bot.go

package bf

import (
	"sync"
	"time"

	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
)

var _ ChatBot = &ChatBotImpl{}

type ChatBotImpl struct {
	// tgbot is a telegram bot api instance.
	tgbot *tgbotapi.BotAPI
	// chatHandlerLayers is a map of chat id to handler layer.
	// Layer is set of handlers that are expected from some user.
	// Example:
	// John (id 1212) open "Say hi" screen. Now he can:
	// 		- press button "Hi"
	// 		- send text "Hello"
	// 		- send voice message
	// So for John there will be 3 handlers in layer "John". After John press button "Hi" layer will be wiped.
	// Set with: RegisterIButton etc.
	chatHandlerLayers map[int64]*HandlerLayer
	// retryLayers previous layer.
	retryLayers map[int64]*string
	// defaultHandlerLayer is a layer that will be used if there is no chat-specific layer. Will not be wiped.
	defaultHandlerLayer *HandlerLayer

	layersMutex      sync.RWMutex
	retryLayersMutex sync.RWMutex

	// middlewares that will be called before any handler. Set with RegisterMiddleware.
	middlewares []MiddlewareFunc

	// errorHandler is a function that will be called if any handler return error. Set with RegisterErrorHandler.
	errorHandler ErrorHandlerFunc

	// logger is a interface for logging. Use any logger that implements Logger interface.
	// default is logrus.
	logger Logger

	// debug is a flag that enables debug features. Set with WithDebug.
	debug     bool
	parseMode string
}

// NewBot creates new bot instance, base layer and starts cleaner.
// apikey - telegram bot api key generated by BotFather.
// opts - options for bot BotOption.
func NewBot(apikey string, opts ...BotOption) (*ChatBotImpl, error) {
	chatBotInstance := &ChatBotImpl{
		tgbot:               nil,
		chatHandlerLayers:   make(map[int64]*HandlerLayer),
		retryLayers:         map[int64]*string{},
		defaultHandlerLayer: nil,
		layersMutex:         sync.RWMutex{},
		retryLayersMutex:    sync.RWMutex{},
		middlewares:         make([]MiddlewareFunc, 0),
		errorHandler:        nil,
		logger:              logrus.New(),
		debug:               false,
		parseMode:           tgbotapi.ModeHTML,
	}
	for _, opt := range opts {
		opt(chatBotInstance)
	}

	bot, err := tgbotapi.NewBotAPI(apikey)
	if err != nil {
		return chatBotInstance, errors.Wrap(err, "failed to create bot")
	}

	chatBotInstance.tgbot = bot

	chatBotInstance.defaultHandlerLayer = chatBotInstance.NewLayer()
	chatBotInstance.defaultHandlerLayer.ttl = time.Now().Add(time.Hour * 24 * 365 * 100) // we don't want to expire it
	chatBotInstance.RegisterErrorHandler(chatBotInstance.defaultErrorHandler)
	chatBotInstance.RegisterDefaultHandler(chatBotInstance.defaultEventHandler)

	go chatBotInstance.cleaner()

	return chatBotInstance, nil
}