/*
 * Redberry: symbolic tensor computations.
 *
 * Copyright (c) 2010-2015:
 *   Stanislav Poslavsky   
 *   Bolotin Dmitriy       
 *
 * This file is part of Redberry.
 *
 * Redberry is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Redberry is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Redberry. If not, see .
 */
package cc.redberry.core.tensor.functions;

import cc.redberry.core.context.OutputFormat;
import cc.redberry.core.indices.Indices;
import cc.redberry.core.indices.IndicesFactory;
import cc.redberry.core.tensor.Tensor;
import cc.redberry.core.tensor.TensorException;
import cc.redberry.core.utils.TensorUtils;

import static cc.redberry.core.context.OutputFormat.*;

/**
 * @author Dmitry Bolotin
 * @author Stanislav Poslavsky
 * @since 1.0
 */
public abstract class ScalarFunction extends Tensor {

    protected final Tensor argument;

    protected ScalarFunction(Tensor argument) {
        if (!TensorUtils.isScalar(argument))
            throw new TensorException("Non scalar argument " + argument + " in scalar function");
        this.argument = argument;
    }

    @Override
    public final Indices getIndices() {
        return IndicesFactory.EMPTY_INDICES;
    }

    protected abstract String functionName();

    public abstract Tensor derivative();

    @Override
    public final Tensor get(int i) {
        if (i != 0)
            throw new IndexOutOfBoundsException();
        return argument;
    }

    @Override
    public final int size() {
        return 1;
    }

    @Override
    public final String toString(OutputFormat mode) {
        String stringSymbol = functionName();
        if (mode.is(UTF8))
            return stringSymbol + "(" + argument.toString(UTF8) + ")";
        if (mode.is(LaTeX))
            return "\\" + stringSymbol.toLowerCase() + "(" + argument.toString(UTF8) + ")";
        if (mode.is(Redberry))
            return Character.toString(Character.toUpperCase(stringSymbol.charAt(0))) + stringSymbol.substring(1, stringSymbol.length()) + "[" + argument.toString(OutputFormat.Redberry) + "]";
        else
            return stringSymbol + "(" + argument.toString(UTF8) + ")";

    }
}