/// @file dpf/experiment.hpp
/// @brief Replayable master seed + paper-ready protocol cost CSVs.
/// @details A master covers the thread that installs it. `derive_party(i)`
///          gives party `i` of a run its own stream, keyed by SHA-256 of the
///          master and `i`, and `app::run_parties` installs one on each party
///          thread, so replaying a master replays every party. Kernels handed
///          to a compute pool draw from their party's stream
///          (`dpf/thread_work.hpp`). Every CSV row carries the invocation id
///          of the process that wrote it (`log::invocation_id()`), and a file
///          whose header does not match this layout is moved aside rather
///          than appended to.
#ifndef LIBDPF_INCLUDE_DPF_EXPERIMENT_HPP__
#define LIBDPF_INCLUDE_DPF_EXPERIMENT_HPP__

#include <algorithm>
#include <array>
#include <chrono>
#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <filesystem>
#include <fstream>
#include <iomanip>
#include <map>
#include <sstream>
#include <stdexcept>
#include <string>
#include <system_error>
#include <utility>
#include <vector>

#include <time.h>

#include "dpf/compose.hpp"
#include "dpf/experiment_note.hpp"
#include "dpf/log.hpp"
#include "dpf/prg_aes.hpp"
#include "dpf/prg_count.hpp"
#include "dpf/protocol.hpp"
#include "dpf/random.hpp"
#include "dpf/thread_work.hpp"

namespace dpf
{

using protocol::round_event;
using protocol::round_probe;

/// @brief Per-thread experiment: master seed stream + cost meter + CSV export.
class experiment : public detail::experiment_seed_sink
{
public:
    static constexpr std::size_t master_bytes = 32;

    using master_seed = std::array<std::uint8_t, master_bytes>;

    /// @brief Where a master came from.
    enum class origin : unsigned char
    {
        fresh,     ///< drawn from OS entropy
        provided,  ///< given to `replay`
        derived    ///< `derive_party` of another master
    };

    struct noted_seed
    {
        std::string name;
        std::vector<std::uint8_t> bytes;
    };

    /// @brief Fresh master seed from the system entropy source.
    /// @details Always reads the OS entropy path (never an outer experiment
    ///          hook), so nested contexts do not steal the parent stream.
    explicit experiment(std::string name, std::string party = "p0")
      : name_(std::move(name)), party_(std::move(party))
    {
        draw_system_master_();
        // Master itself must not count as protocol random consumption.
        reset_random_bytes_count();
        prg::reset_eval_count();
        install_();
        note("master", master_.data(), master_.size());
        log_master_();
    }

    /// @brief Replay a previously recorded master seed.
    static experiment replay(std::string name, const master_seed & seed,
        std::string party = "p0")
    {
        return experiment(std::move(name), std::move(party), seed, origin::provided);
    }

    /// @brief The stream party `party` of a run draws from, installed on the
    ///        calling thread (call it on that party's thread). Its master is
    ///        SHA-256 of this master and the party index, so one master
    ///        always yields the same party streams.
    experiment derive_party(unsigned party) const
    {
        std::uint8_t in[master_bytes + 4];
        std::memcpy(in, master_.data(), master_bytes);
        for (int i = 0; i < 4; ++i)
            in[master_bytes + static_cast<std::size_t>(i)] =
                static_cast<std::uint8_t>((party >> (8 * i)) & 0xffu);
        const auto digest = log::detail::sha256("libdpf experiment party", in, sizeof(in));
        master_seed derived{};
        std::memcpy(derived.data(), digest.data(), derived.size());
        return experiment(name_, "p" + std::to_string(party), derived, origin::derived);
    }

    experiment(const experiment &) = delete;
    experiment & operator=(const experiment &) = delete;

    experiment(experiment && other) noexcept
      : name_(std::move(other.name_)),
        party_(std::move(other.party_)),
        run_id_(other.run_id_),
        master_(other.master_),
        origin_(other.origin_),
        aes_seed_(other.aes_seed_),
        ctr_(other.ctr_),
        buf_pos_(other.buf_pos_),
        prev_hook_(other.prev_hook_),
        prev_ctx_(other.prev_ctx_),
        prev_sink_(other.prev_sink_),
        installed_(other.installed_),
        seeds_(std::move(other.seeds_)),
        rounds_(std::move(other.rounds_)),
        edge_in_(std::move(other.edge_in_)),
        edge_out_(std::move(other.edge_out_)),
        edge_plan_out_(std::move(other.edge_plan_out_)),
        interactive_rounds_(other.interactive_rounds_),
        dag_depth_(other.dag_depth_),
        critical_path_(std::move(other.critical_path_)),
        wall_ns_(other.wall_ns_),
        cpu_ns_(other.cpu_ns_),
        prg_evals_(other.prg_evals_),
        sym_(other.sym_),
        random_bytes_(other.random_bytes_),
        bytes_in_(other.bytes_in_),
        bytes_out_(other.bytes_out_),
        plan_bytes_out_(other.plan_bytes_out_),
        config_(std::move(other.config_)),
        trials_(std::move(other.trials_)),
        party_trials_(std::move(other.party_trials_)),
        wire_(other.wire_),
        timing_started_(other.timing_started_),
        wall0_(other.wall0_),
        cpu0_(other.cpu0_)
    {
        std::memcpy(buf_, other.buf_, sizeof(buf_));
        other.installed_ = false;
        if (installed_)
        {
            detail::uniform_bytes_hook = &experiment::hook_;
            detail::uniform_bytes_ctx = this;
            detail::experiment_seed_sink_tls = this;
        }
    }

    ~experiment() override { uninstall_(); }

    const std::string & name() const noexcept { return name_; }
    const std::string & party() const noexcept { return party_; }
    const master_seed & seed() const noexcept { return master_; }
    std::uint64_t run_id() const noexcept { return run_id_; }

    void set_run_id(std::uint64_t id) noexcept { run_id_ = id; }
    void set_party(std::string party) { party_ = std::move(party); }

    /// @brief Public alias of `note` for call-site labels.
    void note_seed(const char * name, const void * bytes, std::size_t n)
    {
        note(name, static_cast<const std::uint8_t *>(bytes), n);
    }

    template <typename T>
    void note_seed(const char * name, const T & seed)
    {
        note_seed(name, &seed, sizeof(seed));
    }

    void note(const char * name, const std::uint8_t * bytes,
        std::size_t n) override
    {
        if (name == nullptr || bytes == nullptr || n == 0)
            return;
        seeds_.push_back({name, std::vector<std::uint8_t>(bytes, bytes + n)});
        if (std::strcmp(name, "master") != 0)
            DPF_LOG(debug, "seed").kv("name", name).kv("experiment", name_)
                .kv("party", party_).kv("source", "noted").kv("bytes", n)
                .seed("value", bytes, n);
    }

    /// @brief Noted seeds in order, starting with `master`.
    const std::vector<noted_seed> & seeds() const noexcept { return seeds_; }

    /// @brief Append a party stream's noted seeds, each name prefixed by
    ///        `party` (`p1/master`, `p1/buffered_prg`).
    void fold_seeds(const std::string & party, const std::vector<noted_seed> & seeds)
    {
        for (const auto & s : seeds)
            seeds_.push_back({party + "/" + s.name, s.bytes});
    }

    origin seed_origin() const noexcept { return origin_; }

    /// @brief True when the master was not drawn fresh (`replay` or
    ///        `derive_party`).
    bool seed_provided() const noexcept { return origin_ != origin::fresh; }

    static const char * origin_name(origin o) noexcept
    {
        switch (o)
        {
        case origin::fresh:
            return "fresh";
        case origin::provided:
            return "provided";
        case origin::derived:
            return "derived";
        }
        return "fresh";
    }

    /// @brief Symmetric-key blocks counted between `begin_timing` and
    ///        `end_timing`, by purpose and primitive (see `prg_count.hpp`).
    const prg::counts & sym_counts() const noexcept { return sym_; }

    /// @brief Record static plan facts (chain length, per-edge schedule bytes).
    void ingest_plan(const protocol::plan & p)
    {
        interactive_rounds_ = p.rounds();
        dag_depth_ = p.waves();
        plan_bytes_out_ = 0;
        for (auto n : p.slot_bytes_all())
            plan_bytes_out_ += n;
        edge_plan_out_.clear();
        for (std::size_t wi = 0; wi < p.waves(); ++wi)
        {
            const auto & w = p.wave(wi);
            if (w.exchanges.empty())
                continue;
            const auto ch = protocol::detail::wave_channel(p, w);
            edge_plan_out_[static_cast<int>(ch)] += w.slot_bytes;
        }
        critical_path_ = build_critical_path_(p);
    }

    /// @brief Probe that records live round events into this experiment.
    round_probe probe() noexcept
    {
        return round_probe{this, &experiment::on_round_};
    }

    /// @brief Start wall/CPU/PRG/random timers (call before drive).
    void begin_timing()
    {
        prg::reset_eval_count();
        reset_random_bytes_count();
        wall0_ = steady_now_();
        cpu0_ = thread_cpu_now_();
        timing_started_ = true;
    }

    /// @brief Stop timers and fold totals.
    void end_timing()
    {
        if (!timing_started_)
            return;
        wall_ns_ += steady_now_() - wall0_;
        cpu_ns_ += thread_cpu_now_() - cpu0_;
        prg_evals_ += prg::eval_count();
        const auto sym = prg::snapshot();
        for (std::size_t i = 0; i < sym.size(); ++i)
            sym_[i] += sym[i];
        random_bytes_ += random_bytes_count();
        timing_started_ = false;
    }

    std::uint64_t wall_ns() const noexcept { return wall_ns_; }
    std::uint64_t cpu_ns() const noexcept { return cpu_ns_; }
    std::uint64_t prg_evals() const noexcept { return prg_evals_; }
    std::uint64_t random_bytes() const noexcept { return random_bytes_; }
    std::size_t bytes_in() const noexcept { return bytes_in_; }
    std::size_t bytes_out() const noexcept { return bytes_out_; }
    std::size_t interactive_rounds() const noexcept
    {
        return interactive_rounds_;
    }
    std::size_t dag_depth() const noexcept { return dag_depth_; }
    std::size_t plan_bytes_out() const noexcept { return plan_bytes_out_; }
    const std::vector<round_event> & rounds() const noexcept { return rounds_; }
    std::size_t seed_count() const noexcept { return seeds_.size(); }
    std::size_t critical_path_length() const noexcept
    {
        return critical_path_.size();
    }

    /// @brief True if a seed named `name` was noted (including `"master"`).
    bool has_seed_named(const char * name) const
    {
        if (name == nullptr)
            return false;
        for (const auto & s : seeds_)
            if (s.name == name)
                return true;
        return false;
    }

    /// @brief Schedule bytes attributed to `channel` by `ingest_plan`.
    std::size_t plan_edge_bytes(protocol::edge_channel channel) const
    {
        return edge_get_(edge_plan_out_, static_cast<int>(channel));
    }

    /// @brief Live bytes in/out attributed to `channel` by the round probe.
    std::size_t edge_bytes_in(protocol::edge_channel channel) const
    {
        return edge_get_(edge_in_, static_cast<int>(channel));
    }
    std::size_t edge_bytes_out(protocol::edge_channel channel) const
    {
        return edge_get_(edge_out_, static_cast<int>(channel));
    }

    std::string seed_hex() const { return to_hex_(master_.data(), master_.size()); }

    /// @brief On-the-wire counters for party 0's links (headers included).
    struct wire_counts
    {
        std::uint64_t bytes_out = 0;
        std::uint64_t bytes_in = 0;
        std::uint64_t payload_out = 0;
        std::uint64_t payload_in = 0;
        std::uint64_t frames_out = 0;
        std::uint64_t frames_in = 0;
        std::uint64_t write_calls = 0;
    };

    /// @brief Run configuration recorded in `config.csv` (key, value).
    void set_config(std::vector<std::pair<std::string, std::string>> kv)
    {
        config_ = std::move(kv);
    }
    const std::vector<std::pair<std::string, std::string>> & config() const noexcept
    {
        return config_;
    }

    /// @brief One timed trial: party 0's wall time and, when given, every
    ///        party's (`party_walls[i]` is party `i`). Recorded in `trials.csv`.
    void add_trial(std::uint64_t wall_ns,
        const std::vector<std::uint64_t> & party_walls = {})
    {
        trials_.push_back(wall_ns);
        party_trials_.push_back(party_walls);
    }
    const std::vector<std::uint64_t> & trials() const noexcept { return trials_; }

    /// @brief Median of party 0's trial wall times (0 when none).
    std::uint64_t median_trial_ns() const { return median_(trials_); }

    /// @brief Median over trials of the slowest party's wall time (party 0's
    ///        when a trial did not record the others).
    std::uint64_t slowest_median_ns() const
    {
        std::vector<std::uint64_t> slowest;
        for (std::size_t t = 0; t < trials_.size(); ++t)
        {
            std::uint64_t w = trials_[t];
            if (t < party_trials_.size())
                for (auto p : party_trials_[t])
                    w = std::max(w, p);
            slowest.push_back(w);
        }
        return median_(slowest);
    }

    void set_wire(const wire_counts & w) { wire_ = w; }
    const wire_counts & wire() const noexcept { return wire_; }

    /// @brief Write / append CSV tables under `dir` (created if missing).
    void write_csv(const std::string & dir) const
    {
        if (dir.empty())
            throw std::invalid_argument("experiment::write_csv empty dir");
        std::error_code ec;
        std::filesystem::create_directories(dir, ec);
        if (ec)
            throw std::runtime_error("experiment: cannot create '" + dir + "': "
                + ec.message());
        write_summary_(dir);
        write_rounds_(dir);
        write_edges_(dir);
        write_seeds_(dir);
        write_critical_path_(dir);
        write_config_(dir);
        write_trials_(dir);
        write_wire_(dir);
        write_sym_(dir);
        write_runs_(dir);
        DPF_LOG(info, "csv").kv("dir", dir).kv("experiment", name_)
            .kv("party", party_).kv("run_id", run_id_).kv("rounds", rounds_.size())
            .kv("trials", trials_.size()).kv("seeds", seeds_.size());
    }

private:
    experiment(std::string name, std::string party, master_seed seed, origin o)
      : name_(std::move(name)), party_(std::move(party)), master_(seed), origin_(o)
    {
        reset_random_bytes_count();
        prg::reset_eval_count();
        install_();
        note("master", master_.data(), master_.size());
        log_master_();
    }

    static const char * entropy_name_() noexcept
    {
#if defined(LIBDPF_USE_ARC4RANDOM)
        return "arc4random";
#elif defined(LIBDPF_USE_DEV_RANDOM)
        return "/dev/random";
#else
        return "/dev/urandom";
#endif
    }

    void log_master_() const
    {
        const bool derived = origin_ == origin::derived;
        if (!log::enabled(derived ? log::level::debug : log::level::info))
            return;
        log::record(derived ? log::level::debug : log::level::info, "seed")
            .kv("name", "master").kv("experiment", name_).kv("party", party_)
            .kv("source", origin_name(origin_))
            .kv("entropy", origin_ == origin::fresh ? entropy_name_()
                                                    : derived ? "sha256(master,party)"
                                                              : "replay")
            .kv("bytes", master_.size()).seed("value", master_.data(), master_.size());
    }

    void draw_system_master_()
    {
        // Bypass any installed hook so the master is true OS entropy.
        auto * saved = detail::uniform_bytes_hook;
        detail::uniform_bytes_hook = nullptr;
        for (auto & b : master_)
            uniform_fill(b);
        detail::uniform_bytes_hook = saved;
    }

    void install_()
    {
        prev_hook_ = detail::uniform_bytes_hook;
        prev_ctx_ = detail::uniform_bytes_ctx;
        prev_sink_ = detail::experiment_seed_sink_tls;
        detail::uniform_bytes_hook = &experiment::hook_;
        detail::uniform_bytes_ctx = this;
        detail::experiment_seed_sink_tls = this;
        installed_ = true;
        // Derive AES key from the first 16 master bytes.
        std::memcpy(&aes_seed_, master_.data(), sizeof(aes_seed_));
        ctr_ = 0;
        buf_pos_ = sizeof(buf_);  // force refill
    }

    void uninstall_()
    {
        if (!installed_)
            return;
        if (detail::uniform_bytes_ctx == this)
            detail::uniform_bytes_ctx = prev_ctx_;
        if (detail::uniform_bytes_hook == &experiment::hook_)
            detail::uniform_bytes_hook = prev_hook_;
        if (detail::experiment_seed_sink_tls == this)
            detail::experiment_seed_sink_tls = prev_sink_;
        installed_ = false;
    }

    static void hook_(void * dst, std::size_t n)
    {
        auto * self = static_cast<experiment *>(detail::uniform_bytes_ctx);
        if (self == nullptr)
            throw std::logic_error("experiment hook without active context");
        self->fill_(dst, n);
    }

    void fill_(void * dst, std::size_t n)
    {
        auto * out = static_cast<std::uint8_t *>(dst);
        while (n > 0)
        {
            if (buf_pos_ >= sizeof(buf_))
            {
                const prg::purpose_scope harness(prg::purpose::harness);
                auto blk = prg::aes128::eval(aes_seed_,
                    static_cast<psnip_uint32_t>(ctr_++));
                std::memcpy(buf_, &blk, sizeof(buf_));
                buf_pos_ = 0;
            }
            const std::size_t take =
                std::min(n, sizeof(buf_) - buf_pos_);
            std::memcpy(out, buf_ + buf_pos_, take);
            buf_pos_ += take;
            out += take;
            n -= take;
        }
    }

    static void on_round_(void * ctx, const round_event & ev)
    {
        static_cast<experiment *>(ctx)->record_round_(ev);
    }

    void record_round_(const round_event & ev)
    {
        rounds_.push_back(ev);
        bytes_in_ += ev.bytes_in;
        bytes_out_ += ev.bytes_out;
        edge_in_[static_cast<int>(ev.channel)] += ev.bytes_in;
        edge_out_[static_cast<int>(ev.channel)] += ev.bytes_out;
        // wall / cpu / prg / random totals come from begin_timing/end_timing
        // so finish_schedule local work is included once.
    }

    static std::uint64_t steady_now_()
    {
        using clock = std::chrono::steady_clock;
        return static_cast<std::uint64_t>(
            std::chrono::duration_cast<std::chrono::nanoseconds>(
                clock::now().time_since_epoch())
                .count());
    }

    static std::uint64_t thread_cpu_now_()
    {
        if (have_thread_cpu_clock())
            return thread_cpu_ns();
        return steady_now_();
    }

    static std::uint64_t median_(std::vector<std::uint64_t> v)
    {
        if (v.empty())
            return 0;
        std::sort(v.begin(), v.end());
        return v[v.size() / 2];
    }

    static std::string to_hex_(const std::uint8_t * p, std::size_t n)
    {
        std::ostringstream os;
        os << std::hex << std::setfill('0');
        for (std::size_t i = 0; i < n; ++i)
            os << std::setw(2) << static_cast<unsigned>(p[i]);
        return os.str();
    }

    static const char * channel_name_(protocol::edge_channel c)
    {
        switch (c)
        {
        case protocol::edge_channel::peer:
            return "peer";
        case protocol::edge_channel::rss_next:
            return "rss_next";
        case protocol::edge_channel::dealer:
            return "dealer";
        }
        return "edge";
    }

    struct path_node
    {
        std::uint32_t id = 0;
        std::size_t wave = 0;
        std::uint32_t opcode = 0;
        int effect = 0;
    };

    static std::vector<path_node> build_critical_path_(const protocol::plan & p)
    {
        std::vector<path_node> path;
        if (p.nodes().empty())
            return path;
        std::uint32_t tip = p.nodes().front().id;
        std::size_t best_w = p.wave_of(protocol::node{tip});
        for (auto n : p.nodes())
        {
            const auto w = p.wave_of(n);
            if (w >= best_w)
            {
                best_w = w;
                tip = n.id;
            }
        }
        for (;;)
        {
            path_node pn;
            pn.id = tip;
            pn.wave = p.wave_of(protocol::node{tip});
            pn.opcode = p.opcode_of(tip);
            pn.effect = static_cast<int>(p.effect_of(tip));
            path.push_back(pn);
            const auto & ins = p.inputs_of(tip);
            if (ins.empty())
                break;
            std::uint32_t next = ins.front();
            std::size_t nw = p.wave_of(protocol::node{next});
            for (auto in : ins)
            {
                const auto w = p.wave_of(protocol::node{in});
                if (w >= nw)
                {
                    nw = w;
                    next = in;
                }
            }
            if (next == tip)
                break;
            tip = next;
        }
        std::reverse(path.begin(), path.end());
        return path;
    }

    /// @brief Open `dir/file` for append, writing `header` first when the file
    ///        is new. A file with a different header is renamed to
    ///        `<stem>.before-<UTC>.csv` so rows never land under the wrong
    ///        columns.
    static std::ofstream open_table_(const std::string & dir, const char * file,
        const char * header)
    {
        const std::string path = dir + "/" + file;
        std::string existing;
        {
            std::ifstream in(path);
            if (in)
                std::getline(in, existing);
        }
        if (!existing.empty() && existing != header)
        {
            std::string stamp;
            for (char c : log::detail::utc_text(std::chrono::system_clock::now()))
                if (c != '-' && c != ':')
                    stamp += c;
            const std::string moved = path.substr(0, path.size() - 4) + ".before-"
                + stamp + ".csv";
            if (std::rename(path.c_str(), moved.c_str()) != 0)
                throw std::runtime_error("experiment: " + path
                    + " has another column layout and cannot be moved aside");
            DPF_LOG(warning, "csv.moved").kv("file", path).kv("to", moved)
                .kv("detail", "its header differs from this build's columns");
            existing.clear();
        }
        std::ofstream out(path, std::ios::app);
        if (!out)
            throw std::runtime_error(std::string("experiment: cannot write ") + file);
        if (existing.empty())
            out << header << '\n';
        return out;
    }

    void write_summary_(const std::string & dir) const
    {
        auto out = open_table_(dir, "summary.csv",
            "name,party,run_id,master_seed,interactive_rounds,dag_depth,"
            "wall_ns,cpu_ns,prg_evals,random_bytes,bytes_in,bytes_out,"
            "plan_bytes_out,peer_in,peer_out,rss_in,rss_out,dealer_in,"
            "dealer_out,median_ns,slowest_median_ns,trials,invocation");
        out << csv_escape_(name_) << ',' << csv_escape_(party_) << ','
            << run_id_ << ',' << seed_hex() << ',' << interactive_rounds_ << ','
            << dag_depth_ << ',' << wall_ns_ << ',' << cpu_ns_ << ','
            << prg_evals_ << ',' << random_bytes_ << ',' << bytes_in_ << ','
            << bytes_out_ << ',' << plan_bytes_out_ << ','
            << edge_get_(edge_in_, 0) << ',' << edge_get_(edge_out_, 0) << ','
            << edge_get_(edge_in_, 1) << ',' << edge_get_(edge_out_, 1) << ','
            << edge_get_(edge_in_, 2) << ',' << edge_get_(edge_out_, 2) << ','
            << median_trial_ns() << ',' << slowest_median_ns() << ','
            << trials_.size() << ',' << log::invocation_id() << '\n';
    }

    void write_rounds_(const std::string & dir) const
    {
        auto out = open_table_(dir, "rounds.csv",
            "name,party,run_id,round,edge,channel,bytes_out,bytes_in,"
            "wall_ns,cpu_ns,prg_evals,random_bytes,invocation");
        for (const auto & r : rounds_)
        {
            out << csv_escape_(name_) << ',' << csv_escape_(party_) << ','
                << run_id_ << ',' << r.round << ',' << r.edge << ','
                << channel_name_(r.channel) << ',' << r.bytes_out << ','
                << r.bytes_in << ',' << r.wall_ns << ',' << r.cpu_ns << ','
                << r.prg_evals << ',' << r.random_bytes << ','
                << log::invocation_id() << '\n';
        }
    }

    void write_edges_(const std::string & dir) const
    {
        auto out = open_table_(dir, "edges.csv",
            "name,party,run_id,channel,bytes_in,bytes_out,plan_bytes_out,invocation");
        for (int c = 0; c < 3; ++c)
        {
            const auto ch = static_cast<protocol::edge_channel>(c);
            out << csv_escape_(name_) << ',' << csv_escape_(party_) << ','
                << run_id_ << ',' << channel_name_(ch) << ','
                << edge_get_(edge_in_, c) << ',' << edge_get_(edge_out_, c)
                << ',' << edge_get_(edge_plan_out_, c) << ','
                << log::invocation_id() << '\n';
        }
    }

    void write_seeds_(const std::string & dir) const
    {
        auto out = open_table_(dir, "seeds.csv",
            "name,party,run_id,seed_name,seed_hex,seed_bytes,invocation");
        for (const auto & s : seeds_)
        {
            out << csv_escape_(name_) << ',' << csv_escape_(party_) << ','
                << run_id_ << ',' << csv_escape_(s.name) << ','
                << to_hex_(s.bytes.data(), s.bytes.size()) << ','
                << s.bytes.size() << ',' << log::invocation_id() << '\n';
        }
    }

    void write_critical_path_(const std::string & dir) const
    {
        auto out = open_table_(dir, "critical_path.csv",
            "name,party,run_id,step,node_id,wave,opcode,effect,invocation");
        for (std::size_t i = 0; i < critical_path_.size(); ++i)
        {
            const auto & n = critical_path_[i];
            out << csv_escape_(name_) << ',' << csv_escape_(party_) << ','
                << run_id_ << ',' << i << ',' << n.id << ',' << n.wave << ','
                << n.opcode << ',' << n.effect << ',' << log::invocation_id() << '\n';
        }
    }

    void write_config_(const std::string & dir) const
    {
        auto out = open_table_(dir, "config.csv", "name,party,run_id,key,value,invocation");
        for (const auto & kv : config_)
            out << csv_escape_(name_) << ',' << csv_escape_(party_) << ','
                << run_id_ << ',' << csv_escape_(kv.first) << ','
                << csv_escape_(kv.second) << ',' << log::invocation_id() << '\n';
    }

    /// @brief One row per party per trial when parties were recorded, one row
    ///        per trial for this experiment's party otherwise.
    void write_trials_(const std::string & dir) const
    {
        auto out = open_table_(dir, "trials.csv",
            "name,party,run_id,trial,wall_ns,invocation");
        for (std::size_t t = 0; t < trials_.size(); ++t)
        {
            const bool all = t < party_trials_.size() && !party_trials_[t].empty();
            if (!all)
            {
                out << csv_escape_(name_) << ',' << csv_escape_(party_) << ','
                    << run_id_ << ',' << t << ',' << trials_[t] << ','
                    << log::invocation_id() << '\n';
                continue;
            }
            for (std::size_t p = 0; p < party_trials_[t].size(); ++p)
                out << csv_escape_(name_) << ",p" << p << ',' << run_id_ << ','
                    << t << ',' << party_trials_[t][p] << ','
                    << log::invocation_id() << '\n';
        }
    }

    void write_wire_(const std::string & dir) const
    {
        auto out = open_table_(dir, "wire.csv",
            "name,party,run_id,bytes_out,bytes_in,payload_out,payload_in,"
            "frames_out,frames_in,write_calls,invocation");
        out << csv_escape_(name_) << ',' << csv_escape_(party_) << ',' << run_id_
            << ',' << wire_.bytes_out << ',' << wire_.bytes_in << ','
            << wire_.payload_out << ',' << wire_.payload_in << ','
            << wire_.frames_out << ',' << wire_.frames_in << ','
            << wire_.write_calls << ',' << log::invocation_id() << '\n';
    }

    void write_sym_(const std::string & dir) const
    {
        auto out = open_table_(dir, "sym.csv",
            "name,party,run_id,purpose,primitive,blocks,invocation");
        for (std::size_t u = 0; u < prg::purpose_count; ++u)
            for (std::size_t p = 0; p < prg::primitive_count; ++p)
            {
                const auto n = sym_[u * prg::primitive_count + p];
                if (n == 0)
                    continue;
                out << csv_escape_(name_) << ',' << csv_escape_(party_) << ','
                    << run_id_ << ','
                    << prg::purpose_name(static_cast<prg::purpose>(u)) << ','
                    << prg::primitive_name(static_cast<prg::primitive>(p)) << ','
                    << n << ',' << log::invocation_id() << '\n';
            }
    }

    void write_runs_(const std::string & dir) const
    {
        auto out = open_table_(dir, "runs.csv",
            "name,party,run_id,invocation,seed_source,written_utc");
        out << csv_escape_(name_) << ',' << csv_escape_(party_) << ',' << run_id_
            << ',' << log::invocation_id() << ',' << origin_name(origin_) << ','
            << log::detail::utc_text(std::chrono::system_clock::now()) << '\n';
    }

    static std::string csv_escape_(const std::string & s)
    {
        if (s.find_first_of(",\"\n\r") == std::string::npos)
            return s;
        std::string out = "\"";
        for (char c : s)
        {
            if (c == '"')
                out += "\"\"";
            else
                out += c;
        }
        out += '"';
        return out;
    }

    static std::size_t edge_get_(const std::map<int, std::size_t> & m, int k)
    {
        auto it = m.find(k);
        return it == m.end() ? 0 : it->second;
    }

    std::string name_;
    std::string party_;
    std::uint64_t run_id_ = 0;
    master_seed master_{};
    origin origin_ = origin::fresh;
    prg::aes128::block_type aes_seed_{};
    std::uint32_t ctr_ = 0;
    std::uint8_t buf_[16]{};
    std::size_t buf_pos_ = 16;
    void (*prev_hook_)(void *, std::size_t) = nullptr;
    void * prev_ctx_ = nullptr;
    detail::experiment_seed_sink * prev_sink_ = nullptr;
    bool installed_ = false;
    std::vector<noted_seed> seeds_;
    std::vector<round_event> rounds_;
    std::map<int, std::size_t> edge_in_;
    std::map<int, std::size_t> edge_out_;
    std::map<int, std::size_t> edge_plan_out_;
    std::size_t interactive_rounds_ = 0;
    std::size_t dag_depth_ = 0;
    std::vector<path_node> critical_path_;
    std::uint64_t wall_ns_ = 0;
    std::uint64_t cpu_ns_ = 0;
    std::uint64_t prg_evals_ = 0;
    prg::counts sym_{};
    std::uint64_t random_bytes_ = 0;
    std::size_t bytes_in_ = 0;
    std::size_t bytes_out_ = 0;
    std::size_t plan_bytes_out_ = 0;
    std::vector<std::pair<std::string, std::string>> config_;
    std::vector<std::uint64_t> trials_;
    std::vector<std::vector<std::uint64_t>> party_trials_;
    wire_counts wire_{};
    bool timing_started_ = false;
    std::uint64_t wall0_ = 0;
    std::uint64_t cpu0_ = 0;
};

}  // namespace dpf

#endif  // LIBDPF_INCLUDE_DPF_EXPERIMENT_HPP__