/*
 *  ******************************************************************************
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 *  *
 *  * This program and the accompanying materials are made available under the
 *  * terms of the Apache License, Version 2.0 which is available at
 *  * https://www.apache.org/licenses/LICENSE-2.0.
 *  *
 *  *  See the NOTICE file distributed with this work for additional
 *  *  information regarding copyright ownership.
 *  * Unless required by applicable law or agreed to in writing, software
 *  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 *  * License for the specific language governing permissions and limitations
 *  * under the License.
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 *  * SPDX-License-Identifier: Apache-2.0
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package org.nd4j.linalg.api.ops.impl.layers.recurrent;

import lombok.Getter;
import lombok.NonNull;
import org.nd4j.autodiff.samediff.SDVariable;
import org.nd4j.autodiff.samediff.SameDiff;
import org.nd4j.common.base.Preconditions;
import org.nd4j.linalg.api.buffer.DataType;
import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.api.ops.DynamicCustomOp;
import org.nd4j.linalg.api.ops.impl.layers.recurrent.config.LSTMActivations;
import org.nd4j.linalg.api.ops.impl.layers.recurrent.config.LSTMDataFormat;
import org.nd4j.linalg.api.ops.impl.layers.recurrent.config.LSTMDirectionMode;
import org.nd4j.linalg.api.ops.impl.layers.recurrent.config.LSTMLayerConfig;
import org.nd4j.linalg.api.ops.impl.layers.recurrent.weights.LSTMLayerWeights;
import org.nd4j.shade.guava.primitives.Booleans;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;


public class LSTMLayer extends DynamicCustomOp {

    @Getter
    private LSTMLayerConfig configuration;

    @Getter
    private LSTMLayerWeights weights;

    private SDVariable cLast;
    private SDVariable yLast;
    private String cLastName,yLastName;
    private SDVariable maxTSLength;


    public LSTMLayer() {
    }

    public LSTMLayer(@NonNull SameDiff sameDiff, SDVariable x, SDVariable cLast, SDVariable yLast, SDVariable maxTSLength, LSTMLayerWeights weights, LSTMLayerConfig configuration) {
        super(null, sameDiff, weights.argsWithInputs(x, maxTSLength, cLast, yLast));
        this.configuration = configuration;
        this.weights = weights;
        this.cLast = cLast;
        this.yLast = yLast;
        this.maxTSLength = maxTSLength;
        addIArgument(iArgs());
        addTArgument(tArgs());
        addBArgument(bArgs(weights, maxTSLength, yLast, cLast));

        Preconditions.checkState(this.configuration.isRetLastH() || this.configuration.isRetLastC() || this.configuration.isRetFullSequence(),
                "You have to specify at least one output you want to return. Use isRetLastC, isRetLast and isRetFullSequence  methods  in LSTMLayerConfig builder to specify them");


    }

    public LSTMLayer(INDArray x, INDArray cLast, INDArray yLast, INDArray maxTSLength, LSTMLayerWeights lstmWeights, LSTMLayerConfig LSTMLayerConfig) {
        super( lstmWeights.argsWithInputs(x,maxTSLength, cLast, yLast),null);
        this.configuration = LSTMLayerConfig;
        this.weights = lstmWeights;
        addIArgument(iArgs());
        addTArgument(tArgs());
        addBArgument(bArgs(weights, maxTSLength, yLast, cLast));

        Preconditions.checkState(this.configuration.isRetLastH() || this.configuration.isRetLastC() || this.configuration.isRetFullSequence(),
                "You have to specify at least one output you want to return. Use isRetLastC, isRetLast and isRetFullSequence  methods  in LSTMLayerConfig builder to specify them");
    }

    @Override
    public List<DataType> calculateOutputDataTypes(List<DataType> inputDataTypes) {
        Preconditions.checkState(inputDataTypes != null && 3 <= inputDataTypes.size() && inputDataTypes.size() <= 8, "Expected amount of inputs to LSTMLayer between 3 inputs minimum (input, Wx, Wr only) or 8 maximum, got %s", inputDataTypes);
        //7 outputs, all of same type as input. Note that input 0 is max sequence length (int64), input 1 is actual input
        DataType dt = inputDataTypes.get(1);
        List<DataType> list = new ArrayList<>();
        if (configuration.isRetFullSequence()) {
            list.add(dt);
        }

        if (configuration.isRetLastC()) {
            list.add(dt);
        }
        if (configuration.isRetLastH()) {
            list.add(dt);
        }

        Preconditions.checkState(dt.isFPType(), "Input type 1 must be a floating point type, got %s", dt);
        return list;
    }

    @Override
    public List<SDVariable> doDiff(List<SDVariable> grads) {
        int i = 0;
        SDVariable grad0 = this.configuration.isRetFullSequence() ? grads.get(i++): null;
        SDVariable grad1 = this.configuration.isRetLastH() ? grads.get(i++): null;
        SDVariable grad2 = this.configuration.isRetLastC() ? grads.get(i++): null;

        return Arrays.asList(new LSTMLayerBp(sameDiff, arg(0), this.cLast, this.yLast, this.maxTSLength,
                this.weights, this.configuration, grad0, grad1,grad2).outputVariables());
    }

    @Override
    public SDVariable[] variablesExpectingGrads() {
        List<SDVariable> ret = new ArrayList<>();
        ret.add(arg(0));
        ret.add(arg(1));
        ret.add((arg(2)));
        if(weights.hasBias()) {
            ret.add(weights.getBias());
        }


        if(maxTSLength != null) {
            ret.add(maxTSLength);
        }

        if(cLast != null) {
            ret.add(cLast);
        }

        if(yLast != null) {
            ret.add(yLast);
        }

        if(weights.hasPH()) {
            ret.add(weights.getPeepholeWeights());
        }

        return ret.toArray(new SDVariable[ret.size()]);
    }

    @Override
    public String opName() {
        return "lstmLayer";
    }

    @Override
    public Map<String, Object> propertiesForFunction() {
        Map<String,Object> base =  configuration.toProperties(true, true);
        if(cLast != null) {
            base.put("cLastName",cLast);
        }
        if(yLast != null) {
            base.put("yLastName",yLast);
        }

        return base;
    }


    public long[] iArgs() {
        return new long[]{
                configuration.getLstmdataformat().ordinal(),// INT_ARG(0)
                configuration.getDirectionMode().ordinal(), // INT_ARG(1)
                configuration.getGateAct().ordinal(),  // INT_ARG(2)
                configuration.getOutAct().ordinal(), // INT_ARG(3)
                configuration.getCellAct().ordinal()  // INT_ARG(4)

        };
    }

    public double[] tArgs() {
        return new double[]{this.configuration.getCellClip()}; // T_ARG(0)
    }


    protected <T> boolean[] bArgs(LSTMLayerWeights weights, T maxTSLength, T yLast, T cLast) {
        return new boolean[]{
                weights.hasBias(),         // hasBiases: B_ARG(0)
                maxTSLength != null,         // hasSeqLen: B_ARG(1)
                yLast != null,               // hasInitH: B_ARG(2)
                cLast != null,              // hasInitC: B_ARG(3)
                weights.hasPH(),          // hasPH: B_ARG(4)
                configuration.isRetFullSequence(), //retFullSequence: B_ARG(5)
                configuration.isRetLastH(),  //  retLastH: B_ARG(6)
                configuration.isRetLastC()   // retLastC: B_ARG(7)
        };

    }

    @Override
    public void configureFromArguments() {
        if(configuration == null && !bArguments.isEmpty() && !iArguments.isEmpty() && !tArguments.isEmpty()) {
            LSTMLayerConfig.LSTMLayerConfigBuilder builder = LSTMLayerConfig.builder();
            builder.retLastH(bArguments.get(6));
            builder.retFullSequence(bArguments.get(5));
            builder.retLastC(bArguments.get(4));


            //this.configuration.getCellClip()}; // T_ARG(0)
            builder.cellClip(tArguments.get(0));


            builder.lstmdataformat(LSTMDataFormat.values()[iArguments.get(0).intValue()]);
            builder.directionMode(LSTMDirectionMode.values()[iArguments.get(1).intValue()]);
            builder.gateAct(LSTMActivations.values()[iArguments.get(2).intValue()]);
            builder.outAct(LSTMActivations.values()[iArguments.get(3).intValue()]);
            builder.cellAct(LSTMActivations.values()[iArguments.get(4).intValue()]);
            this.configuration = builder.build();

        }
    }

    @Override
    public void configureWithSameDiff(SameDiff sameDiff) {
        this.sameDiff = sameDiff;
        String[] inputsForOp = sameDiff.getInputsForOp(this);
        LSTMLayerWeights.LSTMLayerWeightsBuilder builder = LSTMLayerWeights.builder();
        boolean  hasBiases = bArguments.get(0);   // indicates whether biases array is provided
        boolean  hasSeqLen = bArguments.get(1);   // indicates whether seqLen array is provided
        boolean  hasInitH = bArguments.get(2);    // indicates whether initial output is provided
        boolean  hasInitC =bArguments.get(3);    // indicates whether initial cell state is provided
        boolean  hasPH = bArguments.get(4);       // indicates whether peephole connections are present
        boolean  retFullSeq = bArguments.get(5);  // indicates whether gradient vs. outputs is given for whole time sequence dLdh
        // {dLdh_0, dLdh_1, ... , dLdh_sL-1}
        boolean  retLastH = bArguments.get(6);    // indicates whether gradient vs. output at last time step (dLdhL) is given
        boolean  retLastC = bArguments.get(7);    // indicates whether gradient vs. cell state at last time step (dLdcL) is given

        if(inputsForOp != null && inputsForOp.length > 1)
            builder.weights(sameDiff.getVariable(inputsForOp[1]));
        if(inputsForOp != null && inputsForOp.length > 2)
            builder.rWeights(sameDiff.getVariable(inputsForOp[2]));


        if(hasBiases) {
            builder.bias(sameDiff.getVariable(inputsForOp[3]));
        }

        if(hasPH) {
            builder.peepholeWeights(sameDiff.getVariable(inputsForOp[inputsForOp.length - 1]));
        }

        this.weights = builder.build();

        if(yLastName != null) {
            this.yLast = sameDiff.getVariable(yLastName);
        }

        if(cLastName != null) {
            this.cLast = sameDiff.getVariable(cLastName);
        }

    }

    @Override
    public void setPropertiesForFunction(Map<String, Object> properties) {
        if(configuration == null) {
            LSTMLayerConfig.LSTMLayerConfigBuilder builder = LSTMLayerConfig.builder();
            Boolean retFullSequence = getBooleanFromProperty("retFullSequence",properties);
            if(retFullSequence != null)
                builder.retFullSequence(retFullSequence);
            String act = getStringFromProperty("outAct",properties);
            if(act != null)
                builder.outAct(LSTMActivations.valueOf(act));
            String directionMode = getStringFromProperty("directionMode",properties);
            if(directionMode != null)
                builder.directionMode(LSTMDirectionMode.valueOf(directionMode));
            Double cellClip = getDoubleValueFromProperty("cellClip",properties);
            if(cellClip != null)
                builder.cellClip(cellClip);
            String cellAct = getStringFromProperty("cellAct",properties);
            if(cellAct != null)
                builder.cellAct(LSTMActivations.valueOf(cellAct));
            Boolean retLastC = getBooleanFromProperty("retLastC",properties);
            if(retLastC != null)
                builder.retLastC(retLastC);
            Boolean retLastH = getBooleanFromProperty("retLastH",properties);
            if(retLastH != null)
                builder.retLastH(retLastH);
            String gateAct = getStringFromProperty("gateAct",properties);
            if(gateAct != null)
                builder.gateAct(LSTMActivations.valueOf(gateAct));
            String lstmdataformat = getStringFromProperty("lstmdataformat",properties);
            if(lstmdataformat != null)
                builder.lstmdataformat(LSTMDataFormat.valueOf(LSTMDataFormat.class,lstmdataformat));

            //note we can't set the property directly due to not having samediff access here yet
            String cLast = getStringFromProperty("cLastName",properties);
            if(cLast != null) {
                this.cLastName = cLast;
            }

            String yLast = getStringFromProperty("yLastName",properties);
            if(yLast != null) {
                this.yLastName = yLast;
            }

            this.configuration = builder.build();


        }

    }

    @Override
    public boolean isConfigProperties() {
        return true;
    }

    @Override
    public String configFieldName() {
        return "configuration";
    }

    @Override
    public int getNumOutputs() {

        return Booleans.countTrue(
                configuration.isRetFullSequence(), //retFullSequence: B_ARG(5)
                configuration.isRetLastH(),  //  retLastH: B_ARG(6)
                configuration.isRetLastC()    // retLastC: B_ARG(7)
        );
    }




}


