/*
 * Copyright 2020 Red Hat, Inc. and/or its affiliates.
 *
 * 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.kie.kogito.timer.impl;

import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Date;

import org.kie.kogito.timer.Calendars;
import org.kie.kogito.timer.Trigger;

public class IntervalTrigger
        implements
        Trigger {
    private Date startTime;
    private Date endTime;
    private int repeatLimit;
    private int repeatCount;
    private Date nextFireTime;
    private Date lastFireTime;
    private Date createdTime;
    private long delay;
    private long period;
    private String[] calendarNames;
    private Calendars calendars;

    public IntervalTrigger() {

    }

    public IntervalTrigger(long timestamp,
            Date startTime,
            Date endTime,
            int repeatLimit,
            long delay,
            long period,
            String[] calendarNames,
            Calendars calendars) {
        this(timestamp, startTime, endTime, repeatLimit, delay, period, calendarNames, calendars, null, null);
    }

    public IntervalTrigger(long timestamp,
            Date startTime,
            Date endTime,
            int repeatLimit,
            long delay,
            long period,
            String[] calendarNames,
            Calendars calendars,
            Date createdTime,
            Date lastFireTime) {
        this.delay = delay;
        this.period = period;
        this.createdTime = createdTime == null ? new Date(timestamp) : createdTime;
        this.lastFireTime = lastFireTime;

        if (startTime == null) {
            this.nextFireTime = new Date(timestamp + delay);
            startTime = new Date(timestamp);
        }
        setStartTime(startTime);

        if (endTime != null) {
            setEndTime(endTime);
        }

        this.repeatLimit = repeatLimit;

        this.calendarNames = calendarNames;
        this.calendars = calendars;

        setFirstFireTime(timestamp);

        // Update to next include time, if we have calendars
        updateToNextIncludeDate();
    }

    public int getRepeatLimit() {
        return repeatLimit;
    }

    public int getRepeatCount() {
        return repeatCount;
    }

    public Date getNextFireTime() {
        return nextFireTime;
    }

    public long getPeriod() {
        return period;
    }

    public String[] getCalendarNames() {
        return calendarNames;
    }

    public Calendars getCalendars() {
        return calendars;
    }

    public Date getStartTime() {
        return this.startTime;
    }

    public void setStartTime(Date startTime) {
        if (startTime == null) {
            throw new IllegalArgumentException("Start time cannot be null");
        }

        Date eTime = getEndTime();
        if (eTime != null && eTime.before(startTime)) {
            throw new IllegalArgumentException("End time cannot be before start time");
        }

        // round off millisecond...
        // Note timeZone is not needed here as parameter for
        // Calendar.getInstance(),
        // since time zone is implicit when using a Date in the setTime method.
        Calendar cl = Calendar.getInstance();
        cl.setTime(startTime);

        this.startTime = cl.getTime();
    }

    /**
     * <p>
     * Get the time at which the <code>CronTrigger</code> should quit
     * repeating - even if repeastCount isn't yet satisfied.
     * </p>
     */
    public Date getEndTime() {
        return this.endTime;
    }

    public void setEndTime(Date endTime) {
        Date sTime = getStartTime();
        if (sTime != null && endTime != null && sTime.after(endTime)) {
            throw new IllegalArgumentException("End time cannot be before start time");
        }

        this.endTime = endTime;
    }

    public Date getLastFireTime() {
        return lastFireTime;
    }

    public Date getCreatedTime() {
        return createdTime;
    }

    private void setFirstFireTime(long timestamp) {
        if (this.nextFireTime == null) {
            long start = this.startTime.getTime() + delay;
            if (timestamp > start) {
                long distanceFromLastPhase = (timestamp - start) % period;
                if (distanceFromLastPhase == 0) {
                    this.nextFireTime = new Date(timestamp);
                } else {
                    long phase = period - distanceFromLastPhase;
                    this.nextFireTime = new Date(timestamp + phase);
                }
            } else {
                this.nextFireTime = new Date(start);
            }
        }

        if (getEndTime() != null && this.nextFireTime.after(getEndTime())) {
            this.nextFireTime = null;
        }

        Date pot = getTimeAfter();
        if (getEndTime() != null && pot != null && pot.after(getEndTime())) {
            this.nextFireTime = null;
        }
    }

    public Date hasNextFireTime() {
        return nextFireTime;
    }

    public synchronized Date nextFireTime() {
        if (this.nextFireTime == null) {
            return null;
        }
        Date date = this.nextFireTime;
        // FIXME: this is not safe for serialization
        this.nextFireTime = getTimeAfter();
        updateToNextIncludeDate();
        if (this.endTime != null && this.nextFireTime.after(this.endTime)) {
            this.nextFireTime = null;
        } else if (repeatLimit != -1 && repeatCount >= repeatLimit) {
            this.nextFireTime = null;
        }
        lastFireTime = date;
        return date;
    }

    private Date getTimeAfter() {
        this.repeatCount++;

        Date date;
        if (this.period != 0) {
            // repeated fires for the given period
            date = new Date(nextFireTime.getTime() + this.period);
        } else {
            date = null;
        }
        return date;
    }

    public void readExternal(ObjectInput in) throws IOException,
            ClassNotFoundException {
        this.nextFireTime = (Date) in.readObject();
        this.period = in.readLong();
        this.delay = in.readLong();
    }

    public void writeExternal(ObjectOutput out) throws IOException {
        out.writeObject(this.nextFireTime);
        out.writeLong(this.period);
        out.writeLong(this.delay);
    }

    public void updateToNextIncludeDate() {
        if (this.calendars == null || calendarNames == null || calendarNames.length == 0) {
            // There are no assigned calendars
            return;
        }

        // If we have calendars, check we can fire, or get next time until we can fire.
        while (this.nextFireTime != null && (this.endTime == null || this.nextFireTime.before(this.endTime))) {
            // this will loop forever if the trigger repeats forever and
            // included calendar position cannot be found
            boolean included = true;
            for (String calName : this.calendarNames) {
                // all calendars must not block, as soon as one blocks break
                org.kie.kogito.timer.Calendar cal = this.calendars.get(calName);
                if (cal != null && !cal.isTimeIncluded(this.nextFireTime.getTime())) {
                    included = false;
                    break;
                }
            }
            if (included) {
                // if no calendars blocked, break
                break;
            } else {
                // otherwise increase the time and try again
                this.nextFireTime = getTimeAfter();
            }
        }
    }

    public void setRepeatLimit(int repeatLimit) {
        this.repeatLimit = repeatLimit;
    }

    public void setRepeatCount(int repeatCount) {
        this.repeatCount = repeatCount;
    }

    public void setNextFireTime(Date nextFireTime) {
        this.nextFireTime = nextFireTime;
    }

    public void setPeriod(long period) {
        this.period = period;
    }

    public void setCalendarNames(String[] calendarNames) {
        this.calendarNames = calendarNames;
    }

    public void setCalendars(Calendars calendars) {
        this.calendars = calendars;
    }

    @Override
    public String toString() {
        return "IntervalTrigger [startTime=" + startTime + ", endTime=" + endTime + ", repeatLimit=" + repeatLimit + ", repeatCount=" + repeatCount + ", nextFireTime=" + nextFireTime + ", delay="
                + delay + ", period=" + period + ", calendarNames=" + Arrays.toString(calendarNames) + ", calendars=" + calendars + "]";
    }
}
