package main

import (
	"encoding/binary"
	"encoding/json"
	"github.com/nanobox-io/golang-scribble"
	"math"
	"net"
	"os"
	"os/signal"
	"syscall"

	"fmt"
	"gen/ledd"
	"github.com/golang/protobuf/proto"
	"github.com/lucasb-eyer/go-colorful"
	"github.com/op/go-logging"
	"gopkg.in/yaml.v2"
	"io/ioutil"
)

// CONSTANTS

const VERSION = "0.1"
const LOG_BACKEND = "BH"
const LOG_CLIENTS = "CH"

// STRUCTS

type Config struct {
	Name   string
	Daemon struct {
		Frontend struct {
			Host string
			Port int
		}
		Backend struct {
			Host string
			Port int
		}
	}
	Mongodb struct {
		Host     string
		Port     int
		Database string
	}
}

type BackendManager struct {
	backends   map[string]*Backend
	broadcast  chan []byte
	register   chan *Backend
	unregister chan *Backend
}

type Backend struct {
	name         string
	platformType string
	version      string
	channel      int32
	resolution   int32
	socket       net.Conn
	data         chan []byte
}

type ClientManager struct {
	clients    map[*Client]bool
	broadcast  chan []byte
	register   chan *Client
	unregister chan *Client
}

type Client struct {
	platform string
	socket   net.Conn
	data     chan []byte
}

type LED struct {
	Name    string
	Channel []int32
	Backend string
	color   chan colorful.Color
}

type LEDManager struct {
	leds      map[string]*LED
	broadcast chan colorful.Color
	add       chan *LED
	remove    chan *LED
}

// GLOBAL VARS

var log = logging.MustGetLogger("LedD")
var backManager BackendManager
var clientManager ClientManager
var ledManager LEDManager
var db *scribble.Driver
var config Config

// SOCKET SETUP

func setupSocket(host string, port int, logTag string, backend bool) (func(), error) {
	ln, err := net.Listen("tcp4", fmt.Sprintf("%s:%d", host, port))
	if err != nil {
		return nil, err
	}
	log.Infof("[%s] Ready to handle connections.", logTag)

	return func() {
		for {
			conn, err := ln.Accept()
			if err != nil {
				log.Warningf("%s", err)
			}
			log.Infof("[%s] New connection from %s", logTag, conn.RemoteAddr())
			if backend {
				backend := &Backend{socket: conn, data: make(chan []byte, 20)}
				go backManager.receive(backend)
				go backManager.send(backend)
			} else {
				client := &Client{socket: conn, data: make(chan []byte, 20)}
				go clientManager.receive(client)
				go clientManager.send(client)
			}
		}
	}, nil
}

// LED MANAGER

func (manager *LEDManager) start() {
	for {
		select {
		case led := <-manager.add:
			log.Debugf("[%s] Request to add LED: %s (%s)", led.Backend, led.Name, led.Channel)

			if led.Name == "" || len(led.Channel) == 0 || led.Backend == "" {
				log.Warningf("[%s] Can't add LED without required information! (%s)", LOG_CLIENTS, led)
				continue
			}

			if _, ok := manager.leds[led.Name]; ok {
				log.Warningf("[%s] Can't add LED: already in LEDM! (%s)", LOG_CLIENTS, led.Name)
				continue
			}

			var dbLED LED
			err := db.Read("led", led.Name, &dbLED)
			if err == nil {
				// log.Warningf("[%s] LED already in DB! (%s)", LOG_CLIENTS, led.Name)
			} else if os.IsNotExist(err) {
				err = db.Write("led", led.Name, led)
				if err != nil {
					log.Warning("[%s] Error while adding LED to database: %s", LOG_BACKEND, err)
				}
			} else {
				log.Warning("[%s] Error while checking database for LED: %s", LOG_BACKEND, err)
			}

			manager.leds[led.Name] = led
			go manager.color(led)
		case led := <-manager.remove:
			if _, ok := manager.leds[led.Name]; ok {
				log.Debugf("[%s] Request to remove %s", led.Backend, led.Name)
				err := db.Delete("led", led.Name)
				check(err)
				delete(manager.leds, led.Name)
			}
		case color := <-manager.broadcast:
			for _, led := range manager.leds {
				select {
				case led.color <- color:
				}
			}
		}
	}
}

func (manager *LEDManager) color(led *LED) {
	for {
		select {
		case color := <-led.color:
			if backend, ok := backManager.backends[led.Backend]; ok {
				if len(led.Channel) != 3 {
					log.Warningf("[%s] Currently only RGB LEDs are supported", led.Name)
					return
				}

				cMap := make(map[int32]int32)

				if !color.IsValid() {
					log.Warningf("[%s] Got invalid HCL->RGB color, clamping!", led.Name)
					color = color.Clamped()
				}

				log.Debugf("[%s] New color: \x1b[38;2;%d;%d;%dm%s\x1b[0m", led.Name, int(math.Round(color.R*255)), int(math.Round(color.G*255)), int(math.Round(color.B*255)), color.Hex())

				cMap[led.Channel[0]] = int32(color.R * float64(backend.resolution))
				cMap[led.Channel[1]] = int32(color.G * float64(backend.resolution))
				cMap[led.Channel[2]] = int32(color.B * float64(backend.resolution))

				wrapperMsg := &ledd.BackendWrapperMessage{
					Msg: &ledd.BackendWrapperMessage_MSetChannel{
						MSetChannel: &ledd.BackendSetChannel{
							NewChannelValues: cMap}}}

				data, err := proto.Marshal(wrapperMsg)
				if err != nil {
					log.Warningf("[%s] Failed to encode protobuf msg to %s: %s", led.Name, backend.name, err)
				}

				backend.data <- prepareProtobuf(data)
			} else {
				log.Warningf("[LM] Failed to set color for %s: backend %s not found", led.Name, led.Backend)
			}
		}
	}
}

// BACKEND HANDLER

func (manager *BackendManager) start() {
	for {
		select {
		case backend := <-manager.register:
			manager.backends[backend.name] = backend
			log.Debugf("[%s] %s registered", LOG_BACKEND, backend.niceName())
			wrapperMsg := &ledd.BackendWrapperMessage{
				Msg: &ledd.BackendWrapperMessage_MLedd{
					MLedd: &ledd.LedD{
						Name: config.Name,
					},
				},
			}

			data, err := proto.Marshal(wrapperMsg)
			if err != nil {
				log.Warningf("[%s] Failed to encode protobuf: %s", backend.niceName(), err)
			}

			backend.data <- prepareProtobuf(data)
		case backend := <-manager.unregister:
			if _, ok := manager.backends[backend.name]; ok {
				log.Debugf("[%s] %s removed: connection terminated", LOG_BACKEND, backend.socket.RemoteAddr())
				close(backend.data)
				delete(manager.backends, backend.name)
			}
		case message := <-manager.broadcast:
			for _, backend := range manager.backends {
				select {
				case backend.data <- message:
				default:
					close(backend.data)
					delete(manager.backends, backend.name)
				}
			}
		}
	}
}

func (manager *BackendManager) stop() {
	for _, backend := range manager.backends {
		close(backend.data)
	}
}

func (manager *BackendManager) send(backend *Backend) {
	defer backend.socket.Close()
	for {
		select {
		case message, ok := <-backend.data:
			if !ok {
				return
			}
			backend.socket.Write(message)
		}
	}
}

func (manager *BackendManager) receive(backend *Backend) {
	for {
		message := make([]byte, 4096)

		length, err := backend.socket.Read(message)
		if err != nil {
			log.Warningf("[%s] Read failed: %s", backend.niceName(), err)
			manager.unregister <- backend
			backend.socket.Close()
			break
		}

		if length > 0 {
			msgLen := binary.BigEndian.Uint32(message[0:4])

			// log.Debugf("[%s] Read %d bytes, first protobuf is %d long", Backend.niceName(), length, msgLen)

			backendMsg := &ledd.BackendWrapperMessage{}
			err = proto.Unmarshal(message[4:msgLen+4], backendMsg)
			if err != nil {
				log.Warningf("[%s] Couldn't decode protobuf msg!", backend.niceName())
				continue
			}

			switch msg := backendMsg.Msg.(type) {
			case *ledd.BackendWrapperMessage_MBackend:
				nBackend := msg.MBackend
				backend.name = nBackend.Name
				backend.channel = nBackend.Channel
				backend.resolution = nBackend.Resolution
				backend.platformType = nBackend.Type
				backend.version = nBackend.Version
				log.Infof("[%s] %s is now identified as %s", LOG_BACKEND, backend.socket.RemoteAddr(), backend.niceName())
				backManager.register <- backend
			}
		}
	}
}

// CLIENT HANDLER

func (manager *ClientManager) start() {
	for {
		select {
		case client := <-manager.register:
			manager.clients[client] = true
			log.Debugf("[%s] Client %s (%s) registered", LOG_CLIENTS, client.socket.RemoteAddr(), client.platform)

			backends := make([]*ledd.Backend, 0, len(backManager.backends))
			leds := make([]*ledd.LED, 0, len(ledManager.leds))

			for _, led := range ledManager.leds {
				leds = append(leds, &ledd.LED{
					Name: led.Name,
				})
			}

			for _, backend := range backManager.backends {
				backends = append(backends, &ledd.Backend{
					Name:       backend.name,
					Channel:    backend.channel,
					Resolution: backend.resolution,
					Type:       backend.platformType,
					Version:    backend.version,
				})
			}

			wrapperMsg := &ledd.ClientWrapperMessage{
				Leds:     leds,
				Backends: backends,
				Msg: &ledd.ClientWrapperMessage_MLedd{
					MLedd: &ledd.LedD{
						Name: config.Name,
					},
				},
			}

			data, err := proto.Marshal(wrapperMsg)
			if err != nil {
				log.Warningf("[%s] Failed to encode protobuf msg: %s", client.socket.RemoteAddr(), err)
			}

			client.data <- prepareProtobuf(data)
		case client := <-manager.unregister:
			if _, ok := manager.clients[client]; ok {
				log.Debugf("[%s] %s (%s) removed", LOG_CLIENTS, client.socket.RemoteAddr(), client.platform)
				close(client.data)
				delete(manager.clients, client)
			}
		case message := <-manager.broadcast:
			for connection := range manager.clients {
				select {
				case connection.data <- message:
				default:
					close(connection.data)
					delete(manager.clients, connection)
				}
			}
		}
	}
}

func (manager *ClientManager) send(client *Client) {
	defer client.socket.Close()
	for {
		select {
		case message, ok := <-client.data:
			if !ok {
				return
			}
			client.socket.Write(message)
		}
	}
}

func (manager *ClientManager) receive(client *Client) {
	for {
		message := make([]byte, 4096)
		length, err := client.socket.Read(message)
		if err != nil {
			log.Warningf("[%s] Read failed: %s", client.socket.RemoteAddr(), err)
			manager.unregister <- client
			client.socket.Close()
			break
		}
		if length > 0 {
			for i := 0; i < length; {
				msgLen := int(binary.BigEndian.Uint32(message[i : i+4]))

				// log.Debugf("[%s] Reading protobuf after %d (len=%d)", client.socket.RemoteAddr(), i+4, msgLen)

				clientMsg := &ledd.ClientWrapperMessage{}
				err = proto.Unmarshal(message[i+4:i+msgLen+4], clientMsg)
				i += msgLen + 4
				if err != nil {
					log.Warningf("[%s] Couldn't decode protobuf msg!", client.socket.RemoteAddr())
					continue
				}

				switch msg := clientMsg.Msg.(type) {
				case *ledd.ClientWrapperMessage_MClient:
					client.platform = msg.MClient.Type
					log.Infof("[%s] %s is now identified as client (%s)", LOG_CLIENTS, client.socket.RemoteAddr(), client.platform)
					clientManager.register <- client
				case *ledd.ClientWrapperMessage_MGetLed:
					allLED := make([]*ledd.LED, 0)

					for _, led := range ledManager.leds {
						allLED = append(allLED, &ledd.LED{Name: led.Name})
					}

					data, err := proto.Marshal(&ledd.ClientWrapperMessage{Leds: allLED})
					if err != nil {
						log.Errorf("[%s] Error encoding protobuf: %s", client.socket.RemoteAddr(), err)
						break
					}

					client.data <- prepareProtobuf(data)
				case *ledd.ClientWrapperMessage_MAddLed:
					backend, ok := backManager.backends[msg.MAddLed.Backend]
					if !ok {
						log.Warningf("[%s] Can't add LED for non-existing backend %s", client.socket.RemoteAddr(), msg.MAddLed.Backend)
						break
					}

					if _, ok := ledManager.leds[msg.MAddLed.Name]; ok {
						log.Warningf("[%s] Can't add LED with exisiting name %s", client.socket.RemoteAddr(), msg.MAddLed.Name)
						break
					}

					nLED := LED{
						Name:    msg.MAddLed.Name,
						Channel: msg.MAddLed.Channel,
						Backend: backend.name,
						color:   make(chan colorful.Color, 20),
					}

					ledManager.add <- &nLED
				case *ledd.ClientWrapperMessage_MSetLed:
					leds := clientMsg.Leds

					if len(leds) == 0 {
						log.Warningf("[%s] Got setLED with no LEDs attached!", client.socket.RemoteAddr())
						break
					}

					for _, pLED := range leds {
						led, ok := ledManager.leds[pLED.Name]
						if !ok {
							log.Warningf("[%s] Failed to set %s: not found", client.socket.RemoteAddr(), pLED.Name)
							break
						}
						// log.Debugf("[%s] Set %s to %s", client.socket.RemoteAddr(), led.Name, colorful.Hcl(msg.MSetLed.Colour.Hue, msg.MSetLed.Colour.Chroma, msg.MSetLed.Colour.Light))

						if pLED.Color == nil {
							led.color <- colorful.Hcl(msg.MSetLed.Colour.Hue, msg.MSetLed.Colour.Chroma, msg.MSetLed.Colour.Light)
						} else {
							led.color <- colorful.Hcl(pLED.Color.Hue, pLED.Color.Chroma, pLED.Color.Light)
						}
					}
				case *ledd.ClientWrapperMessage_MSetDirect:
					backend, ok := backManager.backends[msg.MSetDirect.Backend]
					if !ok {
						log.Warningf("[%s] Can't set channel for non-existing backend %s", client.socket.RemoteAddr(), msg.MSetDirect.Backend)
						break
					}

					backend.setChannel(msg.MSetDirect.Channel, msg.MSetDirect.Value)
				case *ledd.ClientWrapperMessage_MRemoveLed:
					led, ok := ledManager.leds[msg.MRemoveLed.Name]
					if !ok {
						log.Warningf("[%s] Failed to remove %s: not found", client.socket.RemoteAddr(), msg.MRemoveLed.Name)
						break
					}

					ledManager.remove <- led
				}
			}
		}
	}
}

// HELPER

func check(e error) {
	if e != nil {
		panic(e)
	}
}

func (backend *Backend) niceName() string {
	if backend.name != "" {
		return backend.name
	} else {
		return backend.socket.RemoteAddr().String()
	}
}

func (backend Backend) setChannel(channel int32, val int32) {
	cMap := make(map[int32]int32)

	cMap[channel] = val

	wrapperMsg := &ledd.BackendWrapperMessage{
		Msg: &ledd.BackendWrapperMessage_MSetChannel{
			MSetChannel: &ledd.BackendSetChannel{
				NewChannelValues: cMap}}}

	data, err := proto.Marshal(wrapperMsg)
	if err != nil {
		log.Warningf("[%s] Failed to encode protobuf msg: %s", backend.niceName(), err)
	}

	backend.data <- prepareProtobuf(data)
}

func prepareProtobuf(data []byte) []byte {
	size := make([]byte, 4)
	binary.BigEndian.PutUint32(size, uint32(len(data)))
	return append(size, data...)
}

// MAIN
func main() {
	killSignals := make(chan os.Signal, 1)
	signal.Notify(killSignals, syscall.SIGINT, syscall.SIGTERM)

	log.Info("LedD", VERSION)

	content, err := ioutil.ReadFile("ledd.yaml")
	check(err)

	err = yaml.Unmarshal(content, &config)
	check(err)

	db, err = scribble.New("db", nil)
	check(err)

	backManager = BackendManager{
		backends:   make(map[string]*Backend),
		broadcast:  make(chan []byte, 20),
		register:   make(chan *Backend, 10),
		unregister: make(chan *Backend, 10),
	}
	go backManager.start()

	clientManager = ClientManager{
		clients:    make(map[*Client]bool),
		broadcast:  make(chan []byte, 20),
		register:   make(chan *Client, 10),
		unregister: make(chan *Client, 10),
	}
	go clientManager.start()

	ledManager = LEDManager{
		leds:      make(map[string]*LED),
		broadcast: make(chan colorful.Color, 10),
		add:       make(chan *LED, 10),
		remove:    make(chan *LED, 10),
	}
	go ledManager.start()

	leds, err := db.ReadAll("led")
	if os.IsNotExist(err) {
		log.Infof("No DB found.")
	} else {
		check(err)
	}

	for _, ledJson := range leds {
		led := LED{}
		err = json.Unmarshal([]byte(ledJson), &led)
		check(err)

		led.color = make(chan colorful.Color, 20)
		ledManager.add <- &led
	}

	backendThread, err := setupSocket(config.Daemon.Backend.Host, config.Daemon.Backend.Port, LOG_BACKEND, true)
	check(err)
	go backendThread()

	frontendThread, err := setupSocket(config.Daemon.Frontend.Host, config.Daemon.Frontend.Port, LOG_CLIENTS, false)
	check(err)
	go frontendThread()

	log.Infof("All connection handler ready.")

	<-killSignals

	backManager.stop()
}