//
//  dolmetschctl
//
//
//  Copyright (C) 2019 Christian Pointner <equinox@spreadspace.org>
//
//  This file is part of dolmetschctl.
//
//  dolmetschctl 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
//  any later version.
//
//  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
//

package main

import (
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"os"
	"time"

	"github.com/gorilla/websocket"
	"spreadspace.org/dolmetschctl/pkg/controller"
	"spreadspace.org/dolmetschctl/pkg/types"
)

const (
	blinkTime = 20
	lang1     = "en"
	lang2     = "de"
)

func wsReader(ws *websocket.Conn, ch chan<- types.WebSocketResponseFull) {
	defer close(ch)

	for {
		t, r, err := ws.NextReader()
		if err != nil {
			log.Println("websocket disconnected:", err)
			return
		}

		switch t {
		case websocket.TextMessage:
			var msg types.WebSocketResponseFull
			dec := json.NewDecoder(r)
			dec.DisallowUnknownFields()
			if err := dec.Decode(&msg); err != nil {
				if err == io.EOF {
					err = io.ErrUnexpectedEOF
				}
				log.Println("webclient response parse error:", err)
				return
			}

			ch <- msg
		case websocket.BinaryMessage:
			io.Copy(ioutil.Discard, r) // consume all the data
		}
	}
}

func handleControllerEvent(ctrl *controller.Controller, ws *websocket.Conn, ev controller.Event) error {
	if ev.Type != controller.ButtonPressed {
		return nil
	}
	lang := ""
	switch ev.Button {
	case 0:
		lang = "en"
	case 1:
		lang = "de"
	default:
		lang = "none"
	}
	return ws.WriteJSON(types.WebSocketRequest{Command: "language", Args: []string{lang}})
}

func ledOnOrBlink(ctrl *controller.Controller, num uint8, state types.State) {
	if state == types.StateSettled {
		ctrl.LedOn(num)
	} else {
		ctrl.LedBlink(num, blinkTime)
	}
}

func handleWebSocketMessage(ctrl *controller.Controller, ws *websocket.Conn, msg types.WebSocketResponseFull) error {
	if msg.Type == "state" {
		switch msg.Lang {
		case lang1:
			ledOnOrBlink(ctrl, 0, msg.State)
			ctrl.LedOff(1)
			ctrl.LedOff(2)
			ctrl.LedOff(3)
		case lang2:
			ctrl.LedOff(0)
			ledOnOrBlink(ctrl, 1, msg.State)
			ctrl.LedOff(2)
			ctrl.LedOff(3)
		default:
			ctrl.LedOff(0)
			ctrl.LedOff(1)
			ledOnOrBlink(ctrl, 2, msg.State)
			ledOnOrBlink(ctrl, 3, msg.State)
		}
	}
	return nil
}

func run(ctrl *controller.Controller, ws *websocket.Conn) (error, bool) {
	ctrlCh := make(chan controller.Event, 100)
	unsub := ctrl.Subscribe(ctrlCh)
	defer close(unsub)

	wsCh := make(chan types.WebSocketResponseFull)
	go wsReader(ws, wsCh)

	if err := ws.WriteJSON(types.WebSocketRequest{Command: "subscribe"}); err != nil {
		return err, true
	}
	log.Printf("subscribed to state changes!")

	for {
		select {
		case ev, ok := <-ctrlCh:
			if !ok {
				return fmt.Errorf("controller channel was closed."), false
			}
			if err := handleControllerEvent(ctrl, ws, ev); err != nil {
				return err, true
			}
		case msg, ok := <-wsCh:
			if !ok {
				return fmt.Errorf("websocket channel was closed."), true
			}
			if err := handleWebSocketMessage(ctrl, ws, msg); err != nil {
				return err, true
			}
		}
	}
}

func main() {
	log.Println("hello world.")

	c, err := controller.NewController(controller.Config{Dev: "dolmetsch controller"})
	if err != nil {
		log.Printf("Error opening the controller: %v", err)
		os.Exit(1)
	}
	defer c.Shutdown()

	if err = c.Init(); err != nil {
		log.Printf("Error initializeing the controller: %v", err)
		os.Exit(1)
	}
	log.Printf("controller successfully initialized!")

	for {
		ws, _, err := websocket.DefaultDialer.Dial("ws://127.0.0.1:8234/api/v1/socket", nil)
		if err != nil {
			log.Printf("Error connecting to daemon: %v", err)
		} else {
			log.Printf("successfully conncted!")
			err, restart := run(c, ws)
			if restart {
				log.Printf("run() returned temporary error: %v", err)
			} else {
				log.Printf("run() returned fatal error: %v", err)
				break
			}
		}
		log.Printf("will retry in one second...")
		time.Sleep(time.Second)
	}

	log.Printf("exiting.")
}