/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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.
 */

package org.apache.commons.cli;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

/** <p>Describes a single command-line option.  It maintains
 * information regarding the short-name of the option, the long-name,
 * if any exists, a flag indicating if an argument is required for
 * this option, and a self-documenting description of the option.</p>
 *
 * <p>An Option is not created independantly, but is create through
 * an instance of {@link Options}.<p>
 *
 * @see org.apache.commons.cli.Options
 * @see org.apache.commons.cli.CommandLine
 *
 * @author bob mcwhirter (bob @ werken.com)
 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
 * @version $Revision$, $Date$
 */
public class Option implements Cloneable, Serializable
{
    private static final long serialVersionUID = 1L;

    /** constant that specifies the number of argument values has not been specified */
    public static final int UNINITIALIZED = -1;

    /** constant that specifies the number of argument values is infinite */
    public static final int UNLIMITED_VALUES = -2;

    /** the name of the option */
    private String opt;

    /** the long representation of the option */
    private String longOpt;

    /** the name of the argument for this option */
    private String argName = "arg";

    /** description of the option */
    private String description;

    /** specifies whether this option is required to be present */
    private boolean required;

    /** specifies whether the argument value of this Option is optional */
    private boolean optionalArg;

    /** the number of argument values this option can have */
    private int numberOfArgs = UNINITIALIZED;

    /** the type of this Option */
    private Object type;

    /** the list of argument values **/
    private List values = new ArrayList();

    /** the character that is the value separator */
    private char valuesep;

    /**
     * Creates an Option using the specified parameters.
     *
     * @param opt short representation of the option
     * @param description describes the function of the option
     *
     * @throws IllegalArgumentException if there are any non valid
     * Option characters in <code>opt</code>.
     */
    public Option(String opt, String description) throws IllegalArgumentException
    {
        this(opt, null, false, description);
    }

    /**
     * Creates an Option using the specified parameters.
     *
     * @param opt short representation of the option
     * @param hasArg specifies whether the Option takes an argument or not
     * @param description describes the function of the option
     *
     * @throws IllegalArgumentException if there are any non valid
     * Option characters in <code>opt</code>.
     */
    public Option(String opt, boolean hasArg, String description) throws IllegalArgumentException
    {
        this(opt, null, hasArg, description);
    }

    /**
     * Creates an Option using the specified parameters.
     *
     * @param opt short representation of the option
     * @param longOpt the long representation of the option
     * @param hasArg specifies whether the Option takes an argument or not
     * @param description describes the function of the option
     *
     * @throws IllegalArgumentException if there are any non valid
     * Option characters in <code>opt</code>.
     */
    public Option(String opt, String longOpt, boolean hasArg, String description)
           throws IllegalArgumentException
    {
        // ensure that the option is valid
        OptionValidator.validateOption(opt);

        this.opt = opt;
        this.longOpt = longOpt;

        // if hasArg is set then the number of arguments is 1
        if (hasArg)
        {
            this.numberOfArgs = 1;
        }

        this.description = description;
    }

    /**
     * Returns the id of this Option.  This is only set when the
     * Option shortOpt is a single character.  This is used for switch
     * statements.
     *
     * @return the id of this Option
     */
    public int getId()
    {
        return getKey().charAt(0);
    }

    /**
     * Returns the 'unique' Option identifier.
     * 
     * @return the 'unique' Option identifier
     */
    String getKey()
    {
        // if 'opt' is null, then it is a 'long' option
        if (opt == null)
        {
            return longOpt;
        }

        return opt;
    }

    /** 
     * Retrieve the name of this Option.
     *
     * It is this String which can be used with
     * {@link CommandLine#hasOption(String opt)} and
     * {@link CommandLine#getOptionValue(String opt)} to check
     * for existence and argument.
     *
     * @return The name of this option
     */
    public String getOpt()
    {
        return opt;
    }

    /**
     * Retrieve the type of this Option.
     * 
     * @return The type of this option
     */
    public Object getType()
    {
        return type;
    }

    /**
     * Sets the type of this Option.
     *
     * @param type the type of this Option
     */
    public void setType(Object type)
    {
        this.type = type;
    }

    /** 
     * Retrieve the long name of this Option.
     *
     * @return Long name of this option, or null, if there is no long name
     */
    public String getLongOpt()
    {
        return longOpt;
    }

    /**
     * Sets the long name of this Option.
     *
     * @param longOpt the long name of this Option
     */
    public void setLongOpt(String longOpt)
    {
        this.longOpt = longOpt;
    }

    /**
     * Sets whether this Option can have an optional argument.
     *
     * @param optionalArg specifies whether the Option can have
     * an optional argument.
     */
    public void setOptionalArg(boolean optionalArg)
    {
        this.optionalArg = optionalArg;
    }

    /**
     * @return whether this Option can have an optional argument
     */
    public boolean hasOptionalArg()
    {
        return optionalArg;
    }

    /** 
     * Query to see if this Option has a long name
     *
     * @return boolean flag indicating existence of a long name
     */
    public boolean hasLongOpt()
    {
        return longOpt != null;
    }

    /** 
     * Query to see if this Option requires an argument
     *
     * @return boolean flag indicating if an argument is required
     */
    public boolean hasArg()
    {
        return numberOfArgs > 0 || numberOfArgs == UNLIMITED_VALUES;
    }

    /** 
     * Retrieve the self-documenting description of this Option
     *
     * @return The string description of this option
     */
    public String getDescription()
    {
        return description;
    }

    /**
     * Sets the self-documenting description of this Option
     *
     * @param description The description of this option
     * @since 1.1
     */
    public void setDescription(String description)
    {
        this.description = description;
    }

    /** 
     * Query to see if this Option requires an argument
     *
     * @return boolean flag indicating if an argument is required
     */
    public boolean isRequired()
    {
        return required;
    }

    /**
     * Sets whether this Option is mandatory.
     *
     * @param required specifies whether this Option is mandatory
     */
    public void setRequired(boolean required)
    {
        this.required = required;
    }

    /**
     * Sets the display name for the argument value.
     *
     * @param argName the display name for the argument value.
     */
    public void setArgName(String argName)
    {
        this.argName = argName;
    }

    /**
     * Gets the display name for the argument value.
     *
     * @return the display name for the argument value.
     */
    public String getArgName()
    {
        return argName;
    }

    /**
     * Returns whether the display name for the argument value
     * has been set.
     *
     * @return if the display name for the argument value has been
     * set.
     */
    public boolean hasArgName()
    {
        return argName != null && argName.length() > 0;
    }

    /** 
     * Query to see if this Option can take many values.
     *
     * @return boolean flag indicating if multiple values are allowed
     */
    public boolean hasArgs()
    {
        return numberOfArgs > 1 || numberOfArgs == UNLIMITED_VALUES;
    }

    /** 
     * Sets the number of argument values this Option can take.
     *
     * @param num the number of argument values
     */
    public void setArgs(int num)
    {
        this.numberOfArgs = num;
    }

    /**
     * Sets the value separator.  For example if the argument value
     * was a Java property, the value separator would be '='.
     *
     * @param sep The value separator.
     */
    public void setValueSeparator(char sep)
    {
        this.valuesep = sep;
    }

    /**
     * Returns the value separator character.
     *
     * @return the value separator character.
     */
    public char getValueSeparator()
    {
        return valuesep;
    }

    /**
     * Return whether this Option has specified a value separator.
     * 
     * @return whether this Option has specified a value separator.
     * @since 1.1
     */
    public boolean hasValueSeparator()
    {
        return valuesep > 0;
    }

    /** 
     * Returns the number of argument values this Option can take.
     *
     * @return num the number of argument values
     */
    public int getArgs()
    {
        return numberOfArgs;
    }

    /**
     * Adds the specified value to this Option.
     * 
     * @param value is a/the value of this Option
     */
    void addValueForProcessing(String value)
    {
        switch (numberOfArgs)
        {
            case UNINITIALIZED:
                throw new RuntimeException("NO_ARGS_ALLOWED");

            default:
                processValue(value);
        }
    }

    /**
     * Processes the value.  If this Option has a value separator
     * the value will have to be parsed into individual tokens.  When
     * n-1 tokens have been processed and there are more value separators
     * in the value, parsing is ceased and the remaining characters are
     * added as a single token.
     *
     * @param value The String to be processed.
     *
     * @since 1.0.1
     */
    private void processValue(String value)
    {
        // this Option has a separator character
        if (hasValueSeparator())
        {
            // get the separator character
            char sep = getValueSeparator();

            // store the index for the value separator
            int index = value.indexOf(sep);

            // while there are more value separators
            while (index != -1)
            {
                // next value to be added 
                if (values.size() == (numberOfArgs - 1))
                {
                    break;
                }

                // store
                add(value.substring(0, index));

                // parse
                value = value.substring(index + 1);

                // get new index
                index = value.indexOf(sep);
            }
        }

        // store the actual value or the last value that has been parsed
        add(value);
    }

    /**
     * Add the value to this Option.  If the number of arguments
     * is greater than zero and there is enough space in the list then
     * add the value.  Otherwise, throw a runtime exception.
     *
     * @param value The value to be added to this Option
     *
     * @since 1.0.1
     */
    private void add(String value)
    {
        if ((numberOfArgs > 0) && (values.size() > (numberOfArgs - 1)))
        {
            throw new RuntimeException("Cannot add value, list full.");
        }

        // store value
        values.add(value);
    }

    /**
     * Returns the specified value of this Option or 
     * <code>null</code> if there is no value.
     *
     * @return the value/first value of this Option or 
     * <code>null</code> if there is no value.
     */
    public String getValue()
    {
        return hasNoValues() ? null : (String) values.get(0);
    }

    /**
     * Returns the specified value of this Option or 
     * <code>null</code> if there is no value.
     *
     * @param index The index of the value to be returned.
     *
     * @return the specified value of this Option or 
     * <code>null</code> if there is no value.
     *
     * @throws IndexOutOfBoundsException if index is less than 1
     * or greater than the number of the values for this Option.
     */
    public String getValue(int index) throws IndexOutOfBoundsException
    {
        return hasNoValues() ? null : (String) values.get(index);
    }

    /**
     * Returns the value/first value of this Option or the 
     * <code>defaultValue</code> if there is no value.
     *
     * @param defaultValue The value to be returned if ther
     * is no value.
     *
     * @return the value/first value of this Option or the 
     * <code>defaultValue</code> if there are no values.
     */
    public String getValue(String defaultValue)
    {
        String value = getValue();

        return (value != null) ? value : defaultValue;
    }

    /**
     * Return the values of this Option as a String array 
     * or null if there are no values
     *
     * @return the values of this Option as a String array 
     * or null if there are no values
     */
    public String[] getValues()
    {
        return hasNoValues() ? null : (String[]) values.toArray(new String[values.size()]);
    }

    /**
     * @return the values of this Option as a List
     * or null if there are no values
     */
    public List getValuesList()
    {
        return values;
    }

    /** 
     * Dump state, suitable for debugging.
     *
     * @return Stringified form of this object
     */
    public String toString()
    {
        StringBuffer buf = new StringBuffer().append("[ option: ");

        buf.append(opt);

        if (longOpt != null)
        {
            buf.append(" ").append(longOpt);
        }

        buf.append(" ");

        if (hasArgs())
        {
            buf.append("[ARG...]");
        }
        else if (hasArg())
        {
            buf.append(" [ARG]");
        }

        buf.append(" :: ").append(description);

        if (type != null)
        {
            buf.append(" :: ").append(type);
        }

        buf.append(" ]");

        return buf.toString();
    }

    /**
     * Returns whether this Option has any values.
     *
     * @return whether this Option has any values.
     */
    private boolean hasNoValues()
    {
        return values.isEmpty();
    }

    public boolean equals(Object o)
    {
        if (this == o)
        {
            return true;
        }
        if (o == null || getClass() != o.getClass())
        {
            return false;
        }

        Option option = (Option) o;


        if (opt != null ? !opt.equals(option.opt) : option.opt != null)
        {
            return false;
        }
        if (longOpt != null ? !longOpt.equals(option.longOpt) : option.longOpt != null)
        {
            return false;
        }

        return true;
    }

    public int hashCode()
    {
        int result;
        result = (opt != null ? opt.hashCode() : 0);
        result = 31 * result + (longOpt != null ? longOpt.hashCode() : 0);
        return result;
    }

    /**
     * A rather odd clone method - due to incorrect code in 1.0 it is public 
     * and in 1.1 rather than throwing a CloneNotSupportedException it throws 
     * a RuntimeException so as to maintain backwards compat at the API level. 
     *
     * After calling this method, it is very likely you will want to call 
     * clearValues(). 
     *
     * @throws RuntimeException
     */
    public Object clone()
    {
        try
        {
            Option option = (Option) super.clone();
            option.values = new ArrayList(values);
            return option;
        }
        catch (CloneNotSupportedException cnse)
        {
            throw new RuntimeException("A CloneNotSupportedException was thrown: " + cnse.getMessage());
        }
    }

    /**
     * Clear the Option values. After a parse is complete, these are left with
     * data in them and they need clearing if another parse is done.
     *
     * See: <a href="https://issues.apache.org/jira/browse/CLI-71">CLI-71</a>
     */
    void clearValues()
    {
        values.clear();
    }

    /**
     * This method is not intended to be used. It was a piece of internal 
     * API that was made public in 1.0. It currently throws an UnsupportedOperationException. 
     * @deprecated
     * @throws UnsupportedOperationException
     */
    public boolean addValue(String value)
    {
        throw new UnsupportedOperationException("The addValue method is not intended for client use. "
                + "Subclasses should use the addValueForProcessing method instead. ");
    }

}