// The per-hull-class ship census, checked against the census the game itself
// wrote.
//
// Every save carries the archived per-player turn record for its own frame,
// and six of that record's fields are the ship census: `shpt` and `satt` in
// each of the three `cls` groups. Neither the hull size nor the platform flag
// that produce those six numbers is on the wire -- both are recomputed from
// the section catalog -- so this test rebuilds them from $SOTS_DATA_DIR and
// compares against bytes the original produced.
//
// It is NOT a live comparison against the running game: it is a comparison
// against what the game archived. Needs $SOTS_SAVES_DIR and $SOTS_DATA_DIR;
// skips cleanly when either is unset. No save and no game data enters the
// repo.
#include <array>
#include <cstdio>
#include <cstdlib>
#include <map>
#include <string>
#include <vector>

#include <dirent.h>

#include "game/data/catalog.h"
#include "game/design/hull.h"
#include "mars/stream/save.h"

using namespace game::data;
using namespace game::design;
namespace shapes = mars::stream::shapes;

static int failures = 0;
#define CHECK(c)                                                     \
    do {                                                             \
        if (!(c)) {                                                  \
            std::printf("FAIL %s:%d  %s\n", __FILE__, __LINE__, #c); \
            ++failures;                                              \
        }                                                            \
    } while (0)

namespace {

// One save `Des` record, classified. The record names its sections as
// (species index, id in that race's manifest), which is exactly what the
// catalog's id lookup takes.
HullClass classify_saved_design(const Catalog& cat, const shapes::Design& d) {
    std::vector<const ShipSectionDef*> found;
    int unresolved = 0;
    for (const shapes::DesignSection& s : d.sections) {
        const int species = s.sec.a, id = s.sec.b;
        if (species == 0 && id == 0) continue;   // empty slot
        if (species < 0 || species >= kSpeciesCount) {
            ++unresolved;
            continue;
        }
        const ShipSectionDef* def =
            cat.section_by_id(species_name(static_cast<Species>(species)), id);
        if (!def) {
            ++unresolved;
            continue;
        }
        found.push_back(def);
    }
    HullClass h = classify_sections(found);
    h.unresolved_sections = unresolved;
    return h;
}

const shapes::PlayerTurnStats* archived(const shapes::PlayerTurnHistory& hist, std::int32_t turn) {
    for (const shapes::PlayerTurnStats& s : hist.stats)
        if (s.trn == turn) return &s;
    return nullptr;
}

}  // namespace

int main() {
    const char* savesDir = std::getenv("SOTS_SAVES_DIR");
    const char* dataDir = std::getenv("SOTS_DATA_DIR");
    if (!savesDir || !*savesDir || !dataDir || !*dataDir) {
        std::printf("game_design_census: SOTS_SAVES_DIR / SOTS_DATA_DIR unset, skipped\n");
        return 0;
    }
    DIR* dir = opendir(savesDir);
    if (!dir) {
        std::fprintf(stderr, "game_design_census: cannot open %s\n", savesDir);
        return 1;
    }
    std::vector<std::string> saves;
    while (struct dirent* e = readdir(dir)) {
        const std::string n = e->d_name;
        if (n.size() > 4 && n.compare(n.size() - 4, 4, ".sav") == 0)
            saves.push_back(std::string(savesDir) + "/" + n);
    }
    closedir(dir);
    if (saves.empty()) {
        std::printf("game_design_census: no .sav in %s, skipped\n", savesDir);
        return 0;
    }

    const Catalog cat = load_catalog(dataDir);
    if (cat.sections.empty()) {
        std::fprintf(stderr, "game_design_census: no sections under %s\n", dataDir);
        return 1;
    }

    int files = 0, compared = 0, mismatches = 0, nonzero = 0;
    int designsSeen = 0, designsUnclassified = 0, shipsWithoutDesign = 0;
    int hullAssignmentDiffers = 0;
    std::array<int, 6> nonzeroByLeaf{};   // cls0.shpt, cls0.satt, cls1.shpt, ...

    for (const std::string& path : saves) {
        mars::stream::SaveDocument doc;
        try {
            doc = mars::stream::read_save_file(path);
        } catch (const std::exception& ex) {
            std::printf("  %s: unreadable (%s), skipped\n", path.c_str(), ex.what());
            continue;
        }
        if (doc.count(mars::stream::Issue::Error)) {
            std::printf("  %s: parse errors, skipped\n", path.c_str());
            continue;
        }
        ++files;
        const auto& sim = doc.game.sim;

        // Design ids are unique across the whole game, so one map serves every
        // player's fleets. Legacy (rider) designs are in the same id space.
        std::map<std::int32_t, HullClass> byId;
        for (const shapes::PlayerEntry& pe : sim.players) {
            for (const auto* list : {&pe.player.designs, &pe.player.legacyDesigns}) {
                for (const shapes::DesignEntry& de : *list) {
                    HullClass h = classify_saved_design(cat, de.des);
                    ++designsSeen;
                    if (!h.ok()) ++designsUnclassified;
                    // First-wins vs last-wins: rule A6 makes every shipped
                    // design class-homogeneous, so a difference here would be
                    // news. Counted rather than asserted.
                    int first = -1;
                    for (const shapes::DesignSection& s : de.des.sections) {
                        if (s.sec.a == 0 && s.sec.b == 0) continue;
                        if (s.sec.a < 0 || s.sec.a >= kSpeciesCount) continue;
                        if (const ShipSectionDef* d2 =
                                cat.section_by_id(species_name(static_cast<Species>(s.sec.a)), s.sec.b)) {
                            first = hull_size(d2->section_class);
                            break;
                        }
                    }
                    if (h.ok() && first >= 0 && first != h.hull_size) ++hullAssignmentDiffers;
                    byId[de.desID] = h;
                }
            }
        }

        // Player object id -> index into sim.players, which is the index the
        // turn-statistics archive is keyed by.
        std::map<std::int32_t, std::size_t> playerIndex;
        for (std::size_t i = 0; i < sim.players.size(); ++i) playerIndex[sim.players[i].playerID] = i;

        std::vector<ShipCensus> built(sim.players.size());
        for (const shapes::FleetEntry& fe : sim.fleets) {
            auto it = playerIndex.find(fe.flt.pid);
            if (it == playerIndex.end()) continue;      // unowned / NPC-pool fleet
            ShipCensus& c = built[it->second];
            for (const shapes::ShipEntry& se : fe.flt.ships) {
                auto d = byId.find(se.ship.desID);
                if (d == byId.end() || !d->second.ok()) {
                    ++shipsWithoutDesign;
                    continue;
                }
                c.add(d->second);
            }
        }

        int fileCompared = 0, fileBad = 0;
        for (std::size_t i = 0; i < sim.players.size(); ++i) {
            if (i >= sim.turnstats.players.size()) break;
            const shapes::PlayerTurnStats* stored =
                archived(sim.turnstats.players[i].hist, sim.frame);
            if (!stored) continue;
            for (std::size_t k = 0; k < stored->classes.size() && k < 3; ++k) {
                const shapes::ClassStats& cs = stored->classes[k];
                const int wantShips = cs.shpt, wantPlat = cs.satt;
                const int gotShips = built[i].ships[k], gotPlat = built[i].platforms[k];
                for (int which = 0; which < 2; ++which) {
                    const int want = which ? wantPlat : wantShips;
                    const int got = which ? gotPlat : gotShips;
                    ++compared;
                    ++fileCompared;
                    if (want != 0) {
                        ++nonzero;
                        ++nonzeroByLeaf[k * 2 + static_cast<std::size_t>(which)];
                    }
                    if (want != got) {
                        ++mismatches;
                        ++fileBad;
                        std::printf("  %s p%zu cls%zu %s: built %d != archived %d\n", path.c_str(), i,
                                    k, which ? "satt" : "shpt", got, want);
                    }
                }
            }
        }
        std::printf("  %-34s turn %3d  %3d compared  %d mismatched\n",
                    path.c_str(), sim.frame, fileCompared, fileBad);
    }

    CHECK(files > 0);
    CHECK(compared > 0);
    CHECK(mismatches == 0);
    CHECK(shipsWithoutDesign == 0);
    CHECK(designsUnclassified == 0);

    std::printf("game_design_census: %d saves, %d designs, %d census leaves, %d mismatched\n",
                files, designsSeen, compared, mismatches);
    std::printf("  coverage: %d of %d leaves are NONZERO in the archive; per leaf "
                "(cls0 shpt/satt, cls1 shpt/satt, cls2 shpt/satt) = %d/%d %d/%d %d/%d\n",
                nonzero, compared, nonzeroByLeaf[0], nonzeroByLeaf[1], nonzeroByLeaf[2],
                nonzeroByLeaf[3], nonzeroByLeaf[4], nonzeroByLeaf[5]);
    std::printf("  a zero leaf agrees for free -- the leaves with no nonzero observation are "
                "UNEXERCISED, not verified\n");
    std::printf("  designs whose first- and last-resolved section disagree on hull size: %d "
                "(rule A6 predicts 0)\n", hullAssignmentDiffers);
    if (failures) std::printf("game_design_census: %d FAILURES\n", failures);
    return failures ? 1 : 0;
}