/*
 * Copyright (c) 2002-2007 JGoodies Karsten Lentzsch. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  o Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 *  o Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 *  o Neither the name of JGoodies Karsten Lentzsch nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.jgoodies.forms.layout;

import java.awt.Container;
import java.io.Serializable;
import java.util.List;
import java.util.Locale;
import java.util.StringTokenizer;

/**
 * An abstract class that specifies columns and rows in FormLayout
 * by their default alignment, start size and resizing behavior.
 * API users will use the subclasses {@link ColumnSpec} and  {@link RowSpec}.
 *
 * @author        Karsten Lentzsch
 * @version $Revision$
 *
 * @see     ColumnSpec
 * @see     RowSpec
 * @see     FormLayout
 * @see     CellConstraints
 */
@SuppressWarnings("serial")
public abstract class FormSpec implements Serializable {

    // Horizontal and Vertical Default Alignments ***************************

    /**
     * By default put components in the left.
     */
    static final DefaultAlignment LEFT_ALIGN = new DefaultAlignment("left");

    /**
     * By default put components in the right.
     */
    static final DefaultAlignment RIGHT_ALIGN = new DefaultAlignment("right");

    /**
     * By default put the components in the top.
     */
    static final DefaultAlignment TOP_ALIGN = new DefaultAlignment("top");

    /**
     * By default put the components in the bottom.
     */
    static final DefaultAlignment BOTTOM_ALIGN = new DefaultAlignment("bottom");

    /**
     * By default put the components in the center.
     */
    static final DefaultAlignment CENTER_ALIGN = new DefaultAlignment("center");

    /**
     * By default fill the column or row.
     */
    static final DefaultAlignment FILL_ALIGN = new DefaultAlignment("fill");

    /**
     * An array of all enumeration values used to canonicalize
     * deserialized default alignments.
     */
    private static final DefaultAlignment[] VALUES = { LEFT_ALIGN, RIGHT_ALIGN,
            TOP_ALIGN, BOTTOM_ALIGN, CENTER_ALIGN, FILL_ALIGN };

    // Resizing Weights *****************************************************

    /**
     * Gives a column or row a fixed size.
     */
    public static final double NO_GROW = 0.0d;

    /**
     * The default resize weight.
     */
    public static final double DEFAULT_GROW = 1.0d;

    // Fields ***************************************************************

    /**
     * Holds the default alignment that will be used if a cell does not
     * override this default.
     */
    private DefaultAlignment defaultAlignment;

    /**
     * Holds the size that describes how to size this column or row.
     */
    private Size size;

    /**
     * Holds the resize weight; is 0 if not used.
     */
    private double resizeWeight;

    // Instance Creation ****************************************************

    /**
     * Constructs a <code>FormSpec</code> for the given default alignment,
     * size, and resize weight. The resize weight must be a non-negative
     * double; you can use <code>NONE</code> as a convenience value for no
     * resize.
     *
     * @param defaultAlignment the spec's default alignment
     * @param size             a constant, component or bounded size
     * @param resizeWeight     the spec resize weight
     * @exception IllegalArgumentException if the resize weight is negative
     */
    protected FormSpec(DefaultAlignment defaultAlignment, Size size,
            double resizeWeight) {
        this.defaultAlignment = defaultAlignment;
        this.size = size;
        this.resizeWeight = resizeWeight;
        if (resizeWeight < 0) {
            throw new IllegalArgumentException(
                    "The resize weight must be non-negative.");
        }
    }

    /**
     * Constructs a <code>FormSpec</code> from the specified encoded
     * description. The description will be parsed to set initial values.
     *
     * @param defaultAlignment         the default alignment
     * @param encodedDescription        the encoded description
     */
    protected FormSpec(DefaultAlignment defaultAlignment,
            String encodedDescription) {
        this(defaultAlignment, Sizes.DEFAULT, NO_GROW);
        parseAndInitValues(encodedDescription.toLowerCase(Locale.ENGLISH));
    }

    // Public API ***********************************************************

    /**
     * Returns the default alignment.
     *
     * @return the default alignment
     */
    public final DefaultAlignment getDefaultAlignment() {
        return defaultAlignment;
    }

    /**
     * Returns the size.
     *
     * @return the size
     */
    public final Size getSize() {
        return size;
    }

    /**
     * Returns the current resize weight.
     *
     * @return the resize weight.
     */
    public final double getResizeWeight() {
        return resizeWeight;
    }

    /**
     * Checks and answers whether this spec can grow or not.
     * That is the case if and only if the resize weight is
     * != <code>NO_GROW</code>.
     *
     * @return true if it can grow, false if it can't grow
     */
    final boolean canGrow() {
        return getResizeWeight() != NO_GROW;
    }

    // Parsing **************************************************************

    /**
     * Parses an encoded form spec and initializes all required fields.
     * The encoded description must be in lower case.
     *
     * @param encodedDescription   the FormSpec in an encoded format
     * @exception IllegalArgumentException if the string is empty, has no size,
     * or is otherwise invalid
     */
    private void parseAndInitValues(String encodedDescription) {
        StringTokenizer tokenizer = new StringTokenizer(encodedDescription,
                ":");
        if (!tokenizer.hasMoreTokens()) {
            throw new IllegalArgumentException(
                    "The form spec must not be empty.");
        }
        String token = tokenizer.nextToken();

        // Check if the first token is an orientation.
        DefaultAlignment alignment = DefaultAlignment.valueOf(token,
                isHorizontal());
        if (alignment != null) {
            defaultAlignment = alignment;
            if (!tokenizer.hasMoreTokens()) {
                throw new IllegalArgumentException(
                        "The form spec must provide a size.");
            }
            token = tokenizer.nextToken();
        }

        parseAndInitSize(token);

        if (tokenizer.hasMoreTokens()) {
            resizeWeight = decodeResize(tokenizer.nextToken());
        }
    }

    /**
     * Parses an encoded size spec and initializes the size fields.
     *
     * @param token    a token that represents a size, either bounded or plain
     */
    private void parseAndInitSize(String token) {
        if (token.startsWith("max(") && token.endsWith(")")) {
            size = parseAndInitBoundedSize(token, false);
            return;
        }
        if (token.startsWith("min(") && token.endsWith(")")) {
            size = parseAndInitBoundedSize(token, true);
            return;
        }
        size = decodeAtomicSize(token);
    }

    /**
     * Parses an encoded compound size and sets the size fields.
     * The compound size has format:
     * max(&lt;atomic size&gt;;&lt;atomic size2&gt;) | min(&lt;atomic size1&gt;;&lt;atomic size2&gt;)
     * One of the two atomic sizes must be a logical size, the other must
     * be a size constant.
     *
     * @param token  a token for a bounded size, e.g. "max(50dlu; pref)"
     * @param setMax  if true we set a maximum size, otherwise a minimum size
     * @return a Size that represents the parse result
     */
    private Size parseAndInitBoundedSize(String token, boolean setMax) {
        int semicolonIndex = token.indexOf(';');
        String sizeToken1 = token.substring(4, semicolonIndex);
        String sizeToken2 = token.substring(semicolonIndex + 1,
                token.length() - 1);

        Size size1 = decodeAtomicSize(sizeToken1);
        Size size2 = decodeAtomicSize(sizeToken2);

        // Check valid combinations and set min or max.
        if (size1 instanceof ConstantSize) {
            if (size2 instanceof Sizes.ComponentSize) {
                return new BoundedSize(size2, setMax ? null : size1,
                        setMax ? size1 : null);
            }
            throw new IllegalArgumentException(
                    "Bounded sizes must not be both constants.");
        }
        if (size2 instanceof ConstantSize) {
            return new BoundedSize(size1, setMax ? null : size2,
                    setMax ? size2 : null);
        }
        throw new IllegalArgumentException(
                "Bounded sizes must not be both logical.");
    }

    /**
     * Decodes and returns an atomic size that is either a constant size or a
     * component size.
     *
     * @param token        the encoded size
     * @return the decoded size either a constant or component size
     */
    private Size decodeAtomicSize(String token) {
        Sizes.ComponentSize componentSize = Sizes.ComponentSize.valueOf(token);
        if (componentSize != null) {
            return componentSize;
        }
        return ConstantSize.valueOf(token, isHorizontal());
    }

    /**
     * Decodes an encoded resize mode and resize weight and answers
     * the resize weight.
     *
     * @param token        the encoded resize weight
     * @return the decoded resize weight
     * @exception IllegalArgumentException if the string description is an
     *     invalid string representation
     */
    private double decodeResize(String token) {
        if (token.equals("g") || token.equals("grow")) {
            return DEFAULT_GROW;
        }
        if (token.equals("n") || token.equals("nogrow")
                || token.equals("none")) {
            return NO_GROW;
        }
        // Must have format: grow(<double>)
        if ((token.startsWith("grow(") || token.startsWith("g("))
                && token.endsWith(")")) {
            int leftParen = token.indexOf('(');
            int rightParen = token.indexOf(')');
            String substring = token.substring(leftParen + 1, rightParen);
            return Double.parseDouble(substring);
        }
        throw new IllegalArgumentException("The resize argument '" + token
                + "' is invalid. "
                + " Must be one of: grow, g, none, n, grow(<double>), g(<double>)");
    }

    // Misc *****************************************************************

    /**
     * Returns a string representation of this form specification.
     * The string representation consists of three elements separated by
     * a colon (<tt>":"</tt>), first the alignment, second the size,
     * and third the resize spec.<p>
     *
     * This method does <em>not</em> return a decoded version
     * of this object; the contrary is the case. Many instances
     * will return a string that cannot be parsed.<p>
     *
     * <strong>Note:</strong> The string representation may change
     * at any time. It is strongly recommended to not use this string
     * for parsing purposes.
     *
     * @return        a string representation of the form specification.
     */
    @Override
    public final String toString() {
        StringBuffer buffer = new StringBuffer();
        buffer.append(defaultAlignment);

        buffer.append(":");
        buffer.append(size.toString());
        buffer.append(':');
        if (resizeWeight == NO_GROW) {
            buffer.append("noGrow");
        } else if (resizeWeight == DEFAULT_GROW) {
            buffer.append("grow");
        } else {
            buffer.append("grow(");
            buffer.append(resizeWeight);
            buffer.append(')');
        }
        return buffer.toString();
    }

    /**
     * Returns a string representation of this form specification.
     * The string representation consists of three elements separated by
     * a colon (<tt>":"</tt>), first the alignment, second the size,
     * and third the resize spec.<p>
     *
     * This method does <em>not</em> return a decoded version
     * of this object; the contrary is the case. Many instances
     * will return a string that cannot be parsed.<p>
     *
     * <strong>Note:</strong> The string representation may change
     * at any time. It is strongly recommended to not use this string
     * for parsing purposes.
     *
     * @return  a string representation of the form specification.
     */
    public final String toShortString() {
        StringBuffer buffer = new StringBuffer();
        buffer.append(defaultAlignment.abbreviation());

        buffer.append(":");
        buffer.append(size.toString());
        buffer.append(':');
        if (resizeWeight == NO_GROW) {
            buffer.append("n");
        } else if (resizeWeight == DEFAULT_GROW) {
            buffer.append("g");
        } else {
            buffer.append("g(");
            buffer.append(resizeWeight);
            buffer.append(')');
        }
        return buffer.toString();
    }

    // Abstract Behavior ****************************************************

    /**
     * Returns if this is a horizontal specification (vs. vertical).
     * Used to distinct between horizontal and vertical dialog units,
     * which have different conversion factors.
     * @return true for horizontal, false for vertical
     */
    abstract boolean isHorizontal();

    // Helper Code **********************************************************

    /**
     * Computes the maximum size for the given list of components, using
     * this form spec and the specified measure.<p>
     *
     * Invoked by FormLayout to determine the size of one of my elements
     *
     * @param container       the layout container
     * @param components      the list of components to measure
     * @param minMeasure      the measure used to determine the minimum size
     * @param prefMeasure     the measure used to determine the preferred size
     * @param defaultMeasure  the measure used to determine the default size
     * @return the maximum size in pixels
     */
    final int maximumSize(Container container, List components,
            FormLayout.Measure minMeasure, FormLayout.Measure prefMeasure,
            FormLayout.Measure defaultMeasure) {
        return size.maximumSize(container, components, minMeasure, prefMeasure,
                defaultMeasure);
    }

    /**
     * An ordinal-based serializable typesafe enumeration for the
     * column and row default alignment types.
     */
    public static final class DefaultAlignment implements Serializable {

        private final transient String name;

        private DefaultAlignment(String name) {
            this.name = name;
        }

        /**
         * Returns a DefaultAlignment that corresponds to the specified
         * string, null if no such alignment exists.
         *
         * @param str        the encoded alignment
         * @param isHorizontal   indicates the values orientation
         * @return the corresponding DefaultAlignment or null
         */
        private static DefaultAlignment valueOf(String str,
                boolean isHorizontal) {
            if (str.equals("f") || str.equals("fill")) {
                return FILL_ALIGN;
            } else if (str.equals("c") || str.equals("center")) {
                return CENTER_ALIGN;
            } else if (isHorizontal) {
                if (str.equals("r") || str.equals("right")) {
                    return RIGHT_ALIGN;
                } else if (str.equals("l") || str.equals("left")) {
                    return LEFT_ALIGN;
                } else {
                    return null;
                }
            } else {
                if (str.equals("t") || str.equals("top")) {
                    return TOP_ALIGN;
                } else if (str.equals("b") || str.equals("bottom")) {
                    return BOTTOM_ALIGN;
                } else {
                    return null;
                }
            }
        }

        /**
         * Returns this Alignment's name.
         *
         * @return this alignment's name.
         */
        @Override
        public String toString() {
            return name;
        }

        /**
         * Returns the first character of this Alignment's name.
         * Used to identify it in short format strings.
         *
         * @return the name's first character.
         */
        public char abbreviation() {
            return name.charAt(0);
        }

        // Serialization *****************************************************

        private static int nextOrdinal = 0;

        private final int ordinal = nextOrdinal++;

        private Object readResolve() {
            return VALUES[ordinal]; // Canonicalize
        }

    }

}