main.go

package main

import (
	"log"
	"net/http"
	"os"
	"wolfbot/domain/model"
	"wolfbot/handler"
	"wolfbot/initializer"

	"github.com/joho/godotenv"
	"github.com/line/line-bot-sdk-go/linebot"
)

func main() {
	env := os.Getenv("APP_ENV")

	if env == "local" {
		godotenv.Load(".env.local")
	}

	channelSecret := mustGetenv("CHANNEL_SECRET")
	channelAccessToken := mustGetenv("CHANNEL_ACCESS_TOKEN")
	port := mustGetenv("PORT")
	dbURL := mustGetenv("DATABASE_URL")

	_, service := initializer.Initialize(dbURL)

	messageHandler := handler.NewMessageHandler(
		service.VillageService,
		service.PlayerService,
		service.UserPlayerRelationService,
	)

	bot, err := linebot.New(channelSecret, channelAccessToken)
	if err != nil {
		log.Fatal(err)
	}

	http.HandleFunc("/callback", func(w http.ResponseWriter, req *http.Request) {
		events, err := bot.ParseRequest(req)
		if err != nil {
			if err == linebot.ErrInvalidSignature {
				w.WriteHeader(400)
			} else {
				w.WriteHeader(500)
			}
			return
		}

		for _, event := range events {
			if event.Type == linebot.EventTypeMessage {
				switch message := event.Message.(type) {
				case *linebot.TextMessage:
					var output Replyer
					var err error

					switch event.Source.Type {
					case linebot.EventSourceTypeGroup:
						output, err = messageHandler.HandleGroupMessage(
							message.Text,
							model.UserID(event.Source.UserID),
							event.Source.GroupID,
						)

					case linebot.EventSourceTypeUser:
						output, err = messageHandler.HandleUserMessage(
							message.Text,
							model.UserID(event.Source.UserID),
						)
					}

					if err != nil {
						log.Println(err)

						// 特別なエラーメッセージが設定されている場合にはそれを返して終了
						if e, ok := err.(Replyer); ok {
							if _, err := bot.ReplyMessage(
								event.ReplyToken,
								linebot.NewTextMessage(e.Reply()),
							).Do(); err != nil {
								log.Println(err)
							}
							continue
						}

						// 特別なエラーメッセージが設定されていない場合にはエラー発生の旨のみ通知して終了
						if _, err := bot.ReplyMessage(
							event.ReplyToken,
							linebot.NewTextMessage("エラーが発生しました"),
						).Do(); err != nil {
							log.Println(err)
						}
						continue
					}

					if _, err = bot.ReplyMessage(
						event.ReplyToken,
						linebot.NewTextMessage(output.Reply()),
					).
						Do(); err != nil {
						log.Println(err)
					}
				}
			}
		}
	})

	if err := http.ListenAndServe(":"+port, nil); err != nil {
		log.Fatal(err)
	}
}

func mustGetenv(key string) string {
	val := os.Getenv(key)
	if val == "" {
		log.Fatal("failed to read environment variable: " + key)
	}
	return val
}

type Replyer interface {
	Reply() string
}