/*
 * The contents of this file are subject to the terms of the Common Development and
 * Distribution License (the License). You may not use this file except in compliance with the
 * License.
 *
 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
 * specific language governing permission and limitations under the License.
 *
 * When distributing Covered Software, include this CDDL Header Notice in each file and include
 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
 * Header, with the fields enclosed by brackets [] replaced by your own identifying
 * information: "Portions Copyright [year] [name of copyright owner]".
 *
 * Copyright 2008 Sun Microsystems, Inc.
 */

package org.forgerock.opendj.config;

import org.forgerock.util.Reject;

import java.util.EnumSet;

/**
 * Duration property definition.
 * <p>
 * A duration property definition comprises of:
 * <ul>
 * <li>a <i>base unit</i> - specifies the minimum granularity which can be used
 * to specify duration property values. For example, if the base unit is in
 * seconds then values represented in milliseconds will not be permitted. The
 * default base unit is seconds
 * <li>an optional <i>maximum unit</i> - specifies the biggest duration unit
 * which can be used to specify duration property values. Values presented in
 * units greater than this unit will not be permitted. There is no default
 * maximum unit
 * <li><i>lower limit</i> - specifies the smallest duration permitted by the
 * property. The default lower limit is 0 and can never be less than 0
 * <li>an optional <i>upper limit</i> - specifies the biggest duration permitted
 * by the property. By default, there is no upper limit
 * <li>support for <i>unlimited</i> durations - when permitted users can specify
 * "unlimited" durations. These are represented using the decoded value, -1, or
 * the encoded string value "unlimited". By default, unlimited durations are not
 * permitted. In addition, it is not possible to define an upper limit and
 * support unlimited values.
 * </ul>
 * Decoded values are represented using <code>long</code> values in the base
 * unit defined for the duration property definition.
 */
public final class DurationPropertyDefinition extends PropertyDefinition<Long> {

    /** String used to represent unlimited durations. */
    private static final String UNLIMITED = "unlimited";

    /** The base unit for this property definition. */
    private final DurationUnit baseUnit;

    /** The optional maximum unit for this property definition. */
    private final DurationUnit maximumUnit;

    /** The lower limit of the property value in milli-seconds. */
    private final long lowerLimit;

    /** The optional upper limit of the property value in milli-seconds. */
    private final Long upperLimit;

    /**
     * Indicates whether this property allows the use of the "unlimited"
     * duration value (represented using a -1L or the string
     * "unlimited").
     */
    private final boolean allowUnlimited;

    /**
     * An interface for incrementally constructing duration property
     * definitions.
     */
    public static final class Builder extends AbstractBuilder<Long, DurationPropertyDefinition> {

        /** The base unit for this property definition. */
        private DurationUnit baseUnit = DurationUnit.SECONDS;

        /** The optional maximum unit for this property definition. */
        private DurationUnit maximumUnit;

        /** The lower limit of the property value in milli-seconds. */
        private long lowerLimit;

        /** The optional upper limit of the property value in milli-seconds. */
        private Long upperLimit;

        /**
         * Indicates whether this property allows the use of the
         * "unlimited" duration value (represented using a -1L or the
         * string "unlimited").
         */
        private boolean allowUnlimited;

        /** Private constructor. */
        private Builder(AbstractManagedObjectDefinition<?, ?> d, String propertyName) {
            super(d, propertyName);
        }

        /**
         * Set the base unit for this property definition (values including
         * limits are specified in this unit). By default a duration property
         * definition uses seconds.
         *
         * @param unit
         *            The string representation of the base unit (must not be
         *            <code>null</code>).
         * @throws IllegalArgumentException
         *             If the provided unit name did not correspond to a known
         *             duration unit, or if the base unit is bigger than the
         *             maximum unit.
         */
        public final void setBaseUnit(String unit) {
            Reject.ifNull(unit);

            setBaseUnit(DurationUnit.getUnit(unit));
        }

        /**
         * Set the base unit for this property definition (values including
         * limits are specified in this unit). By default a duration property
         * definition uses seconds.
         *
         * @param unit
         *            The base unit (must not be <code>null</code>).
         * @throws IllegalArgumentException
         *             If the provided base unit is bigger than the maximum
         *             unit.
         */
        public final void setBaseUnit(DurationUnit unit) {
            Reject.ifNull(unit);

            // Make sure that the base unit is not bigger than the maximum unit.
            if (maximumUnit != null && unit.getDuration() > maximumUnit.getDuration()) {
                throw new IllegalArgumentException("Base unit greater than maximum unit");
            }

            this.baseUnit = unit;
        }

        /**
         * Set the maximum unit for this property definition. By default there
         * is no maximum unit.
         *
         * @param unit
         *            The string representation of the maximum unit, or
         *            <code>null</code> if there should not be a maximum unit.
         * @throws IllegalArgumentException
         *             If the provided unit name did not correspond to a known
         *             duration unit, or if the maximum unit is smaller than the
         *             base unit.
         */
        public final void setMaximumUnit(String unit) {
            setMaximumUnit(unit != null ? DurationUnit.getUnit(unit) : null);
        }

        /**
         * Set the maximum unit for this property definition. By default there
         * is no maximum unit.
         *
         * @param unit
         *            The maximum unit, or <code>null</code> if there should not
         *            be a maximum unit.
         * @throws IllegalArgumentException
         *             If the provided maximum unit is smaller than the base
         *             unit.
         */
        public final void setMaximumUnit(DurationUnit unit) {
            // Make sure that the maximum unit is not smaller than the base unit.
            if (unit != null && unit.getDuration() < baseUnit.getDuration()) {
                throw new IllegalArgumentException("Maximum unit smaller than base unit");
            }

            this.maximumUnit = unit;
        }

        /**
         * Set the lower limit in milli-seconds.
         *
         * @param lowerLimit
         *            The new lower limit (must be >= 0) in milli-seconds.
         * @throws IllegalArgumentException
         *             If a negative lower limit was specified, or the lower
         *             limit is greater than the upper limit.
         */
        public final void setLowerLimit(long lowerLimit) {
            if (lowerLimit < 0) {
                throw new IllegalArgumentException("Negative lower limit");
            }

            if (upperLimit != null && lowerLimit > upperLimit) {
                throw new IllegalArgumentException("Lower limit greater than upper limit");
            }

            this.lowerLimit = lowerLimit;
        }

        /**
         * Set the lower limit using a string representation of the limit. If
         * the string does not specify a unit, the current base unit will be
         * used.
         *
         * @param lowerLimit
         *            The string representation of the new lower limit.
         * @throws IllegalArgumentException
         *             If the lower limit could not be parsed, or if a negative
         *             lower limit was specified, or the lower limit is greater
         *             than the upper limit.
         */
        public final void setLowerLimit(String lowerLimit) {
            setLowerLimit(DurationUnit.parseValue(lowerLimit, baseUnit));
        }

        /**
         * Set the upper limit in milli-seconds.
         *
         * @param upperLimit
         *            The new upper limit in milli-seconds, or <code>null</code>
         *            if there is no upper limit.
         * @throws IllegalArgumentException
         *             If a negative upper limit was specified, or the lower
         *             limit is greater than the upper limit or unlimited
         *             durations are permitted.
         */
        public final void setUpperLimit(Long upperLimit) {
            if (upperLimit != null) {
                if (upperLimit < 0) {
                    throw new IllegalArgumentException("Negative upper limit");
                }

                if (lowerLimit > upperLimit) {
                    throw new IllegalArgumentException("Lower limit greater than upper limit");
                }

                if (allowUnlimited) {
                    throw new IllegalArgumentException("Upper limit specified when unlimited durations are permitted");
                }
            }

            this.upperLimit = upperLimit;
        }

        /**
         * Set the upper limit using a string representation of the limit. If
         * the string does not specify a unit, the current base unit will be
         * used.
         *
         * @param upperLimit
         *            The string representation of the new upper limit, or
         *            <code>null</code> if there is no upper limit.
         * @throws IllegalArgumentException
         *             If the upper limit could not be parsed, or if the lower
         *             limit is greater than the upper limit.
         */
        public final void setUpperLimit(String upperLimit) {
            setUpperLimit(upperLimit != null ? DurationUnit.parseValue(upperLimit, baseUnit) : null);
        }

        /**
         * Specify whether or not this property definition will allow unlimited
         * values (default is false).
         *
         * @param allowUnlimited
         *            <code>true</code> if the property will allow unlimited
         *            values, or <code>false</code> otherwise.
         * @throws IllegalArgumentException
         *             If unlimited values are to be permitted but there is an
         *             upper limit specified.
         */
        public final void setAllowUnlimited(boolean allowUnlimited) {
            if (allowUnlimited && upperLimit != null) {
                throw new IllegalArgumentException("Upper limit specified when unlimited durations are permitted");
            }

            this.allowUnlimited = allowUnlimited;
        }

        /** {@inheritDoc} */
        @Override
        protected DurationPropertyDefinition buildInstance(AbstractManagedObjectDefinition<?, ?> d,
            String propertyName, EnumSet<PropertyOption> options, AdministratorAction adminAction,
            DefaultBehaviorProvider<Long> defaultBehavior) {
            return new DurationPropertyDefinition(d, propertyName, options, adminAction, defaultBehavior, baseUnit,
                maximumUnit, lowerLimit, upperLimit, allowUnlimited);
        }
    }

    /**
     * Create a duration property definition builder.
     *
     * @param d
     *            The managed object definition associated with this property
     *            definition.
     * @param propertyName
     *            The property name.
     * @return Returns the new integer property definition builder.
     */
    public static Builder createBuilder(AbstractManagedObjectDefinition<?, ?> d, String propertyName) {
        return new Builder(d, propertyName);
    }

    /** Private constructor. */
    private DurationPropertyDefinition(AbstractManagedObjectDefinition<?, ?> d, String propertyName,
        EnumSet<PropertyOption> options, AdministratorAction adminAction,
        DefaultBehaviorProvider<Long> defaultBehavior, DurationUnit baseUnit, DurationUnit maximumUnit,
        Long lowerLimit, Long upperLimit, boolean allowUnlimited) {
        super(d, Long.class, propertyName, options, adminAction, defaultBehavior);
        this.baseUnit = baseUnit;
        this.maximumUnit = maximumUnit;
        this.lowerLimit = lowerLimit;
        this.upperLimit = upperLimit;
        this.allowUnlimited = allowUnlimited;
    }

    /**
     * Get the base unit for this property definition (values including limits
     * are specified in this unit).
     *
     * @return Returns the base unit for this property definition (values
     *         including limits are specified in this unit).
     */
    public DurationUnit getBaseUnit() {
        return baseUnit;
    }

    /**
     * Get the maximum unit for this property definition if specified.
     *
     * @return Returns the maximum unit for this property definition, or
     *         <code>null</code> if there is no maximum unit.
     */
    public DurationUnit getMaximumUnit() {
        return maximumUnit;
    }

    /**
     * Get the lower limit in milli-seconds.
     *
     * @return Returns the lower limit in milli-seconds.
     */
    public long getLowerLimit() {
        return lowerLimit;
    }

    /**
     * Get the upper limit in milli-seconds.
     *
     * @return Returns the upper limit in milli-seconds, or <code>null</code> if
     *         there is no upper limit.
     */
    public Long getUpperLimit() {
        return upperLimit;
    }

    /**
     * Determine whether this property allows unlimited durations.
     *
     * @return Returns <code>true</code> if this this property allows unlimited
     *         durations.
     */
    public boolean isAllowUnlimited() {
        return allowUnlimited;
    }

    /** {@inheritDoc} */
    @Override
    public void validateValue(Long value) {
        Reject.ifNull(value);

        long nvalue = baseUnit.toMilliSeconds(value);
        if (!allowUnlimited && nvalue < lowerLimit) {
            throw PropertyException.illegalPropertyValueException(this, value);

            // unlimited allowed
        } else if (nvalue >= 0 && nvalue < lowerLimit) {
            throw PropertyException.illegalPropertyValueException(this, value);
        }

        if (upperLimit != null && nvalue > upperLimit) {
            throw PropertyException.illegalPropertyValueException(this, value);
        }
    }

    /** {@inheritDoc} */
    @Override
    public String encodeValue(Long value) {
        Reject.ifNull(value);

        // Make sure that we correctly encode negative values as "unlimited".
        if (allowUnlimited && value < 0) {
            return UNLIMITED;
        }

        // Encode the size value using the base unit.
        StringBuilder builder = new StringBuilder();
        builder.append(value);
        builder.append(' ');
        builder.append(baseUnit);
        return builder.toString();
    }

    /** {@inheritDoc} */
    @Override
    public Long decodeValue(String value) {
        Reject.ifNull(value);

        // First check for the special "unlimited" value when necessary.
        if (allowUnlimited && UNLIMITED.equalsIgnoreCase(value.trim())) {
            return -1L;
        }

        // Parse the string representation.
        long ms;
        try {
            ms = DurationUnit.parseValue(value);
        } catch (NumberFormatException e) {
            throw PropertyException.illegalPropertyValueException(this, value);
        }

        // Check the unit is in range - values must not be more granular
        // than the base unit.
        if (ms % baseUnit.getDuration() != 0) {
            throw PropertyException.illegalPropertyValueException(this, value);
        }

        // Convert the value a long in the property's required unit.
        Long i = (long) baseUnit.fromMilliSeconds(ms);
        try {
            validateValue(i);
            return i;
        } catch (PropertyException e) {
            throw PropertyException.illegalPropertyValueException(this, value);
        }
    }

    /** {@inheritDoc} */
    @Override
    public <R, P> R accept(PropertyDefinitionVisitor<R, P> v, P p) {
        return v.visitDuration(this, p);
    }

    /** {@inheritDoc} */
    @Override
    public <R, P> R accept(PropertyValueVisitor<R, P> v, Long value, P p) {
        return v.visitDuration(this, value, p);
    }

    /** {@inheritDoc} */
    @Override
    public void toString(StringBuilder builder) {
        super.toString(builder);

        builder.append(" baseUnit=");
        builder.append(baseUnit);

        if (maximumUnit != null) {
            builder.append(" maximumUnit=");
            builder.append(maximumUnit);
        }

        builder.append(" lowerLimit=");
        builder.append(lowerLimit);
        builder.append("ms");

        if (upperLimit != null) {
            builder.append(" upperLimit=");
            builder.append(upperLimit);
            builder.append("ms");
        }

        builder.append(" allowUnlimited=");
        builder.append(allowUnlimited);
    }

    /** {@inheritDoc} */
    @Override
    public int compare(Long o1, Long o2) {
        return o1.compareTo(o2);
    }

}