state-quality-fn.ts

import {
  CountryResources,
  ResourceDefinitions,
} from './models/country-resources.interface';
import { PEOPLE_PER_HOUSE } from './transformation-templates/transformation-templates';

export const stateQuality = (
  country: CountryResources,
  resourceDefinitions: ResourceDefinitions
) => {
  let result = 0;
  for (const r of Object.keys(country)) {
    const resourceName = r as keyof CountryResources;
    const amount = country[resourceName];
    if (resourceName === 'R23_Housing') {
      const housesPerPerson =
        country.R1_Population === 0 ? 0 : amount / country.R1_Population;
      // Reward = number of houses per person
      let housingReward =
        country.R1_Population *
        // Don't reward extra if there's more than 1 house per person (too many houses)
        Math.min(housesPerPerson, 1) *
        resourceDefinitions.R23_Housing.weight;
      // Shrink reward if housesPerPerson is very small
      if (housesPerPerson < 1 / PEOPLE_PER_HOUSE) {
        housingReward *= housesPerPerson * PEOPLE_PER_HOUSE;
      }

      result += housingReward;
    } else {
      // Every other resource is just a weighted sum
      result += resourceDefinitions[resourceName].weight * amount;
    }
  }

  return result;
};