state-machine.go

// Copyright 2016 Jacques Supcik, HEIA-FR
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// 2015-12-29 | JS | First version
// 2016-07-26 | JS | Last change

//
// Telegram bot
//

package main

import (
	"fmt"
	log "github.com/Sirupsen/logrus"
	"github.com/tucnak/telebot"
	"strings"
)

const (
	printCommand          = "/print"
	anonymousPrintCommand = "/xprint"
	cancelCommand         = "/cancel"
	statusCommand         = "/status"
)

var lastMessage string = "(no message)"

type stateFn func(*session)

// This is the main loop fror processing Telegram messages
func processTelegramMessages(bot *telebot.Bot) {
	messages := make(chan telebot.Message)
	bot.Listen(messages, longPollTime)

	for message := range messages {
		key := fmt.Sprintf("%x:%x", message.Chat.ID, message.Sender.ID)
		currentSession, ok := sessions[key]
		if !ok {
			currentSession = new(session)
			currentSession.state = idleState
			currentSession.conversation = message.Chat
			currentSession.sender = message.Sender
			sessions[key] = currentSession
		}
		currentSession.message = message
		currentSession.state(currentSession)
	}
}

//***************************************************************************
//
// States
//
//***************************************************************************

func idleState(s *session) {
	if s.message.Text == printCommand || s.message.Text == anonymousPrintCommand {
		s.sayHello()
		s.state = checkColorState
		s.anonymous = s.message.Text == anonymousPrintCommand
	} else if s.message.Text == statusCommand {
		s.sayStatus()
	}
}

func checkColorState(s *session) {
	if s.message.Text == cancelCommand {
		s.sayCanceled()
		s.state = idleState
		return
	}
	color, ok := colorNames[strings.ToLower(s.message.Text)]
	if ok {
		s.sayGoodColor()
		s.color = color
		s.state = checkTextState
	} else {
		s.sayBadColor()
	}
}

func checkTextState(s *session) {
	if s.message.Text == cancelCommand {
		s.sayCanceled()
		s.state = idleState
		return
	}
	if len(s.message.Text) <= maxMsgLen {
		// Write log entry
		log.Infof(
			"%s %s (%s/%d) says : \"%s\" in %s",
			s.sender.FirstName, s.sender.LastName, s.sender.Username, s.sender.ID,
			s.message.Text, s.color)
		lastMessage = fmt.Sprintf("%s says : \"%s\"", s.sender.FirstName, s.message.Text)
		if !*silent {
			// Send a notification to channels
			for _, username := range notificationChannels {
				err := bot.SendMessage(
					telebot.Chat{Type: "channel", Username: username},
					fmt.Sprintf("%s says : \"%s\"", s.sender.FirstName, s.message.Text),
					nil)
				if err != nil {
					log.Errorf("Error sending notification: %s", err)
				}
			}
		}
		s.sayGoodText()

		if (s.anonymous) {
			dispatchMessage("", s.message.Text, s.color)
		} else {
			dispatchMessage(s.sender.FirstName, s.message.Text, s.color)
		}

		s.state = idleState
	} else {
		s.sayTooLongText()
	}
}