/*
Rating system designed to be used in VoIP Carriers World
Copyright (C) 2012  Radu Ioan Fericean

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 sessionmanager

import (
	"fmt"
	"github.com/cgrates/cgrates/timespans"
	"net/rpc"
	"time"
)

type Connector interface {
	GetCost(timespans.CallDescriptor, *timespans.CallCost) error
	Debit(timespans.CallDescriptor, *timespans.CallCost) error
	MaxDebit(timespans.CallDescriptor, *timespans.CallCost) error
	DebitCents(timespans.CallDescriptor, *float64) error
	DebitSeconds(timespans.CallDescriptor, *float64) error
	GetMaxSessionTime(timespans.CallDescriptor, *float64) error
}

type RPCClientConnector struct {
	Client *rpc.Client
}

func (rcc *RPCClientConnector) GetCost(cd timespans.CallDescriptor, cc *timespans.CallCost) error {
	return rcc.Client.Call("Responder.GetCost", cd, cc)
}

func (rcc *RPCClientConnector) Debit(cd timespans.CallDescriptor, cc *timespans.CallCost) error {
	return rcc.Client.Call("Responder.Debit", cd, cc)
}

func (rcc *RPCClientConnector) MaxDebit(cd timespans.CallDescriptor, cc *timespans.CallCost) error {
	return rcc.Client.Call("Responder.MaxDebit", cd, cc)
}
func (rcc *RPCClientConnector) DebitCents(cd timespans.CallDescriptor, resp *float64) error {
	return rcc.Client.Call("Responder.DebitCents", cd, resp)
}
func (rcc *RPCClientConnector) DebitSeconds(cd timespans.CallDescriptor, resp *float64) error {
	return rcc.Client.Call("Responder.DebitSeconds", cd, resp)
}
func (rcc *RPCClientConnector) GetMaxSessionTime(cd timespans.CallDescriptor, resp *float64) error {
	return rcc.Client.Call("Responder.GetMaxSessionTime", cd, resp)
}

// Sample SessionDelegate calling the timespans methods through the RPC interface
type SessionDelegate struct {
	Connector   Connector
	DebitPeriod time.Duration
}

func (rsd *SessionDelegate) OnHeartBeat(ev Event) {
	timespans.Logger.Info("freeswitch ♥")
}

func (rsd *SessionDelegate) OnChannelAnswer(ev Event, s *Session) {
	timespans.Logger.Info("freeswitch answer")
}

func (rsd *SessionDelegate) OnChannelHangupComplete(ev Event, s *Session) {
	if s == nil || len(s.CallCosts) == 0 {
		return // why would we have 0 callcosts
	}
	lastCC := s.CallCosts[len(s.CallCosts)-1]
	// put credit back	
	start := time.Now()
	end := lastCC.Timespans[len(lastCC.Timespans)-1].TimeEnd
	refoundDuration := end.Sub(start).Seconds()
	cost := 0.0
	seconds := 0.0
	timespans.Logger.Info(fmt.Sprintf("Refund duration: %v", refoundDuration))
	for i := len(lastCC.Timespans) - 1; i >= 0; i-- {
		ts := lastCC.Timespans[i]
		tsDuration := ts.GetDuration().Seconds()
		if refoundDuration <= tsDuration {
			// find procentage
			procentage := (refoundDuration * 100) / tsDuration
			tmpCost := (procentage * ts.Cost) / 100
			ts.Cost -= tmpCost
			cost += tmpCost
			if ts.MinuteInfo != nil {
				// DestinationPrefix and Price take from lastCC and above caclulus
				seconds += (procentage * ts.MinuteInfo.Quantity) / 100
			}
			// set the end time to now
			ts.TimeEnd = start
			break // do not go to other timespans
		} else {
			cost += ts.Cost
			if ts.MinuteInfo != nil {
				seconds += ts.MinuteInfo.Quantity
			}
			// remove the timestamp entirely
			lastCC.Timespans = lastCC.Timespans[:i]
			// continue to the next timespan with what is left to refound
			refoundDuration -= tsDuration
		}
	}
	if cost > 0 {
		cd := &timespans.CallDescriptor{
			Direction:   lastCC.Direction,
			Tenant:      lastCC.Tenant,
			TOR:         lastCC.TOR,
			Subject:     lastCC.Subject,
			Account:     lastCC.Account,
			Destination: lastCC.Destination,
			Amount:      -cost,
		}
		var response float64
		err := rsd.Connector.DebitCents(*cd, &response)
		if err != nil {
			timespans.Logger.Err(fmt.Sprintf("Debit cents failed: %v", err))
		}
	}
	if seconds > 0 {
		cd := &timespans.CallDescriptor{
			Direction:   lastCC.Direction,
			TOR:         lastCC.TOR,
			Tenant:      lastCC.Tenant,
			Subject:     lastCC.Subject,
			Account:     lastCC.Account,
			Destination: lastCC.Destination,
			Amount:      -seconds,
		}
		var response float64
		err := rsd.Connector.DebitSeconds(*cd, &response)
		if err != nil {
			timespans.Logger.Err(fmt.Sprintf("Debit seconds failed: %v", err))
		}
	}
	lastCC.Cost -= cost
	timespans.Logger.Info(fmt.Sprintf("Rambursed %v cents, %v seconds", cost, seconds))
}

func (rsd *SessionDelegate) LoopAction(s *Session, cd *timespans.CallDescriptor) {
	cc := &timespans.CallCost{}
	cd.Amount = rsd.DebitPeriod.Seconds()
	err := rsd.Connector.MaxDebit(*cd, cc)
	if err != nil {
		timespans.Logger.Err(fmt.Sprintf("Could not complete debit opperation: %v", err))
		// disconnect session
		s.sessionManager.DisconnectSession(s)
	}
	nbts := len(cc.Timespans)
	remainingSeconds := 0.0
	timespans.Logger.Debug(fmt.Sprintf("Result of MaxDebit call: %v", cc))
	if nbts > 0 {
		remainingSeconds = cc.Timespans[nbts-1].TimeEnd.Sub(cc.Timespans[0].TimeStart).Seconds()
	}
	if remainingSeconds == 0 || err != nil {
		timespans.Logger.Info(fmt.Sprintf("No credit left: Disconnect %v", s))
		s.Disconnect()
		return
	}
	s.CallCosts = append(s.CallCosts, cc)
}
func (rsd *SessionDelegate) GetDebitPeriod() time.Duration {
	return rsd.DebitPeriod
}