bid_rate.js

var log = console.log.bind(console);

/**
 * Given a ad
 * calculate max bid rate 
 */

function calculate_max_bid_rate(ad) {

    var org_chain = get_org_chain(ad);

    // this is the selling price to the campaign user
    var max_cpm = ad.max_cpm;

    var org_buying_price = 0;
    var org_selling_price = max_cpm;

    org_chain.forEach(function (org) {

        // get pricing model from organization for this creative
        // each organization has different pricing model for each creative
        var pricing = org.get_pricing_model(ad.creative);

        var pricing_type = pricing.type; 
        var margin_rate = pricing.margin_rate;
        var margin_percentage = pricing.margin_percentage;

        // new fields
        var max_buying_rate = pricing.max_buying_rate;

        switch (pricing_type) {

            case 'fixed_margin_rate':
                org_buying_price = org_selling_price - margin_rate;

                // set selling price for next org
                org_selling_price = org_buying_price;
            break;

            case 'flat_selling_rate':
                org_buying_price = max_buying_rate;

                // set selling price for next org
                org_selling_price = org_buying_price;
            break;

            case 'fixed_margin_percentage':
                org_buying_price = org_selling_price * ( 1 - margin_percentage);

                // set selling price for next org
                org_selling_price = org_buying_price;
            break;
        }
    });

    return org_buying_price;
}

function calculate_earnings_and_costs(bid_rate, ad) {
    // reverse org_chain from top down
    var org_chain = get_org_chain(ad).reverse();
    
    var earnings = [];
    var costs = [];
    
    // this is the actual cost of parent org
    var actual_buy = bid_rate;
    var actual_sell = actual_buy;
    
    // start from root org 
    org_chain.forEach(function (org, i) {
        
        var pricing = org.get_pricing_model(ad);
        
        // no matter what, cost is the actual sell price of parent org
        costs[i] = actual_sell;
        
        switch (pricing.type) {
            
            case 'fixed_margin_rate':
                earnings[i] = pricing.margin_rate;
                actual_sell = costs[i] + pricing.margin_rate;
            break;
            
            case 'fixed_margin_percentage':
                actual_sell = costs[i] / (1 - pricing.margin_percentage)
                earnings[i] = actual_sell * pricing.margin_percentage;
            break;
            
            case 'flat_selling_rate':
                earnings[i] = pricing.flat_selling_price - costs[i];
                actual_sell = pricing.flat_selling_price;
            break;
        }
    });
    
    return earnings.map(function (e, i) {return {earning: e, cost: costs[i]}});
}


/**
 * get a list of organzations
 *
 * bottom up
 *
 */

function get_org_chain(ad) {
    
    // some test cases, ignore ad
    return [
    
    new Organization({
        type: 'fixed_margin_percentage',
        margin_percentage: 0.1
    }),
    
    new Organization({
        type: 'flat_selling_rate',
        flat_selling_price: 20,
        max_buying_rate: 12
    }),
    
    new Organization({
        type: 'fixed_margin_rate',
        margin_rate: 2.0
    }),
    
    new Organization({
        type: 'fixed_margin_rate',
        margin_rate: 1.0
    })
    
    ];
}

/**
 * [Organization description]
 */
function Organization(pricing) {
    this.pricing = pricing;
}

Organization.prototype.get_pricing_model = function (creative) {
    // for testing ignore creative
    return this.pricing;
};

/**
 * Pricing model for each creative
 * 
 * @param {string} type                 the type of pricing model
 * @param {float} margin_rate           if the type is 'fixed_margin_rate', this value is used
 * @param {float} margin_percentage     if the type is 'fixed_margin_percentage', this value is used
 * @param {float} max_buying_rate       if the type is 'flat_selling_price', this value is used
 * @param {float} selling_price         if the type is 'flat_selling_price', this value is used
 */
function Pricing() {}


var ad = {
    max_cpm: 10,
    // for testing, this value can be null
    creative: null
};

var bid = calculate_max_bid_rate(ad);

log(bid);

var bid_rate = bid / 2;
var ec = calculate_earnings_and_costs(bid_rate, ad);

log(JSON.stringify(ec));