/*
 * Copyright 2002,2004 The Apache Software Foundation.
 *
 * Licensed 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.jelly.tags.fmt;

import org.apache.commons.jelly.JellyTagException;
import org.apache.commons.jelly.XMLOutput;
import org.apache.commons.jelly.Tag;
import org.apache.commons.jelly.TagSupport;
import org.apache.commons.jelly.expression.Expression;

import org.xml.sax.SAXException;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;


/**
 * Support for tag handlers for &lt;formatDate&gt;, the date and time formatting
 * tag in JSTL.
 * @author <a href="mailto:willievu@yahoo.com">Willie Vu</a>
 * @version $Revision: 1.5 $
 * @task i18n exception message
 */
public class FormatDateTag extends TagSupport {

    private static final String DEFAULT = "default";
    private static final String SHORT = "short";
    private static final String MEDIUM = "medium";
    private static final String LONG = "long";
    private static final String FULL = "full";

    private static final String DATE = "date";
    private static final String TIME = "time";
    private static final String DATETIME = "both";

    /** Holds value of property value. */
    private Expression value;

    /** Holds value of property type. */
    private Expression type;

    /** Holds value of property dataStyle. */
    private Expression dateStyle;

    /** Holds value of property timeStyle. */
    private Expression timeStyle;

    /** Holds value of property pattern. */
    private Expression pattern;

    /** Holds value of property timeZone. */
    private Expression timeZone;

    /** Holds value of property var. */
    private String var;

    /** Holds value of property scope. */
    private String scope;

    /** Evaluated type */
    private String etype;
    /** Evaluated dateStyle */
    private String edateStyle;
    /** Evaluated timeStyle */
    private String etimeStyle;

    /** Creates a new instance of FormatDateTag */
    public FormatDateTag() {
    }

    /**
     * Evaluates this tag after all the tags properties have been initialized.
     *
     */
    public void doTag(XMLOutput output) throws JellyTagException {

        if (scope != null && var == null) {
            throw new JellyTagException(
            "If 'scope' is specified, 'var' must be defined for this tag" );
        }

        Object valueInput = null;
        if (this.value != null) {
            valueInput = this.value.evaluate(context);
        }

        Date date = null;
        if (valueInput != null && valueInput instanceof Date) {
            date = (Date) valueInput;
        }

        if (date == null && var != null) {
            if (scope != null) {
                context.removeVariable(var, scope);
            }
            else {
                context.removeVariable(var);
            }
        }

        etype = DATE;
        if (this.type != null) {
            etype = (String) this.type.evaluate(context);
        }

        edateStyle = DEFAULT;
        if (this.dateStyle != null) {
            edateStyle = (String) this.dateStyle.evaluate(context);
        }

        etimeStyle = DEFAULT;
        if (this.timeStyle != null) {
            etimeStyle = (String) this.timeStyle.evaluate(context);
        }

        String epattern = null;
        if (this.pattern != null) {
            epattern = (String) this.pattern.evaluate(context);
        }

        Object etimeZone = null;
        if (this.timeZone != null) {
            etimeZone = this.timeZone.evaluate(context);
        }

        // Create formatter
        Locale locale = SetLocaleTag.getFormattingLocale(
            context,
            this,
            true,
            DateFormat.getAvailableLocales());

        String formatted = null;
        if (locale != null) {
            DateFormat formatter = createFormatter(locale);

            // Apply pattern, if present
            if (pattern != null) {
                try {
                    ((SimpleDateFormat) formatter).applyPattern(epattern);
                } catch (ClassCastException cce) {
                    formatter = new SimpleDateFormat(epattern, locale);
                }
            }

            // Set time zone
            TimeZone tz = null;
            if ((etimeZone instanceof String)
            && ((String) etimeZone).equals("")) {
                etimeZone = null;
            }
            if (etimeZone != null) {
                if (etimeZone instanceof String) {
                    tz = TimeZone.getTimeZone((String) etimeZone);
                } else if (etimeZone instanceof TimeZone) {
                    tz = (TimeZone) etimeZone;
                } else {
                    throw new JellyTagException("Bad time zone");
                }
            } else {
                tz = TimeZoneTag.getTimeZone(context, this);
            }
            if (tz != null) {
                formatter.setTimeZone(tz);
            }
            formatted = formatter.format(date);
        } else {
            // no formatting locale available, use Date.toString()
            formatted = date.toString();
        }

        if (var != null) {
            if (scope != null) {
                context.setVariable(var, scope, formatted);
            }
            else {
                context.setVariable(var, formatted);
            }
        }
        else {
            try {
                // write the formatted
                output.write(formatted);
            } catch (SAXException e) {
                throw new JellyTagException("could not write formatted text",e);
            }
        }
    }

    /** Setter for property value.
     * @param value New value of property value.
     *
     */
    public void setValue(Expression value) {
        this.value = value;
    }

    /** Setter for property type.
     * @param type New value of property type.
     *
     */
    public void setType(Expression type) {
        this.type = type;
    }

    /** Setter for property dataStyle.
     * @param dataStyle New value of property dataStyle.
     *
     */
    public void setDateStyle(Expression dateStyle) {
        this.dateStyle = dateStyle;
    }

    /** Setter for property timeStyle.
     * @param timeStyle New value of property timeStyle.
     *
     */
    public void setTimeStyle(Expression timeStyle) {
        this.timeStyle = timeStyle;
    }

    /** Setter for property pattern.
     * @param pattern New value of property pattern.
     *
     */
    public void setPattern(Expression pattern) {
        this.pattern = pattern;
    }

    /** Setter for property timeZone.
     * @param timeZone New value of property timeZone.
     *
     */
    public void setTimeZone(Expression timeZone) {
        this.timeZone = timeZone;
    }

    /** Setter for property var.
     * @param var New value of property var.
     *
     */
    public void setVar(String var) {
        this.var = var;
    }

    /** Setter for property scope.
     * @param scope New value of property scope.
     *
     */
    public void setScope(String scope) {
        this.scope = scope;
    }

    //*********************************************************************
    // Private utility methods

    private DateFormat createFormatter(Locale loc) throws JellyTagException {
        DateFormat formatter = null;

        if ((etype == null) || DATE.equalsIgnoreCase(etype)) {
            formatter = DateFormat.getDateInstance(
            getStyle(edateStyle, "FORMAT_DATE_INVALID_DATE_STYLE"),
            loc);
        } else if (TIME.equalsIgnoreCase(etype)) {
            formatter = DateFormat.getTimeInstance(
            getStyle(etimeStyle, "FORMAT_DATE_INVALID_TIME_STYLE"),
            loc);
        } else if (DATETIME.equalsIgnoreCase(etype)) {
            formatter = DateFormat.getDateTimeInstance(
            getStyle(edateStyle, "FORMAT_DATE_INVALID_DATE_STYLE"),
            getStyle(etimeStyle, "FORMAT_DATE_INVALID_TIME_STYLE"),
            loc);
        } else {
            throw new JellyTagException("Date format invalue");
        }

        return formatter;
    }

    /*
     * Converts the given string description of a formatting style for
     * dates and times to the corresponding java.util.DateFormat constant.
     *
     * @param style String description of formatting style for dates and times
     * @param errCode Error code to throw if given style is invalid
     *
     * @return java.util.DateFormat constant corresponding to given style
     *
     * @throws JellyException if the given style is invalid
     */
    public static int getStyle(String style, String errCode)
    throws JellyTagException {
        int ret = DateFormat.DEFAULT;

        if (style != null) {
            if (DEFAULT.equalsIgnoreCase(style)) {
                ret = DateFormat.DEFAULT;
            } else if (SHORT.equalsIgnoreCase(style)) {
                ret = DateFormat.SHORT;
            } else if (MEDIUM.equalsIgnoreCase(style)) {
                ret = DateFormat.MEDIUM;
            } else if (LONG.equalsIgnoreCase(style)) {
                ret = DateFormat.LONG;
            } else if (FULL.equalsIgnoreCase(style)) {
                ret = DateFormat.FULL;
            } else {
                throw new JellyTagException("Invalid style " + errCode);
            }
        }

        return ret;
    }

}