package edu.uci.ics.asterix.runtime.aggregates.std;

import java.io.DataOutput;
import java.io.IOException;

import edu.uci.ics.asterix.common.config.GlobalConfig;
import edu.uci.ics.asterix.common.functions.FunctionConstants;
import edu.uci.ics.asterix.dataflow.data.nontagged.serde.ADoubleSerializerDeserializer;
import edu.uci.ics.asterix.dataflow.data.nontagged.serde.AFloatSerializerDeserializer;
import edu.uci.ics.asterix.dataflow.data.nontagged.serde.AInt16SerializerDeserializer;
import edu.uci.ics.asterix.dataflow.data.nontagged.serde.AInt32SerializerDeserializer;
import edu.uci.ics.asterix.dataflow.data.nontagged.serde.AInt64SerializerDeserializer;
import edu.uci.ics.asterix.formats.nontagged.AqlSerializerDeserializerProvider;
import edu.uci.ics.asterix.om.base.AMutableDouble;
import edu.uci.ics.asterix.om.base.AMutableFloat;
import edu.uci.ics.asterix.om.base.AMutableInt16;
import edu.uci.ics.asterix.om.base.AMutableInt32;
import edu.uci.ics.asterix.om.base.AMutableInt64;
import edu.uci.ics.asterix.om.base.ANull;
import edu.uci.ics.asterix.om.types.ATypeTag;
import edu.uci.ics.asterix.om.types.BuiltinType;
import edu.uci.ics.asterix.om.types.EnumDeserializer;
import edu.uci.ics.asterix.runtime.aggregates.base.AbstractAggregateFunctionDynamicDescriptor;
import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
import edu.uci.ics.hyracks.algebricks.common.exceptions.NotImplementedException;
import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
import edu.uci.ics.hyracks.algebricks.runtime.base.IAggregateFunction;
import edu.uci.ics.hyracks.algebricks.runtime.base.IAggregateFunctionFactory;
import edu.uci.ics.hyracks.algebricks.runtime.base.IEvaluator;
import edu.uci.ics.hyracks.algebricks.runtime.base.IEvaluatorFactory;
import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
import edu.uci.ics.hyracks.dataflow.common.data.accessors.ArrayBackedValueStorage;
import edu.uci.ics.hyracks.dataflow.common.data.accessors.IDataOutputProvider;
import edu.uci.ics.hyracks.dataflow.common.data.accessors.IFrameTupleReference;

public class MaxAggregateDescriptor extends AbstractAggregateFunctionDynamicDescriptor {

    private static final long serialVersionUID = 1L;
    private final static FunctionIdentifier FID = new FunctionIdentifier(FunctionConstants.ASTERIX_NS, "agg-max", 1,
            true);

    @Override
    public FunctionIdentifier getIdentifier() {
        return FID;
    }

    @SuppressWarnings("unchecked")
    @Override
    public IAggregateFunctionFactory createAggregateFunctionFactory(final IEvaluatorFactory[] args)
            throws AlgebricksException {
        return new IAggregateFunctionFactory() {
            private static final long serialVersionUID = 1L;

            @Override
            public IAggregateFunction createAggregateFunction(final IDataOutputProvider provider)
                    throws AlgebricksException {

                return new IAggregateFunction() {

                    private DataOutput out = provider.getDataOutput();
                    private ArrayBackedValueStorage inputVal = new ArrayBackedValueStorage();
                    private IEvaluator eval = args[0].createEvaluator(inputVal);
                    private boolean metInt8s, metInt16s, metInt32s, metInt64s, metFloats, metDoubles, metNull;

                    private short shortVal = Short.MIN_VALUE;
                    private int intVal = Integer.MIN_VALUE;
                    private long longVal = Long.MIN_VALUE;
                    private float floatVal = Float.MIN_VALUE;
                    private double doubleVal = Double.MIN_VALUE;

                    private AMutableDouble aDouble = new AMutableDouble(0);
                    private AMutableFloat aFloat = new AMutableFloat(0);
                    private AMutableInt64 aInt64 = new AMutableInt64(0);
                    private AMutableInt32 aInt32 = new AMutableInt32(0);
                    private AMutableInt16 aInt16 = new AMutableInt16((short) 0);
                    private ISerializerDeserializer serde;

                    @Override
                    public void init() {
                        shortVal = Short.MIN_VALUE;
                        intVal = Integer.MIN_VALUE;
                        longVal = Long.MIN_VALUE;
                        floatVal = Float.MIN_VALUE;
                        doubleVal = Double.MIN_VALUE;

                        metInt8s = false;
                        metInt16s = false;
                        metInt32s = false;
                        metInt64s = false;
                        metFloats = false;
                        metDoubles = false;
                        metNull = false;
                    }

                    @Override
                    public void step(IFrameTupleReference tuple) throws AlgebricksException {
                        inputVal.reset();
                        eval.evaluate(tuple);
                        if (inputVal.getLength() > 0) {
                            ATypeTag typeTag = EnumDeserializer.ATYPETAGDESERIALIZER
                                    .deserialize(inputVal.getBytes()[0]);
                            switch (typeTag) {
                                case INT8: {
                                    metInt8s = true;
                                    throw new NotImplementedException("no implementation for int8's comparator");
                                }
                                case INT16: {
                                    metInt16s = true;
                                    short val = AInt16SerializerDeserializer.getShort(inputVal.getBytes(), 1);
                                    if (val > shortVal)
                                        shortVal = val;
                                    throw new NotImplementedException("no implementation for int16's comparator");
                                }
                                case INT32: {
                                    metInt32s = true;
                                    int val = AInt32SerializerDeserializer.getInt(inputVal.getBytes(), 1);
                                    if (val > intVal)
                                        intVal = val;
                                    break;
                                }
                                case INT64: {
                                    metInt64s = true;
                                    long val = AInt64SerializerDeserializer.getLong(inputVal.getBytes(), 1);
                                    if (val > longVal)
                                        longVal = val;
                                    break;
                                }
                                case FLOAT: {
                                    metFloats = true;
                                    float val = AFloatSerializerDeserializer.getFloat(inputVal.getBytes(), 1);
                                    if (val > floatVal)
                                        floatVal = val;
                                    break;
                                }
                                case DOUBLE: {
                                    metDoubles = true;
                                    double val = ADoubleSerializerDeserializer.getDouble(inputVal.getBytes(), 1);
                                    if (val > doubleVal)
                                        doubleVal = val;
                                    break;
                                }
                                case NULL: {
                                    metNull = true;
                                    break;
                                }
                                default: {
                                    throw new NotImplementedException("Cannot compute SUM for values of type "
                                            + typeTag);
                                }
                            }
                        }
                    }

                    @Override
                    public void finish() throws AlgebricksException {
                        try {
                            if (metNull) {
                                serde = AqlSerializerDeserializerProvider.INSTANCE
                                        .getSerializerDeserializer(BuiltinType.ANULL);
                                serde.serialize(ANull.NULL, out);
                            } else if (metDoubles) {
                                serde = AqlSerializerDeserializerProvider.INSTANCE
                                        .getSerializerDeserializer(BuiltinType.ADOUBLE);
                                aDouble.setValue(doubleVal);
                                serde.serialize(aDouble, out);
                            } else if (metFloats) {
                                serde = AqlSerializerDeserializerProvider.INSTANCE
                                        .getSerializerDeserializer(BuiltinType.AFLOAT);
                                aFloat.setValue(floatVal);
                                serde.serialize(aFloat, out);
                            } else if (metInt64s) {
                                serde = AqlSerializerDeserializerProvider.INSTANCE
                                        .getSerializerDeserializer(BuiltinType.AINT64);
                                aInt64.setValue(longVal);
                                serde.serialize(aInt64, out);
                            } else if (metInt32s) {
                                serde = AqlSerializerDeserializerProvider.INSTANCE
                                        .getSerializerDeserializer(BuiltinType.AINT32);
                                aInt32.setValue(intVal);
                                serde.serialize(aInt32, out);
                            } else if (metInt16s) {
                                serde = AqlSerializerDeserializerProvider.INSTANCE
                                        .getSerializerDeserializer(BuiltinType.AINT16);
                                aInt16.setValue(shortVal);
                                serde.serialize(aInt16, out);
                            } else if (metInt8s) {
                                throw new NotImplementedException("no implementation for int8's comparator");
                            } else {
                                GlobalConfig.ASTERIX_LOGGER.fine("SUM aggregate ran over empty input.");
                            }
                        } catch (IOException e) {
                            throw new AlgebricksException(e);
                        }

                    }

                    @Override
                    public void finishPartial() throws AlgebricksException {
                        finish();
                    }
                };
            }
        };
    }

}