import { MAP_H, MAP_W, SIZE, clamp, indexOf } from "./mapUtils.js";
import { influenceFromPoints } from "./mapGeneratorHelpers.js";

export function buildSettlementDemandFields(ctx) {
  const {
    sea, agriculture, plain, basinField, coastalLowland, slope, ridgeField,
    modernCities, markets, commercialPorts, villages,
  } = ctx;

  const preliminaryUrbanInfluence = influenceFromPoints(modernCities, 18, (c) => clamp((c.population || 60000) / 260000, 0.55, 2.0));
  const preliminaryTownInfluence = influenceFromPoints([...markets, ...commercialPorts], 10, (p) => p.portClass === "major" ? 1.35 : clamp((p.population || 12000) / 36000, 0.42, 1.1));
  const preliminaryVillageInfluence = influenceFromPoints(villages, 7, (v) => clamp((v.population || 1800) / 5200, 0.22, 0.9));
  const settlementDemand = new Float32Array(SIZE);
  const urbanEdge = new Float32Array(SIZE);
  const logisticsPreSuitability = new Float32Array(SIZE);

  for (let y = 0; y < MAP_H; y++) {
    for (let x = 0; x < MAP_W; x++) {
      const i = indexOf(x, y);
      if (sea[i]) continue;
      const density = clamp(preliminaryUrbanInfluence[i] * 0.62 + preliminaryTownInfluence[i] * 0.34 + preliminaryVillageInfluence[i] * 0.16);
      settlementDemand[i] = density;
      urbanEdge[i] = clamp(1 - Math.abs(density - 0.46) / 0.32);
      logisticsPreSuitability[i] = clamp(
        agriculture[i] * 0.30 +
        plain[i] * 0.24 +
        basinField[i] * 0.14 +
        coastalLowland[i] * 0.12 +
        preliminaryTownInfluence[i] * 0.18 +
        urbanEdge[i] * 0.34 -
        preliminaryUrbanInfluence[i] * 0.20 -
        slope[i] * 0.50 -
        ridgeField[i] * 0.32
      );
    }
  }


  return {
    preliminaryUrbanInfluence,
    preliminaryTownInfluence,
    preliminaryVillageInfluence,
    settlementDemand,
    urbanEdge,
    logisticsPreSuitability,
  };
}