package ca.bcit.cst.comp2526.assign3.a00752818.operations;


/**
 * Create operations.
 *
 * @author D'Arcy Smith
 * @version 1.0
 */
public class OperationFactory
{
    public static OperationType opera;
    /**
     * Represents the operation object.
     */
    protected Operation operation;
    /**
     * Represents the addition operation.
     */
    public static final String ADDITION_OPERATION_KEY = "+";
    /**
     * Represents the subtraction operation.
     */
    public static final String SUBTRATION_OPERATION_KEY = "-";
    /**
     * Represents the factorial operation.
     */
    public static final String FACTORIAL_OPERATION_KEY = "!";

    /**
     * The different types of operations.
     */
    public static enum OperationType
    {
        /**
         * Addition operation.
         */
        ADDITION,
        /**
         * Subtraction operation.
         */
        SUBTRACTION,
        /**
         * Factorial operation.
         */
        FACTORIAL;

        /**
         * Check if an operation is binary (takes two operands).
         *
         * @return true if the operation is binary, false otherwise.
         */
        public boolean isBinary()
        {
            boolean value = false;
            if(OperationFactory.OperationType.ADDITION.equals(this))
            {
                value = true;
                //return true;
            }
            else if(OperationFactory.OperationType.SUBTRACTION.equals(this))
            {
                value = true;
                //return true;
            }
            else if(OperationFactory.OperationType.FACTORIAL.equals(this))
            {
                value = false;
                //return false;
            }
            return value;
        }

        /**
         * Check if an operation is unary (takes one operand).
         *
         * @return true if the operation is unary, false otherwise.
         */
        public boolean isUnary()
        {
            boolean value = false;
            if(OperationFactory.OperationType.ADDITION.equals(this))
            {
                value = false;
            }
            if(OperationFactory.OperationType.SUBTRACTION.equals(this))
            {
                value = false;
            }
            if(OperationFactory.OperationType.FACTORIAL.equals(this))
            {
                value = true;
            }
            return value;
        }

        /**
         * Convert a string to an OperationType.
         *
         * @param key the string to base the value on.
         * @return the operation type associated with the key
         * @throws InvalidOperationException if the key is not recognized.
         */
        public static OperationType fromString(final String key)
            throws InvalidOperationException
        {
            if(key == null)
            {
                throw new IllegalArgumentException("key cannot be " + key);
            }
            else if(key.equals(SUBTRATION_OPERATION_KEY))
            {
                return SUBTRACTION;
            }
            else if(key.equals(ADDITION_OPERATION_KEY))
            {
                return ADDITION;
            }
            else if(key.equals(FACTORIAL_OPERATION_KEY))
            {
                return FACTORIAL;
            }

            throw new InvalidOperationException(key);

        }
    }

    /**
     * Get an instance of an Operation based in the type.
     *
     * @param type the type of operation to get.
     * @return an instance of the operation represented by the type.
     */
    public Operation getInstance(final OperationType type)
    {
        if(type == null)
        {
            throw new IllegalArgumentException("type cannot be null");
        }
        if(type == OperationType.ADDITION)
        {
            operation = new AdditionOperation();
        }
        else if(type == OperationType.FACTORIAL)
        {
            operation = new FactorialOperation();
        }
        else if(type == OperationType.SUBTRACTION)
        {
            operation = new SubtractionOperation();
        }
        return operation;
    }
}