   const item_price = state.item_price;
   send_message(agent_id, position, item_price);
   send_message(agent_id, position, item_price + 1);
   if (item_price > 1) {
     send_message(agent_id, position, item_price - 1);
   }
 }
 
 const query_customers = (neighbors, state_position) => {
   const possible_movement = [[-1, 0], [0, 0], [1, 0], [0, -1], [0, 1]];
   neighbors.filter((neighbor) => neighbor.behaviors.includes("customer.js"))
     .forEach((neighbor) => {
       possible_movement.forEach((movement) => {
         const new_position = [state_position[0] + movement[0], state_position[1] + movement[1]];
         price_messaging(neighbor.agent_id, new_position);
       })
     })
 }
 
 query_customers(context.neighbors(), state.position));
}
​