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/*-
 * ========================LICENSE_START=================================
 * jgea-problem
 * %%
 * Copyright (C) 2018 - 2024 Eric Medvet
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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.
 * =========================LICENSE_END==================================
 */

package io.github.ericmedvet.jgea.problem.mapper;

import io.github.ericmedvet.jgea.core.representation.grammar.string.StringGrammar;
import io.github.ericmedvet.jgea.core.representation.grammar.string.ge.WeightedHierarchicalMapper;
import io.github.ericmedvet.jgea.core.representation.sequence.bit.BitString;
import io.github.ericmedvet.jgea.core.representation.tree.Tree;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

public class RecursiveMapper extends WeightedHierarchicalMapper {

  private final Tree optionChooser;
  private final Tree genoAssigner;
  private final int maxMappingDepth;

  public RecursiveMapper(
      Tree optionChooser,
      Tree genoAssigner,
      int maxMappingDepth,
      int maxDepth,
      StringGrammar grammar) {
    super(maxDepth, grammar);
    this.maxMappingDepth = maxMappingDepth;
    this.optionChooser = optionChooser;
    this.genoAssigner = genoAssigner;
  }

  @Override
  public Tree apply(BitString genotype) {
    AtomicInteger mappingGlobalCounter = new AtomicInteger();
    AtomicInteger finalizationGlobalCounter = new AtomicInteger();
    return mapRecursively(grammar.startingSymbol(), genotype, mappingGlobalCounter, finalizationGlobalCounter, 0);
  }

  private Tree mapRecursively(
      T symbol,
      BitString genotype,
      AtomicInteger mappingGlobalCounter,
      AtomicInteger finalizationGlobalCounter,
      int depth) {
    Tree tree = Tree.of(symbol);
    if (!grammar.rules().containsKey(symbol)) {
      return tree;
    }
    if (depth >= maxMappingDepth) {
      List shortestOptionIndexTies = shortestOptionIndexesMap.get(symbol);
      List shortestOption = grammar.rules()
          .get(symbol)
          .get(shortestOptionIndexTies.get(
              finalizationGlobalCounter.getAndIncrement() % shortestOptionIndexTies.size()));
      for (T optionSymbol : shortestOption) {
        tree.addChild(mapRecursively(
            optionSymbol, genotype, mappingGlobalCounter, finalizationGlobalCounter, depth + 1));
      }
      return tree;
    }
    // choose option
    List> options = grammar.rules().get(symbol);
    List expressivenesses = new ArrayList<>(options.size());
    for (List option : options) {
      double expressiveness = 1d;
      for (T optionSymbol : option) {
        expressiveness = expressiveness * (double) weightsMap.getOrDefault(optionSymbol, 1);
      }
      expressivenesses.add(expressiveness);
    }
    int optionIndex = ((Double)
            MapperUtils.compute(optionChooser, genotype, expressivenesses, depth, mappingGlobalCounter))
        .intValue();
    optionIndex = Math.min(optionIndex, options.size() - 1);
    optionIndex = Math.max(0, optionIndex);
    // split genotype
    expressivenesses.clear();
    for (T optionSymbol : options.get(optionIndex)) {
      expressivenesses.add((double) weightsMap.getOrDefault(optionSymbol, 1));
    }
    @SuppressWarnings("unchecked")
    List pieces = ((List)
        MapperUtils.compute(genoAssigner, genotype, expressivenesses, depth, mappingGlobalCounter));
    for (int i = 0; i < options.get(optionIndex).size(); i++) {
      BitString piece;
      if (pieces.size() > i) {
        piece = pieces.get(i);
      } else {
        piece = new BitString(0);
      }
      tree.addChild(mapRecursively(
          options.get(optionIndex).get(i),
          piece,
          mappingGlobalCounter,
          finalizationGlobalCounter,
          depth + 1));
    }
    return tree;
  }
}