/*
 * Copyright (c) 2009, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.termux.shared.file.filesystem;

import androidx.annotation.NonNull;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Objects;
import java.util.concurrent.TimeUnit;

/**
 * Represents the value of a file's time stamp attribute. For example, it may
 * represent the time that the file was last
 * {@link FileAttributes#lastModifiedTime() modified},
 * {@link FileAttributes#lastAccessTime() accessed},
 * or {@link FileAttributes#creationTime() created}.
 *
 * <p> Instances of this class are immutable.
 *
 * https://cs.android.com/android/platform/superproject/+/android-11.0.0_r3:libcore/ojluni/src/main/java/java/nio/file/attribute/FileTime.java
 *
 * @since 1.7
 * @see java.nio.file.Files#setLastModifiedTime
 * @see java.nio.file.Files#getLastModifiedTime
 */
public final class FileTime {

    /**
     * The unit of granularity to interpret the value. Null if
     * this {@code FileTime} is converted from an {@code Instant},
     * the {@code value} and {@code unit} pair will not be used
     * in this scenario.
     */
    private final TimeUnit unit;

    /**
     * The value since the epoch; can be negative.
     */
    private final long value;

    /**
     * The value return by toString (created lazily)
     */
    private String valueAsString;

    /**
     * Initializes a new instance of this class.
     */
    private FileTime(long value, TimeUnit unit) {
        this.value = value;
        this.unit = unit;
    }

    /**
     * Returns a {@code FileTime} representing a value at the given unit of
     * granularity.
     *
     * @param   value
     *          the value since the epoch (1970-01-01T00:00:00Z); can be
     *          negative
     * @param   unit
     *          the unit of granularity to interpret the value
     *
     * @return  a {@code FileTime} representing the given value
     */
    public static FileTime from(long value, @NonNull TimeUnit unit) {
        Objects.requireNonNull(unit, "unit");
        return new FileTime(value, unit);
    }

    /**
     * Returns a {@code FileTime} representing the given value in milliseconds.
     *
     * @param   value
     *          the value, in milliseconds, since the epoch
     *          (1970-01-01T00:00:00Z); can be negative
     *
     * @return  a {@code FileTime} representing the given value
     */
    public static FileTime fromMillis(long value) {
        return new FileTime(value, TimeUnit.MILLISECONDS);
    }

    /**
     * Returns the value at the given unit of granularity.
     *
     * <p> Conversion from a coarser granularity that would numerically overflow
     * saturate to {@code Long.MIN_VALUE} if negative or {@code Long.MAX_VALUE}
     * if positive.
     *
     * @param   unit
     *          the unit of granularity for the return value
     *
     * @return  value in the given unit of granularity, since the epoch
     *          since the epoch (1970-01-01T00:00:00Z); can be negative
     */
    public long to(TimeUnit unit) {
        Objects.requireNonNull(unit, "unit");
        return unit.convert(this.value, this.unit);
    }

    /**
     * Returns the value in milliseconds.
     *
     * <p> Conversion from a coarser granularity that would numerically overflow
     * saturate to {@code Long.MIN_VALUE} if negative or {@code Long.MAX_VALUE}
     * if positive.
     *
     * @return  the value in milliseconds, since the epoch (1970-01-01T00:00:00Z)
     */
    public long toMillis() {
        return unit.toMillis(value);
    }

    @NonNull
    @Override
    public String toString() {
        return getDate(toMillis(), "yyyy.MM.dd HH:mm:ss.SSS z");
    }

    public static String getDate(long milliSeconds, String format) {
        try {
            Calendar calendar = Calendar.getInstance();
            calendar.setTimeInMillis(milliSeconds);
            return new SimpleDateFormat(format).format(calendar.getTime());
        } catch (Exception e) {
            return Long.toString(milliSeconds);
        }
    }
}
