package org.hamcrest.collection;

import org.hamcrest.Description;
import org.hamcrest.Matcher;
import org.hamcrest.TypeSafeDiagnosingMatcher;

import java.util.ArrayList;
import java.util.List;

import static java.util.Arrays.asList;
import static org.hamcrest.core.IsEqual.equalTo;

public class IsIterableContainingInRelativeOrder<E> extends TypeSafeDiagnosingMatcher<Iterable<? extends E>> {
    
private final List<Matcher<? super E>> matchers;

    
public IsIterableContainingInRelativeOrder(List<Matcher<? super E>> matchers) {
        
this.matchers = matchers;
    
}

    
@Override
    
protected boolean matchesSafely(Iterable<? extends E> iterable, Description mismatchDescription) {
        
MatchSeriesInRelativeOrder<E> matchSeriesInRelativeOrder = new MatchSeriesInRelativeOrder<>(matchers, mismatchDescription);
        
matchSeriesInRelativeOrder.processItems(iterable);
        
return matchSeriesInRelativeOrder.isFinished();
    
}

    
public void describeTo(Description description) {
        
description.appendText("iterable containing ").appendList("[", ", ", "]", matchers).appendText(" in relative order");
    
}

    
private static class MatchSeriesInRelativeOrder<F> {
        
public final List<Matcher<? super F>> matchers;
        
private final Description mismatchDescription;
        
private int nextMatchIx = 0;
        
private F lastMatchedItem = null;

        
public MatchSeriesInRelativeOrder(List<Matcher<? super F>> matchers, Description mismatchDescription) {
            
this.mismatchDescription = mismatchDescription;
            
if (matchers.isEmpty()) {
                
throw new IllegalArgumentException("Should specify at least one expected element");
            
}
            
this.matchers = matchers;
        
}

        
public void processItems(Iterable<? extends F> iterable) {
            
for (F item : iterable) {
                
if (nextMatchIx < matchers.size()) {
                    
Matcher<? super F> matcher = matchers.get(nextMatchIx);
                    
if (matcher.matches(item)) {
                        
lastMatchedItem = item;
                        
nextMatchIx++;
                    
}
                
}
            
}
        
}

        
public boolean isFinished() {
            
if (nextMatchIx < matchers.size()) {
                
mismatchDescription.appendDescriptionOf(matchers.get(nextMatchIx)).appendText(" was not found");
                
if (lastMatchedItem != null) {
                    
mismatchDescription.appendText(" after ").appendValue(lastMatchedItem);
                
}
                
return false;
            
}
            
return true;
        
}

    
}

    
/**
     
* Creates a matcher for {@link Iterable}s that matches when a single pass over the
     
* examined {@link Iterable} yields a series of items, that contains items logically equal to the
     
* corresponding item in the specified items, in the same relative order
     
* For example:
     
* <pre>assertThat(Arrays.asList("a", "b", "c", "d", "e"), containsInRelativeOrder("b", "d"))</pre>
     
*
 

     
* @param items
     
*the items that must be contained within items provided by an examined {@link Iterable} in the same relative order
     
*/

    
@SafeVarargs
    
public static <E> Matcher<Iterable<? extends E>> containsInRelativeOrder(E... items) {
        
List<Matcher<? super E>> matchers = new ArrayList<>();
        
for (E item : items) {
            
matchers.add(equalTo(item));
        
}

        
return containsInRelativeOrder(matchers);
    
}

    
/**
     
* Creates a matcher for {@link Iterable}s that matches when a single pass over the
     
* examined {@link Iterable} yields a series of items, that each satisfying the corresponding
     
* matcher in the specified matchers, in the same relative order.
     
* For example:
     
* <pre>assertThat(Arrays.asList("a", "b", "c", "d", "e"), containsInRelativeOrder(equalTo("b"), equalTo("d")))</pre>
     
*
 

     
* @param itemMatchers
     
*the matchers that must be satisfied by the items provided by an examined {@link Iterable} in the same relative order
     
*/

    
@SafeVarargs
    
public static <E> Matcher<Iterable<? extends E>> containsInRelativeOrder(Matcher<? super E>... itemMatchers) {
        
return containsInRelativeOrder(asList(itemMatchers));
    
}

    
/**
     
* Creates a matcher for {@link Iterable}s that matches when a single pass over the
     
* examined {@link Iterable} yields a series of items, that contains items satisfying the corresponding
     
* matcher in the specified list of matchers, in the same relative order.
     
* For example:
     
* <pre>assertThat(Arrays.asList("a", "b", "c", "d", "e"), contains(Arrays.asList(equalTo("b"), equalTo("d"))))</pre>
     
*
 

     
* @param itemMatchers
     
*a list of matchers, each of which must be satisfied by the items provided by
     
*an examined {@link Iterable} in the same relative order
     
*/

    
public static <E> Matcher<Iterable<? extends E>> containsInRelativeOrder(List<Matcher<? super E>> itemMatchers) {
        
return new IsIterableContainingInRelativeOrder<>(itemMatchers);
    
}
}