package data.io.filters;

import static org.junit.Assert.*;

import java.util.Iterator;

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

import data.MVDataEntry;
import data.filters.MVDataCombiner;
import data.filters.MVDataCombiner.MVDataCombineMode;
import data.io.MVDataReader;
import data.io.stub.StubDataReader;

public class MVDataCombinerTest {
	
	@Rule
	public ExpectedException exception = ExpectedException.none();
	
	@Test
	public void testOutOfOrderCase() {
		// Test Data
		MVDataEntry e10 = new MVDataEntry("line2");
		e10.getAttrValPairs().put("merge", "e10");
		MVDataEntry e11 = new MVDataEntry("line1");
		e11.getAttrValPairs().put("merge", "e11");
		
		MVDataEntry e21 = new MVDataEntry("line2");
		e21.getAttrValPairs().put("merge", "e21");

		MVDataEntry[][] fakeEntries = new MVDataEntry[][] {
				new MVDataEntry[] { e10, e11 },
				new MVDataEntry[] { e21 },
		};

		MVDataCombineMode mergeModes[] = new MVDataCombineMode[]{
				MVDataCombineMode.PRIMARY_SOURCE,
				MVDataCombineMode.MERGE_APPEND,
		};
		
		// Expected results
		MVDataEntry line1 = new MVDataEntry(e10);
		line1.mergeValues(true, e21);
		
		MVDataEntry expected[] = new MVDataEntry[] {
				line1,
				null /* Should throw UnsupportedOperationException() before comparing */
		};
		
		// Test run
		exception.expect(UnsupportedOperationException.class);
		doCombineTest(expected, fakeEntries, mergeModes);
	}
	

	@Test
	public void testGeneralCase() {
		
		// Test Data
		MVDataEntry e10 = new MVDataEntry("line3");
		e10.getAttrValPairs().put("from1", "e10");
		e10.getAttrValPairs().put("merge", "e10");
		MVDataEntry e11 = new MVDataEntry("line4");
		e11.getAttrValPairs().put("from1", "e11");
		e11.getAttrValPairs().put("merge", "e11");
		
		MVDataEntry e20 = new MVDataEntry("line1");
		e20.getAttrValPairs().put("from2", "e20");
		e20.getAttrValPairs().put("merge", "e20");
		MVDataEntry e21 = new MVDataEntry("line2");
		e21.getAttrValPairs().put("from2", "e21");
		e21.getAttrValPairs().put("merge", "e21");
		MVDataEntry e22 = new MVDataEntry("line3");
		e22.getAttrValPairs().put("from2", "e22");
		e22.getAttrValPairs().put("merge", "e22");
		
		MVDataEntry e30 = new MVDataEntry("line2");
		e30.getAttrValPairs().put("from3", "e30");
		e30.getAttrValPairs().put("merge", "e30");
		
		
		MVDataEntry[][] fakeEntries = new MVDataEntry[][] {
				new MVDataEntry[] { e10, e11 },
				new MVDataEntry[] { e20, e21, e22 },
				new MVDataEntry[] { e30 },
		};
		
		MVDataCombineMode mergeModes[] = new MVDataCombineMode[]{
				MVDataCombineMode.PRIMARY_SOURCE,
				MVDataCombineMode.MERGE_REPLACE,
				MVDataCombineMode.MERGE_APPEND,
		};
		
		// Expected results
		MVDataEntry line1 = new MVDataEntry(e20);
		
		MVDataEntry line2 = new MVDataEntry(e21);
		line2.mergeValues(true, e30);
		
		MVDataEntry line3 = new MVDataEntry(e10);
		line3.mergeValues(false, e22);
		
		MVDataEntry line4 = new MVDataEntry(e11);
		
		MVDataEntry expected[] = new MVDataEntry[] {
				line1,line2,line3,line4
		};
		
		// Test run
		doCombineTest(expected, fakeEntries, mergeModes);
	}

	// TODO : test all Combine modes

	/**
	 * Helper function to factorise Combiner tests.
	 * @param expected
	 * @param fakeEntries
	 * @param mergeModes
	 */
	public void doCombineTest(MVDataEntry expected[], MVDataEntry[][] fakeEntries, MVDataCombineMode mergeModes[]) {
		// Test init		
		MVDataReader readers[] = new MVDataReader[fakeEntries.length];
		for (int i = 0; i < fakeEntries.length; i++) {
			readers[i] = new StubDataReader("fakeReader"+i,fakeEntries[i]);
		}

		MVDataCombiner combiner = new MVDataCombiner("combiner", readers, mergeModes);
		
		// Test twice to check if asking a new iterator "rewinds" correctly
		for (int i=0;i<2;i++) {
			//System.out.println("Loop " + (i+1));
			
			Iterator<MVDataEntry> combinerIt = combiner.iterator();
			for (int j = 0; j < expected.length; j++) {
				assertTrue(combinerIt.hasNext());
				MVDataEntry item = combinerIt.next();
				//System.out.println(expected[i]);
				//System.out.println(item);
				//System.out.println();
				assertEquals(expected[j], item);
			}
			assertFalse(combinerIt.hasNext());
		}
	}
}