// World-generation configuration. The seed is overridden per game; the rest
// tunes the shape and populating of the map.

export const MAP_CONFIG = {
  mapSize: { x: 100, y: 100 },
  topology: "cylindrical",
  terrainSeed: 0,
  // Continents grow from `minContinents` smooth domes rather than a plain
  // continent noise field. The domes are spread by farthest-point sampling and
  // the sea level is then found by lowering the water in `seaLevelStep` steps
  // until exactly that many landmasses remain; `seaLevel` is only the fallback
  // when the search finds no exact match.
  seaLevel: 0,
  // Fraction of the shorter map side used as each dome's radius. There is no
  // falloff: the domes are simply islands in one ocean, and where a dome
  // reaches a pole it parts the ocean there.
  domeRadius: 0.26,
  // How far the detail noise may bend the dome edge. The field is rescaled to
  // [-1, 1] per map so the coast stays rough whatever the map size.
  detailAmplitude: 0.25,
  // Domes are kept this fraction of a half-map away from the poles, so their
  // peaks are never buried under the polar ice.
  domePolarMargin: 0.25,
  // The detail field that roughens the coastline. `cycles` is how many base
  // waves span the map width, so the coasts stay ragged on a small map as well
  // as on the default one; the frequency is derived per map.
  detailNoise: {
    cycles: 1,
    octaves: 8,
    lacunarity: 2.0,
    gain: 0.5,
  },
  seaLevelStep: 0.01,
  // A body of land has to reach this fraction of the map to count as a
  // continent while the sea level is being chosen, so speckle cannot stand in
  // for one.
  minContinentFraction: 0.01,
  // The share of the ice-free tiles the water search aims to leave as land.
  // The water is lowered in `seaLevelStep` steps and the level whose land is
  // closest to this fraction wins; the ocean is then joined into one body, so
  // the map keeps a single connected sea whatever the continents do.
  landFraction: 0.6,
  // A few small islands are stamped into open water after the continents have
  // settled. They never join a continent or sway the water search, and each is
  // kept under `minCapitalLandmass`. The count is scaled by map area (so the
  // small test fixtures get none) and capped at the number of nations, because
  // every island is a starting island: `pickCapitals` puts one nation on each
  // before the rest go on the continents.
  smallIslandCount: 5,
  smallIslandSize: 30,
  // A field that chews the small-island rims so they read as ragged coast
  // rather than as dice. It is coarse enough to grow lobes a couple of tiles
  // across without splitting the island.
  smallIslandNoise: {
    frequency: 0.14,
    octaves: 2,
    lacunarity: 2.0,
    gain: 0.5,
  },
  falloffEnabled: false,
  falloffStart: 0.55,
  falloffStrength: 0.6,
  // The polar ice is exactly `iceRows` rows at each edge of the map, and the
  // tundra fringes it for `tundraRows` rows more. Fixed bands, so the sheets
  // take only the most extreme rows and never wander deep toward the equator.
  iceRows: 3,
  tundraRows: 3,
  // A finer field that roughens the coastline on top of the detail noise, and
  // how strongly it bends the shore away from the smooth dome outline.
  coastNoise: {
    frequency: 0.09,
    octaves: 2,
    lacunarity: 2.0,
    gain: 0.5,
  },
  coastRoughness: 0.4,
  // Third pass: clusters of terrain laid over the plains, independent of the
  // continent shape so no terrain type follows the landmasses. `coverage` is
  // the share of the land aimed for and `size` the tiles per cluster (jittered
  // per cluster). Earlier entries take priority where clusters overlap.
  terrainBiomes: [
    { terrainType: "Mountain", coverage: 0.03, size: 10 },
    { terrainType: "Hills", coverage: 0.1, size: 26 },
    { terrainType: "Forest", coverage: 0.22, size: 30 },
    { terrainType: "Desert", coverage: 0.08, size: 48 },
  ],
  capitalMargin: 2,
  minCapitalDistance: 8,
  minCapitalLandmass: 40,
  // Landmasses and seas smaller than these fractions of the map are smoothed
  // away, so the world reads as a few big continents rather than speckle. The
  // thresholds scale with the map, so tiny test maps are left alone.
  minIslandFraction: 0.0015,
  minLakeFraction: 0.0015,
  // How many continents to seed and to keep once the water has settled: the
  // generator places one dome per continent and searches for the sea level that
  // leaves exactly this many landmasses.
  minContinents: 3,
  connectOceans: true,
  citiesPerCiv: 10,
  // Minimum distance between any two cities during generation (never below 5).
  citySpacing: 5,
};