/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 org.apache.maven.surefire.api.util;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Set;
  
  import org.apache.maven.surefire.api.testset.TestSetFailedException;
  
  import static java.lang.Math.max;
  
  /**
   * Contains all the tests that have been found according to specified include/exclude
   * specification for a given surefire run.
   *
   * @author Kristian Rosenvold (junit core adaption)
   */
  public class TestsToRun implements Iterable<Class<?>> {
      private final List<Class<?>> locatedClasses;
  
      private volatile boolean finished;
  
      private int iteratedCount;
  
      /**
       * Constructor
       *
       * @param locatedClasses A set of java.lang.Class objects representing tests to run
       */
      public TestsToRun(Set<Class<?>> locatedClasses) {
          this.locatedClasses = new ArrayList<>(locatedClasses);
      }
  
      public static TestsToRun fromClass(Class<?> clazz) throws TestSetFailedException {
          return new TestsToRun(Collections.<Class<?>>singleton(clazz));
      }
  
      /**
       * @return test classes which have been retrieved by {@link TestsToRun#iterator()}.
       */
      public Iterator<Class<?>> iterated() {
          return newWeakIterator();
      }
  
      /**
       * Returns an iterator over the located java.lang.Class objects
       *
       * @return an unmodifiable iterator
       */
      @Override
      public Iterator<Class<?>> iterator() {
          return new ClassesIterator();
      }
  
      private final class ClassesIterator extends CloseableIterator<Class<?>> {
          private final Iterator<Class<?>> it = TestsToRun.this.locatedClasses.iterator();
  
          private int iteratedCount;
  
          @Override
          protected boolean isClosed() {
              return TestsToRun.this.isFinished();
          }
  
          @Override
          protected boolean doHasNext() {
              return it.hasNext();
          }
  
          @Override
          protected Class<?> doNext() {
              Class<?> nextTest = it.next();
              TestsToRun.this.iteratedCount = max(++iteratedCount, TestsToRun.this.iteratedCount);
              return nextTest;
          }
  
          @Override
          protected void doRemove() {}
  
         @Override
         public void remove() {
             throw new UnsupportedOperationException("unsupported remove");
         }
     }
 
     public final void markTestSetFinished() {
         finished = true;
     }
 
     public final boolean isFinished() {
         return finished;
     }
 
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder("TestsToRun: [");
         for (Class<?> clazz : this) {
             sb.append(' ').append(clazz.getName());
         }
 
         sb.append(']');
         return sb.toString();
     }
 
     public boolean containsAtLeast(int atLeast) {
         return containsAtLeast(iterator(), atLeast);
     }
 
     private boolean containsAtLeast(Iterator<Class<?>> it, int atLeast) {
         for (int i = 0; i < atLeast; i++) {
             if (!it.hasNext()) {
                 return false;
             }
 
             it.next();
         }
 
         return true;
     }
 
     public boolean containsExactly(int items) {
         Iterator<Class<?>> it = iterator();
         return containsAtLeast(it, items) && !it.hasNext();
     }
 
     /**
      * @return {@code true}, if the classes may be read eagerly. {@code false},
      *         if the classes must only be read lazy.
      */
     public boolean allowEagerReading() {
         return true;
     }
 
     public Class<?>[] getLocatedClasses() {
         if (!allowEagerReading()) {
             throw new IllegalStateException("Cannot eagerly read");
         }
         Collection<Class<?>> result = new ArrayList<>();
         for (Class<?> clazz : this) {
             result.add(clazz);
         }
         return result.toArray(new Class<?>[result.size()]);
     }
 
     /**
      * Get test class which matches className
      *
      * @param className string used to find the test class
      * @return Class object with the matching name, null if could not find a class with the matching name
      */
     public Class<?> getClassByName(String className) {
         for (Class<?> clazz : this) {
             if (clazz.getName().equals(className)) {
                 return clazz;
             }
         }
         return null;
     }
 
     /**
      * @return snapshot of tests upon constructs of internal iterator.
      * Therefore weakly consistent while {@link TestsToRun#iterator()} is being iterated.
      */
     private Iterator<Class<?>> newWeakIterator() {
         final Iterator<Class<?>> it = locatedClasses.subList(0, iteratedCount).iterator();
         return new CloseableIterator<Class<?>>() {
             @Override
             protected boolean isClosed() {
                 return TestsToRun.this.isFinished();
             }
 
             @Override
             protected boolean doHasNext() {
                 return it.hasNext();
             }
 
             @Override
             protected Class<?> doNext() {
                 return it.next();
             }
 
             @Override
             protected void doRemove() {}
 
             @Override
             public void remove() {
                 throw new UnsupportedOperationException("unsupported remove");
             }
         };
     }
 }