islaApocalypse-v2/Tools/Scripts/TerrainGenConfig.cs

using IslaApocalypse.Core;

namespace IslaApocalypse.Tools
{
	/// <summary>
	/// The generator's configuration, including the per-element ABLATION TOGGLES.
	///
	/// ═══ WHY EVERY PASS-1 ELEMENT IS GATED ═══
	///
	/// This is the standing A/B discipline: every shaping change ships behind a gate with the
	/// previous behaviour surviving on the other side, so changes stay comparable as a pair rather
	/// than as a memory of last week's render, and a rejected change costs a flipped default rather
	/// than a reverted commit. → `Design - Tooling - Iteration and Batching.md`.
	///
	/// For THIS task the gates do a second job: they are the PORT-FIDELITY CHECK. Generating
	/// base-noise-only, then adding one element at a time, shows each ported element doing what the
	/// reference's did — rather than judging six simultaneous changes by their sum.
	///
	/// ⚠ Lives in Tools/, not Core/. It configures the generator specifically; Core carries the
	/// world's data contracts and the scaling rule, not a tool's dials.
	/// </summary>
	public sealed class TerrainGenConfig
	{
		// ---- world ----------------------------------------------------------

		/// <summary>
		/// Map side in columns. A GENERATION PARAMETER — never baked in.
		/// Iteration runs small (2048–4096); the shape is scale-invariant by construction, so the
		/// island reads the same at any size and a full-size pass is confirmation, not iteration.
		/// </summary>
		public int MapSize = 2048;

		/// <summary>
		/// The noise seed. POSITIVE ONLY. Zero or negative means "pick one and print it" — a run
		/// whose seed is not recorded is a run that cannot be reproduced, so the resolved seed is
		/// always printed and always in the filename.
		/// </summary>
		public int Seed = 0;

		// ---- island shape (reference ConfigManager defaults, READ from source) ----

		/// <summary>Falloff X axis ratio. Reference: <c>ConfigManager.LEGACY_AXIS_X = 1.15f</c>.</summary>
		public float IslandAxisX = 1.15f;

		/// <summary>Falloff Y axis ratio. Reference: <c>ConfigManager.LEGACY_AXIS_Y = 0.90f</c>.</summary>
		public float IslandAxisY = 0.90f;

		/// <summary>
		/// Multiplier on the falloff term in the combine.
		/// Reference: <c>[Export] public float FalloffStrength = 1.0f;</c> (MapGenerator ~:11),
		/// and NOT overridden in MapPreview.tscn — so 1.0f is the value the island was tuned at.
		/// </summary>
		public float FalloffStrength = 1.0f;

		/// <summary>
		/// The flat sea level, in raw height units. Reference: <c>ConfigManager.SeaLevelValue = 0.15f</c>
		/// with <c>SeaLevelModel = "flat"</c>, so <c>GetSeaLevel</c> ignores latitude entirely.
		///
		/// ⚠ PHASE 1 USES THIS AS A VISUALIZATION THRESHOLD ONLY — the boundary between the
		/// bathymetric and hypsometric colour ramps. No water is modelled, no water bodies are
		/// identified, nothing floods. That is Phase 2.
		/// </summary>
		public float SeaLevel = 0.15f;

		// ---- ABLATION TOGGLES — the pass-1 ladder ---------------------------

		/// <summary>Rung 1: the base terrain noise, <c>(noise(x,y)+1)/2</c>. Off = flat zero.</summary>
		public bool BaseNoise = true;

		/// <summary>
		/// Rung 2: the island falloff/mask — squircle + ellipse blend, and the <c>Pow(·, 2.5f)</c>.
		/// ⚠ Off also disables rungs 3–5 in effect: edge noise, the sinker and the Trench are all
		/// modifiers OF the falloff, so with no falloff there is nothing for them to modify. The
		/// toggles stay independent so the ladder reads honestly; the report says so.
		/// </summary>
		public bool IslandFalloff = true;

		/// <summary>Rung 3: coastline edge roughness, modulated by the squircle.</summary>
		public bool EdgeNoise = true;

		/// <summary>Rung 4: the southern sinker — extra sinking pressure in the bottom 25%.</summary>
		public bool SouthernSinker = true;

		/// <summary>Rung 5: the Trench — the map-anchored outer-band wall that guarantees an ocean border.</summary>
		public bool Trench = true;

		/// <summary>Rung 6: the mountain spine up the centre-X axis.</summary>
		public bool MountainSpine = true;

		// ---- PASS 2a — the redistribution curve and shelf detail (Phase 2) ----
		//
		// ⚠ THE PRIMARY A/B OF THIS PHASE IS `Curve`. Off must reproduce Phase 1's pass-1 output
		// BIT-IDENTICALLY — that is the regression oracle, not a figure of speech.

		/// <summary>
		/// ⭐ Pass 2a rung 1: the height-redistribution curve. → <see cref="HeightCurve"/>.
		/// Off = raw pass-1 height, unshaped (the control half of every A/B in this phase).
		/// </summary>
		public bool Curve = true;

		/// <summary>
		/// ⭐ Pass 2a rung 2: the shelf detail passes — micro-relief skin + shelf-edge knot warp.
		/// ⚠ REQUIRES <see cref="Curve"/>: the edge warp slides the CURVE's knots, so with no curve
		/// there is nothing to warp. Requesting it with the curve off is a logged no-op, not an error.
		/// </summary>
		public bool ShelfDetail = true;

		/// <summary>
		/// Micro-relief amplitude, in METRES of output height. Reference default: 3 m.
		/// Converted through <see cref="WorldScale"/> at the call site — never a literal /251.
		/// </summary>
		public float ShelfReliefAmpM = TerrainDetailPass.ReliefAmpDefaultM;

		/// <summary>
		/// Shelf-edge warp amplitude, in METRES OF INPUT HEIGHT (not output elevation — see
		/// <see cref="TerrainDetailPass"/>). Reference default: 12 m.
		///
		/// ⚠ CLAMPED, LOUDLY, to the knot set's safe bound (<c>TerrainDetailPass.MaxEdgeShift</c>).
		/// Monotonicity is never a tuning question; an ignored dial is always reported.
		/// </summary>
		public float ShelfEdgeVariationM = TerrainDetailPass.EdgeAmpDefaultM;

		/// <summary>
		/// The input knot set — WHERE the land distribution is cut.
		/// Default: <see cref="CurveKnots.V2Baseline"/>, re-measured on v2's own pass-1 output.
		/// <see cref="CurveKnots.Reference"/> is available for a fidelity A/B against the prototype's.
		/// </summary>
		public CurveKnots Knots = CurveKnots.V2Baseline;

		/// <summary>
		/// The output anchors — WHAT HEIGHT each cut lands at. Default: the storm-ladder values,
		/// reproducing the reference's constants bit-for-bit.
		/// </summary>
		public CurveAnchors Anchors = CurveAnchors.Default;

		// ---- the crater seam — INERT THIS PHASE -----------------------------

		/// <summary>
		/// Crater radius in columns. ⚠ <b>0 = NO CRATER, which is this phase's state.</b> The detail
		/// pass's crater exclusion is ported and wired, but with no crater it evaluates to "detail
		/// everywhere" and the distance is never computed. It is exercised when the carve lands.
		/// </summary>
		public float CraterRadius = 0f;

		/// <summary>Crater centre X, columns. Unused while <see cref="CraterRadius"/> is 0.</summary>
		public float CraterCenterX = 0f;

		/// <summary>Crater centre Y, columns. Unused while <see cref="CraterRadius"/> is 0.</summary>
		public float CraterCenterY = 0f;

		/// <summary>A short label for this variant, used in output filenames. E.g. "full", "base_only".</summary>
		public string VariantLabel = "full";

		/// <summary>The scale object every distance and frequency in the generator derives from.</summary>
		public GenerationScale Scale => new GenerationScale(MapSize);

		/// <summary>
		/// ⚠ DEEP on <see cref="Anchors"/>. <c>MemberwiseClone</c> is shallow, so two configs cloned
		/// from one parent would share a single mutable anchor object and an A/B that edited one
		/// would silently move the other. The one reference type that is a DIAL gets copied; the one
		/// that is immutable (<see cref="CurveKnots"/>) does not need to be.
		/// </summary>
		public TerrainGenConfig Clone()
		{
			var c = (TerrainGenConfig)MemberwiseClone();
			c.Anchors = Anchors?.Clone();
			return c;
		}

		public override string ToString() =>
			$"MapSize={MapSize} Seed={Seed} axis={IslandAxisX:F2}x/{IslandAxisY:F2}y " +
			$"falloffStrength={FalloffStrength:F2} sea={SeaLevel:F2} variant={VariantLabel} " +
			$"[base={BaseNoise} falloff={IslandFalloff} edge={EdgeNoise} sinker={SouthernSinker} " +
			$"trench={Trench} spine={MountainSpine}] " +
			$"[curve={Curve} detail={ShelfDetail} relief={ShelfReliefAmpM:F1}m edge={ShelfEdgeVariationM:F1}m " +
			$"knots={(Knots == null ? "-" : Knots.Name)}]";
	}
}