using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using Godot;
using IslaApocalypse.Core;

namespace IslaApocalypse.Tools
{
	/// <summary>
	/// ⭐ THE FRAG-4 SEED GALLERY (chat2/10) — RENDER-ONLY. Does the chat2/09 `frag_4` look generalize?
	/// Every setting is FROZEN at frag_4 (pinned explicitly here, not left to a default), 2 anchor seeds +
	/// 6 fresh seeds, at showpiece size, each with grayscale + .f32 + relief + the labeled-regions overlay,
	/// and the hemisphere-split count/size table as the instrument. No knob, no ladder, no logic change.
	///
	/// ═══ RUNNING IT ═══
	///
	///   xvfb-run -a Godot_v4.7.2-stable_mono_linux.x86_64 \
	///     --path ~/celerNexus/islaApocalypse-v2 res://Tools/Scenes/FragGalleryTool.tscn
	///
	///   ISLA_TASK / ISLA_BATCH / ISLA_SKIP_RAW / ISLA_OUTPUT_DIR
	///   ISLA_MAPSIZE        gallery size (default 8192)
	///   ISLA_CALIB_SIZE     curve calibration size (default 2048)
	///   ISLA_SEEDS          the gallery seeds (default: the 2 anchors + 6 fresh below)
	///   ISLA_SKIP_ANCHOR_CHECK=1   skip the 4096 bit-identity check against the 09 frag_4 dumps
	/// </summary>
	public partial class FragGalleryTool : Node
	{
		/// <summary>The two seeds frag_4 was judged on (chat2/09).</summary>
		private static readonly int[] AnchorSeeds = { 1063685222, 999999937 };

		/// <summary>Six fresh seeds, chosen BEFORE any render — constants, not picks: the date and five famous digit strings.</summary>
		private static readonly int[] FreshSeeds = { 20260822, 31415926, 27182818, 16180339, 14142135, 17320508 };

		/// <summary>⚠ Task 01's pool, verbatim — the curve's identity.</summary>
		private static readonly int[] CalibrationSeeds = { 1063685222, 20260819, 777001, 424242, 90210, 31337 };

		// ═══ THE FROZEN frag_4 SETTING — every value pinned explicitly (chat2/09 batch, level 4) ═══
		private const float FrozenFragmentAmp = 0.5f;
		private const float FrozenFragmentFreq = 12f;
		private const float FrozenBandCentre = 0.66f;
		private const float FrozenBandHalfWidth = 0.18f;
		private const bool  FrozenBitesOnly = false;
		private const float FrozenStretch = 2f;
		private const float FrozenBandStart = 0.70f;
		private const float FrozenBandFeather = 0.05f;
		private const bool  FrozenStretchSinker = true;
		private const float FrozenSpeckFrac = 2.5e-7f;     // 09's low speck revert (≈ 4 cells at 4096, ≈ 17 at 8192)

		private const int DefaultMapSize = 8192;
		private const int DefaultCalibSize = 2048;
		private const int AnchorCheckSize = 4096;          // the 09 batch's size

		public override void _Ready()
		{
			try { Run(); }
			catch (Exception e)
			{
				GD.PrintErr("==================================================================");
				GD.PrintErr($"  REFUSED: {e.Message}");
				GD.PrintErr(e.StackTrace);
				GD.PrintErr("==================================================================");
				GetTree().Quit(2);
			}
		}

		private sealed class HemiStats
		{
			public int All, Big; public long Min, Med, Max; public double Mean; public int[] Hist; public long[] Largest = Array.Empty<long>();
		}

		private sealed class Row
		{
			public int Seed; public bool Anchor;
			public HemiStats N, S; public long MainlandCells; public double MainlandFrac; public int SpecksReverted;
			public string Read; public bool Ok; public ulong Ms;
		}

		private void Run()
		{
			ToolingPaths.Configure(OS.GetUserDataDir());

			int task        = EnvInt("ISLA_TASK", 10);
			string descr    = EnvStr("ISLA_BATCH", "frag4_seed_gallery");
			int mapSize     = EnvInt("ISLA_MAPSIZE", DefaultMapSize);
			int calibSize   = EnvInt("ISLA_CALIB_SIZE", DefaultCalibSize);
			int[] seedsEnv  = EnvSeeds("ISLA_SEEDS", null);
			bool skipRaw    = EnvStr("ISLA_SKIP_RAW", "0") == "1";
			bool skipAnchor = EnvStr("ISLA_SKIP_ANCHOR_CHECK", "0") == "1";
			string p1Source = EnvStr("ISLA_PHASE1_SOURCE", "02_pass1_port");
			string t08Source = EnvStr("ISLA_T08_SOURCE", "08_southern_stretch_explore");
			string t09Source = EnvStr("ISLA_T09_SOURCE", "09_coastal_fragment");

			var seeds = new List<int>(AnchorSeeds); if (seedsEnv == null) seeds.AddRange(FreshSeeds); else { seeds.Clear(); seeds.AddRange(seedsEnv); }
			var anchorSet = new HashSet<int>(AnchorSeeds);

			string batchRoot = ToolingPaths.BatchRoot(task, descr);
			DirAccess.MakeDirRecursiveAbsolute(batchRoot);
			DirAccess.MakeDirRecursiveAbsolute(ToolingPaths.BatchScratch(batchRoot));

			var anchors = CurveAnchors.Default;
			float sea = 0.15f;
			long big = Cells(RegionPass.ThresholdMidFrac, mapSize);
			long speckCells = Cells(FrozenSpeckFrac, mapSize);

			GD.Print("==================================================================");
			GD.Print("  FRAG-4 SEED GALLERY (chat2/10) — render-only: does frag_4 generalize?");
			GD.Print("==================================================================");
			GD.Print($"MapSize   : {mapSize}   curve calibrated at {calibSize} (offshore off)");
			GD.Print($"seeds     : anchors {string.Join(", ", AnchorSeeds)} · fresh {string.Join(", ", seeds.FindAll(s => !anchorSet.Contains(s)))}");
			GD.Print($"FROZEN    : FragmentAmp {FrozenFragmentAmp} · freq {FrozenFragmentFreq}/map · window {FrozenBandCentre} ± {FrozenBandHalfWidth} · bitesOnly {FrozenBitesOnly} · " +
					 $"stretch {FrozenStretch} (band {FrozenBandStart}/{FrozenBandFeather}, sinker stretched {FrozenStretchSinker}) · speck revert < {speckCells} cells ({FrozenSpeckFrac:G2}) · offshore OFF · shelf OFF · labeling ON");
			GD.Print($"\"big\"     : ≥ {big:N0} cells at {mapSize} (the 07 mid threshold)");
			GD.Print($"batch     : {batchRoot}");
			GD.Print("==================================================================");

			GD.Print($"\n--- 0. CURVE (task-01 pool at {calibSize}, offshore off) ---");
			var (knots, calibration) = CalibrateCurve(calibSize, sea, anchors);
			GD.Print($"  {knots}");

			TerrainGenConfig Frozen(int size, int seed, string label, bool frag = true, bool revert = true, bool stretch = true) => new TerrainGenConfig
			{
				MapSize = size, Seed = seed, VariantLabel = label,
				Curve = true, ShelfDetail = false, CurveMode = CurveModeKind.Continuous,
				Knots = knots, Anchors = anchors, ClimbCalibration = calibration, LowlandCeilingM = 30f,
				CoastShelf = false, Offshore = new OffshoreSettings(),
				RegionLabeling = true, SpeckRevert = revert, MinLandComponentFrac = FrozenSpeckFrac,
				SouthStretch = stretch ? FrozenStretch : 0f, SouthBandStartFrac = FrozenBandStart, SouthBandFeatherFrac = FrozenBandFeather, StretchSinker = FrozenStretchSinker,
				FragmentAmp = frag ? FrozenFragmentAmp : 0f, FragmentFreqPerMapWidth = FrozenFragmentFreq,
				FragmentBandCentre = FrozenBandCentre, FragmentBandHalfWidth = FrozenBandHalfWidth, FragmentBitesOnly = FrozenBitesOnly,
			};

			// ═══ 1. THE ORACLE — no code change, same setting ═══
			GD.Print($"\n--- 1. ORACLE: the setting is the 09 frag_4 setting, and nothing upstream moved ---");
			var hard = new List<ShapingOracle.Check>();
			{
				var offCfg = Frozen(calibSize, AnchorSeeds[0], "off", frag: false, revert: false, stretch: false);
				Pass1Result p1 = Topography.Generate(offCfg);
				var curveOff = offCfg.Clone(); curveOff.Curve = false;
				string p1Dump = Path.Combine(ToolingPaths.BatchesRoot, p1Source, $"{AnchorSeeds[0]}_full", "height.f32");
				hard.Add(ShapingOracle.DumpRegression("a1", "curve OFF, stretch OFF, frag OFF == Phase-1 .f32 dump (the curve is untouched)", Shaping.Shape(p1, curveOff).Height, HeightField.Load(p1Dump, calibSize), calibSize, p1Dump));

				if (!skipAnchor)
				{
					foreach (int seed in AnchorSeeds)
					{
						// ⭐ a9 — the frozen setting at the 09 batch's size reproduces the 09 frag_4 field bit for bit.
						string t09Dump = Path.Combine(ToolingPaths.BatchesRoot, t09Source, $"{seed}_frag_4", "height.f32");
						var c9 = Frozen(AnchorCheckSize, seed, "frag_4");
						Pass1Result q9p = Topography.Generate(c9);
						Pass2Result q9 = Shaping.Shape(q9p, c9);
						hard.Add(ShapingOracle.DumpRegression("a9", $"frozen frag_4 at {AnchorCheckSize} == task-09 frag_4 dump [{seed}] (no code change, same setting)", q9.Height, HeightField.Load(t09Dump, AnchorCheckSize), AnchorCheckSize, t09Dump));

						// a8 — the stretch-2, frag-off baseline still equals the 08 field, and the interior is still locked against it.
						string t08Dump = Path.Combine(ToolingPaths.BatchesRoot, t08Source, $"{seed}_stretch_3", "height.f32");
						var c8 = Frozen(AnchorCheckSize, seed, "t08", frag: false, revert: false);
						Pass1Result q8p = Topography.Generate(c8);
						hard.Add(ShapingOracle.DumpRegression("a8", $"frag OFF, stretch 2 at {AnchorCheckSize} == task-08 stretch_3 dump [{seed}]", Shaping.Shape(q8p, c8).Height, HeightField.Load(t08Dump, AnchorCheckSize), AnchorCheckSize, t08Dump));
						var r = ShapingOracle.InteriorLocked(q8p, q9p, FrozenBandCentre, FrozenBandHalfWidth); r.Name += $" [{seed}, {AnchorCheckSize}]"; hard.Add(r);
					}
					// determinism at the check size
					var a = Topography.Generate(Frozen(AnchorCheckSize, AnchorSeeds[0], "det"));
					var b = Topography.Generate(Frozen(AnchorCheckSize, AnchorSeeds[0], "det"));
					var det = ShapingOracle.LabelsDeterministic(a, b); det.Name += $" [{AnchorSeeds[0]}, {AnchorCheckSize}]"; hard.Add(det);
				}
				foreach (var c in hard) GD.Print("  " + c);
			}

			// ═══ 2. THE GALLERY ═══
			GD.Print($"\n--- 2. THE GALLERY at {mapSize} ---");
			var rows = new List<Row>();
			var perSeed = new List<ShapingOracle.Check>();
			foreach (int seed in seeds)
			{
				var cfg = Frozen(mapSize, seed, "frag_4");
				Pass1Result p1 = Topography.Generate(cfg);
				Pass2Result p2 = Shaping.Shape(p1, cfg);
				var checks = new List<ShapingOracle.Check>
				{
					ShapingOracle.CentreIsLand(p1),
					ShapingOracle.TagCoastlineConsistent(p2, sea),
					ShapingOracle.ClassifyFidelity(p1, p2),
				};
				foreach (var c in checks) { c.Name += $" [{seed}]"; perSeed.Add(c); }
				bool ok = checks.TrueForAll(c => c.Passed);

				var (n, s) = Stats(p1.Regions, big);
				long landCells = p1.Regions.LandCells;
				var row = new Row
				{
					Seed = seed, Anchor = anchorSet.Contains(seed), N = n, S = s,
					MainlandCells = p1.Regions.Mainland.SizeCells, MainlandFrac = landCells == 0 ? 0 : p1.Regions.Mainland.SizeCells / (double)landCells,
					SpecksReverted = p1.RegionLedger?.RevertedComponents ?? 0, Ok = ok, Ms = p1.ElapsedMs,
				};
				row.Read = AutoRead(row);
				rows.Add(row);
				WriteSeed(batchRoot, p1, p2, sea, anchors, skipRaw);
				GD.Print($"  seed {seed,-11}{(row.Anchor ? " ⭐" : "  ")} N {n.All,3}/{n.Big,3} med {n.Med,6} largest {Largest(n.Largest)}   S {s.All,3}/{s.Big,3} med {s.Med,6} largest {Largest(s.Largest)}   mainland {row.MainlandCells:N0} ({row.MainlandFrac:P1} of land)  → {row.Read}  {(ok ? "ok" : "⚠ CHECK FAILED")}  {p1.ElapsedMs} ms");
			}

			bool allOk = hard.TrueForAll(c => c.Passed) && perSeed.TrueForAll(c => c.Passed);
			GD.Print($"\n  ORACLE: {(allOk ? "ALL HARD CHECKS PASS" : "*** FAILURES ***")}");
			foreach (var c in perSeed) if (!c.Passed) GD.PrintErr("  " + c);

			WriteTable(batchRoot, mapSize, rows, big, speckCells);
			WriteIndex(batchRoot, mapSize, calibSize, rows, big, speckCells, hard, perSeed, allOk);

			GD.Print("\n==================================================================");
			GD.Print($"  DONE — {batchRoot}");
			GD.Print($"  ORACLE {(allOk ? "HARD CHECKS ALL PASS" : "*** FAILURES — see the table ***")}");
			GD.Print("==================================================================");
			GetTree().Quit(allOk ? 0 : 3);
		}

		// ---- the instrument --------------------------------------------------

		private static long Cells(float frac, int size) => Math.Max(1L, (long)Math.Round(frac * (double)size * size));

		private static (HemiStats north, HemiStats south) Stats(RegionLabels l, long big)
		{
			var n = new List<long>(); var s = new List<long>();
			foreach (var r in l.Regions)
			{
				if (r.IsMainland) continue;
				if (r.Hemisphere == RegionLabeling.HemiSouth) s.Add(r.SizeCells); else n.Add(r.SizeCells);
			}
			return (Make(n, big), Make(s, big));
		}

		private static HemiStats Make(List<long> sizes, long big)
		{
			sizes.Sort();
			var h = new HemiStats { All = sizes.Count, Hist = new int[RegionLabeling.HistogramEdges.Length + 1] };
			if (sizes.Count == 0) return h;
			double sum = 0;
			foreach (long v in sizes) { h.Hist[RegionLabeling.HistogramBin(v)]++; if (v >= big) h.Big++; sum += v; }
			h.Min = sizes[0]; h.Med = sizes[sizes.Count / 2]; h.Max = sizes[^1]; h.Mean = sum / sizes.Count;
			int k = Math.Min(3, sizes.Count); h.Largest = new long[k];
			for (int i = 0; i < k; i++) h.Largest[i] = sizes[sizes.Count - 1 - i];
			return h;
		}

		/// <summary>
		/// The one-word NUMERIC read — a stated rule, not a judgement: "too solid" if fewer than 12 big
		/// (≥ the 07 mid threshold) islands detached across both hemispheres (the 09 anchors had 23–27);
		/// "shredded" if fewer than a quarter of the islands are big (all specks, no bigs); else "good
		/// spread". The eye's read is in the report.
		/// </summary>
		private static string AutoRead(Row r)
		{
			int all = r.N.All + r.S.All, bigs = r.N.Big + r.S.Big;
			if (bigs < 12) return "too solid";
			if (all > 0 && bigs < all * 0.25) return "shredded";
			return "good spread";
		}

		// ---- the curve --------------------------------------------------------

		private static (CurveKnots, ClimbCalibration) CalibrateCurve(int calibSize, float sea, CurveAnchors anchors)
		{
			var rawPool = new LandHistogram(sea);
			var pass1 = new Dictionary<int, Pass1Result>();
			foreach (int s in CalibrationSeeds)
			{
				var p1 = Topography.Generate(new TerrainGenConfig { MapSize = calibSize, Seed = s });
				pass1[s] = p1;
				rawPool.Accumulate(p1.Height, calibSize);
			}
			var knots = new CurveKnots(2, "v2_balanced",
				rawPool.Quantile(CurveKnots.Percentiles[0]), rawPool.Quantile(CurveKnots.Percentiles[1]),
				rawPool.Quantile(CurveKnots.Percentiles[2]), rawPool.Quantile(CurveKnots.Percentiles[3]),
				rawPool.Quantile(CurveKnots.Percentiles[4]), rawPool.Quantile(CurveKnots.Percentiles[5]));
			float ceilingRaw = knots.K2;
			var rawAbove = new LandHistogram(sea);
			var outAbove = new LandHistogram(sea);
			foreach (int s in CalibrationSeeds)
			{
				var scfg = new TerrainGenConfig
				{
					MapSize = calibSize, Seed = s, Curve = true, ShelfDetail = true,
					CurveMode = CurveModeKind.Staircase, Knots = knots, Anchors = anchors, VariantLabel = "staircase",
				};
				Pass2Result st = Shaping.Shape(pass1[s], scfg);
				rawAbove.AccumulateWhere(pass1[s].Height, pass1[s].Height, calibSize, ceilingRaw);
				outAbove.AccumulateWhere(st.Height,       pass1[s].Height, calibSize, ceilingRaw);
			}
			var pcts = ClimbCalibration.DefaultPercentiles;
			var rawQ = new float[pcts.Length]; var outQ = new float[pcts.Length];
			for (int i = 0; i < pcts.Length; i++) { rawQ[i] = rawAbove.Quantile(pcts[i]); outQ[i] = outAbove.Quantile(pcts[i]); }
			var cal = ClimbCalibration.FromPercentiles(pcts, rawQ, outQ, ceilingRaw,
				HeightCurve.EffectiveSpikeMax(pass1[CalibrationSeeds[0]].HMaxSeed, knots, anchors),
				anchors.RedCeil, anchors.PeakCap, mountainLift: 1.0f, peakSharpness: 1.0f);
			return (knots, cal);
		}

		// ---- output -----------------------------------------------------------

		private static void WriteSeed(string batchRoot, Pass1Result p1, Pass2Result p2, float sea, CurveAnchors anchors, bool skipRaw)
		{
			string dir = Path.Combine(batchRoot, $"{p2.Seed}");
			DirAccess.MakeDirRecursiveAbsolute(dir);
			GrayscaleRenderer.SavePng(p2.Height, p2.MapSize, Path.Combine(dir, "grayscale.png"));
			if (!skipRaw) HeightField.Save(p2.Height, p2.MapSize, Path.Combine(dir, "height.f32"));
			var look = new LookConfig
			{
				Name = "hillshade_even", Palette = ReliefPalette.Kind.ProvisionalEven,
				ZExaggeration = 18f, LightAzimuth = 315f, LightAltitude = 45f, HillshadeStrength = 0.30f, SeaLevel = sea,
			};
			Image map = ReliefRenderer.Render(p2.Height, p2.MapSize, look);
			LegendRenderer.WithLegend(map, look.Palette, sea, anchors.PeakCap, $"FRAG_4 {p2.Seed}").SavePng(Path.Combine(dir, "relief.png"));
			var led = p1.RegionLedger;
			RegionOverlayRenderer.SavePng(p1.Regions, led != null && led.RevertOn ? p1.RegionsPre : null, p1.MapSize,
				led?.RevertedComponents ?? 0, led?.ThresholdCells ?? 0, Path.Combine(dir, "regions.png"));
		}

		private static string HistRow(int[] h)
		{
			var sb = new StringBuilder();
			for (int i = 0; i < h.Length; i++) { if (i > 0) sb.Append(" · "); sb.Append(h[i]); }
			return sb.ToString();
		}

		private static string Largest(long[] l) => l.Length == 0 ? "—" : string.Join(" / ", Array.ConvertAll(l, v => v.ToString("N0")));

		private static string TableMarkdown(List<Row> rows, long big)
		{
			var sb = new StringBuilder();
			var histHead = new StringBuilder();
			for (int i = 0; i <= RegionLabeling.HistogramEdges.Length; i++) { if (i > 0) histHead.Append(" · "); histHead.Append(RegionLabeling.HistogramLabel(i)); }
			sb.AppendLine($"| Seed | read | **N islands all / ≥ {big:N0}** | N median / largest three | N histogram ({histHead}) | **S islands all / ≥ {big:N0}** | S median / largest three | S histogram | mainland cells (% of land) | specks reverted | oracle |");
			sb.AppendLine("|---|---|---|---|---|---|---|---|---|---|---|");
			foreach (var r in rows)
				sb.AppendLine($"| `{r.Seed}`{(r.Anchor ? " ⭐ anchor" : "")} | **{r.Read}** | **{r.N.All} / {r.N.Big}** | {r.N.Med} / {Largest(r.N.Largest)} | {HistRow(r.N.Hist)} | **{r.S.All} / {r.S.Big}** | {r.S.Med} / {Largest(r.S.Largest)} | {HistRow(r.S.Hist)} | {r.MainlandCells:N0} ({r.MainlandFrac:P1}) | {r.SpecksReverted} | {(r.Ok ? "pass" : "**FAIL**")} |");
			return sb.ToString();
		}

		private static void WriteTable(string batchRoot, int mapSize, List<Row> rows, long big, long speckCells)
		{
			var sb = new StringBuilder();
			sb.AppendLine($"# The count/size table — frag_4 frozen, {rows.Count} seeds at {mapSize}");
			sb.AppendLine();
			sb.AppendLine($"Islands = non-mainland 8-connected land components of the classify field; hemisphere by centroid; \"big\" = ≥ {big:N0} cells; speck revert < {speckCells} cells.");
			sb.AppendLine("Read rule (numeric, stated): **too solid** if < 12 big islands across both hemispheres · **shredded** if big < 25 % of all · else **good spread**. The eye's read is in the report.");
			sb.AppendLine();
			sb.Append(TableMarkdown(rows, big));
			WriteText(Path.Combine(batchRoot, "count_size_table.md"), sb.ToString());

			var csv = new StringBuilder();
			csv.AppendLine("seed,anchor,read,n_all,n_big,n_med,n_mean,n_max,n_largest,n_hist,s_all,s_big,s_med,s_mean,s_max,s_largest,s_hist,mainland_cells,mainland_frac,specks_reverted,oracle,ms");
			var ic = System.Globalization.CultureInfo.InvariantCulture;
			foreach (var r in rows)
				csv.AppendLine(string.Join(",", r.Seed, r.Anchor ? 1 : 0, r.Read,
					r.N.All, r.N.Big, r.N.Med, r.N.Mean.ToString("F1", ic), r.N.Max, "\"" + Largest(r.N.Largest) + "\"", "\"" + HistRow(r.N.Hist) + "\"",
					r.S.All, r.S.Big, r.S.Med, r.S.Mean.ToString("F1", ic), r.S.Max, "\"" + Largest(r.S.Largest) + "\"", "\"" + HistRow(r.S.Hist) + "\"",
					r.MainlandCells, r.MainlandFrac.ToString("F4", ic), r.SpecksReverted, r.Ok ? "pass" : "FAIL", r.Ms));
			WriteText(Path.Combine(batchRoot, "count_size_table.csv"), csv.ToString());
		}

		private static void WriteIndex(string batchRoot, int mapSize, int calibSize, List<Row> rows, long big, long speckCells,
			List<ShapingOracle.Check> hard, List<ShapingOracle.Check> perSeed, bool allOk)
		{
			var sb = new StringBuilder();
			sb.AppendLine($"# Batch 10 — frag_4 seed gallery: does the look generalize? (render-only, {mapSize})");
			sb.AppendLine();
			sb.AppendLine("**A contact sheet, not a tune.** Every plate is the SAME setting — chat2/09's `frag_4`, frozen — across the two");
			sb.AppendLine("seeds it was judged on (⭐ anchors) and six fresh seeds chosen before any render. The question: does a coherent");
			sb.AppendLine("mainland with medium/large lobes detaching all around generalize, or do some seeds come out too solid or shredded?");
			sb.AppendLine();
			sb.AppendLine("## The frozen setting");
			sb.AppendLine();
			sb.AppendLine($"`FragmentAmp {FrozenFragmentAmp}` · `FragmentFreqPerMapWidth {FrozenFragmentFreq}` · window `{FrozenBandCentre} ± {FrozenBandHalfWidth}` · bites-only `{FrozenBitesOnly}` · " +
						  $"`SouthStretch {FrozenStretch}` (band `{FrozenBandStart}` / feather `{FrozenBandFeather}`, sinker stretched `{FrozenStretchSinker}`) · speck revert < {speckCells} cells (`{FrozenSpeckFrac:G2}` of the map) · " +
						  "offshore OFF · shelf OFF · region labeling ON · the tagged curve (calibrated on task 01's pool at " + calibSize + "). Pinned explicitly in `FragGalleryTool` — nothing is left to a default.");
			sb.AppendLine();
			sb.AppendLine("## ⭐ The contact sheet");
			sb.AppendLine();
			sb.AppendLine("Open each seed's `regions.png` (the key view — detached pieces in colour) beside its `relief.png`.");
			sb.AppendLine();
			sb.AppendLine("| Seed | read | overlay | relief | N islands all / big | S islands all / big | largest N / S piece |");
			sb.AppendLine("|---|---|---|---|---|---|---|");
			foreach (var r in rows)
				sb.AppendLine($"| `{r.Seed}`{(r.Anchor ? " ⭐ anchor" : "")} | **{r.Read}** | [`{r.Seed}/regions.png`]({r.Seed}/regions.png) | [`{r.Seed}/relief.png`]({r.Seed}/relief.png) | {r.N.All} / {r.N.Big} | {r.S.All} / {r.S.Big} | {r.N.Max:N0} / {r.S.Max:N0} |");
			sb.AppendLine();
			sb.AppendLine($"## ⭐ The count/size table — hemisphere-split, with the size distribution");
			sb.AppendLine();
			sb.Append(TableMarkdown(rows, big));
			sb.AppendLine();
			sb.AppendLine("Read rule (numeric, stated): **too solid** if < 12 big islands across both hemispheres (the anchors had 23–27 at 4096) · **shredded** if big < 25 % of all · else **good spread**. The eye's read is in the report. Also as `count_size_table.md` / `.csv`.");
			sb.AppendLine();
			sb.AppendLine("## ⚠ The palette is PROVISIONAL");
			sb.AppendLine();
			sb.AppendLine("`ProvisionalEven`, flagged. The grayscale is the honest instrument; the overlay is the region layer's data.");
			sb.AppendLine();
			sb.AppendLine("## The oracle (render-only: the setting is the 09 setting, nothing upstream moved)");
			sb.AppendLine();
			sb.AppendLine(ShapingOracle.ToMarkdownTable(hard));
			sb.AppendLine("Per seed (centre-is-land m · tag/coastline k · classify b):");
			sb.AppendLine();
			sb.AppendLine(ShapingOracle.ToMarkdownTable(perSeed));
			sb.AppendLine($"**{(allOk ? "ALL HARD CHECKS PASS" : "⚠⚠ FAILURES — do not judge this batch")}**");
			sb.AppendLine();
			sb.AppendLine("## Disposability");
			sb.AppendLine();
			sb.AppendLine("| Artifact | Keep? |");
			sb.AppendLine("|---|---|");
			sb.AppendLine("| `regions.png`, `relief.png`, `INDEX.md`, `count_size_table.md` / `.csv` | **keep** |");
			sb.AppendLine("| `grayscale.png` | ♻ regenerable from the `.f32` |");
			sb.AppendLine("| `height.f32` | ♻ regenerable from seed + the frozen setting — large (256 MB each), clear freely |");
			sb.AppendLine("| `scratch/` | persistent by rule; never cleaned |");
			sb.AppendLine();
			sb.AppendLine($"Gallery at {mapSize}, curve calibrated at {calibSize} with offshore off. {WorldScale.Describe()}.");
			WriteText(Path.Combine(batchRoot, "INDEX.md"), sb.ToString());
		}

		private static void WriteText(string path, string text)
		{
			using var f = Godot.FileAccess.Open(path, Godot.FileAccess.ModeFlags.Write);
			if (f == null) { GD.PrintErr($"could not write {path}"); return; }
			f.StoreString(text);
		}

		// ---- env helpers --------------------------------------------------------

		private static string EnvStr(string k, string fallback)
		{
			string v = System.Environment.GetEnvironmentVariable(k);
			return string.IsNullOrWhiteSpace(v) ? fallback : v;
		}

		private static int EnvInt(string k, int fallback)
			=> int.TryParse(EnvStr(k, null) ?? "", out int v) ? v : fallback;

		private static int[] EnvSeeds(string k, int[] fallback)
		{
			string v = EnvStr(k, null);
			if (v == null) return fallback;
			var outp = new List<int>();
			foreach (string part in v.Split(',', StringSplitOptions.RemoveEmptyEntries))
				if (int.TryParse(part.Trim(), out int s) && s > 0) outp.Add(s);
			return outp.Count > 0 ? outp.ToArray() : fallback;
		}
	}
}