// SPDX-License-Identifier: LGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

// Crafter.DB against a cleaned-up copy of Nostro's hand-rolled format
// (iostream, uint16-prefixed strings inline, linear scans) on the five
// operations Nostro performs. Prints a table; never fails. Runs on 100k
// rows so a full suite stays fast; raise `rowCount` for a serious run.

import Crafter.DB;
import std;

using namespace Crafter;
namespace fs = std::filesystem;
using TimePoint = std::chrono::system_clock::time_point;
using Clock = std::chrono::steady_clock;

namespace {
    enum class Currency : std::uint16_t { Euro };

    struct Transaction {
        std::string name;
        std::string bic;
        std::string iban;
        std::string description;
        Currency currency;
        std::int64_t amount;
        TimePoint timePoint;

        static constexpr std::uint32_t version = 1;
        static constexpr auto orderedBy = &Transaction::timePoint;
    };

    inline constexpr DB::Column<&Transaction::iban> iban{};
    inline constexpr DB::Column<&Transaction::timePoint> timePoint{};

    constexpr std::uint64_t rowCount = 100'000;

    std::vector<Transaction> MakeRows() {
        std::mt19937_64 rng(42);
        const std::array<std::string_view, 6> names = { "Albert Heijn", "Jumbo Supermarkten", "NS Reizigers", "Vattenfall", "Bol.com", "Gemeente Utrecht" };
        const std::array<std::string_view, 4> bics = { "ABNANL2A", "RABONL2U", "INGBNL2A", "TRIONL2U" };
        std::vector<std::string> ibans;
        for (std::uint32_t i = 0; i < 1000; i++) ibans.push_back(std::format("NL{:02}ABNA{:010}", i % 97, 417164300u + i));
        std::vector<Transaction> rows;
        rows.reserve(rowCount);
        for (std::uint64_t i = 0; i < rowCount; i++) {
            rows.push_back({ std::string(names[rng() % names.size()]), std::string(bics[rng() % bics.size()]), ibans[rng() % ibans.size()], std::format("payment {} for order {}", i, rng() % 100000), Currency::Euro, static_cast<std::int64_t>(rng() % 200000) - 100000, TimePoint(std::chrono::microseconds(1'700'000'000'000'000 + i * 60'000'000)) });
        }
        return rows;
    }

    // --- the Nostro format, cleaned up -----------------------------------------
    namespace Nostro {
        void WriteString(std::ofstream& file, std::string_view str) {
            const std::uint16_t size = static_cast<std::uint16_t>(str.size());
            file.write(reinterpret_cast<const char*>(&size), sizeof(size));
            file.write(str.data(), size);
        }

        void ReadString(std::ifstream& file, std::string& str) {
            std::uint16_t size;
            file.read(reinterpret_cast<char*>(&size), sizeof(size));
            str.resize(size);
            file.read(str.data(), size);
        }

        void Save(const fs::path& path, std::span<const Transaction> rows) {
            std::ofstream file(path, std::ios::binary | std::ios::app);
            for (const Transaction& tr : rows) {
                WriteString(file, tr.name);
                WriteString(file, tr.bic);
                WriteString(file, tr.iban);
                WriteString(file, tr.description);
                file.write(reinterpret_cast<const char*>(&tr.amount), sizeof(tr.amount));
                file.write(reinterpret_cast<const char*>(&tr.currency), sizeof(Currency));
                const std::int64_t time = std::chrono::duration_cast<std::chrono::microseconds>(tr.timePoint.time_since_epoch()).count();
                file.write(reinterpret_cast<const char*>(&time), sizeof(time));
            }
        }

        bool Load(std::ifstream& file, Transaction& tr) {
            if (file.peek() == std::ifstream::traits_type::eof()) return false;
            ReadString(file, tr.name);
            ReadString(file, tr.bic);
            ReadString(file, tr.iban);
            ReadString(file, tr.description);
            file.read(reinterpret_cast<char*>(&tr.amount), sizeof(tr.amount));
            file.read(reinterpret_cast<char*>(&tr.currency), sizeof(tr.currency));
            std::int64_t time;
            file.read(reinterpret_cast<char*>(&time), sizeof(time));
            tr.timePoint = TimePoint(std::chrono::microseconds(time));
            return true;
        }

        TimePoint LastTime(const fs::path& path) {
            std::ifstream file(path, std::ios::binary);
            file.seekg(-static_cast<std::streamoff>(sizeof(std::int64_t)), std::ios::end);
            std::int64_t time;
            file.read(reinterpret_cast<char*>(&time), sizeof(time));
            return TimePoint(std::chrono::microseconds(time));
        }

        std::vector<Transaction> LoadAll(const fs::path& path) {
            std::ifstream file(path, std::ios::binary);
            std::vector<Transaction> out;
            Transaction tr;
            while (Load(file, tr)) out.push_back(tr);
            return out;
        }

        std::vector<Transaction> LoadRange(const fs::path& path, TimePoint from, TimePoint to) {
            std::ifstream file(path, std::ios::binary);
            std::vector<Transaction> out;
            Transaction tr;
            while (Load(file, tr)) {
                if (tr.timePoint >= from && tr.timePoint <= to) out.push_back(tr);
                if (tr.timePoint > to) break;
            }
            return out;
        }

        std::vector<Transaction> LoadByIban(const fs::path& path, std::string_view wanted) {
            std::ifstream file(path, std::ios::binary);
            std::vector<Transaction> out;
            Transaction tr;
            while (Load(file, tr)) {
                if (tr.iban == wanted) out.push_back(tr);
            }
            return out;
        }
    }

    template<class F>
    double Millis(F&& f) {
        const Clock::time_point start = Clock::now();
        f();
        return std::chrono::duration<double, std::milli>(Clock::now() - start).count();
    }

    struct Line {
        std::string name;
        double nostro;
        double crafter;
        std::string note;
    };
}

int main() {
    const fs::path dir = fs::temp_directory_path() / "crafter-db-benchmark";
    fs::remove_all(dir);
    fs::create_directories(dir);
    const fs::path nostroPath = dir / "nostro.bin";
    const fs::path crafterPath = dir / "crafter.cdb";
    const std::vector<Transaction> rows = MakeRows();
    const std::string_view wantedIban = rows[rowCount / 2].iban;
    const TimePoint from = rows[rowCount * 45 / 100].timePoint;
    const TimePoint to = rows[rowCount * 55 / 100].timePoint;
    std::vector<Line> lines;
    std::size_t sink = 0;

    // append
    {
        const double nostro = Millis([&] { Nostro::Save(nostroPath, rows); });
        const double crafter = Millis([&] {
            DB::Table<Transaction> table(crafterPath);
            table.Append(rows);
            table.Flush();
        });
        lines.push_back({ std::format("append {} rows", rowCount), nostro, crafter, "incl. open, Crafter.DB incl. fdatasync" });
    }

    // last timestamp (1000 opens each)
    {
        const double nostro = Millis([&] { for (std::int32_t i = 0; i < 1000; i++) sink += Nostro::LastTime(nostroPath).time_since_epoch().count() & 1; });
        const double crafter = Millis([&] {
            for (std::int32_t i = 0; i < 1000; i++) {
                const DB::Table<Transaction> table(crafterPath, { .readOnly = true });
                sink += table.Back()[&Transaction::timePoint].time_since_epoch().count() & 1;
            }
        });
        lines.push_back({ "last timestamp (1000x open+read)", nostro, crafter, "open dominates both" });
    }

    DB::Table<Transaction> table(crafterPath, { .readOnly = true });

    // load all
    {
        const double nostro = Millis([&] { sink += Nostro::LoadAll(nostroPath).size(); });
        const double crafter = Millis([&] { sink += table.Materialize().size(); });
        double zeroCopy = Millis([&] {
            std::int64_t total = 0;
            for (DB::Row<Transaction> row : table) total += row[&Transaction::amount] + static_cast<std::int64_t>(row[&Transaction::iban].Length());
            sink += static_cast<std::size_t>(total & 1);
        });
        lines.push_back({ "load all (materialised)", nostro, crafter, std::format("zero-copy scan of two columns: {:.2f} ms", zeroCopy) });
    }

    // time range (10% of rows)
    {
        std::size_t nostroCount = 0;
        std::size_t crafterCount = 0;
        const double nostro = Millis([&] { nostroCount = Nostro::LoadRange(nostroPath, from, to).size(); });
        const double crafter = Millis([&] { crafterCount = table.Range<&Transaction::timePoint>(from, to).Materialize().size(); });
        lines.push_back({ "time range (10% of rows, materialised)", nostro, crafter, std::format("{} / {} rows", nostroCount, crafterCount) });
    }

    // iban ==
    {
        std::size_t nostroCount = 0;
        std::size_t keyCount = 0;
        std::size_t exprCount = 0;
        std::size_t viewCount = 0;
        const double nostro = Millis([&] { nostroCount = Nostro::LoadByIban(nostroPath, wantedIban).size(); });
        const double withKey = Millis([&] {
            const DB::Key key(wantedIban);
            keyCount = table.Where([&](DB::Row<Transaction> r) { return r[&Transaction::iban] == key; }).Count();
        });
        const double withExpression = Millis([&] { exprCount = table.Where(iban == wantedIban).Count(); });
        const double withView = Millis([&] { viewCount = table.Where([&](DB::Row<Transaction> r) { return r[&Transaction::iban] == wantedIban; }).Count(); });
        lines.push_back({ "iban == x (lambda + Key)", nostro, withKey, std::format("{} / {} rows, {:.1f} ns/row", nostroCount, keyCount, withKey * 1e6 / rowCount) });
        lines.push_back({ "iban == x (expression)", nostro, withExpression, std::format("{} rows, {:.1f} ns/row", exprCount, withExpression * 1e6 / rowCount) });
        lines.push_back({ "iban == x (lambda + string_view)", nostro, withView, std::format("{} rows, {:.1f} ns/row", viewCount, withView * 1e6 / rowCount) });
    }

    // range + iban
    {
        std::size_t nostroCount = 0;
        std::size_t crafterCount = 0;
        const double nostro = Millis([&] {
            for (const Transaction& tr : Nostro::LoadRange(nostroPath, from, to)) nostroCount += tr.iban == wantedIban ? 1 : 0;
        });
        const double crafter = Millis([&] { crafterCount = table.Where(timePoint >= from && timePoint <= to && iban == wantedIban).Count(); });
        lines.push_back({ "time range + iban == x", nostro, crafter, std::format("{} / {} rows", nostroCount, crafterCount) });
    }

    std::println("{:<42} {:>12} {:>12} {:>8}  {}", "operation", "nostro ms", "crafter ms", "speedup", "note");
    for (const Line& line : lines) {
        std::println("{:<42} {:>12.3f} {:>12.3f} {:>7.1f}x  {}", line.name, line.nostro, line.crafter, line.nostro / std::max(line.crafter, 0.0001), line.note);
    }
    std::println("files: nostro {} bytes, crafter {} bytes", fs::file_size(nostroPath), fs::file_size(crafterPath));
    std::println("(sink {})", sink & 1);

    fs::remove_all(dir);
    return 0;
}