otiai10/amesh-bot

package controllers

import (
    "context"
    "encoding/json"
    "fmt"
    "net/http"
    "os"
    "regexp"

    "github.com/otiai10/amesh-bot/service"
    "github.com/otiai10/marmoset"
    "github.com/slack-go/slack/slackevents"
)

var (
    ReminderExpressions = []*regexp.Regexp{
        regexp.MustCompile("^Reminder: +"),
        regexp.MustCompile("^リマインダー : +"),
    }
)

func (c *Controller) Webhook(w http.ResponseWriter, req *http.Request) {

    render := marmoset.Render(w, true)

    payload := Payload{}
    defer req.Body.Close()

    if err := json.NewDecoder(req.Body).Decode(&payload); err != nil {
        render.JSON(http.StatusBadRequest, marmoset.P{"message": err.Error()})
        return
    }

    if payload.Token != os.Getenv("SLACK_VERIFICATION_TOKEN") {
        render.JSON(http.StatusBadRequest, marmoset.P{"message": "invalid verification"})
        return
    }

    if payload.Type == slackevents.URLVerification {
        w.Header().Set("Content-Type", "text/plain")
        w.WriteHeader(http.StatusOK)
        w.Write([]byte(payload.Challenge))
        return
    }

    // OK, it's valid event callback
    // https://api.slack.com/events-api#the-events-api__responding-to-events
    render.JSON(http.StatusAccepted, marmoset.P{"message": "ok"})

    // Fetch oauth information and recover Slack client
    team := service.OAuthResponse{}
    key := fmt.Sprintf("Teams/%s", payload.TeamID)
    if err := c.Datastore.Get(req.Context(), key, &team); err != nil {
        // TODO: Fix
        panic(fmt.Errorf("datastore.Get failed: %v", err))
    }

    if payload.APIAppID == os.Getenv("DEV_SLACK_APP_ID") {
        team.AccessToken = os.Getenv("DEV_SLACK_BOT_USER_OAUTH_TOKEN")
    }

    payload.Event = cleanup(payload.Event)

    ctx := context.WithValue(context.Background(), "webhook_request", req)
    go c.Bot.Handle(ctx, team, payload.Event)

    return

}

func cleanup(event slackevents.AppMentionEvent) slackevents.AppMentionEvent {
    // Cleanup Reminder case
    for _, exp := range ReminderExpressions {
        if exp.MatchString(event.Text) {
            event.Text = exp.ReplaceAllString(event.Text, "")
            return event
        }
    }
    return event
}