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// Copyright 2015-2024 Nstream, inc.
//
// Licensed under the Redis Source Available License 2.0 (RSALv2) Agreement;
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://redis.com/legal/rsalv2-agreement/
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package nstream.adapter.aggr.online;

import swim.structure.Field;
import swim.structure.Record;
import swim.structure.Slot;
import swim.structure.Value;

public class OnlineComputer {

  protected OnlineAggr[] aggrs;
  protected Record kpi;  // must be mutable
  private int idx;

  @SuppressWarnings({"unchecked", "rawtypes"})
  public OnlineComputer(int rows) {
    this.aggrs = new OnlineAggr[rows];
    this.kpi = Record.create(rows);
  }

  public void addAggr(OnlineAggr aggr) {
    if (this.idx >= this.aggrs.length) {
      throw new IllegalStateException("OnlineComputer capacity exceeded");
    }
    this.aggrs[idx++] = aggr;
    if (aggr.alias() == null) {
      throw new IllegalArgumentException("aggr must have a defined alias()");
    }
    this.kpi.add(Slot.of(aggr.alias()));
  }

  public void receive(M v) {
    if (this.idx != this.aggrs.length) {
      throw new IllegalStateException("Can't receive before declaring all Aggrs");
    }
    for (int i = 0; i < this.aggrs.length; i++) {
      final OnlineAggr aggr = this.aggrs[i];
      try {
        if (aggr.receive(v)) {
          ((Field) this.kpi.getItem(i)).setValue(aggr.resultToValue());
        }
      } catch (Exception e) {
        new Exception("OnlineKpiComputer exception at index " + i, e).printStackTrace();
      }
    }
  }

  public Record moldState() {
    final Record state = Record.create(this.aggrs.length);
    for (OnlineAggr aggr : this.aggrs) {
      state.add(aggr.moldState());
    }
    return state;
  }

  //  public void castState(Record state) throws QuiltComputeException {
  //    if (state.length() != this.aggrs.length) {
  //      throw new QuiltComputeException(this.idx + "-length state required, received: " + state);
  //    }
  //    for (int i = 0; i < this.aggrs.length; i++) {
  //      try {
  //        this.aggrs[i].castState((Value) state.getItem(i));
  //      } catch ()
  //
  //      ((Field) this.kpi.getItem(i)).setValue(this.aggrs[i].resultToValue());
  //    }
  //  }

  public void reset() {
    for (int i = 0; i < this.aggrs.length; i++) {
      this.aggrs[i].reset();
      ((Field) this.kpi.getItem(i)).setValue(Value.extant());
    }
  }

  public Value evaluate() {
    return cloneKpi();
  }

  private Value cloneKpi() {
    final Record result = Record.create(this.kpi.length());
    for (int i = 0; i < this.kpi.length(); i++) {
      result.add(Slot.of(this.kpi.getItem(i).key(), this.kpi.getItem(i).toValue()));
    }
    return result;
  }

}