/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.openejb.util;

import java.beans.PropertyEditorManager;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;

@SuppressWarnings("PMD.OverrideBothEqualsAndHashcode")
public class Duration {

    private long time;
    private TimeUnit unit;

    public Duration() {
    }

    public Duration(final long time, final TimeUnit unit) {
        this.time = time;
        this.unit = unit;
    }

    public Duration(final String string) {
        final String[] strings = string.split(",| and ");

        Duration total = new Duration();

        for (String s : strings) {
            final Duration part = new Duration();
            s = s.trim();

            final StringBuilder t = new StringBuilder();
            final StringBuilder u = new StringBuilder();

            int i = 0;

            // get the number
            for (; i < s.length(); i++) {
                final char c = s.charAt(i);
                if (Character.isDigit(c) || i == 0 && c == '-') {
                    t.append(c);
                } else {
                    break;
                }
            }

            if (t.length() == 0) {
                invalidFormat(s);
            }

            // skip whitespace
            for (; i < s.length(); i++) {
                final char c = s.charAt(i);
                if (Character.isWhitespace(c)) { //NOPMD
                    // no-op. Just continue the loop
                } else {
                    break;
                }
            }

            // get time unit text part
            for (; i < s.length(); i++) {
                final char c = s.charAt(i);
                if (Character.isLetter(c)) {
                    u.append(c);
                } else {
                    invalidFormat(s);
                }
            }

            part.time = Integer.parseInt(t.toString());

            part.unit = parseUnit(u.toString());

            total = total.add(part);
        }

        this.time = total.time;
        this.unit = total.unit;
    }

    public long getTime() {
        return time;
    }

    public long getTime(final TimeUnit unit) {
        return unit.convert(this.time, this.unit);
    }

    public void setTime(final long time) {
        this.time = time;
    }

    public TimeUnit getUnit() {
        return unit;
    }

    public void setUnit(final TimeUnit unit) {
        this.unit = unit;
    }

    private static final class Normalize {
        private final long a;
        private final long b;
        private final TimeUnit base;

        private Normalize(final Duration a, final Duration b) {
            this.base = lowest(a, b);
            this.a = a.unit == null ? a.time : base.convert(a.time, a.unit);
            this.b = b.unit == null ? b.time : base.convert(b.time, b.unit);
        }

        private static TimeUnit lowest(final Duration a, final Duration b) {
            if (a.unit == null) {
                return b.unit;
            }
            if (b.unit == null) {
                return a.unit;
            }
            if (a.time == 0) {
                return b.unit;
            }
            if (b.time == 0) {
                return a.unit;
            }
            return TimeUnit.values()[Math.min(a.unit.ordinal(), b.unit.ordinal())];
        }
    }

    @Override
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        final Duration that = (Duration) o;

        final Normalize n = new Normalize(this, that);
        return n.a == n.b;
    }

    public Duration add(final Duration that) {
        final Normalize n = new Normalize(this, that);
        return new Duration(n.a + n.b, n.base);
    }

    public Duration subtract(final Duration that) {
        final Normalize n = new Normalize(this, that);
        return new Duration(n.a - n.b, n.base);
    }

    public static Duration parse(final String text) {
        return new Duration(text);
    }

    private static void invalidFormat(final String text) {
        throw new IllegalArgumentException("Illegal duration format: '" + text + "'.  Valid examples are '10s' or '10 seconds'.");
    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder();
        sb.append(time);
        if (unit != null) {
            sb.append(" ");
            sb.append(unit);
        }
        return sb.toString();
    }

    private static TimeUnit parseUnit(final String u) {
        if (u.length() == 0) {
            return null;
        }

        if (u.equalsIgnoreCase("NANOSECONDS")) {
            return TimeUnit.NANOSECONDS;
        }
        if (u.equalsIgnoreCase("NANOSECOND")) {
            return TimeUnit.NANOSECONDS;
        }
        if (u.equalsIgnoreCase("NANOS")) {
            return TimeUnit.NANOSECONDS;
        }
        if (u.equalsIgnoreCase("NANO")) {
            return TimeUnit.NANOSECONDS;
        }
        if (u.equalsIgnoreCase("NS")) {
            return TimeUnit.NANOSECONDS;
        }

        if (u.equalsIgnoreCase("MICROSECONDS")) {
            return TimeUnit.MICROSECONDS;
        }
        if (u.equalsIgnoreCase("MICROSECOND")) {
            return TimeUnit.MICROSECONDS;
        }
        if (u.equalsIgnoreCase("MICROS")) {
            return TimeUnit.MICROSECONDS;
        }
        if (u.equalsIgnoreCase("MICRO")) {
            return TimeUnit.MICROSECONDS;
        }

        if (u.equalsIgnoreCase("MILLISECONDS")) {
            return TimeUnit.MILLISECONDS;
        }
        if (u.equalsIgnoreCase("MILLISECOND")) {
            return TimeUnit.MILLISECONDS;
        }
        if (u.equalsIgnoreCase("MILLIS")) {
            return TimeUnit.MILLISECONDS;
        }
        if (u.equalsIgnoreCase("MILLI")) {
            return TimeUnit.MILLISECONDS;
        }
        if (u.equalsIgnoreCase("MS")) {
            return TimeUnit.MILLISECONDS;
        }

        if (u.equalsIgnoreCase("SECONDS")) {
            return TimeUnit.SECONDS;
        }
        if (u.equalsIgnoreCase("SECOND")) {
            return TimeUnit.SECONDS;
        }
        if (u.equalsIgnoreCase("SEC")) {
            return TimeUnit.SECONDS;
        }
        if (u.equalsIgnoreCase("S")) {
            return TimeUnit.SECONDS;
        }

        if (u.equalsIgnoreCase("MINUTES")) {
            return TimeUnit.MINUTES;
        }
        if (u.equalsIgnoreCase("MINUTE")) {
            return TimeUnit.MINUTES;
        }
        if (u.equalsIgnoreCase("MIN")) {
            return TimeUnit.MINUTES;
        }
        if (u.equalsIgnoreCase("M")) {
            return TimeUnit.MINUTES;
        }

        if (u.equalsIgnoreCase("HOURS")) {
            return TimeUnit.HOURS;
        }
        if (u.equalsIgnoreCase("HOUR")) {
            return TimeUnit.HOURS;
        }
        if (u.equalsIgnoreCase("HRS")) {
            return TimeUnit.HOURS;
        }
        if (u.equalsIgnoreCase("HR")) {
            return TimeUnit.HOURS;
        }
        if (u.equalsIgnoreCase("H")) {
            return TimeUnit.HOURS;
        }

        if (u.equalsIgnoreCase("DAYS")) {
            return TimeUnit.DAYS;
        }
        if (u.equalsIgnoreCase("DAY")) {
            return TimeUnit.DAYS;
        }
        if (u.equalsIgnoreCase("D")) {
            return TimeUnit.DAYS;
        }

        throw new IllegalArgumentException("Unknown time unit '" + u + "'.  Supported units " + Join.join(", ", lowercase(TimeUnit.values())));
    }

    private static List<String> lowercase(final Enum... units) {
        final List<String> list = new ArrayList<String>();
        for (final Enum unit : units) {
            list.add(unit.name().toLowerCase());
        }
        return list;
    }

    static {
        PropertyEditorManager.registerEditor(Duration.class, DurationEditor.class);
    }

}
