package utils

import (
	"bytes"
	"fmt"
	"sync"

	"github.com/netsampler/goflow2/v2/decoders/netflow"
	"github.com/netsampler/goflow2/v2/decoders/netflowlegacy"
	"github.com/netsampler/goflow2/v2/decoders/sflow"
	"github.com/netsampler/goflow2/v2/decoders/utils"
	"github.com/netsampler/goflow2/v2/format"
	"github.com/netsampler/goflow2/v2/producer"
	"github.com/netsampler/goflow2/v2/transport"
	"github.com/netsampler/goflow2/v2/utils/templates"
)

type FlowPipe interface {
	DecodeFlow(msg interface{}) error
	Close()
}

type flowpipe struct {
	format    format.FormatInterface
	transport transport.TransportInterface
	producer  producer.ProducerInterface

	netFlowTemplater templates.TemplateSystemGenerator
}

type PipeConfig struct {
	Format    format.FormatInterface
	Transport transport.TransportInterface
	Producer  producer.ProducerInterface

	NetFlowTemplater templates.TemplateSystemGenerator
}

func (p *flowpipe) formatSend(flowMessageSet []producer.ProducerMessage) error {
	for _, msg := range flowMessageSet {
		// todo: pass normal
		if p.format != nil {
			key, data, err := p.format.Format(msg)
			if err != nil {
				return err
			}
			if p.transport != nil {
				if err = p.transport.Send(key, data); err != nil {
					return err
				}
			}
			// send to pool for reuse
		}
	}
	return nil

}

func (p *flowpipe) parseConfig(cfg *PipeConfig) {
	p.format = cfg.Format
	p.transport = cfg.Transport
	p.producer = cfg.Producer
	if cfg.NetFlowTemplater != nil {
		p.netFlowTemplater = cfg.NetFlowTemplater
	} else {
		p.netFlowTemplater = templates.DefaultTemplateGenerator
	}

}

type SFlowPipe struct {
	flowpipe
}

type NetFlowPipe struct {
	flowpipe

	templateslock *sync.RWMutex
	templates     map[string]netflow.NetFlowTemplateSystem
}

type PipeMessageError struct {
	Message *Message
	Err     error
}

func (e *PipeMessageError) Error() string {
	return fmt.Sprintf("message from %s %s", e.Message.Src.String(), e.Err.Error())
}

func (e *PipeMessageError) Unwrap() error {
	return e.Err
}

func NewSFlowPipe(cfg *PipeConfig) *SFlowPipe {
	p := &SFlowPipe{}
	p.parseConfig(cfg)
	return p
}

func (p *SFlowPipe) Close() {
}

func (p *SFlowPipe) DecodeFlow(msg interface{}) error {
	pkt, ok := msg.(*Message)
	if !ok {
		return fmt.Errorf("flow is not *Message")
	}
	buf := bytes.NewBuffer(pkt.Payload)
	//key := pkt.Src.String()

	var packet sflow.Packet
	if err := sflow.DecodeMessageVersion(buf, &packet); err != nil {
		return &PipeMessageError{pkt, err}
	}

	args := producer.ProduceArgs{
		Src: pkt.Src,
		Dst: pkt.Dst,

		TimeReceived:   pkt.Received,
		SamplerAddress: pkt.Src.Addr(),
	}
	if p.producer == nil {
		return nil
	}
	flowMessageSet, err := p.producer.Produce(&packet, &args)
	defer p.producer.Commit(flowMessageSet)
	if err != nil {
		return &PipeMessageError{pkt, err}
	}
	return p.formatSend(flowMessageSet)
}

func NewNetFlowPipe(cfg *PipeConfig) *NetFlowPipe {
	p := &NetFlowPipe{
		templateslock: &sync.RWMutex{},
		templates:     make(map[string]netflow.NetFlowTemplateSystem),
	}
	p.parseConfig(cfg)
	return p
}

func (p *NetFlowPipe) DecodeFlow(msg interface{}) error {
	pkt, ok := msg.(*Message)
	if !ok {
		return fmt.Errorf("flow is not *Message")
	}
	buf := bytes.NewBuffer(pkt.Payload)

	key := pkt.Src.String()

	p.templateslock.RLock()
	templates, ok := p.templates[key]
	p.templateslock.RUnlock()
	if !ok {
		templates = p.netFlowTemplater(key)
		p.templateslock.Lock()
		p.templates[key] = templates
		p.templateslock.Unlock()
	}

	var packetV5 netflowlegacy.PacketNetFlowV5
	var packetNFv9 netflow.NFv9Packet
	var packetIPFIX netflow.IPFIXPacket

	// decode the version
	var version uint16
	if err := utils.BinaryDecoder(buf, &version); err != nil {
		return &PipeMessageError{pkt, err}
	}
	switch version {
	case 5:
		packetV5.Version = 5
		if err := netflowlegacy.DecodeMessage(buf, &packetV5); err != nil {
			return &PipeMessageError{pkt, err}
		}
	case 9:
		packetNFv9.Version = 9
		if err := netflow.DecodeMessageNetFlow(buf, templates, &packetNFv9); err != nil {
			return &PipeMessageError{pkt, err}
		}
	case 10:
		packetIPFIX.Version = 10
		if err := netflow.DecodeMessageIPFIX(buf, templates, &packetIPFIX); err != nil {
			return &PipeMessageError{pkt, err}
		}
	default:
		return &PipeMessageError{pkt, fmt.Errorf("Not a NetFlow packet")}
	}

	var flowMessageSet []producer.ProducerMessage
	var err error

	args := producer.ProduceArgs{
		Src: pkt.Src,
		Dst: pkt.Dst,

		TimeReceived:   pkt.Received,
		SamplerAddress: pkt.Src.Addr(),
	}

	if p.producer == nil {
		return nil
	}

	switch version {
	case 5:
		flowMessageSet, err = p.producer.Produce(&packetV5, &args)
	case 9:
		flowMessageSet, err = p.producer.Produce(&packetNFv9, &args)
	case 10:
		flowMessageSet, err = p.producer.Produce(&packetIPFIX, &args)
	}
	defer p.producer.Commit(flowMessageSet)
	if err != nil {
		return &PipeMessageError{pkt, err}
	}

	return p.formatSend(flowMessageSet)
}

func (p *NetFlowPipe) Close() {
}