/**
 * JNI bridge for Rosetta E2EE.
 *
 * Provides:
 *  1. HSalsa20 — for nacl.box.before() compatible key derivation
 *  2. XChaCha20 FrameEncryptor / FrameDecryptor — inherits DIRECTLY from
 *     webrtc::FrameEncryptorInterface / FrameDecryptorInterface so the
 *     vtable is generated by the compiler, not guessed by us.
 */

#include <jni.h>
#include <cstdint>
#include <cstring>
#include <atomic>
#include <vector>
#include <signal.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <stdarg.h>
#include <stdio.h>
#include <android/log.h>

/* WebRTC M125 interface stubs (exact copies of the real headers) */
#include "webrtc/api/crypto/frame_encryptor_interface.h"
#include "webrtc/api/crypto/frame_decryptor_interface.h"

#include "crypto.h"

#define TAG "RosettaE2EE"
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, TAG, __VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR, TAG, __VA_ARGS__)

/* ── Diagnostics file — written from native, visible in crash reports ── */

static char g_diag_path[512] = {0};
static int  g_diag_fd = -1;
static std::atomic<int> g_diag_event_count{0};
static constexpr int kDiagEventLimit = 4000;
static constexpr int kDiagFrameLimit = 400;
static constexpr size_t kFrameHashSampleBytes = 320;

static void diag_write(const char *fmt, ...) {
    if (g_diag_fd < 0) return;
    char buf[512];
    va_list ap;
    va_start(ap, fmt);
    int n = vsnprintf(buf, sizeof(buf), fmt, ap);
    va_end(ap);
    if (n > 0) write(g_diag_fd, buf, n);
}

static void diag_event(const char *fmt, ...) {
    if (g_diag_fd < 0) return;
    const int idx = g_diag_event_count.fetch_add(1, std::memory_order_relaxed);
    if (idx >= kDiagEventLimit) return;
    char buf[640];
    va_list ap;
    va_start(ap, fmt);
    int n = vsnprintf(buf, sizeof(buf), fmt, ap);
    va_end(ap);
    if (n > 0) write(g_diag_fd, buf, n);
}

static inline uint32_t fnv1a32(const uint8_t* data, size_t len, size_t sample_limit = 0) {
    if (!data || len == 0) return 0;
    const size_t n = (sample_limit > 0 && len > sample_limit) ? sample_limit : len;
    uint32_t h = 2166136261u;
    for (size_t i = 0; i < n; ++i) {
        h ^= data[i];
        h *= 16777619u;
    }
    return h;
}

static inline uint32_t key_fingerprint32(const uint8_t key[32]) {
    return fnv1a32(key, 32, 32);
}

static inline uint32_t nonce_ts32(const uint8_t nonce[24]) {
    return ((uint32_t)nonce[4] << 24) |
           ((uint32_t)nonce[5] << 16) |
           ((uint32_t)nonce[6] << 8) |
           ((uint32_t)nonce[7]);
}

static const char* media_type_name(cricket::MediaType media_type) {
    switch (media_type) {
        case cricket::MEDIA_TYPE_AUDIO: return "audio";
        case cricket::MEDIA_TYPE_VIDEO: return "video";
        case cricket::MEDIA_TYPE_DATA: return "data";
        case cricket::MEDIA_TYPE_UNSUPPORTED: return "unsupported";
        default: return "unknown";
    }
}

/* ── RTP helpers (for cases when additional_data is empty) ───── */

struct ParsedRtpPacket {
    size_t header_size = 0;
    uint16_t sequence = 0;
    uint32_t timestamp = 0;
    uint32_t ssrc = 0;
};

struct RtpProbeState {
    bool locked = false;
    bool has_probe = false;
    uint32_t probe_ssrc = 0;
    uint16_t probe_sequence = 0;
    uint32_t probe_timestamp = 0;

    uint32_t ssrc = 0;
    uint16_t last_sequence = 0;
    uint32_t last_timestamp = 0;
};

struct GeneratedTsState {
    bool initialized = false;
    uint32_t next_timestamp = 0;
    uint32_t next_step = 960;  // 20 ms @ 48 kHz (default Opus packetization)
};

struct AdditionalTsState {
    bool initialized = false;
    uint64_t base_timestamp = 0;
};

struct SenderTsOffsetState {
    bool initialized = false;
    bool enabled = false;
    uint64_t offset = 0;
};

static inline uint16_t load16_be(const uint8_t* p) {
    return (uint16_t)(((uint16_t)p[0] << 8) | (uint16_t)p[1]);
}

static inline uint32_t load32_be(const uint8_t* p) {
    return ((uint32_t)p[0] << 24) |
           ((uint32_t)p[1] << 16) |
           ((uint32_t)p[2] << 8) |
           ((uint32_t)p[3]);
}

static inline uint64_t load64_be(const uint8_t* p) {
    return ((uint64_t)p[0] << 56) |
           ((uint64_t)p[1] << 48) |
           ((uint64_t)p[2] << 40) |
           ((uint64_t)p[3] << 32) |
           ((uint64_t)p[4] << 24) |
           ((uint64_t)p[5] << 16) |
           ((uint64_t)p[6] << 8) |
           ((uint64_t)p[7]);
}


static bool parse_rtp_packet(const uint8_t* data, size_t len, ParsedRtpPacket* out) {
    if (!data || !out || len < 12) return false;

    // RTP version must be 2.
    const uint8_t version = (data[0] >> 6) & 0x03;
    if (version != 2) return false;

    const size_t csrc_count = (size_t)(data[0] & 0x0F);
    const bool has_extension = (data[0] & 0x10) != 0;

    size_t header = 12 + csrc_count * 4;
    if (header > len) return false;

    if (has_extension) {
        // Extension header: 16-bit profile + 16-bit length (in 32-bit words)
        if (len < header + 4) return false;
        const uint16_t ext_len_words =
            (uint16_t)(((uint16_t)data[header + 2] << 8) | (uint16_t)data[header + 3]);
        const size_t ext_bytes = (size_t)ext_len_words * 4;
        header += 4 + ext_bytes;
        if (header > len) return false;
    }

    const size_t payload_size = len - header;
    if (payload_size == 0 || payload_size > 1200) return false;

    out->header_size = header;
    out->sequence = load16_be(data + 2);
    out->timestamp = load32_be(data + 4);
    out->ssrc = load32_be(data + 8);
    return true;
}

static bool fill_nonce_from_rtp_frame(const uint8_t* data,
                                      size_t len,
                                      RtpProbeState* state,
                                      uint8_t nonce[24],
                                      size_t* header_size) {
    if (!state) return false;

    ParsedRtpPacket packet;
    if (!parse_rtp_packet(data, len, &packet)) return false;

    if (!state->locked) {
        if (!state->has_probe) {
            state->has_probe = true;
            state->probe_ssrc = packet.ssrc;
            state->probe_sequence = packet.sequence;
            state->probe_timestamp = packet.timestamp;
            diag_event("RTP probe-start ssrc=%u seq=%u ts=%u hdr=%zu\n",
                       packet.ssrc, packet.sequence, packet.timestamp, packet.header_size);
            return false;
        }

        const bool same_ssrc = packet.ssrc == state->probe_ssrc;
        const uint16_t seq_delta = (uint16_t)(packet.sequence - state->probe_sequence);
        const bool sequence_progressed = seq_delta > 0 && seq_delta <= 10;
        if (!same_ssrc || !sequence_progressed) {
            state->probe_ssrc = packet.ssrc;
            state->probe_sequence = packet.sequence;
            state->probe_timestamp = packet.timestamp;
            return false;
        }

        state->locked = true;
        state->has_probe = false;
        state->ssrc = packet.ssrc;
        state->last_sequence = packet.sequence;
        state->last_timestamp = packet.timestamp;
        diag_event("RTP probe-lock ssrc=%u seq=%u ts=%u hdr=%zu\n",
                   packet.ssrc, packet.sequence, packet.timestamp, packet.header_size);
    } else {
        if (packet.ssrc != state->ssrc) {
            diag_event("RTP probe-unlock reason=ssrc-change old=%u new=%u seq=%u ts=%u\n",
                       state->ssrc, packet.ssrc, packet.sequence, packet.timestamp);
            state->locked = false;
            state->has_probe = true;
            state->probe_ssrc = packet.ssrc;
            state->probe_sequence = packet.sequence;
            state->probe_timestamp = packet.timestamp;
            return false;
        }

        const uint16_t seq_delta = (uint16_t)(packet.sequence - state->last_sequence);
        // Accept in-order packets and small jumps (packet loss).
        if (seq_delta != 0 && seq_delta <= 200) {
            state->last_sequence = packet.sequence;
            state->last_timestamp = packet.timestamp;
        } else if (seq_delta != 0) {
            // Not plausible for a continuous stream: re-probe.
            diag_event("RTP probe-unlock reason=seq-jump delta=%u ssrc=%u last_seq=%u seq=%u ts=%u\n",
                       seq_delta, packet.ssrc, state->last_sequence, packet.sequence, packet.timestamp);
            state->locked = false;
            state->has_probe = true;
            state->probe_ssrc = packet.ssrc;
            state->probe_sequence = packet.sequence;
            state->probe_timestamp = packet.timestamp;
            return false;
        }
    }

    nonce[4] = (uint8_t)(packet.timestamp >> 24);
    nonce[5] = (uint8_t)(packet.timestamp >> 16);
    nonce[6] = (uint8_t)(packet.timestamp >> 8);
    nonce[7] = (uint8_t)(packet.timestamp);
    if (header_size) *header_size = packet.header_size;
    return true;
}

static bool fill_nonce_from_additional_data(const uint8_t* data,
                                            size_t len,
                                            uint8_t nonce[24],
                                            bool* used_rtp_header,
                                            AdditionalTsState* ts_state,
                                            bool* used_relative_ts) {
    if (used_rtp_header) *used_rtp_header = false;
    if (used_relative_ts) *used_relative_ts = false;
    if (!data || len < 8) return false;

    // Desktop-compatible path: additional_data contains encoded frame timestamp
    // as 8-byte BE value. On Android sender/receiver can have different absolute
    // base in some pipelines; ts_state enables optional relative fallback.
    // Primary desktop-compatible mode uses absolute timestamp (ts_state == nullptr).
    if (len == 8) {
        uint64_t ts64 = load64_be(data);
        uint64_t ts_rel = ts64;
        if (ts_state != nullptr) {
            if (!ts_state->initialized) {
                ts_state->initialized = true;
                ts_state->base_timestamp = ts64;
            } else if (ts64 < ts_state->base_timestamp) {
                // New stream or reset; avoid huge wrapped nonce drift.
                ts_state->base_timestamp = ts64;
            }
            ts_rel = ts64 - ts_state->base_timestamp;
            if (used_relative_ts) *used_relative_ts = true;
        }
        nonce[0] = (uint8_t)(ts_rel >> 56);
        nonce[1] = (uint8_t)(ts_rel >> 48);
        nonce[2] = (uint8_t)(ts_rel >> 40);
        nonce[3] = (uint8_t)(ts_rel >> 32);
        nonce[4] = (uint8_t)(ts_rel >> 24);
        nonce[5] = (uint8_t)(ts_rel >> 16);
        nonce[6] = (uint8_t)(ts_rel >> 8);
        nonce[7] = (uint8_t)(ts_rel);
        return true;
    }

    // Legacy native WebRTC layout: additional_data can be RTP header bytes.
    if (len >= 12) {
        const uint8_t version = (data[0] >> 6) & 0x03;
        if (version == 2) {
            uint32_t ts = load32_be(data + 4);
            nonce[4] = (uint8_t)(ts >> 24);
            nonce[5] = (uint8_t)(ts >> 16);
            nonce[6] = (uint8_t)(ts >> 8);
            nonce[7] = (uint8_t)(ts);
            if (used_rtp_header) *used_rtp_header = true;
            return true;
        }
    }

    // Generic fallback: first 8 bytes as BE timestamp-like payload.
    memcpy(nonce, data, 8);
    return true;
}

static bool is_plausible_opus_packet(const uint8_t* packet, size_t len);

static bool is_plausible_decrypted_audio_frame(const uint8_t* data, size_t len) {
    if (!data || len == 0) return false;

    ParsedRtpPacket packet;
    if (parse_rtp_packet(data, len, &packet) && packet.header_size < len) {
        return is_plausible_opus_packet(data + packet.header_size, len - packet.header_size);
    }
    return is_plausible_opus_packet(data, len);
}

static inline void fill_nonce_from_ts32(uint32_t ts, uint8_t nonce[24]) {
    nonce[4] = (uint8_t)(ts >> 24);
    nonce[5] = (uint8_t)(ts >> 16);
    nonce[6] = (uint8_t)(ts >> 8);
    nonce[7] = (uint8_t)(ts);
}

static inline void fill_nonce_from_ts64(uint64_t ts, uint8_t nonce[24]) {
    nonce[0] = (uint8_t)(ts >> 56);
    nonce[1] = (uint8_t)(ts >> 48);
    nonce[2] = (uint8_t)(ts >> 40);
    nonce[3] = (uint8_t)(ts >> 32);
    nonce[4] = (uint8_t)(ts >> 24);
    nonce[5] = (uint8_t)(ts >> 16);
    nonce[6] = (uint8_t)(ts >> 8);
    nonce[7] = (uint8_t)(ts);
}

static inline uint64_t monotonic_48k_ticks() {
    struct timespec ts {};
    if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0) return 0;
    const uint64_t sec = (uint64_t)ts.tv_sec;
    const uint64_t nsec = (uint64_t)ts.tv_nsec;
    return sec * 48000ULL + (nsec * 48000ULL) / 1000000000ULL;
}

static inline uint32_t opus_base_frame_samples(uint8_t config) {
    // RFC 6716 TOC config mapping at 48 kHz.
    if (config <= 11) {
        // SILK: 10/20/40/60 ms
        static const uint32_t kSilk[4] = {480, 960, 1920, 2880};
        return kSilk[config & 0x03];
    }
    if (config <= 15) {
        // Hybrid: 10/20 ms
        return (config & 0x01) ? 960 : 480;
    }
    // CELT-only: 2.5/5/10/20 ms
    static const uint32_t kCelt[4] = {120, 240, 480, 960};
    return kCelt[config & 0x03];
}

static uint32_t infer_opus_packet_duration_samples(const uint8_t* packet, size_t len) {
    if (!packet || len == 0) return 960;

    const uint8_t toc = packet[0];
    const uint8_t config = (uint8_t)(toc >> 3);
    const uint8_t frame_code = (uint8_t)(toc & 0x03);

    uint32_t frame_count = 1;
    if (frame_code == 1 || frame_code == 2) {
        frame_count = 2;
    } else if (frame_code == 3) {
        if (len < 2) return 960;
        frame_count = (uint32_t)(packet[1] & 0x3F);
        if (frame_count == 0 || frame_count > 48) return 960;
    }

    uint32_t base = opus_base_frame_samples(config);
    uint32_t total = base * frame_count;
    if (total < 120 || total > 5760) return 960;
    return total;
}

static bool decode_opus_frame_len(const uint8_t* packet,
                                  size_t len,
                                  size_t* offset,
                                  size_t* frame_len) {
    if (!packet || !offset || !frame_len) return false;
    if (*offset >= len) return false;

    const uint8_t b0 = packet[*offset];
    (*offset)++;
    if (b0 < 252) {
        *frame_len = b0;
        return true;
    }
    if (*offset >= len) return false;
    const uint8_t b1 = packet[*offset];
    (*offset)++;
    *frame_len = (size_t)b1 * 4u + (size_t)b0;
    return true;
}

static bool is_plausible_opus_packet(const uint8_t* packet, size_t len) {
    if (!packet || len == 0 || len > 2000) return false;

    const uint8_t toc = packet[0];
    const uint8_t config = (uint8_t)(toc >> 3);
    if (config > 31) return false;

    const uint8_t frame_code = (uint8_t)(toc & 0x03);
    const size_t payload_len = len - 1;

    if (frame_code == 0) {
        // 1 frame, full payload
        return payload_len >= 1;
    }

    if (frame_code == 1) {
        // 2 CBR frames, equal sizes.
        if (payload_len < 2) return false;
        return (payload_len % 2) == 0;
    }

    if (frame_code == 2) {
        // 2 VBR frames
        size_t off = 1;
        size_t len1 = 0;
        if (!decode_opus_frame_len(packet, len, &off, &len1)) return false;
        if (len1 == 0) return false;
        if (off + len1 >= len) return false;  // need non-empty second frame
        const size_t len2 = len - off - len1;
        if (len2 == 0) return false;
        return true;
    }

    // frame_code == 3: arbitrary number of frames
    if (len < 2) return false;
    const uint8_t ch = packet[1];
    const bool vbr = (ch & 0x80) != 0;
    const bool has_padding = (ch & 0x40) != 0;
    const uint8_t frame_count = (uint8_t)(ch & 0x3F);
    if (frame_count == 0 || frame_count > 48) return false;

    const uint32_t total = opus_base_frame_samples(config) * (uint32_t)frame_count;
    if (total > 5760) return false;

    // Padding bit is rarely used in live voice. Rejecting it improves
    // discrimination between valid Opus and random decrypted noise.
    if (has_padding) return false;

    if (!vbr) {
        const size_t data_len = len - 2;
        if (data_len < (size_t)frame_count) return false;
        return (data_len % frame_count) == 0;
    }

    // VBR: parse lengths for first N-1 frames; last frame consumes rest.
    size_t off = 2;
    size_t consumed = 0;
    for (size_t i = 0; i + 1 < frame_count; ++i) {
        size_t flen = 0;
        if (!decode_opus_frame_len(packet, len, &off, &flen)) return false;
        if (flen == 0) return false;
        consumed += flen;
        if (off + consumed >= len) return false;
    }
    const size_t remaining = len - off;
    if (remaining <= consumed) return false;
    const size_t last = remaining - consumed;
    return last > 0;
}

/* ── Native crash handler — writes to file before dying ──────── */

static char g_crash_path[512] = {0};
static struct sigaction g_old_sigsegv = {};
static struct sigaction g_old_sigabrt = {};

static void native_crash_handler(int sig, siginfo_t *info, void *ctx) {
    if (g_crash_path[0] != 0) {
        int fd = open(g_crash_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
        if (fd >= 0) {
            const char *msg;
            if (sig == SIGSEGV)
                msg = "NATIVE CRASH: SIGSEGV (segmentation fault) in rosetta_e2ee\n"
                      "Fault address: see logcat for details.\n";
            else if (sig == SIGABRT)
                msg = "NATIVE CRASH: SIGABRT (abort) in rosetta_e2ee\n";
            else
                msg = "NATIVE CRASH: unknown signal in rosetta_e2ee\n";
            write(fd, msg, strlen(msg));
            close(fd);
        }
    }
    LOGE("NATIVE CRASH sig=%d addr=%p", sig, info ? info->si_addr : nullptr);

    struct sigaction *old = (sig == SIGSEGV) ? &g_old_sigsegv : &g_old_sigabrt;
    sigaction(sig, old, nullptr);
    raise(sig);
}

/* ════════════════════════════════════════════════════════════════
 * XChaCha20 Encryptor — inherits from the REAL interface
 * ════════════════════════════════════════════════════════════════ */

class XChaCha20Encryptor final : public webrtc::FrameEncryptorInterface {
public:
    explicit XChaCha20Encryptor(const uint8_t key[32]) {
        memcpy(key_, key, 32);
        key_fingerprint_ = key_fingerprint32(key_);
        LOGI("ENC init ptr=%p key_fp=%08x", this, key_fingerprint_);
        diag_event("ENC init ptr=%p key_fp=%08x\n", this, key_fingerprint_);
    }

    uint32_t KeyFingerprint() const { return key_fingerprint_; }
    int FrameCount() const { return diag_count_.load(std::memory_order_relaxed); }

    /* ── RefCountInterface ─────────────────────────────────────── */
    void AddRef() const override {
        ref_.fetch_add(1, std::memory_order_relaxed);
    }

    rtc::RefCountReleaseStatus Release() const override {
        if (ref_.fetch_sub(1, std::memory_order_acq_rel) == 1) {
            delete this;
            return rtc::RefCountReleaseStatus::kDroppedLastRef;
        }
        return rtc::RefCountReleaseStatus::kOtherRefsRemained;
    }

    /**
     * Desktop-compatible frame format: ciphertext only (no custom prefix).
     *
     * Nonce (24 bytes) is derived exactly like desktop:
     * - nonce[0..3] = 0
     * - nonce[4..7] = RTP timestamp
     * - nonce[8..23] = 0
     *
     * Primary source of timestamp: additional_data[4..7] (if provided by WebRTC).
     * Fallback (Android path where additional_data can be empty):
     * parse RTP header from frame and take timestamp from frame[4..7].
     *
     * If RTP header is found inside frame, we leave header bytes unencrypted
     * and encrypt only payload (desktop-compatible).
     */
    int Encrypt(cricket::MediaType media_type,
                uint32_t ssrc,
                rtc::ArrayView<const uint8_t> additional_data,
                rtc::ArrayView<const uint8_t> frame,
                rtc::ArrayView<uint8_t> encrypted_frame,
                size_t* bytes_written) override {
        if (frame.size() == 0 || encrypted_frame.size() < frame.size()) {
            *bytes_written = 0;
            return -1;
        }

        size_t header_size = 0;
        bool nonce_from_rtp_header = false;
        bool nonce_from_generated_ts = false;
        bool nonce_from_additional_data = false;
        bool additional_was_rtp_header = false;
        bool additional_used_mono_offset = false;
        uint32_t generated_ts_used = 0;

        // Build nonce from RTP timestamp in additional_data (preferred).
        uint8_t nonce[24] = {0};
        bool additional_used_relative_ts = false;
        nonce_from_additional_data = fill_nonce_from_additional_data(
            additional_data.data(),
            additional_data.size(),
            nonce,
            &additional_was_rtp_header,
            nullptr,
            &additional_used_relative_ts);
        if (!nonce_from_additional_data) {
            nonce_from_rtp_header =
                fill_nonce_from_rtp_frame(frame.data(), frame.size(), &rtp_probe_, nonce, &header_size);
            if (!nonce_from_rtp_header) {
                if (!generated_ts_.initialized) {
                    generated_ts_.initialized = true;
                    generated_ts_.next_timestamp = 0;
                    generated_ts_.next_step = 960;
                }
                nonce_from_generated_ts = true;
                generated_ts_used = generated_ts_.next_timestamp;
                fill_nonce_from_ts32(generated_ts_used, nonce);
                diag_event("ENC fallback=generated-ts mt=%s ssrc=%u frame_sz=%zu ad_sz=%zu gen_ts=%u\n",
                           media_type_name(media_type), ssrc, frame.size(), additional_data.size(), generated_ts_used);
            }
        }

        // Some Android sender pipelines expose stream-relative ad8 timestamps
        // (0, 960, 1920, ...), while desktop receiver expects an absolute base.
        // For interop, add a monotonic 48k offset once when first ad8 is tiny.
        if (nonce_from_additional_data &&
            additional_data.size() == 8 &&
            !additional_was_rtp_header &&
            additional_data.data() != nullptr) {
            const uint64_t ad_ts64 = load64_be(additional_data.data());
            if (!sender_ts_offset_.initialized) {
                sender_ts_offset_.initialized = true;
                // Keep pure raw-abs mode by default; desktop is the source of truth.
                sender_ts_offset_.enabled = false;
                sender_ts_offset_.offset = 0ULL;
                diag_event("ENC ad8-base init ssrc=%u ad_ts=%llu use_mono=%d mono_off=%llu\n",
                           ssrc,
                           (unsigned long long)ad_ts64,
                           sender_ts_offset_.enabled ? 1 : 0,
                           (unsigned long long)sender_ts_offset_.offset);
            }
            if (sender_ts_offset_.enabled) {
                const uint64_t ts_adj = ad_ts64 + sender_ts_offset_.offset;
                fill_nonce_from_ts64(ts_adj, nonce);
                additional_used_mono_offset = true;
            }
        }

        // Desktop createEncodedStreams encrypts full encoded chunk.
        // To stay wire-compatible, do not preserve any leading RTP-like bytes.
        rosetta_xchacha20_xor(encrypted_frame.data(),
                              frame.data(), frame.size(), nonce, key_);
        *bytes_written = frame.size();

        if (nonce_from_generated_ts) {
            const uint32_t step = infer_opus_packet_duration_samples(frame.data(), frame.size());
            generated_ts_.next_step = step;
            generated_ts_.next_timestamp = generated_ts_used + step;
        }

        // Diag: log first frames with enough context for crash analysis.
        int n = diag_count_.fetch_add(1, std::memory_order_relaxed);
        if (n < kDiagFrameLimit) {
            uint8_t ad_prefix[8] = {0};
            const size_t ad_copy = additional_data.size() < sizeof(ad_prefix)
                                       ? additional_data.size()
                                       : sizeof(ad_prefix);
            if (ad_copy > 0) memcpy(ad_prefix, additional_data.data(), ad_copy);
            ParsedRtpPacket rtp{};
            const bool has_rtp = parse_rtp_packet(frame.data(), frame.size(), &rtp);
            const bool opus_plausible =
                has_rtp && rtp.header_size < frame.size()
                    ? is_plausible_opus_packet(frame.data() + rtp.header_size, frame.size() - rtp.header_size)
                    : is_plausible_opus_packet(frame.data(), frame.size());
            const uint32_t in_hash = fnv1a32(frame.data(), frame.size(), kFrameHashSampleBytes);
            const uint32_t out_hash = fnv1a32(encrypted_frame.data(), frame.size(), kFrameHashSampleBytes);
            const char* mode =
                nonce_from_rtp_header
                    ? "rtp"
                    : (nonce_from_generated_ts
                           ? "gen"
                           : (nonce_from_additional_data
                                  ? (additional_was_rtp_header
                                         ? "ad-rtp"
                                         : (additional_used_mono_offset
                                                ? "raw-abs+mono"
                                                : (additional_used_relative_ts ? "raw-rel" : "raw-abs")))
                                  : "raw-abs"));
            LOGI("ENC frame#%d mt=%s ssrc=%u sz=%zu ad=%zu hdr=%zu mode=%s nonce_ts=%u gen_ts=%u next_step=%u rtp_ok=%d rtp_seq=%u rtp_ts=%u rtp_ssrc=%u opus_ok=%d key_fp=%08x in_h=%08x out_h=%08x ad8=%02x%02x%02x%02x%02x%02x%02x%02x",
                 n, media_type_name(media_type), ssrc, frame.size(), additional_data.size(), header_size, mode,
                 nonce_ts32(nonce), generated_ts_used, generated_ts_.next_step,
                 has_rtp ? 1 : 0, has_rtp ? rtp.sequence : 0, has_rtp ? rtp.timestamp : 0, has_rtp ? rtp.ssrc : 0,
                 opus_plausible ? 1 : 0, key_fingerprint_, in_hash, out_hash,
                 ad_prefix[0], ad_prefix[1], ad_prefix[2], ad_prefix[3],
                 ad_prefix[4], ad_prefix[5], ad_prefix[6], ad_prefix[7]);
            diag_write("ENC frame#%d mt=%s ssrc=%u sz=%zu ad=%zu hdr=%zu mode=%s nonce_ts=%u gen_ts=%u next_step=%u rtp_ok=%d rtp_seq=%u rtp_ts=%u rtp_ssrc=%u opus_ok=%d key_fp=%08x in_h=%08x out_h=%08x ad8=%02x%02x%02x%02x%02x%02x%02x%02x\n",
                       n, media_type_name(media_type), ssrc, frame.size(), additional_data.size(), header_size, mode,
                       nonce_ts32(nonce), generated_ts_used, generated_ts_.next_step,
                       has_rtp ? 1 : 0, has_rtp ? rtp.sequence : 0, has_rtp ? rtp.timestamp : 0, has_rtp ? rtp.ssrc : 0,
                       opus_plausible ? 1 : 0, key_fingerprint_, in_hash, out_hash,
                       ad_prefix[0], ad_prefix[1], ad_prefix[2], ad_prefix[3],
                       ad_prefix[4], ad_prefix[5], ad_prefix[6], ad_prefix[7]);
        }
        return 0;
    }

    size_t GetMaxCiphertextByteSize(cricket::MediaType, size_t frame_size) override {
        return frame_size;
    }

protected:
    ~XChaCha20Encryptor() override {
        diag_event("ENC destroy ptr=%p key_fp=%08x\n", this, key_fingerprint_);
        memset(key_, 0, 32);
    }

private:
    mutable std::atomic<int> ref_{0};
    mutable std::atomic<int> diag_count_{0};
    mutable RtpProbeState rtp_probe_;
    mutable GeneratedTsState generated_ts_;
    mutable SenderTsOffsetState sender_ts_offset_;
    uint32_t key_fingerprint_ = 0;
    uint8_t key_[32];
};

/* ════════════════════════════════════════════════════════════════
 * XChaCha20 Decryptor — inherits from the REAL interface
 * ════════════════════════════════════════════════════════════════ */

class XChaCha20Decryptor final : public webrtc::FrameDecryptorInterface {
public:
    explicit XChaCha20Decryptor(const uint8_t key[32]) {
        memcpy(key_, key, 32);
        key_fingerprint_ = key_fingerprint32(key_);
        LOGI("DEC init ptr=%p key_fp=%08x", this, key_fingerprint_);
        diag_event("DEC init ptr=%p key_fp=%08x\n", this, key_fingerprint_);
    }

    uint32_t KeyFingerprint() const { return key_fingerprint_; }
    int FrameCount() const { return diag_count_.load(std::memory_order_relaxed); }
    uint32_t BadStreak() const { return bad_audio_streak_.load(std::memory_order_relaxed); }

    /* ── RefCountInterface ─────────────────────────────────────── */
    void AddRef() const override {
        ref_.fetch_add(1, std::memory_order_relaxed);
    }

    rtc::RefCountReleaseStatus Release() const override {
        if (ref_.fetch_sub(1, std::memory_order_acq_rel) == 1) {
            delete this;
            return rtc::RefCountReleaseStatus::kDroppedLastRef;
        }
        return rtc::RefCountReleaseStatus::kOtherRefsRemained;
    }

    /**
     * Desktop-compatible decrypt:
     * - nonce from RTP timestamp
     * - if RTP header is present inside encrypted_frame (fallback path),
     *   keep header bytes untouched and decrypt payload only.
     */
    Result Decrypt(cricket::MediaType media_type,
                   const std::vector<uint32_t>& csrcs,
                   rtc::ArrayView<const uint8_t> additional_data,
                   rtc::ArrayView<const uint8_t> encrypted_frame,
                   rtc::ArrayView<uint8_t> frame) override {
        uint8_t nonce[24] = {0};
        size_t header_size = 0;
        bool nonce_from_rtp_header = false;
        bool nonce_from_generated_ts = false;
        bool nonce_from_additional_data = false;
        bool additional_was_rtp_header = false;
        bool additional_used_relative_ts = false;
        bool used_additional_relative_fallback = false;
        bool used_plain_passthrough = false;
        uint32_t generated_ts_used = 0;
        nonce_from_additional_data = fill_nonce_from_additional_data(
            additional_data.data(),
            additional_data.size(),
            nonce,
            &additional_was_rtp_header,
            nullptr,
            &additional_used_relative_ts);
        if (!nonce_from_additional_data) {
            nonce_from_rtp_header =
                fill_nonce_from_rtp_frame(encrypted_frame.data(), encrypted_frame.size(), &rtp_probe_, nonce, &header_size);
            if (!nonce_from_rtp_header) {
                if (!generated_ts_.initialized) {
                    generated_ts_.initialized = true;
                    generated_ts_.next_timestamp = 0;
                    generated_ts_.next_step = 960;
                }
                nonce_from_generated_ts = true;
                generated_ts_used = generated_ts_.next_timestamp;
                fill_nonce_from_ts32(generated_ts_used, nonce);
                diag_event("DEC fallback=generated-ts mt=%s csrcs=%zu enc_sz=%zu ad_sz=%zu gen_ts=%u\n",
                           media_type_name(media_type), csrcs.size(), encrypted_frame.size(), additional_data.size(), generated_ts_used);
            }
        }

        if (encrypted_frame.size() == 0 || frame.size() < encrypted_frame.size()) {
            return {Result::Status::kFailedToDecrypt, 0};
        }

        bool used_generated_resync = false;

        // Desktop createEncodedStreams decrypts full encoded chunk.
        rosetta_xchacha20_xor(frame.data(), encrypted_frame.data(), encrypted_frame.size(), nonce, key_);

        if (nonce_from_additional_data) {
            bool plausible = is_plausible_decrypted_audio_frame(frame.data(), encrypted_frame.size());

            // Fallback for Android pipelines where additional_data timestamps are
            // stream-relative while remote side uses a different absolute base.
            if (!plausible && additional_data.size() == 8 && !additional_was_rtp_header) {
                uint8_t nonce_rel[24] = {0};
                bool rel_used = false;
                if (fill_nonce_from_additional_data(
                        additional_data.data(),
                        additional_data.size(),
                        nonce_rel,
                        nullptr,
                        &additional_rel_ts_state_,
                        &rel_used) &&
                    rel_used) {
                    std::vector<uint8_t> candidate(encrypted_frame.size());
                    rosetta_xchacha20_xor(
                        candidate.data(),
                        encrypted_frame.data(),
                        encrypted_frame.size(),
                        nonce_rel,
                        key_);
                    if (is_plausible_decrypted_audio_frame(candidate.data(), candidate.size())) {
                        memcpy(frame.data(), candidate.data(), candidate.size());
                        memcpy(nonce, nonce_rel, sizeof(nonce));
                        plausible = true;
                        used_additional_relative_fallback = true;
                        additional_used_relative_ts = true;
                        diag_event("DEC fallback=relative-ad-ts mt=%s csrcs=%zu enc_sz=%zu ad_sz=%zu nonce_ts=%u\n",
                                   media_type_name(media_type), csrcs.size(), encrypted_frame.size(),
                                   additional_data.size(), nonce_ts32(nonce));
                    }
                }
            }

            // If payload already looks like valid Opus, keep plaintext.
            // This protects interop when peer stream is unexpectedly unencrypted.
            if (!plausible &&
                is_plausible_decrypted_audio_frame(encrypted_frame.data(), encrypted_frame.size())) {
                memcpy(frame.data(), encrypted_frame.data(), encrypted_frame.size());
                used_plain_passthrough = true;
                diag_event("DEC fallback=plain-passthrough mt=%s csrcs=%zu enc_sz=%zu ad_sz=%zu\n",
                           media_type_name(media_type), csrcs.size(), encrypted_frame.size(), additional_data.size());
            }
        }

        if (nonce_from_generated_ts) {
            bool plausible = is_plausible_opus_packet(frame.data(), encrypted_frame.size());

            // Recover after lost packets by probing a few forward timestamp steps.
            if (!plausible) {
                std::vector<uint8_t> candidate(encrypted_frame.size());
                for (uint32_t i = 1; i <= 8; ++i) {
                    const uint32_t ts_try = generated_ts_used + generated_ts_.next_step * i;
                    uint8_t nonce_try[24] = {0};
                    fill_nonce_from_ts32(ts_try, nonce_try);
                    rosetta_xchacha20_xor(
                        candidate.data(),
                        encrypted_frame.data(),
                        encrypted_frame.size(),
                        nonce_try,
                        key_);
                    if (is_plausible_opus_packet(candidate.data(), candidate.size())) {
                        memcpy(frame.data(), candidate.data(), candidate.size());
                        generated_ts_used = ts_try;
                        used_generated_resync = true;
                        plausible = true;
                        diag_event("DEC fallback=generated-resync mt=%s csrcs=%zu enc_sz=%zu ts_try=%u step=%u probe=%u\n",
                                   media_type_name(media_type), csrcs.size(), encrypted_frame.size(),
                                   ts_try, generated_ts_.next_step, i);
                        break;
                    }
                }
            }

            const uint32_t step = infer_opus_packet_duration_samples(frame.data(), encrypted_frame.size());
            generated_ts_.next_step = step;
            generated_ts_.next_timestamp = generated_ts_used + step;
        }

        // Diag: log first frames with enough context for crash analysis.
        int n = diag_count_.fetch_add(1, std::memory_order_relaxed);
        if (n < kDiagFrameLimit) {
            uint8_t ad_prefix[8] = {0};
            const size_t ad_copy = additional_data.size() < sizeof(ad_prefix)
                                       ? additional_data.size()
                                       : sizeof(ad_prefix);
            if (ad_copy > 0) memcpy(ad_prefix, additional_data.data(), ad_copy);
            ParsedRtpPacket enc_rtp{};
            ParsedRtpPacket dec_rtp{};
            const bool has_enc_rtp = parse_rtp_packet(encrypted_frame.data(), encrypted_frame.size(), &enc_rtp);
            const bool has_dec_rtp = parse_rtp_packet(frame.data(), encrypted_frame.size(), &dec_rtp);
            const bool dec_plausible = is_plausible_decrypted_audio_frame(frame.data(), encrypted_frame.size());
            const uint32_t enc_hash = fnv1a32(encrypted_frame.data(), encrypted_frame.size(), kFrameHashSampleBytes);
            const uint32_t dec_hash = fnv1a32(frame.data(), encrypted_frame.size(), kFrameHashSampleBytes);
            const char* mode = nullptr;
            if (nonce_from_rtp_header) {
                mode = "rtp";
            } else if (nonce_from_generated_ts) {
                mode = used_generated_resync ? "gen-resync" : "gen";
            } else if (nonce_from_additional_data) {
                if (used_plain_passthrough) mode = "raw-plain";
                else if (additional_was_rtp_header) mode = "ad-rtp";
                else if (used_additional_relative_fallback) mode = "raw-rel-fb";
                else mode = additional_used_relative_ts ? "raw-rel" : "raw-abs";
            } else {
                mode = "raw-abs";
            }
            uint32_t bad_streak = 0;
            if (!dec_plausible) {
                bad_streak = bad_audio_streak_.fetch_add(1, std::memory_order_relaxed) + 1;
                if (bad_streak == 1 || bad_streak == 3 || bad_streak == 10 || (bad_streak % 50) == 0) {
                    diag_event("DEC degraded mt=%s csrcs=%zu mode=%s bad_streak=%u nonce_ts=%u key_fp=%08x\n",
                               media_type_name(media_type), csrcs.size(), mode, bad_streak,
                               nonce_ts32(nonce), key_fingerprint_);
                }
            } else {
                const uint32_t prev_bad = bad_audio_streak_.exchange(0, std::memory_order_relaxed);
                if (prev_bad >= 3) {
                    diag_event("DEC recovered mt=%s csrcs=%zu mode=%s prev_bad_streak=%u nonce_ts=%u key_fp=%08x\n",
                               media_type_name(media_type), csrcs.size(), mode, prev_bad,
                               nonce_ts32(nonce), key_fingerprint_);
                }
            }
            LOGI("DEC frame#%d mt=%s csrcs=%zu enc_sz=%zu ad=%zu hdr=%zu mode=%s nonce_ts=%u gen_ts=%u next_step=%u dec_ok=%d bad_streak=%u enc_rtp=%d enc_seq=%u enc_ts=%u enc_ssrc=%u dec_rtp=%d dec_seq=%u dec_ts=%u dec_ssrc=%u key_fp=%08x enc_h=%08x dec_h=%08x ad8=%02x%02x%02x%02x%02x%02x%02x%02x",
                 n, media_type_name(media_type), csrcs.size(), encrypted_frame.size(), additional_data.size(), header_size, mode,
                 nonce_ts32(nonce), generated_ts_used, generated_ts_.next_step,
                 dec_plausible ? 1 : 0, bad_streak,
                 has_enc_rtp ? 1 : 0, has_enc_rtp ? enc_rtp.sequence : 0, has_enc_rtp ? enc_rtp.timestamp : 0, has_enc_rtp ? enc_rtp.ssrc : 0,
                 has_dec_rtp ? 1 : 0, has_dec_rtp ? dec_rtp.sequence : 0, has_dec_rtp ? dec_rtp.timestamp : 0, has_dec_rtp ? dec_rtp.ssrc : 0,
                 key_fingerprint_, enc_hash, dec_hash,
                 ad_prefix[0], ad_prefix[1], ad_prefix[2], ad_prefix[3],
                 ad_prefix[4], ad_prefix[5], ad_prefix[6], ad_prefix[7]);
            diag_write("DEC frame#%d mt=%s csrcs=%zu enc_sz=%zu ad=%zu hdr=%zu mode=%s nonce_ts=%u gen_ts=%u next_step=%u dec_ok=%d bad_streak=%u enc_rtp=%d enc_seq=%u enc_ts=%u enc_ssrc=%u dec_rtp=%d dec_seq=%u dec_ts=%u dec_ssrc=%u key_fp=%08x enc_h=%08x dec_h=%08x ad8=%02x%02x%02x%02x%02x%02x%02x%02x\n",
                       n, media_type_name(media_type), csrcs.size(), encrypted_frame.size(), additional_data.size(), header_size, mode,
                       nonce_ts32(nonce), generated_ts_used, generated_ts_.next_step,
                       dec_plausible ? 1 : 0, bad_streak,
                       has_enc_rtp ? 1 : 0, has_enc_rtp ? enc_rtp.sequence : 0, has_enc_rtp ? enc_rtp.timestamp : 0, has_enc_rtp ? enc_rtp.ssrc : 0,
                       has_dec_rtp ? 1 : 0, has_dec_rtp ? dec_rtp.sequence : 0, has_dec_rtp ? dec_rtp.timestamp : 0, has_dec_rtp ? dec_rtp.ssrc : 0,
                       key_fingerprint_, enc_hash, dec_hash,
                       ad_prefix[0], ad_prefix[1], ad_prefix[2], ad_prefix[3],
                       ad_prefix[4], ad_prefix[5], ad_prefix[6], ad_prefix[7]);
        }

        return {Result::Status::kOk, encrypted_frame.size()};
    }

    size_t GetMaxPlaintextByteSize(cricket::MediaType, size_t encrypted_frame_size) override {
        return encrypted_frame_size;
    }

protected:
    ~XChaCha20Decryptor() override {
        diag_event("DEC destroy ptr=%p key_fp=%08x bad_streak=%u\n",
                   this, key_fingerprint_, bad_audio_streak_.load(std::memory_order_relaxed));
        memset(key_, 0, 32);
    }

private:
    mutable std::atomic<int> ref_{0};
    mutable std::atomic<int> diag_count_{0};
    mutable std::atomic<uint32_t> bad_audio_streak_{0};
    mutable RtpProbeState rtp_probe_;
    mutable GeneratedTsState generated_ts_;
    mutable AdditionalTsState additional_rel_ts_state_;
    uint32_t key_fingerprint_ = 0;
    uint8_t key_[32];
};

/* ════════════════════════════════════════════════════════════════
 * JNI exports
 * ════════════════════════════════════════════════════════════════ */

extern "C" {

/* ── HSalsa20 for nacl.box.before() ──────────────────────────── */

JNIEXPORT jbyteArray JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeHSalsa20(
        JNIEnv *env, jclass, jbyteArray jRawDh)
{
    jsize len = env->GetArrayLength(jRawDh);
    if (len < 32) return nullptr;

    auto *raw = (uint8_t *)env->GetByteArrayElements(jRawDh, nullptr);
    uint8_t out[32];
    uint8_t zeros[16] = {0};

    rosetta_hsalsa20(out, zeros, raw);

    env->ReleaseByteArrayElements(jRawDh, (jbyte *)raw, JNI_ABORT);

    jbyteArray result = env->NewByteArray(32);
    env->SetByteArrayRegion(result, 0, 32, (jbyte *)out);
    memset(out, 0, 32);
    return result;
}

/* ── Create / destroy encryptor ──────────────────────────────── */

JNIEXPORT jlong JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeCreateEncryptor(
        JNIEnv *env, jclass, jbyteArray jKey)
{
    jsize len = env->GetArrayLength(jKey);
    if (len < 32) {
        LOGE("Create encryptor failed: key length=%d (<32)", (int)len);
        diag_event("ENC create-failed key_len=%d\n", (int)len);
        return 0;
    }

    auto *key = (uint8_t *)env->GetByteArrayElements(jKey, nullptr);
    const uint32_t key_fp = key_fingerprint32(key);
    auto *enc = new XChaCha20Encryptor(key);
    env->ReleaseByteArrayElements(jKey, (jbyte *)key, JNI_ABORT);

    // AddRef so the pointer we hand out has ref=1.
    // WebRTC's scoped_refptr will AddRef again when it takes ownership.
    enc->AddRef();

    LOGI("Created XChaCha20 encryptor %p key_fp=%08x", enc, key_fp);
    diag_event("ENC created ptr=%p key_fp=%08x key_len=%d\n", enc, key_fp, (int)len);
    return reinterpret_cast<jlong>(enc);
}

JNIEXPORT void JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeReleaseEncryptor(
        JNIEnv *, jclass, jlong ptr)
{
    if (ptr == 0) return;
    auto *enc = reinterpret_cast<XChaCha20Encryptor *>(ptr);
    LOGI("Release XChaCha20 encryptor %p key_fp=%08x", enc, enc->KeyFingerprint());
    diag_event("ENC release ptr=%p key_fp=%08x\n", enc, enc->KeyFingerprint());
    enc->Release();
}

/* ── Create / destroy decryptor ──────────────────────────────── */

JNIEXPORT jlong JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeCreateDecryptor(
        JNIEnv *env, jclass, jbyteArray jKey)
{
    jsize len = env->GetArrayLength(jKey);
    if (len < 32) {
        LOGE("Create decryptor failed: key length=%d (<32)", (int)len);
        diag_event("DEC create-failed key_len=%d\n", (int)len);
        return 0;
    }

    auto *key = (uint8_t *)env->GetByteArrayElements(jKey, nullptr);
    const uint32_t key_fp = key_fingerprint32(key);
    auto *dec = new XChaCha20Decryptor(key);
    env->ReleaseByteArrayElements(jKey, (jbyte *)key, JNI_ABORT);

    dec->AddRef();

    LOGI("Created XChaCha20 decryptor %p key_fp=%08x", dec, key_fp);
    diag_event("DEC created ptr=%p key_fp=%08x key_len=%d\n", dec, key_fp, (int)len);
    return reinterpret_cast<jlong>(dec);
}

JNIEXPORT void JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeReleaseDecryptor(
        JNIEnv *, jclass, jlong ptr)
{
    if (ptr == 0) return;
    auto *dec = reinterpret_cast<XChaCha20Decryptor *>(ptr);
    LOGI("Release XChaCha20 decryptor %p key_fp=%08x", dec, dec->KeyFingerprint());
    diag_event("DEC release ptr=%p key_fp=%08x\n", dec, dec->KeyFingerprint());
    dec->Release();
}

/* ── Install native crash handler ─────────────────────────────── */

JNIEXPORT void JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeInstallCrashHandler(
        JNIEnv *env, jclass, jstring jPath)
{
    const char *path = env->GetStringUTFChars(jPath, nullptr);
    strncpy(g_crash_path, path, sizeof(g_crash_path) - 1);
    env->ReleaseStringUTFChars(jPath, path);

    struct sigaction sa = {};
    sa.sa_sigaction = native_crash_handler;
    sa.sa_flags = SA_SIGINFO;
    sigemptyset(&sa.sa_mask);

    sigaction(SIGSEGV, &sa, &g_old_sigsegv);
    sigaction(SIGABRT, &sa, &g_old_sigabrt);

    LOGI("Native crash handler installed, path=%s", g_crash_path);
}

/* ── Open diagnostics file for E2EE frame logging ────────────── */

JNIEXPORT void JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeOpenDiagFile(
        JNIEnv *env, jclass, jstring jPath)
{
    if (g_diag_fd >= 0) { close(g_diag_fd); g_diag_fd = -1; }
    g_diag_event_count.store(0, std::memory_order_relaxed);

    const char *path = env->GetStringUTFChars(jPath, nullptr);
    strncpy(g_diag_path, path, sizeof(g_diag_path) - 1);
    g_diag_fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
    env->ReleaseStringUTFChars(jPath, path);

    if (g_diag_fd >= 0) {
        diag_write("=== E2EE DIAGNOSTICS pid=%d ===\n", (int)getpid());
        LOGI("Diag file opened: %s", g_diag_path);
        diag_event("DIAG open path=%s\n", g_diag_path);
    } else {
        LOGE("Failed to open diag file: %s", g_diag_path);
    }
}

JNIEXPORT void JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeCloseDiagFile(
        JNIEnv *, jclass)
{
    if (g_diag_fd >= 0) {
        diag_event("DIAG close path=%s\n", g_diag_path);
        diag_write("=== END ===\n");
        close(g_diag_fd);
        g_diag_fd = -1;
    }
}

/* ── Query frame counts for health checks ────────────────────── */

JNIEXPORT jint JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeGetEncryptorFrameCount(
        JNIEnv *, jclass, jlong ptr)
{
    if (ptr == 0) return -1;
    auto *enc = reinterpret_cast<XChaCha20Encryptor *>(ptr);
    return enc->FrameCount();
}

JNIEXPORT jint JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeGetDecryptorFrameCount(
        JNIEnv *, jclass, jlong ptr)
{
    if (ptr == 0) return -1;
    auto *dec = reinterpret_cast<XChaCha20Decryptor *>(ptr);
    return dec->FrameCount();
}

JNIEXPORT jint JNICALL
Java_com_rosetta_messenger_network_XChaCha20E2EE_nativeGetDecryptorBadStreak(
        JNIEnv *, jclass, jlong ptr)
{
    if (ptr == 0) return -1;
    auto *dec = reinterpret_cast<XChaCha20Decryptor *>(ptr);
    return dec->BadStreak();
}

} /* extern "C" */