// Copyright 2011-2016 Google LLC
//
// 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.security.zynamics.binnavi.Gui.Debug.ToolbarPanel.Implementations;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import com.google.common.collect.Iterables;
import com.google.security.zynamics.binnavi.debug.models.breakpoints.BreakpointAddress;
import com.google.security.zynamics.binnavi.disassembly.UnrelocatedAddress;
import com.google.security.zynamics.binnavi.disassembly.INaviCodeNode;
import com.google.security.zynamics.binnavi.disassembly.INaviEdge;
import com.google.security.zynamics.binnavi.disassembly.INaviFunction;
import com.google.security.zynamics.binnavi.disassembly.INaviFunctionNode;
import com.google.security.zynamics.binnavi.disassembly.INaviInstruction;
import com.google.security.zynamics.binnavi.disassembly.INaviModule;
import com.google.security.zynamics.binnavi.disassembly.INaviViewNode;

/**
 * Provides generic helper functions for stepping operations.
 */
public final class CSteppingHelper {
  /**
   * You are not supposed to instantiate this class.
   */
  private CSteppingHelper() {
  }

  /**
   * Determines the start address of a node.
   *
   * @param node Node whose address is determined.
   *
   * @return The start address of the given node or null if the node does not have an address.
   */
  private static BreakpointAddress getAddress(final INaviViewNode node) {
    if (node instanceof INaviCodeNode) {
      final INaviCodeNode ccnode = (INaviCodeNode) node;

      final INaviInstruction instruction = Iterables.getFirst(ccnode.getInstructions(), null);

      return new BreakpointAddress(instruction.getModule(), new UnrelocatedAddress(instruction
          .getAddress()));
    } else if (node instanceof INaviFunctionNode) {
      final INaviFunction function = ((INaviFunctionNode) node).getFunction();
      final INaviModule module = function.getModule();

      return new BreakpointAddress(module, new UnrelocatedAddress(function.getAddress()));
    } else {
      // Node types we can not step to
      return null;
    }
  }

  /**
   * Determines the addresses of the successor blocks of a node.
   *
   * @param node Node whose successor addresses are added to the list.
   *
   * @return The list of addresses of the successor nodes.
   */
  public static Set<BreakpointAddress> getSuccessors(final INaviViewNode node) {
    final Set<BreakpointAddress> addresses = new HashSet<BreakpointAddress>();

    final List<INaviEdge> edges = node.getOutgoingEdges();

    for (final INaviEdge edge : edges) {
      final BreakpointAddress childAddress = CSteppingHelper.getAddress(edge.getTarget());

      if (childAddress != null) {
        addresses.add(childAddress);
      }
    }

    return addresses;
  }
}
