#ifndef TRAIN_INC_CPP

#define TRAIN_INC_CPP

#include "layer.inc.cpp"

class Trainer: public ThreadControl {

private:

  std::vector<Quality> qualities;

public:

  Layer *layer;

  AccumReal ratio;

  int threadsCount;

  int itersPerBlock;

  int blocksPerSaving;

  int blocksCount;

  AccumReal qmin;

protected:

  std::atomic<unsigned int> skipBackpass;

  Layer *fl;

  Layer *bl;

  Layer *ffl;

  int currentBlock;

  virtual bool prepare() { return true; }

  virtual bool prepareBlock() { return true; }

  virtual void finishBlock() { }

  virtual void finish() { }

  virtual void loadData(Barrier &barrier, int block, int iter) { }

  virtual Quality verifyData(Barrier &barrier, int block, int iter) { return Quality{}; }

private:

  void threadFunc(Barrier &barrier) override {

    int block = currentBlock;

    Quality sumQ;

    for(int i = 0; i < itersPerBlock; ++i) {

      barrier.wait();

      loadData(barrier, block, i);

      for(Layer *l = fl->next; l; l = l->next) {

        barrier.wait();

        l->pass(barrier);

      }

      barrier.wait();

      skipBackpass = 0;

      sumQ += verifyData(barrier, block, i);

      barrier.wait();

      bool skipBp = skipBackpass;

      barrier.wait();

      if (ffl && ratio > 0 && !skipBp) {

        for(Layer *l = bl; l != ffl; l = l->prev) {

          barrier.wait();

          l->backpassDeltas(barrier);

        }

        for(Layer *l = bl; l->prev; l = l->prev) {

          if (!l->skipTrain) {

            barrier.wait();

            l->backpassWeights(barrier);

          }

        }

      }

    }

    qualities[barrier.tid] = sumQ;

  }

  Quality runThreads(int block) {

    currentBlock = block;

    ThreadControl::runThreads(threadsCount);

    Quality q;

    for(int i = 0; i < threadsCount; ++i) q += qualities[i];

    return q *= 1/(AccumReal)itersPerBlock;

  }

public:

  Trainer():

    layer(),

    ratio(),

    threadsCount(1),

    itersPerBlock(100),

    blocksPerSaving(),

    blocksCount(1000),

    qmin(),

    skipBackpass(0),

    fl(),

    bl() { }

  Trainer& configure(

    Layer &layer,

    AccumReal ratio,

    int threadsCount,

    int itersPerBlock,

    int blocksPerSaving,

    int blocksCount,

    AccumReal qmin )

  {

    this->layer           = &layer;

    this->ratio           = ratio;

    this->threadsCount    = threadsCount;

    this->itersPerBlock   = itersPerBlock;

    this->blocksPerSaving = blocksPerSaving;

    this->blocksCount     = blocksCount;

    this->qmin            = qmin;

    return *this;

  }

  Quality run() {

    assert(layer && !layer->prev && layer->next);

    assert(threadsCount > 0);

    assert(itersPerBlock > 0);

    Quality bad = {INFINITY, INFINITY};

    printf("training: threads %d, itersPerBlock %d, ratio: %lf\n", threadsCount, itersPerBlock, ratio);

    fflush(stdout);

    fl = layer;

    bl = &layer->back();

    ffl = fl->next;

    while(ffl && ffl->skipTrain) ffl = ffl->next;

    qualities.clear();

    qualities.resize(threadsCount, Quality{});

    for(Layer *l = layer; l; l = l->next)

      l->split(threadsCount);

    if (!prepare())

      return printf("cannot prepare\n"), bad;

    AccumReal ratioCopy = ratio;

    Quality result = bad, best = result, saved = result;

    long long fullTimeStartUs = timeUs();

    ratio = 0;

    int i = 0;

    int bps = blocksPerSaving > 0 ? blocksPerSaving : 1;

    int nextSave = i + bps;

    while(true) {

      if (!prepareBlock()) {

        printf("cannot prepare block\n");

        result = bad;

        break;

      };

      long long runTimeUs = timeUs();

      result = runThreads(i);

      runTimeUs = timeUs() - runTimeUs;

      finishBlock();

      long long t = timeUs();

      long long fullTimeUs = t - fullTimeStartUs;

      fullTimeStartUs = t;

      ++i;

      if (i == 1) saved = result;

      bool good = result < best;

      bool done = (blocksCount > 0 && i >= blocksCount) || result.human <= qmin;

      bool saving = ratio > 0 && (i >= nextSave || done) && result < saved;

      if (good) best = result;

      printf("%4d, total %7d, avg.result %f (%f), best %f (%f), time: %f / %f%s\n",

        i, i*itersPerBlock,

        result.human, result.train, best.human, best.train,

        runTimeUs*0.000001, fullTimeUs*0.000001,

        (saving ? ", saving" : "" ) );

      fflush(stdout);

      if (saving) {

        if (!layer->save()) {

          printf("saving failed\n");

          result = bad;

          break;

        }

        saved = result;

        nextSave += bps;

      }

      if (done) break;

      ratio = ratioCopy;

    }

    ratio = ratioCopy;

    finish();

    return result;

  }

};

#endif