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package cz.cvut.k36.pr2.hw.hw06.impl;

import cz.cvut.k36.pr2.hw.hw06.Function;
import cz.cvut.k36.pr2.hw.hw06.Pr2List;
import cz.cvut.k36.pr2.hw.hw06.Predicate;
import java.util.Iterator;
import java.util.NoSuchElementException;

/**
 *
 * @author Azathoth
 */
public class NotNilViewFilter<Input, Output> implements Pr2List<Input>{

    protected Pr2List<Input> list;
    private Predicate predicate;
    private boolean lazyEvaluate=false;
    private boolean lazyFilter=false;
    private boolean lazyMap=false;
    private boolean lazyPartialFilter=false;
    private boolean lazyPartialMap=false;
    protected Pr2List<Output> listHead;

    public NotNilViewFilter(Pr2List list, Predicate predicate) {
        this.list = list;
        this.predicate = predicate;
    }

    @Override
    public Pr2List append(Input t) {
        throw new UnsupportedOperationException("Can not append view.");
    }

    @Override
    public Pr2List cons(Input t) {
        throw new UnsupportedOperationException("Can not cons view.");
    }

    @Override
    public boolean isEmpty() {
        lazyIsEmpty();
        return this.list.isEmpty();
    }

    @Override
    public Pr2List filter(Predicate predicate) {
        Pr2List output=new NotNilViewFilter(this, predicate);
        return output;
    }

    @Override
    public <O> Pr2List<O> map(Function<Input, O> function){
        Pr2List output=new NotNilViewMap(this, function);
        return output;
    }

    @Override
    public Input head() {
        lazyHead();
        return this.list.head();
    }

    @Override
    public Pr2List tail() {
        lazyTail();
        NotNilViewFilter<Input, Output> output=new NotNilViewFilter<>(this.list.tail(), predicate);
        return output;
    }

    @Override
    public Pr2List view() {
        NotNilView<Input, Output> output=new NotNilView(this);
        return output;
    }

    @Override
    public int size() {
        lazySize();
        if (this.listHead!=null) {
            return this.listHead.size();
        }
        return this.list.size();
    }

    @Override
    public Iterator iterator() {
        return new MyIterator();
    }

    @Override
    public String toString() {
        return this.getClass()+", "+this.list.toString();
    }

    private class MyIterator implements Iterator{

        Pr2List<Input> iterator;

        private MyIterator() {
            this.iterator = NotNilViewFilter.this;
        }

        @Override
        public boolean hasNext() {
            return !(iterator.tail().isEmpty());
        }

        @Override
        public Input next() {
            if (iterator.isEmpty()) {
                throw new NoSuchElementException("Toto je poslednĂ­ prvek.");
            }
            iterator=iterator.tail();
            return iterator.head();
        }

        @Override
        public void remove() {
            throw new UnsupportedOperationException("Z iteratoru nejde nic odejmout.");
        }
    }

    public void lazyTail(){
        if (!lazyEvaluate) {
            this.lazyEvaluate=true;
            if (this.list instanceof NotNilViewFilter) {
                NotNilViewFilter<Input, Output> temp=(NotNilViewFilter<Input, Output>) this.list;
                temp.lazyTail();
                this.list=temp.list;
            } else if (this.list instanceof NotNilViewMap) {
                NotNilViewMap<Input, Output> temp=(NotNilViewMap<Input, Output>) this.list;
                temp.lazyTail();
                this.list=temp.list;
            } else if (this.list instanceof NotNil) {
                NotNil<Input, Output> temp=(NotNil<Input, Output>) this.list;
                Pr2List<Input> temp2;
                temp2=temp.partialFilter(predicate);
                this.list=temp2;
            } else {
                this.list=this.list.filter(predicate);
            }
        }
    }

    public void lazyHead(){
        this.lazyFilter=true;
        if (this.list instanceof NotNilViewFilter) {
            NotNilViewFilter<Input, Output> temp=(NotNilViewFilter<Input, Output>) this.list;
            temp.lazyHead();
            this.list=temp.list;
        } else if (this.list instanceof NotNilViewMap) {
            NotNilViewMap<Input, Output> temp=(NotNilViewMap<Input, Output>) this.list;
            temp.lazyHead();
            this.list=temp.list;
        } else if (this.list instanceof NotNil) {
            NotNil<Input, Output> temp=(NotNil<Input, Output>) this.list;
            Pr2List<Input> temp2;
            temp2=temp.partialFilter(predicate);
            this.list=temp2;
        } else {
            this.list=this.list.filter(predicate);
        }
    }

    public void lazySize(){
        this.lazyFilter=true;
        if (this.list instanceof NotNilViewFilter) {
            NotNilViewFilter<Input, Output> temp=(NotNilViewFilter<Input, Output>) this.list;
            temp.lazySize();
            this.list=temp.list;
        } else if (this.list instanceof NotNilViewMap) {
            NotNilViewMap<Input, Output> temp=(NotNilViewMap<Input, Output>) this.list;
            temp.lazyMap();
            this.listHead=temp.listHead;
        } if (this.listHead!=null) {
            this.listHead=this.listHead.filter(predicate);
        } else {
            this.list=this.list.filter(predicate);
        }

    }

    public void lazyIsEmpty(){
        this.lazyPartialFilter=true;
        if (this.list instanceof NotNilViewFilter) {
            NotNilViewFilter<Input, Output> temp=(NotNilViewFilter<Input, Output>) this.list;
            temp.lazyIsEmpty();
            this.list=temp.list;
        } else if (this.list instanceof NotNilViewMap) {
            NotNilViewMap<Input, Output> temp=(NotNilViewMap<Input, Output>) this.list;
            temp.lazyIsEmpty();
            this.list=temp.list;
        } else if (this.list instanceof NotNil) {
            NotNil<Input, Output> temp=(NotNil<Input, Output>) this.list;
            Pr2List<Input> temp2;
            temp2=temp.partialFilter(predicate);
            this.list=temp2;
        } else {
            this.list=this.list.filter(predicate);
        }
    }


}