planetsim/test_geography.cpp

// Headless test for the geography / atlas stage (named feature extraction + naming). No display.
//
//   g++ -std=c++17 -O2 -Isrc/sim test_geography.cpp src/sim/IcoSphere.cpp src/sim/Planet.cpp \
//       src/sim/PlanetTectonics.cpp src/sim/PlanetDrift.cpp src/sim/PlanetErosion.cpp \
//       src/sim/PlanetHydrology.cpp src/sim/PlanetBiomes.cpp src/sim/PlanetClimate.cpp \
//       src/sim/PlanetLive.cpp src/sim/PlanetOcean.cpp src/sim/PlanetWeather.cpp \
//       src/sim/PlanetVolcano.cpp src/sim/PlanetBiota.cpp src/sim/PlanetFloraGen.cpp \
//       src/sim/PlanetFaunaGen.cpp src/sim/PlanetFungiGen.cpp src/sim/NameGen.cpp \
//       src/sim/PlanetGeography.cpp src/sim/PlanetIO.cpp -o /tmp/tg && /tmp/tg
//
// Verifies: extraction (continents/oceans/ranges/rivers/lakes), per-cell membership consistency,
// names non-empty/unique/deterministic, RNG isolation from tectonics, and a v17 save round-trip.

#include "Planet.hpp"
#include "NameGen.hpp"
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <set>
#include <sstream>

static int failures = 0;
static void check(bool cond, const char* what) {
    std::printf("  [%s] %s\n", cond ? "PASS" : "FAIL", what);
    if (!cond) ++failures;
}

static void settle(Planet& p, int maxSteps = 800) {
    int run = 0;
    for (int s = 0; s < maxSteps; ++s) {
        double mc = p.step();
        if (mc < 2.0) { if (++run >= 3) break; } else run = 0;
    }
    p.computeClimate();
    p.classifyBiomes();
}
static void drift(Planet& p, int iters) {
    p.drifting = true;
    for (int k = 0; k < iters; ++k) { double dt = p.cflDtMy(); p.advect(dt); p.step(); p.erode(dt); }
}

static int countKind(const Planet& p, FeatureKind k) {
    int c = 0; for (const GeoFeature& f : p.geography()) if (f.kind == k) ++c; return c;
}

int main() {
    PlanetConfig cfg; cfg.subdivisions = 5; cfg.seed = 7777;
    Planet p; p.generate(cfg); settle(p); drift(p, 120);
    const int n = (int)p.cells.size();
    const double sea = p.cfg.seaLevel;

    std::printf("Geography: NameGen\n");
    std::string a1 = namegen::makeName(123, 0), a2 = namegen::makeName(123, 0);
    check(!a1.empty() && a1 == a2, "makeName deterministic + non-empty");
    check(namegen::makeName(124, 0) != a1, "different seeds give different names (usually)");
    check(namegen::bankForRegion(cfg.seed, 5) == namegen::bankForRegion(cfg.seed, 5), "bankForRegion deterministic");

    std::printf("Geography: extraction\n");
    p.generateGeography();
    const auto& F = p.geography();
    check(!F.empty(), "generateGeography produces features");
    int continents = countKind(p, FeatureKind::Continent), islands = countKind(p, FeatureKind::Island);
    int oceans = countKind(p, FeatureKind::Ocean), seas = countKind(p, FeatureKind::Sea);
    int ranges = countKind(p, FeatureKind::MountainRange), peaks = countKind(p, FeatureKind::Peak);
    int rivers = countKind(p, FeatureKind::River), lakes = countKind(p, FeatureKind::Lake);
    std::printf("    continents %d islands %d | oceans %d seas %d | ranges %d peaks %d | rivers %d lakes %d\n",
                continents, islands, oceans, seas, ranges, peaks, rivers, lakes);
    check(continents + islands >= 1, "at least one land mass");
    check(oceans >= 1, "at least one ocean");

    std::printf("Geography: per-cell membership consistency\n");
    const auto& land = p.cellLand(); const auto& water = p.cellWater();
    const auto& range = p.cellRange();
    check((int)land.size() == n && (int)water.size() == n, "index arrays sized n");
    bool landOk = true, waterOk = true, rangeOk = true, idxOk = true;
    for (int i = 0; i < n; ++i) {
        bool isLand = p.cells[i].elevation > sea;
        if (isLand && land[i] < 0) landOk = false;            // every land cell has a continent/island
        if (!isLand && land[i] >= 0) landOk = false;          // ocean cells aren't a land feature
        if (!isLand && water[i] < 0) waterOk = false;         // every ocean cell has a water feature
        if (range[i] >= 0 && !(p.cells[i].elevation > p.cfg.geoMountainElev)) rangeOk = false;  // range cells are high
        for (int v : {land[i], water[i], range[i]})
            if (v >= (int)F.size()) idxOk = false;
    }
    check(landOk, "land cells map to a continent/island; ocean cells don't");
    check(waterOk, "ocean cells map to an ocean/sea feature");
    check(rangeOk, "mountain-range cells are all above geoMountainElev");
    check(idxOk, "per-cell feature indices are in range");

    std::printf("Geography: features anchor on the right terrain\n");
    bool anchorsOk = true;
    for (const GeoFeature& f : F) {
        const Cell& c = p.cells[f.anchorCell];
        bool landKind = (f.kind == FeatureKind::Continent || f.kind == FeatureKind::Island ||
                         f.kind == FeatureKind::MountainRange || f.kind == FeatureKind::Peak ||
                         f.kind == FeatureKind::River || f.kind == FeatureKind::Lake);
        bool oceanKind = (f.kind == FeatureKind::Ocean || f.kind == FeatureKind::Sea);
        if (landKind && c.elevation <= sea) anchorsOk = false;
        if (oceanKind && c.elevation > sea) anchorsOk = false;
    }
    check(anchorsOk, "land features anchor on land, ocean features on water");

    if (rivers > 0) {
        std::printf("Geography: a named river traces downstream to a sink/ocean\n");
        const auto& fl = p.flowTo(); int riverCell = -1;
        for (int i = 0; i < n; ++i) if (p.cellRiver()[i] >= 0) { riverCell = i; break; }
        bool reaches = false;
        for (int cur = riverCell, guard = 0; cur >= 0 && guard < n; ++guard) {
            int d = fl[cur];
            if (d < 0 || p.cells[d].elevation <= sea) { reaches = true; break; }
            cur = d;
        }
        check(riverCell >= 0 && reaches, "a river cell flows down to an ocean/sink");
    }

    std::printf("Geography: names non-empty + unique\n");
    bool namesOk = true; std::set<std::string> seen;
    for (const GeoFeature& f : F) {
        if (f.name.empty()) namesOk = false;
        if (!seen.insert(f.name).second) namesOk = false;     // no duplicates
    }
    check(namesOk, "every feature has a unique non-empty name");

    std::printf("Geography: determinism (same seed -> identical atlas)\n");
    Planet q; q.generate(cfg); settle(q); drift(q, 120); q.generateGeography();
    bool sameAtlas = (q.geography().size() == F.size());
    if (sameAtlas)
        for (size_t i = 0; i < F.size(); ++i)
            if (q.geography()[i].kind != F[i].kind || q.geography()[i].anchorCell != F[i].anchorCell
                || q.geography()[i].name != F[i].name) { sameAtlas = false; break; }
    check(sameAtlas, "generateGeography is deterministic");

    std::printf("Geography: RNG isolation from tectonics\n");
    Planet x; x.generate(cfg); settle(x);
    Planet y; y.generate(cfg); settle(y);
    for (int k = 0; k < 40; ++k) {
        double dtx = x.cflDtMy(); x.advect(dtx); x.step(); x.erode(dtx);
        double dty = y.cflDtMy(); y.advect(dty); y.step(); y.erode(dty);
        if (k == 20) y.generateGeography();          // must not touch the tectonic RNG stream
    }
    bool terrainSame = true;
    for (int i = 0; i < n; ++i) if (std::fabs(x.cells[i].elevation - y.cells[i].elevation) > 1e-9) terrainSame = false;
    check(terrainSame, "generateGeography never perturbs tectonic evolution");

    std::printf("Geography: save v17 round-trip\n");
    {
        std::stringstream ss(std::ios::in | std::ios::out | std::ios::binary);
        p.writeState(ss);
        Planet r;
        bool ok = r.readState(ss, true, true, true, true, true, true, true, true);
        check(ok, "readState accepts a v17 stream");
        bool match = (r.geography().size() == F.size());
        if (match)
            for (size_t i = 0; i < F.size(); ++i)
                if (r.geography()[i].name != F[i].name || r.geography()[i].kind != F[i].kind
                    || r.geography()[i].anchorCell != F[i].anchorCell) { match = false; break; }
        check(match, "geography round-trips through save");
        check(r.cellLand() == p.cellLand() && r.cellRiver() == p.cellRiver(), "per-cell region arrays round-trip");
    }

    std::printf(failures ? "\nFAILURES: %d\n" : "\nALL GEOGRAPHY CHECKS PASSED\n", failures);
    return failures ? 1 : 0;
}