/*

Copyright 2010, Knowledge Integration Ltd.
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    * Redistributions of source code must retain the above copyright
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contributors may be used to endorse or promote products derived from
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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*/

package com.google.refine.expr.functions.math;

import java.util.Properties;

import java.util.concurrent.ThreadLocalRandom;

import com.google.refine.expr.EvalError;
import com.google.refine.grel.ControlFunctionRegistry;
import com.google.refine.grel.Function;

public class RandomNumber implements Function {

    @Override
    public Object call(Properties bindings, Object[] args) {
        if (args.length == 0) {
            // Return a double in the interval 0.0 <= x < 1.0
            return ThreadLocalRandom.current().nextDouble();
        } else if (args.length == 2) {
            // Return a double in the interval lowerBound <= x < upperBound
            if (args[0] instanceof Number && args[1] instanceof Number
                    && ((Number) args[0]).intValue()<((Number) args[1]).intValue()) {

                // check if arguments are long
                if (args[0] instanceof Long && args[1] instanceof Long) {
                    // return a long
                    return ThreadLocalRandom.current().nextLong(((Number) args[0]).longValue(), ((Number) args[1]).longValue()+1);
                } else {
                    // return a double
                    return ThreadLocalRandom.current().nextDouble(((Number) args[0]).doubleValue(), ((Number) args[1]).doubleValue());
                }
            }
        }
        return new EvalError(ControlFunctionRegistry.getFunctionName(this) + " expects no arguments or two numbers, the first must be less than the second");
    }

    @Override
    public String getDescription() {
        return "Returns a random integer in the interval between the lower and upper bounds (inclusively). Will output a different random number in each cell in a column.";
    }
    
    @Override
    public String getParams() {
        return "number lowerBound, number upperBound";
    }
    
    @Override
    public String getReturns() {
        return "number";
    }
    
}