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/*
 * Copyright 2014 Shape Security, Inc.
 *
 * 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.
 */

package com.shapesecurity.shift.minifier;

import com.shapesecurity.functional.data.ImmutableList;
import com.shapesecurity.shift.ast.Script;
import com.shapesecurity.shift.minifier.passes.expansion.ExpandBooleanLiterals;
import com.shapesecurity.shift.minifier.passes.expansion.ReplaceStaticMemberAccessWithDynamicMemberAccess;
import com.shapesecurity.shift.minifier.passes.expansion.TopLevelExpressionWithProhibitedFirstToken;
import com.shapesecurity.shift.minifier.passes.reduction.FlattenBlocks;
import com.shapesecurity.shift.minifier.passes.reduction.ReduceNestedIfStatements;
import com.shapesecurity.shift.minifier.passes.reduction.RemoveEmptyBlocks;
import com.shapesecurity.shift.minifier.passes.reduction.RemoveEmptyStatements;
import com.shapesecurity.shift.minifier.passes.reduction.RemoveEmptyTrailingDefault;
import com.shapesecurity.shift.minifier.passes.reduction.RemoveSingleStatementBlocks;
import com.shapesecurity.shift.minifier.passes.reduction.ReplaceWhileWithFor;
import com.shapesecurity.shift.visitor.FixPointTransformer;

import org.jetbrains.annotations.NotNull;

public class Minifier {
  private static final FixPointTransformer REDUCTION = new FixPointTransformer(new ComposedRule<>(
      new ReductionRule[]{FlattenBlocks.INSTANCE, ReduceNestedIfStatements.INSTANCE, RemoveEmptyBlocks.INSTANCE,
                          RemoveEmptyStatements.INSTANCE, RemoveEmptyTrailingDefault.INSTANCE,
                          RemoveSingleStatementBlocks.INSTANCE, ReplaceWhileWithFor.INSTANCE,}));
  private static final FixPointTransformer EXPANSION = new FixPointTransformer(new ComposedRule<>(
      new ExpansionRule[]{ReplaceStaticMemberAccessWithDynamicMemberAccess.INSTANCE, ExpandBooleanLiterals.INSTANCE,
                          TopLevelExpressionWithProhibitedFirstToken.INSTANCE,}));

  @NotNull
  public static Script minify(@NotNull Script script) {
    return EXPANSION.transform(REDUCTION.transform(script, ImmutableList.nil()), ImmutableList.nil());
  }

  public static Script minify(
      @NotNull Script script,
      @NotNull ReductionRule[] reductionRules,
      @NotNull ExpansionRule[] expansionRules) {
    FixPointTransformer reduction = new FixPointTransformer(new ComposedRule<>(reductionRules));
    FixPointTransformer expansion = new FixPointTransformer(new ComposedRule<>(expansionRules));
    return expansion.transform(reduction.transform(script, ImmutableList.nil()), ImmutableList.nil());
  }

  public static Script minify(
      @NotNull Script script,
      @NotNull ImmutableList reductionRules,
      @NotNull ImmutableList expansionRules) {
    ReductionRule[] reductionRulesArray = reductionRules.toArray(new ReductionRule[reductionRules.length]);
    ExpansionRule[] expansionRulesArray = expansionRules.toArray(new ExpansionRule[expansionRules.length]);
    FixPointTransformer reduction = new FixPointTransformer(new ComposedRule<>(reductionRulesArray));
    FixPointTransformer expansion = new FixPointTransformer(new ComposedRule<>(expansionRulesArray));
    return expansion.transform(reduction.transform(script, ImmutableList.nil()), ImmutableList.nil());
  }
}