/**
 * @file BinaryRecorder.cpp
 * @brief Per-source binary recorder implementation.
 *
 * @copyright Copyright 2015 F4E | European Joint Undertaking for ITER and
 * the Development of Fusion Energy ('Fusion for Energy').
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved
 * by the European Commission - subsequent versions of the EUPL (the "Licence")
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at: http://ec.europa.eu/idabc/eupl
 *
 * @warning Unless required by applicable law or agreed to in writing,
 * software distributed under the Licence is distributed on an "AS IS"
 * basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the Licence permissions and limitations under the Licence.
 */

#include "BinaryRecorder.h"

#include "AdvancedErrorManagement.h"
#include "TypeDescriptor.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/statvfs.h>
#include <fcntl.h>
#include <unistd.h>
#include <dirent.h>

namespace StreamHub {

/*---------------------------------------------------------------------------*/
/* Static helpers                                                             */
/*---------------------------------------------------------------------------*/

uint16 BinaryRecorder::TypeCodeToDescriptorAll(uint8 udpsTypeCode) {
    switch (udpsTypeCode) {
        case MARTe::UDPS_TYPECODE_UINT8:   return MARTe::UnsignedInteger8Bit.all;
        case MARTe::UDPS_TYPECODE_INT8:    return MARTe::SignedInteger8Bit.all;
        case MARTe::UDPS_TYPECODE_UINT16:  return MARTe::UnsignedInteger16Bit.all;
        case MARTe::UDPS_TYPECODE_INT16:   return MARTe::SignedInteger16Bit.all;
        case MARTe::UDPS_TYPECODE_UINT32:  return MARTe::UnsignedInteger32Bit.all;
        case MARTe::UDPS_TYPECODE_INT32:   return MARTe::SignedInteger32Bit.all;
        case MARTe::UDPS_TYPECODE_UINT64:  return MARTe::UnsignedInteger64Bit.all;
        case MARTe::UDPS_TYPECODE_INT64:   return MARTe::SignedInteger64Bit.all;
        case MARTe::UDPS_TYPECODE_FLOAT32: return MARTe::Float32Bit.all;
        case MARTe::UDPS_TYPECODE_FLOAT64: return MARTe::Float64Bit.all;
        default:                           return MARTe::Float64Bit.all;
    }
}

uint32 BinaryRecorder::EncodeNative(uint8 typeCode, float64 v, uint8 *dst) {
    switch (typeCode) {
        case MARTe::UDPS_TYPECODE_UINT8: {
            uint8 x = static_cast<uint8>(v); memcpy(dst, &x, 1u); return 1u;
        }
        case MARTe::UDPS_TYPECODE_INT8: {
            MARTe::int8 x = static_cast<MARTe::int8>(v); memcpy(dst, &x, 1u); return 1u;
        }
        case MARTe::UDPS_TYPECODE_UINT16: {
            uint16 x = static_cast<uint16>(v); memcpy(dst, &x, 2u); return 2u;
        }
        case MARTe::UDPS_TYPECODE_INT16: {
            MARTe::int16 x = static_cast<MARTe::int16>(v); memcpy(dst, &x, 2u); return 2u;
        }
        case MARTe::UDPS_TYPECODE_UINT32: {
            uint32 x = static_cast<uint32>(v); memcpy(dst, &x, 4u); return 4u;
        }
        case MARTe::UDPS_TYPECODE_INT32: {
            MARTe::int32 x = static_cast<MARTe::int32>(v); memcpy(dst, &x, 4u); return 4u;
        }
        case MARTe::UDPS_TYPECODE_UINT64: {
            uint64 x = static_cast<uint64>(v); memcpy(dst, &x, 8u); return 8u;
        }
        case MARTe::UDPS_TYPECODE_INT64: {
            MARTe::int64 x = static_cast<MARTe::int64>(v); memcpy(dst, &x, 8u); return 8u;
        }
        case MARTe::UDPS_TYPECODE_FLOAT32: {
            float x = static_cast<float>(v); memcpy(dst, &x, 4u); return 4u;
        }
        case MARTe::UDPS_TYPECODE_FLOAT64: {
            float64 x = v; memcpy(dst, &x, 8u); return 8u;
        }
        default: return 0u;
    }
}

/** Local dequantization mirror of UDPSourceSession::DequantizeValue. */
static float64 RecDequantize(float64 q, uint8 quantType,
                             float64 rangeMin, float64 rangeMax) {
    const float64 range = rangeMax - rangeMin;
    switch (quantType) {
        case MARTe::UDPS_QUANT_UINT8:  return rangeMin + (q / 255.0) * range;
        case MARTe::UDPS_QUANT_INT8:   return rangeMin + ((q + 127.0) / 254.0) * range;
        case MARTe::UDPS_QUANT_UINT16: return rangeMin + (q / 65535.0) * range;
        case MARTe::UDPS_QUANT_INT16:  return rangeMin + ((q + 32767.0) / 65534.0) * range;
        default:                       return q;
    }
}

/** Read one quantized wire element as a float64 integer value. */
static float64 RecDecodeQuantWire(const uint8 *ptr, uint8 quantType) {
    switch (quantType) {
        case MARTe::UDPS_QUANT_UINT8: {
            uint8 v = 0u; memcpy(&v, ptr, 1u); return static_cast<float64>(v);
        }
        case MARTe::UDPS_QUANT_INT8: {
            MARTe::int8 v = 0; memcpy(&v, ptr, 1u); return static_cast<float64>(v);
        }
        case MARTe::UDPS_QUANT_UINT16: {
            uint16 v = 0u; memcpy(&v, ptr, 2u); return static_cast<float64>(v);
        }
        case MARTe::UDPS_QUANT_INT16: {
            MARTe::int16 v = 0; memcpy(&v, ptr, 2u); return static_cast<float64>(v);
        }
        default: return 0.0;
    }
}

static uint32 RecQuantWireBytes(uint8 quantType) {
    switch (quantType) {
        case MARTe::UDPS_QUANT_UINT8:  return 1u;
        case MARTe::UDPS_QUANT_INT8:   return 1u;
        case MARTe::UDPS_QUANT_UINT16: return 2u;
        case MARTe::UDPS_QUANT_INT16:  return 2u;
        default:                       return 0u;
    }
}

/*---------------------------------------------------------------------------*/
/* Constructor / Destructor                                                   */
/*---------------------------------------------------------------------------*/

BinaryRecorder::BinaryRecorder()
    : nIncluded_(0u),
      rowBytes_(0u),
      headerLen_(0u),
      layoutReady_(false),
      pushHeaderLen_(0u),
      pushRowBytes_(0u),
      front_(static_cast<uint8 *>(0)),
      back_(static_cast<uint8 *>(0)),
      frontLen_(0u),
      backLen_(0u),
      pendingArm_(false),
      pendingDisarm_(false),
      pendingReopen_(false),
      fd_(-1),
      fileOffset_(0u),
      lastSyncSec_(0u),
      fileSeq_(0u),
      armed_(false),
      diskLow_(false),
      bytesWritten_(0u),
      rowsWritten_(0u),
      droppedRows_(0u) {
    memset(&config_, 0, sizeof(config_));
    sourceId_[0] = '\0';
    curFilePath_[0] = '\0';
    stagingMutex_.Create();
}

BinaryRecorder::~BinaryRecorder() {
    CloseFile();
    if (front_ != static_cast<uint8 *>(0)) { delete[] front_; front_ = static_cast<uint8 *>(0); }
    if (back_ != static_cast<uint8 *>(0)) { delete[] back_; back_ = static_cast<uint8 *>(0); }
}

/*---------------------------------------------------------------------------*/
/* Init                                                                       */
/*---------------------------------------------------------------------------*/

void BinaryRecorder::Init(const RecorderConfig &cfg, const char *sourceId) {
    config_ = cfg;
    if (config_.stagingBytes < 4096u) { config_.stagingBytes = 4096u; }
    strncpy(sourceId_, (sourceId != static_cast<const char *>(0)) ? sourceId : "src",
            sizeof(sourceId_) - 1u);
    sourceId_[sizeof(sourceId_) - 1u] = '\0';

    front_ = new uint8[config_.stagingBytes];
    back_  = new uint8[config_.stagingBytes];
    frontLen_ = 0u;
    backLen_  = 0u;

    /* Create output directory (best-effort). */
    if (config_.directory[0] != '\0') {
        (void) mkdir(config_.directory, 0775);
    }

    if (config_.autoStart) {
        pendingArm_ = true;
    }
}

/*---------------------------------------------------------------------------*/
/* Configure (receive thread)                                                 */
/*---------------------------------------------------------------------------*/

void BinaryRecorder::Configure(const MARTe::UDPSSignalDescriptor *descs,
                               uint32 nSigs, const bool *includeMask) {
    uint32 inc = 0u;
    for (uint32 s = 0u; (s < nSigs) && (inc < kRecMaxSig); s++) {
        if ((includeMask != static_cast<const bool *>(0)) && (!includeMask[s])) {
            continue;
        }
        const MARTe::UDPSSignalDescriptor &d = descs[s];
        uint32 nElems = d.numRows * d.numCols;
        if (nElems == 0u) { nElems = 1u; }
        const uint32 native = MARTe::UDPSTypeCodeByteSize(d.typeCode);
        if (native == 0u) { continue; }
        const uint32 wire = (d.quantType != MARTe::UDPS_QUANT_NONE)
                            ? RecQuantWireBytes(d.quantType)
                            : native;
        srcIdx_[inc]        = s;
        typeCode_[inc]      = d.typeCode;
        quantType_[inc]     = d.quantType;
        declaredElems_[inc] = nElems;
        nativeBytes_[inc]   = native;
        wireBytes_[inc]     = wire;
        rangeMin_[inc]      = d.rangeMin;
        rangeMax_[inc]      = d.rangeMax;
        inc++;
    }
    nIncluded_ = inc;

    /* Build the FileWriter header blob and compute the row size. */
    uint32 pos = 0u;
    memcpy(&headerBlob_[pos], &nIncluded_, 4u); pos += 4u;
    uint32 row = 0u;
    for (uint32 i = 0u; i < nIncluded_; i++) {
        const uint16 tcAll = TypeCodeToDescriptorAll(typeCode_[i]);
        memcpy(&headerBlob_[pos], &tcAll, 2u); pos += 2u;
        /* 32-byte name, null-padded, truncated from the descriptor name. */
        char name32[32];
        memset(name32, 0, sizeof(name32));
        strncpy(name32, descs[srcIdx_[i]].name, sizeof(name32) - 1u);
        memcpy(&headerBlob_[pos], name32, 32u); pos += 32u;
        memcpy(&headerBlob_[pos], &declaredElems_[i], 4u); pos += 4u;
        row += declaredElems_[i] * nativeBytes_[i];
    }
    headerLen_ = pos;
    rowBytes_ = row;

    (void) stagingMutex_.FastLock();
    layoutReady_ = true;
    pendingReopen_ = true;
    /* Discard any rows staged under the previous layout: they would belong
     * to the file being closed and must not be mixed into the new layout. */
    frontLen_ = 0u;
    stagingMutex_.FastUnLock();
}

/*---------------------------------------------------------------------------*/
/* CapturePacket (receive thread)                                             */
/*---------------------------------------------------------------------------*/

void BinaryRecorder::CapturePacket(const uint8 *payload, const uint32 *sigOff,
                                   const uint32 *sigElems, uint8 publishMode,
                                   uint32 numSamples) {
    if (!layoutReady_ || (nIncluded_ == 0u) || (rowBytes_ == 0u)) { return; }
    const bool accumulate = (publishMode == MARTe::UDPS_PUBLISH_ACCUMULATE);
    uint32 numRows = accumulate ? numSamples : 1u;
    if (numRows == 0u) { numRows = 1u; }

    const uint32 rowSpan = numRows * rowBytes_;

    (void) stagingMutex_.FastLock();
    if (frontLen_ + rowSpan > config_.stagingBytes) {
        droppedRows_ += static_cast<uint64>(numRows);
        stagingMutex_.FastUnLock();
        return;
    }

    for (uint32 r = 0u; r < numRows; r++) {
        for (uint32 i = 0u; i < nIncluded_; i++) {
            const uint32 s = srcIdx_[i];
            const uint8 *base = payload + sigOff[s];
            /* A per-sample (accumulated) scalar carries numSamples wire values;
             * a plain scalar carries one value that is repeated across rows. */
            const bool isAccumScalar = accumulate && (declaredElems_[i] == 1u) &&
                                       (sigElems[s] > 1u);
            const uint32 nElem = declaredElems_[i];

            if (quantType_[i] == MARTe::UDPS_QUANT_NONE) {
                if (isAccumScalar) {
                    /* Take wire element r for an accumulated scalar. */
                    memcpy(&front_[frontLen_], base + r * wireBytes_[i],
                           nativeBytes_[i]);
                    frontLen_ += nativeBytes_[i];
                }
                else {
                    /* Straight copy of all elements (wire == native size). */
                    const uint32 bytes = nElem * nativeBytes_[i];
                    memcpy(&front_[frontLen_], base, bytes);
                    frontLen_ += bytes;
                }
            }
            else {
                /* Quantized: dequantize + re-encode per element. */
                for (uint32 e = 0u; e < nElem; e++) {
                    const uint32 wireIdx = isAccumScalar ? r : e;
                    const float64 q = RecDecodeQuantWire(
                        base + wireIdx * wireBytes_[i], quantType_[i]);
                    const float64 phys = RecDequantize(q, quantType_[i],
                                                       rangeMin_[i], rangeMax_[i]);
                    frontLen_ += EncodeNative(typeCode_[i], phys,
                                              &front_[frontLen_]);
                }
            }
        }
    }
    stagingMutex_.FastUnLock();
}

/*---------------------------------------------------------------------------*/
/* FlushTick (push thread)                                                     */
/*---------------------------------------------------------------------------*/

void BinaryRecorder::FlushTick(uint32 nowSec) {
    bool doArm = false;
    bool doDisarm = false;
    bool doReopen = false;

    (void) stagingMutex_.FastLock();
    doArm = pendingArm_;       pendingArm_ = false;
    doDisarm = pendingDisarm_; pendingDisarm_ = false;
    doReopen = pendingReopen_; pendingReopen_ = false;
    if (doReopen && layoutReady_) {
        memcpy(pushHeader_, headerBlob_, headerLen_);
        pushHeaderLen_ = headerLen_;
        pushRowBytes_ = rowBytes_;
    }
    /* Swap front -> back. */
    uint8 *tmp = back_;
    back_ = front_;
    front_ = tmp;
    backLen_ = frontLen_;
    frontLen_ = 0u;
    stagingMutex_.FastUnLock();

    if (doArm) { armed_ = true; }

    if (doReopen) {
        /* Layout changed: close the current file. The freshly swapped back
         * buffer holds new-layout rows and is written to the new file below. */
        CloseFile();
    }

    if (doDisarm) {
        if ((fd_ >= 0) && (backLen_ > 0u)) {
            (void) pwrite(fd_, back_, backLen_, static_cast<off_t>(fileOffset_));
            fileOffset_ += backLen_;
            bytesWritten_ += backLen_;
        }
        backLen_ = 0u;
        armed_ = false;
        CloseFile();
        return;
    }

    if (!armed_) {
        backLen_ = 0u;
        return;
    }

    /* Disk-free guard. */
    if (!HasSufficientDisk()) {
        if (!diskLow_) {
            diskLow_ = true;
            REPORT_ERROR_STATIC(MARTe::ErrorManagement::Warning,
                "BinaryRecorder: free disk below MinDiskFreeMB; recording stopped");
        }
        armed_ = false;
        backLen_ = 0u;
        CloseFile();
        return;
    }
    diskLow_ = false;

    /* Open a file if none is active. */
    if ((fd_ < 0) && (pushHeaderLen_ > 0u)) {
        OpenNewFile();
    }
    if (fd_ < 0) {
        backLen_ = 0u;
        return;
    }

    /* Flush staged rows. */
    if (backLen_ > 0u) {
        const ssize_t w = pwrite(fd_, back_, backLen_,
                                 static_cast<off_t>(fileOffset_));
        if (w > 0) {
            fileOffset_ += static_cast<uint64>(w);
            bytesWritten_ += static_cast<uint64>(w);
            if (pushRowBytes_ > 0u) {
                rowsWritten_ += static_cast<uint64>(w) / pushRowBytes_;
            }
        }
        backLen_ = 0u;
    }

    /* Rotate on size cap. */
    if (fileOffset_ >= static_cast<uint64>(config_.maxFileBytes)) {
        CloseFile();
        OpenNewFile();
        PruneOldFiles();
    }

    /* Periodic durability. */
    if ((fd_ >= 0) &&
        ((nowSec - lastSyncSec_) >= config_.flushIntervalSec)) {
        (void) fdatasync(fd_);
        lastSyncSec_ = nowSec;
    }
}

/*---------------------------------------------------------------------------*/
/* File management (push thread)                                              */
/*---------------------------------------------------------------------------*/

void BinaryRecorder::OpenNewFile() {
    struct timeval tv;
    (void) gettimeofday(&tv, static_cast<struct timezone *>(0));
    struct tm tmv;
    time_t secs = static_cast<time_t>(tv.tv_sec);
    (void) gmtime_r(&secs, &tmv);
    char stamp[32];
    (void) strftime(stamp, sizeof(stamp), "%Y%m%dT%H%M%S", &tmv);

    fileSeq_++;
    (void) snprintf(curFilePath_, sizeof(curFilePath_),
                    "%s/%s_%s_%08u.bin",
                    config_.directory, sourceId_, stamp, fileSeq_);

    fd_ = open(curFilePath_, O_WRONLY | O_CREAT | O_TRUNC, 0664);
    if (fd_ < 0) {
        REPORT_ERROR_STATIC(MARTe::ErrorManagement::Warning,
            "BinaryRecorder: failed to open recording file");
        fileOffset_ = 0u;
        return;
    }
    (void) pwrite(fd_, pushHeader_, pushHeaderLen_, 0);
    fileOffset_ = pushHeaderLen_;
}

void BinaryRecorder::CloseFile() {
    if (fd_ >= 0) {
        (void) fdatasync(fd_);
        (void) close(fd_);
        fd_ = -1;
    }
    fileOffset_ = 0u;
}

void BinaryRecorder::PruneOldFiles() {
    DIR *dir = opendir(config_.directory);
    if (dir == static_cast<DIR *>(0)) { return; }

    char prefix[160];
    (void) snprintf(prefix, sizeof(prefix), "%s_", sourceId_);
    const size_t prefixLen = strlen(prefix);

    static const uint32 kMaxList = 4096u;
    char (*names)[256] = new char[kMaxList][256];
    uint32 count = 0u;

    struct dirent *ent;
    while (((ent = readdir(dir)) != static_cast<struct dirent *>(0)) &&
           (count < kMaxList)) {
        const char *nm = ent->d_name;
        const size_t nlen = strlen(nm);
        if (nlen < prefixLen + 4u) { continue; }
        if (strncmp(nm, prefix, prefixLen) != 0) { continue; }
        if (strcmp(nm + (nlen - 4u), ".bin") != 0) { continue; }
        strncpy(names[count], nm, 255u);
        names[count][255] = '\0';
        count++;
    }
    (void) closedir(dir);

    /* Sort ascending (lexicographic == chronological via timestamp+seq). */
    for (uint32 a = 0u; a < count; a++) {
        for (uint32 b = a + 1u; b < count; b++) {
            if (strcmp(names[a], names[b]) > 0) {
                char t[256];
                strncpy(t, names[a], 256u);
                strncpy(names[a], names[b], 256u);
                strncpy(names[b], t, 256u);
            }
        }
    }

    /* Unlink oldest until at most keepFiles remain. */
    if (count > config_.keepFiles) {
        const uint32 toRemove = count - config_.keepFiles;
        for (uint32 i = 0u; i < toRemove; i++) {
            char full[768];
            (void) snprintf(full, sizeof(full), "%s/%s",
                            config_.directory, names[i]);
            (void) unlink(full);
        }
    }

    delete[] names;
}

bool BinaryRecorder::HasSufficientDisk() {
    if (config_.minDiskFreeMB == 0u) { return true; }
    struct statvfs st;
    if (statvfs(config_.directory, &st) != 0) { return true; }
    const uint64 freeBytes = static_cast<uint64>(st.f_bavail) *
                             static_cast<uint64>(st.f_frsize);
    const uint64 freeMB = freeBytes / (1024u * 1024u);
    return freeMB >= static_cast<uint64>(config_.minDiskFreeMB);
}

/*---------------------------------------------------------------------------*/
/* Control + info                                                             */
/*---------------------------------------------------------------------------*/

void BinaryRecorder::RequestArm() {
    (void) stagingMutex_.FastLock();
    pendingArm_ = true;
    pendingDisarm_ = false;
    stagingMutex_.FastUnLock();
}

void BinaryRecorder::RequestDisarm() {
    (void) stagingMutex_.FastLock();
    pendingDisarm_ = true;
    pendingArm_ = false;
    stagingMutex_.FastUnLock();
}

bool BinaryRecorder::IsEnabled() const {
    return config_.enabled;
}

void BinaryRecorder::GetInfo(bool &recording, char *file, uint32 fileSz,
                             uint64 &bytesWritten, uint64 &rowsWritten,
                             uint64 &droppedRows, uint64 &freeMB) const {
    recording = armed_ && (fd_ >= 0);
    if ((file != static_cast<char *>(0)) && (fileSz > 0u)) {
        strncpy(file, curFilePath_, fileSz - 1u);
        file[fileSz - 1u] = '\0';
    }
    bytesWritten = bytesWritten_;
    rowsWritten = rowsWritten_;
    droppedRows = droppedRows_;

    freeMB = 0u;
    struct statvfs st;
    if (statvfs(config_.directory, &st) == 0) {
        const uint64 freeBytes = static_cast<uint64>(st.f_bavail) *
                                 static_cast<uint64>(st.f_frsize);
        freeMB = freeBytes / (1024u * 1024u);
    }
}

} /* namespace StreamHub */