package org.hybird.continuation;

import java.util.Iterator;

import org.hybird.generator.Generator;

public class ContinuationTest
{
    public static void main (String [] args)
    {
        // full read
        for (String s : new ExampleGenerator())
        {
            System.out.println (s);
        }

        // reading 3 out of 4 values
        System.out.println ("");
        Iterator<String> i = new ExampleGenerator().iterator ();
        for (int x = 0; x < 3 && i.hasNext (); ++x)
            System.out.println (x + ": '" + i.next () + "'");

        // generators filtering other generators
        System.out.println ("");
        for (int even : new EvenNumbersGenerator (new RangeGenerator (10)))
        {
            System.out.println (even);
        }
    }

    @Continuation
    private static class ExampleGenerator extends Generator<String>
    {
        @Override
        protected void run ()
        {
            yield ("1");
            yield ("2");
            yield ("3");
            yield ("4");
        }
    }

    @Continuation
    public static final class EvenNumbersGenerator extends Generator<Integer>
    {
        private RangeGenerator generator;

        public EvenNumbersGenerator (RangeGenerator generator)
        {
            this.generator = generator;
        }

        @Override
        protected void run ()
        {
            for (int i : generator)
            {
                if (i % 2 == 0)
                    yield (i);
            }
        }
    }

    @Continuation
    public static final class RangeGenerator extends Generator<Integer>
    {
        private int to;

        public RangeGenerator (int to)
        {
            this.to = to;
        }

        @Override
        protected void run ()
        {
            for (int i = 0; i < to; i++)
                yield (i);
        }
    }

    @Continuation
    public static class FibonnaciGenerator extends Generator<Integer>
    {
        private int to;

        public FibonnaciGenerator (int to)
        {
            this.to = to;
        }

        @Override
        protected void run ()
        {
            int a = 0;
            int b = 1;

            while (a < to)
            {
                yield (a);

                int next = a + b;
                a = b;
                b = next;
            }
        }
    }
}