/*
 * 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.tools.ant.types.selectors;

import java.io.File;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.text.ParseException;
import java.util.Locale;

import org.apache.tools.ant.Project;
import org.apache.tools.ant.taskdefs.condition.Os;
import org.apache.tools.ant.types.EnumeratedAttribute;
import org.apache.tools.ant.types.Parameter;

/**
 * Selector that chooses files based on their last modified date.
 *
 * @since 1.5
 */
public class DateSelector extends BaseExtendSelector {

    private long millis = -1;
    private String dateTime = null;
    private boolean includeDirs = false;
    private int granularity = 0;
    private int cmp = 2;
    private String pattern;
    /** Key to used for parameterized custom selector */
    public static final String MILLIS_KEY = "millis";
    /** Key to used for parameterized custom selector */
    public static final String DATETIME_KEY = "datetime";
    /** Key to used for parameterized custom selector */
    public static final String CHECKDIRS_KEY = "checkdirs";
    /** Key to used for parameterized custom selector */
    public static final String GRANULARITY_KEY = "granularity";
    /** Key to used for parameterized custom selector */
    public static final String WHEN_KEY = "when";
    /** Key to used for parameterized custom selector */
    public static final String PATTERN_KEY = "pattern";

    /**
     * Creates a new <code>DateSelector</code> instance.
     *
     */
    public DateSelector() {
        if (Os.isFamily("dos")) {
            granularity = 2000;
        }
    }

    /**
     * @return a string describing this object
     */
    public String toString() {
        StringBuffer buf = new StringBuffer("{dateselector date: ");
        buf.append(dateTime);
        buf.append(" compare: ");
        if (cmp == 0) {
            buf.append("before");
        } else if (cmp == 1) {
            buf.append("after");
        } else {
            buf.append("equal");
        }
        buf.append(" granularity: ");
        buf.append(granularity);
        if (pattern != null) {
            buf.append(" pattern: ").append(pattern);
        }
        buf.append("}");
        return buf.toString();
    }

    /**
     * For users that prefer to express time in milliseconds since 1970
     *
     * @param millis the time to compare file's last modified date to,
     *        expressed in milliseconds
     */
    public void setMillis(long millis) {
        this.millis = millis;
    }

    /**
     * Returns the millisecond value the selector is set for.
     * @return the millisecond value
     */
    public long getMillis() {
        if (dateTime != null) {
            validate();
        }
        return millis;
    }

    /**
     * Sets the date. The user must supply it in MM/DD/YYYY HH:MM AM_PM
     * format
     *
     * @param dateTime a string in MM/DD/YYYY HH:MM AM_PM format
     */
    public void setDatetime(String dateTime) {
        this.dateTime = dateTime;
    }

    /**
     * Should we be checking dates on directories?
     *
     * @param includeDirs whether to check the timestamp on directories
     */
    public void setCheckdirs(boolean includeDirs) {
        this.includeDirs = includeDirs;
    }

    /**
     * Sets the number of milliseconds leeway we will give before we consider
     * a file not to have matched a date.
     * @param granularity the number of milliconds leeway
     */
    public void setGranularity(int granularity) {
        this.granularity = granularity;
    }

    /**
     * Sets the type of comparison to be done on the file's last modified
     * date.
     *
     * @param cmp The comparison to perform, an EnumeratedAttribute
     */
    public void setWhen(TimeComparisons cmp) {
        this.cmp = cmp.getIndex();
    }

    /**
     * Sets the pattern to be used for the SimpleDateFormat
     *
     * @param pattern the pattern that defines the date format
     */
    public void setPattern(String pattern) {
        this.pattern = pattern;
    }

    /**
     * When using this as a custom selector, this method will be called.
     * It translates each parameter into the appropriate setXXX() call.
     *
     * @param parameters the complete set of parameters for this selector
     */
    public void setParameters(Parameter[] parameters) {
        super.setParameters(parameters);
        if (parameters != null) {
            for (int i = 0; i < parameters.length; i++) {
                String paramname = parameters[i].getName();
                if (MILLIS_KEY.equalsIgnoreCase(paramname)) {
                    try {
                        setMillis(new Long(parameters[i].getValue()
                        ).longValue());
                    } catch (NumberFormatException nfe) {
                        setError("Invalid millisecond setting "
                                + parameters[i].getValue());
                    }
                } else if (DATETIME_KEY.equalsIgnoreCase(paramname)) {
                    setDatetime(parameters[i].getValue());
                } else if (CHECKDIRS_KEY.equalsIgnoreCase(paramname)) {
                    setCheckdirs(Project.toBoolean(parameters[i].getValue()));
                } else if (GRANULARITY_KEY.equalsIgnoreCase(paramname)) {
                    try {
                        setGranularity(new Integer(parameters[i].getValue()
                        ).intValue());
                    } catch (NumberFormatException nfe) {
                        setError("Invalid granularity setting "
                            + parameters[i].getValue());
                    }
                } else if (WHEN_KEY.equalsIgnoreCase(paramname)) {
                    TimeComparisons cmp = new TimeComparisons();
                    cmp.setValue(parameters[i].getValue());
                    setWhen(cmp);
                } else if (PATTERN_KEY.equalsIgnoreCase(paramname)) {
                    setPattern(parameters[i].getValue());
                } else {
                    setError("Invalid parameter " + paramname);
                }
            }
        }
    }

    /**
     * This is a consistency check to ensure the selector's required
     * values have been set.
     */
    public void verifySettings() {
        if (dateTime == null && millis < 0) {
            setError("You must provide a datetime or the number of "
                    + "milliseconds.");
        } else if (millis < 0 && dateTime != null) {
            // check millis and only set it once.
            DateFormat df = ((pattern == null)
                ? DateFormat.getDateTimeInstance(
                    DateFormat.SHORT, DateFormat.SHORT, Locale.US)
                : new SimpleDateFormat(pattern));

            try {
                setMillis(df.parse(dateTime).getTime());
                if (millis < 0) {
                    setError("Date of " + dateTime
                        + " results in negative milliseconds value"
                        + " relative to epoch (January 1, 1970, 00:00:00 GMT).");
                }
            } catch (ParseException pe) {
                setError("Date of " + dateTime
                        + " Cannot be parsed correctly. It should be in"
                        + ((pattern == null)
                        ? " MM/DD/YYYY HH:MM AM_PM" : pattern) + " format.");
            }
        }
    }

    /**
     * The heart of the matter. This is where the selector gets to decide
     * on the inclusion of a file in a particular fileset.
     *
     * @param basedir the base directory the scan is being done from
     * @param filename is the name of the file to check
     * @param file is a java.io.File object the selector can use
     * @return whether the file should be selected or not
     */
    public boolean isSelected(File basedir, String filename, File file) {

        validate();

        if (file.isDirectory() && (!includeDirs)) {
            return true;
        }
        if (cmp == 0) {
            return ((file.lastModified() - granularity) < millis);
        } else if (cmp == 1) {
            return ((file.lastModified() + granularity) > millis);
        } else {
            return (Math.abs(file.lastModified() - millis) <= granularity);
        }
    }

    /**
     * Enumerated attribute with the values for time comparison.
     * <p>
     */
    public static class TimeComparisons extends EnumeratedAttribute {
        /**
         * @return the values as an array of strings
         */
        public String[] getValues() {
            return new String[]{"before", "after", "equal"};
        }
    }

}