/*
 * Copyright 2011 Google 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.google.gwt.dev.jjs;

import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.dev.javac.CompilationState;
import com.google.gwt.dev.javac.StandardGeneratorContext;
import com.google.gwt.dev.jdt.RebindPermutationOracle;
import com.google.gwt.dev.jjs.CorrelationFactory.DummyCorrelationFactory;
import com.google.gwt.dev.jjs.ast.JProgram;
import com.google.gwt.dev.jjs.impl.AssertionNormalizer;
import com.google.gwt.dev.jjs.impl.AssertionRemover;
import com.google.gwt.dev.jjs.impl.FixAssignmentToUnbox;
import com.google.gwt.dev.jjs.impl.GwtAstBuilder;
import com.google.gwt.dev.jjs.impl.ImplementClassLiteralsAsFields;
import com.google.gwt.dev.jjs.impl.ReplaceRunAsyncs;
import com.google.gwt.dev.jjs.impl.UnifyAst;
import com.google.gwt.dev.js.ast.JsProgram;

/**
 * Constructs a full Java AST from source.
 */
public class AstConstructor {

  /**
   * Construct an simple AST representing an entire {@link CompilationState}.
   * Does not support deferred binding. Implementation mostly copied from
   * {@link JavaToJavaScriptCompiler}.
   */
  public static JProgram construct(TreeLogger logger, final CompilationState state,
      JJSOptions options) throws UnableToCompleteException {

    InternalCompilerException.preload();

    RebindPermutationOracle rpo = new RebindPermutationOracle() {
      @Override
      public void clear() {
      }

      @Override
      public String[] getAllPossibleRebindAnswers(TreeLogger logger, String sourceTypeName)
          throws UnableToCompleteException {
        return new String[0];
      }

      public CompilationState getCompilationState() {
        return state;
      }

      public StandardGeneratorContext getGeneratorContext() {
        return null;
      }
    };

    JProgram jprogram = new JProgram(DummyCorrelationFactory.INSTANCE);
    JsProgram jsProgram = new JsProgram(DummyCorrelationFactory.INSTANCE);
    assert GwtAstBuilder.ENABLED;
    UnifyAst unifyAst = new UnifyAst(jprogram, jsProgram, options, rpo);
    unifyAst.buildEverything(logger);

    // Compute all super type/sub type info
    jprogram.typeOracle.computeBeforeAST();

    // (3) Perform Java AST normalizations.
    FixAssignmentToUnbox.exec(jprogram);

    /*
     * TODO: If we defer this until later, we could maybe use the results of the
     * assertions to enable more optimizations.
     */
    if (options.isEnableAssertions()) {
      // Turn into assertion checking calls.
      AssertionNormalizer.exec(jprogram);
    } else {
      // Remove all assert statements.
      AssertionRemover.exec(jprogram);
    }

    if (options.isRunAsyncEnabled()) {
      ReplaceRunAsyncs.exec(logger, jprogram);
    }

    ImplementClassLiteralsAsFields.exec(jprogram);
    return jprogram;
  }
}