/*
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html.
 *
 * This file is a derivative of code released under the terms listed below.
 *
 */
/*
*  Copyright (c) 2013,
*      Tobias Blaschke <code@tobiasblaschke.de>
*  All rights reserved.

*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions are met:
*
*  1. Redistributions of source code must retain the above copyright notice,
*     this list of conditions and the following disclaimer.
*
*  2. Redistributions in binary form must reproduce the above copyright notice,
*     this list of conditions and the following disclaimer in the documentation
*     and/or other materials provided with the distribution.
*
*  3. The names of the contributors may not be used to endorse or promote
*     products derived from this software without specific prior written
*     permission.
*
*  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
*  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
*  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
*  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
*  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
*  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
*  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
*  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
*  POSSIBILITY OF SUCH DAMAGE.
*/
package com.ibm.wala.dalvik.ipa.callgraph.androidModel;

import com.ibm.wala.classLoader.CallSiteReference;
import com.ibm.wala.classLoader.FieldImpl;
import com.ibm.wala.classLoader.IClass;
import com.ibm.wala.classLoader.IField;
import com.ibm.wala.classLoader.IMethod;
import com.ibm.wala.classLoader.NewSiteReference;
import com.ibm.wala.classLoader.SyntheticClass;
import com.ibm.wala.dalvik.util.AndroidEntryPointManager;
import com.ibm.wala.ipa.cha.IClassHierarchy;
import com.ibm.wala.ipa.summaries.MethodSummary;
import com.ibm.wala.ipa.summaries.SummarizedMethod;
import com.ibm.wala.ipa.summaries.SummarizedMethodWithNames;
import com.ibm.wala.ipa.summaries.VolatileMethodSummary;
import com.ibm.wala.shrikeBT.IInvokeInstruction;
import com.ibm.wala.shrikeCT.ClassConstants;
import com.ibm.wala.ssa.SSAInstruction;
import com.ibm.wala.types.ClassLoaderReference;
import com.ibm.wala.types.FieldReference;
import com.ibm.wala.types.MethodReference;
import com.ibm.wala.types.Selector;
import com.ibm.wala.types.TypeName;
import com.ibm.wala.types.TypeReference;
import com.ibm.wala.util.collections.HashMapFactory;
import com.ibm.wala.util.collections.HashSetFactory;
import com.ibm.wala.util.ssa.SSAValue;
import com.ibm.wala.util.ssa.TypeSafeInstructionFactory;
import com.ibm.wala.util.strings.Atom;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Encapsulates synthetic methods for modeling Androids lifecycle.
 *
 * <p>In the generated code this class may be found as "Lcom/ibm/wala/AndroidModelClass"
 *
 * @see com.ibm.wala.ipa.callgraph.impl.FakeRootClass
 * @author Tobias Blaschke &lt;code@tobiasblaschke.de&gt; TODO: Move this class into an other
 *     loader? Currently: Primordial
 */
public final /* singleton */ class AndroidModelClass extends SyntheticClass {
  private static Logger logger = LoggerFactory.getLogger(AndroidModelClass.class);

  public static final TypeReference ANDROID_MODEL_CLASS =
      TypeReference.findOrCreate(
          ClassLoaderReference.Primordial,
          TypeName.string2TypeName("Lcom/ibm/wala/AndroidModelClass"));
  private IClassHierarchy cha;

  public static AndroidModelClass getInstance(IClassHierarchy cha) {
    IClass android = cha.lookupClass(ANDROID_MODEL_CLASS);
    AndroidModelClass mClass;
    if (android == null) {
      mClass = new AndroidModelClass(cha);
    } else if (!(android instanceof AndroidModelClass)) {
      throw new IllegalArgumentException(
          String.format(
              "android model class does not have expected type %s, but %s!",
              AndroidModelClass.class, android.getClass().toString()));
    } else {
      mClass = (AndroidModelClass) android;
    }
    return mClass;
  }

  private AndroidModelClass(IClassHierarchy cha) {
    super(ANDROID_MODEL_CLASS, cha);
    this.addMethod(this.clinit());
    this.cha = cha;
    this.cha.addClass(this);
  }

  /**
   * Generate clinit for AndroidModelClass.
   *
   * <p>clinit initializes AndroidComponents
   */
  private SummarizedMethod clinit() {
    final MethodReference clinitRef =
        MethodReference.findOrCreate(this.getReference(), MethodReference.clinitSelector);
    final VolatileMethodSummary clinit = new VolatileMethodSummary(new MethodSummary(clinitRef));
    clinit.setStatic(true);
    final TypeSafeInstructionFactory instructionFactory = new TypeSafeInstructionFactory(cha);

    final Set<TypeReference> components = AndroidEntryPointManager.getComponents();
    int ssaNo = 1;

    if (AndroidEntryPointManager.MANAGER.doFlatComponents()) {
      for (TypeReference component : components) {
        final SSAValue instance = new SSAValue(ssaNo++, component, clinitRef);
        { // New
          final int pc = clinit.getNextProgramCounter();
          final NewSiteReference nRef = NewSiteReference.make(pc, component);
          final SSAInstruction instr = instructionFactory.NewInstruction(pc, instance, nRef);
          clinit.addStatement(instr);
        }
        { // Call cTor
          final int pc = clinit.getNextProgramCounter();
          final MethodReference ctor =
              MethodReference.findOrCreate(component, MethodReference.initSelector);
          final CallSiteReference site =
              CallSiteReference.make(pc, ctor, IInvokeInstruction.Dispatch.SPECIAL);
          final SSAValue exception =
              new SSAValue(ssaNo++, TypeReference.JavaLangException, clinitRef);
          final List<SSAValue> params = new ArrayList<>();
          params.add(instance);
          final SSAInstruction ctorCall =
              instructionFactory.InvokeInstruction(pc, params, exception, site);
          clinit.addStatement(ctorCall);
        }
        { // Put into AndroidModelClass
          final Atom fdName = component.getName().getClassName();
          putField(fdName, component);
          final int pc = clinit.getNextProgramCounter();
          final FieldReference fdRef =
              FieldReference.findOrCreate(this.getReference(), fdName, component);
          final SSAInstruction putInst = instructionFactory.PutInstruction(pc, instance, fdRef);
          clinit.addStatement(putInst);
        }
      }
    }

    return new SummarizedMethodWithNames(clinitRef, clinit, this);
  }

  //
  //  Contents of the class: Methods
  //
  private IMethod macroModel = null;
  //    private IMethod allActivitiesModel = null;
  private Map<Selector, IMethod> methods = HashMapFactory.make(); // does not contain macroModel

  public boolean containsMethod(Selector selector) {
    return (((macroModel != null) && macroModel.getSelector().equals(selector))
        || methods.containsKey(selector));
  }

  @Override
  public IMethod getMethod(Selector selector) {
    // assert (macroModel != null) : "Macro Model was not set yet!";

    if ((macroModel != null) && (macroModel.getSelector().equals(selector))) {
      return macroModel;
    }

    if (methods.containsKey(selector)) {
      return methods.get(selector);
    }
    if (selector.equals(MethodReference.initSelector)) {
      logger.warn("AndroidModelClass is not intended to be initialized");
      return null;
    }
    throw new IllegalArgumentException("Could not resolve " + selector);
  }

  @Override
  public Collection<IMethod> getDeclaredMethods() {
    Set<IMethod> methods = HashSetFactory.make();
    if (this.macroModel != null) {
      methods.add(macroModel);
    }

    methods.addAll(this.methods.values());

    return Collections.unmodifiableCollection(methods);
  }

  @Override
  public Collection<IMethod> getAllMethods() {
    return getDeclaredMethods();
  }

  /* package private */ void setMacroModel(IMethod model) {
    assert (this.macroModel == null);
    this.macroModel = model;
  }

  public void addMethod(IMethod method) {
    if (this.methods.containsKey(method.getSelector())) {
      // TODO: Check this matches on signature not on contents!
      // TODO: What on different Context versions
      throw new IllegalStateException(
          "The AndroidModelClass already contains a Method called" + method.getName());
    }
    assert (this.methods != null);
    this.methods.put(method.getSelector(), method);
  }

  @Override
  public IMethod getClassInitializer() {
    return getMethod(MethodReference.clinitSelector);
  }

  //
  //  Contents of the class: Fields
  //  We have none...
  //
  private Map<Atom, IField> fields = new HashMap<>();

  @Override
  public IField getField(Atom name) {
    return fields.getOrDefault(name, null);
  }

  public void putField(Atom name, TypeReference type) {
    final FieldReference fdRef = FieldReference.findOrCreate(this.getReference(), name, type);
    final int accessFlags = ClassConstants.ACC_STATIC | ClassConstants.ACC_PUBLIC;
    final IField field = new FieldImpl(this, fdRef, accessFlags, null, null);

    this.fields.put(name, field);
  }

  /** This class does not contain any fields. */
  @Override
  public Collection<IField> getAllFields() {
    return fields.values();
  }

  /** This class does not contain any fields. */
  @Override
  public Collection<IField> getDeclaredStaticFields() {
    return fields.values();
  }

  /** This class does not contain any fields. */
  @Override
  public Collection<IField> getAllStaticFields() {
    return fields.values();
  }

  /** This class does not contain any fields. */
  @Override
  public Collection<IField> getDeclaredInstanceFields() throws UnsupportedOperationException {
    return Collections.emptySet();
  }

  /** This class does not contain any fields. */
  @Override
  public Collection<IField> getAllInstanceFields() {
    return Collections.emptySet();
  }

  //
  //  Class Modifiers
  //

  /** This is a public final class. */
  @Override
  public int getModifiers() {
    return ClassConstants.ACC_PUBLIC | ClassConstants.ACC_FINAL;
  }

  @Override
  public boolean isPublic() {
    return true;
  }

  @Override
  public boolean isPrivate() {
    return false;
  }

  @Override
  public boolean isInterface() {
    return false;
  }

  @Override
  public boolean isAbstract() {
    return false;
  }

  @Override
  public boolean isArrayClass() {
    return false;
  }

  /** This is a subclass of the root class. */
  @Override
  public IClass getSuperclass() throws UnsupportedOperationException {
    return getClassHierarchy().getRootClass();
  }

  /** This class does not impement any interfaces. */
  @Override
  public Collection<IClass> getAllImplementedInterfaces() {
    return Collections.emptySet();
  }

  @Override
  public Collection<IClass> getDirectInterfaces() {
    return Collections.emptySet();
  }

  //
  //  Misc
  //

  @Override
  public boolean isReferenceType() {
    return getReference().isReferenceType();
  }
}
