/*
Rating system designed to be used in VoIP Carriers World
Copyright (C) 2013 ITsysCOM

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program 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 for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>
*/

package engine

import (
	//"fmt"
	"github.com/cgrates/cgrates/utils"
	"time"
)

/*
A unit in which a call will be split that has a specific price related interval attached to it.
*/
type TimeSpan struct {
	TimeStart, TimeEnd            time.Time
	Cost                          float64
	ratingInfo                    *RatingInfo
	RateInterval                  *RateInterval
	CallDuration                  time.Duration // the call duration so far till TimeEnd
	overlapped                    bool          // mark a timespan as overlapped by an expanded one
	Increments                    Increments
	MatchedSubject, MatchedPrefix string
}

type Increment struct {
	Duration            time.Duration
	Cost                float64
	BalanceUuids        []string // need more than one for minutes with cost
	BalanceRateInterval *RateInterval
	MinuteInfo          *MinuteInfo
}

// Holds the minute information related to a specified timespan
type MinuteInfo struct {
	DestinationId string
	Quantity      float64
	Price         float64
}

func (incr *Increment) Clone() *Increment {
	nIncr := &Increment{
		Duration:            incr.Duration,
		Cost:                incr.Cost,
		BalanceRateInterval: incr.BalanceRateInterval,
		MinuteInfo:          incr.MinuteInfo,
	}
	nIncr.BalanceUuids = make([]string, len(incr.BalanceUuids))
	copy(nIncr.BalanceUuids, incr.BalanceUuids)
	return nIncr
}

type Increments []*Increment

func (incs Increments) GetTotalCost() float64 {
	cost := 0.0
	for _, increment := range incs {
		cost += increment.Cost
	}
	return cost
}

// Returns the duration of the timespan
func (ts *TimeSpan) GetDuration() time.Duration {
	return ts.TimeEnd.Sub(ts.TimeStart)
}

// Returns true if the given time is inside timespan range.
func (ts *TimeSpan) Contains(t time.Time) bool {
	return t.After(ts.TimeStart) && t.Before(ts.TimeEnd)
}

// Returns the cost of the timespan according to the relevant cost interval.
// It also sets the Cost field of this timespan (used for refound on session
// manager debit loop where the cost cannot be recalculated)
func (ts *TimeSpan) getCost() float64 {
	if ts.RateInterval == nil {
		return 0
	}
	ts.Cost = ts.RateInterval.GetCost(ts.GetDuration(), ts.GetGroupStart())
	return ts.Cost
}

/*
Will set the interval as spans's interval if new Weight is lower then span's interval Weight
or if the Weights are equal and new price is lower then spans's interval price
*/
func (ts *TimeSpan) SetRateInterval(i *RateInterval) {
	if ts.RateInterval == nil || ts.RateInterval.Weight < i.Weight {
		ts.RateInterval = i
		return
	}
	iPrice, _, _ := i.GetRateParameters(ts.GetGroupStart())
	tsPrice, _, _ := ts.RateInterval.GetRateParameters(ts.GetGroupStart())
	if ts.RateInterval.Weight == i.Weight && iPrice < tsPrice {
		ts.RateInterval = i
	}
}

func (ts *TimeSpan) createIncrementsSlice() {
	if ts.RateInterval == nil {
		return
	}
	ts.Increments = make([]*Increment, 0)
	// create rated units series
	rate, rateIncrement, rateUnit := ts.RateInterval.GetRateParameters(ts.GetGroupStart())
	incrementCost := rate / rateUnit.Seconds() * rateIncrement.Seconds()
	totalCost := 0.0
	for s := 0; s < int(ts.GetDuration()/rateIncrement); s++ {
		ts.Increments = append(ts.Increments, &Increment{Duration: rateIncrement, Cost: incrementCost})
		totalCost += incrementCost
	}
}

/*
Splits the given timespan according to how it relates to the interval.
It will modify the endtime of the received timespan and it will return
a new timespan starting from the end of the received one.
The interval will attach itself to the timespan that overlaps the interval.
*/
func (ts *TimeSpan) SplitByRateInterval(i *RateInterval) (nts *TimeSpan) {
	//Logger.Debug("here: ", ts, " +++ ", i)
	//log.Printf("TS: %+v", ts)
	// if the span is not in interval return nil
	if !(i.Contains(ts.TimeStart, false) || i.Contains(ts.TimeEnd, true)) {
		//Logger.Debug("Not in interval")
		//log.Printf("NOT in interval: %+v", i)
		return
	}
	//Logger.Debug(fmt.Sprintf("TS: %+v", ts))
	// split by GroupStart
	if i.Rating != nil {
		i.Rating.Rates.Sort()
		for _, rate := range i.Rating.Rates {
			// Logger.Debug(fmt.Sprintf("Rate: %+v", rate))
			if ts.GetGroupStart() < rate.GroupIntervalStart && ts.GetGroupEnd() > rate.GroupIntervalStart {
				// Logger.Debug(fmt.Sprintf("Splitting"))
				ts.SetRateInterval(i)
				splitTime := ts.TimeStart.Add(rate.GroupIntervalStart - ts.GetGroupStart())
				//log.Print("SPLIT: ", splitTime)
				nts = &TimeSpan{
					TimeStart: splitTime,
					TimeEnd:   ts.TimeEnd,
				}
				nts.copyRatingInfo(ts)
				ts.TimeEnd = splitTime
				nts.SetRateInterval(i)
				nts.CallDuration = ts.CallDuration
				ts.SetNewCallDuration(nts)
				// Logger.Debug(fmt.Sprintf("Group splitting: %+v %+v", ts, nts))
				//log.Printf("Group splitting: %+v %+v", ts, nts)
				return
			}
		}
	}
	//log.Printf("*************TS: %+v", ts)
	// if the span is enclosed in the interval try to set as new interval and return nil
	if i.Contains(ts.TimeStart, false) && i.Contains(ts.TimeEnd, true) {
		//Logger.Debug("All in interval")
		ts.SetRateInterval(i)
		return
	}
	// if only the start time is in the interval split the interval to the right
	if i.Contains(ts.TimeStart, false) {
		//Logger.Debug("Start in interval")
		splitTime := i.getRightMargin(ts.TimeStart)

		ts.SetRateInterval(i)
		if splitTime == ts.TimeStart || splitTime.Equal(ts.TimeEnd) {
			return
		}
		nts = &TimeSpan{
			TimeStart: splitTime,
			TimeEnd:   ts.TimeEnd,
		}
		nts.copyRatingInfo(ts)
		ts.TimeEnd = splitTime
		nts.CallDuration = ts.CallDuration
		ts.SetNewCallDuration(nts)
		// Logger.Debug(fmt.Sprintf("right: %+v %+v", ts, nts))
		//log.Printf("right: %+v %+v", ts, nts)
		return
	}
	// if only the end time is in the interval split the interval to the left
	if i.Contains(ts.TimeEnd, true) {
		//Logger.Debug("End in interval")
		//tmpTime := time.Date(ts.TimeStart.)
		splitTime := i.getLeftMargin(ts.TimeEnd)
		splitTime = utils.CopyHour(splitTime, ts.TimeStart)
		if splitTime.Equal(ts.TimeEnd) {
			return
		}
		nts = &TimeSpan{
			TimeStart: splitTime,
			TimeEnd:   ts.TimeEnd,
		}
		nts.copyRatingInfo(ts)
		ts.TimeEnd = splitTime

		nts.SetRateInterval(i)
		nts.CallDuration = ts.CallDuration
		ts.SetNewCallDuration(nts)
		// Logger.Debug(fmt.Sprintf("left: %+v %+v", ts, nts))
		//log.Printf("left: %+v %+v", ts, nts)
		return
	}
	return
}

// Split the timespan at the given increment start
func (ts *TimeSpan) SplitByIncrement(index int) *TimeSpan {
	if index <= 0 || index >= len(ts.Increments) {
		return nil
	}
	timeStart := ts.GetTimeStartForIncrement(index)
	newTs := &TimeSpan{
		RateInterval: ts.RateInterval,
		TimeStart:    timeStart,
		TimeEnd:      ts.TimeEnd,
	}
	newTs.copyRatingInfo(ts)
	newTs.CallDuration = ts.CallDuration
	ts.TimeEnd = timeStart
	newTs.Increments = ts.Increments[index:]
	ts.Increments = ts.Increments[:index]
	ts.SetNewCallDuration(newTs)
	return newTs
}

// Split the timespan at the given second
func (ts *TimeSpan) SplitByDuration(duration time.Duration) *TimeSpan {
	if duration <= 0 || duration >= ts.GetDuration() {
		return nil
	}
	timeStart := ts.TimeStart.Add(duration)
	newTs := &TimeSpan{
		RateInterval: ts.RateInterval,
		TimeStart:    timeStart,
		TimeEnd:      ts.TimeEnd,
	}
	newTs.copyRatingInfo(ts)
	newTs.CallDuration = ts.CallDuration
	ts.TimeEnd = timeStart
	// split the increment
	for incrIndex, incr := range ts.Increments {
		if duration-incr.Duration >= 0 {
			duration -= incr.Duration
		} else {

			splitIncrement := ts.Increments[incrIndex].Clone()
			splitIncrement.Duration -= duration
			ts.Increments[incrIndex].Duration = duration
			newTs.Increments = Increments{splitIncrement}
			if incrIndex < len(ts.Increments)-1 {
				newTs.Increments = append(newTs.Increments, ts.Increments[incrIndex+1:]...)
			}
			ts.Increments = ts.Increments[:incrIndex+1]
			break
		}
	}
	ts.SetNewCallDuration(newTs)
	return newTs
}

// Splits the given timespan on activation period's activation time.
func (ts *TimeSpan) SplitByRatingPlan(rp *RatingInfo) (newTs *TimeSpan) {
	if !ts.Contains(rp.ActivationTime) {
		return nil
	}
	newTs = &TimeSpan{
		TimeStart: rp.ActivationTime,
		TimeEnd:   ts.TimeEnd,
	}
	newTs.copyRatingInfo(ts)
	newTs.CallDuration = ts.CallDuration
	ts.TimeEnd = rp.ActivationTime
	ts.SetNewCallDuration(newTs)
	// Logger.Debug(fmt.Sprintf("RP SPLITTING: %+v %+v", ts, newTs))
	//log.Printf("RP SPLITTING: %+v %+v", ts, newTs)
	return
}

// Returns the starting time of this timespan
func (ts *TimeSpan) GetGroupStart() time.Duration {
	s := ts.CallDuration - ts.GetDuration()
	if s < 0 {
		s = 0
	}
	return s
}

func (ts *TimeSpan) GetGroupEnd() time.Duration {
	return ts.CallDuration
}

// sets the CallDuration attribute to reflect new timespan
func (ts *TimeSpan) SetNewCallDuration(nts *TimeSpan) {
	d := ts.CallDuration - nts.GetDuration()
	if d < 0 {
		d = 0
	}
	ts.CallDuration = d
}

func (nts *TimeSpan) copyRatingInfo(ts *TimeSpan) {
	nts.ratingInfo = ts.ratingInfo
	nts.MatchedSubject = ts.ratingInfo.MatchedSubject
	nts.MatchedPrefix = ts.ratingInfo.MatchedPrefix
}

// returns a time for the specified second in the time span
func (ts *TimeSpan) GetTimeStartForIncrement(index int) time.Time {
	return ts.TimeStart.Add(time.Duration(int64(index) * ts.Increments[0].Duration.Nanoseconds()))
}

func (ts *TimeSpan) RoundToDuration(duration time.Duration) {
	if duration < ts.GetDuration() {
		duration = utils.RoundTo(duration, ts.GetDuration())
	}
	if duration > ts.GetDuration() {
		initialDuration := ts.GetDuration()
		ts.TimeEnd = ts.TimeStart.Add(duration)
		ts.CallDuration = ts.CallDuration + (duration - initialDuration)
	}
}