oauth.go

package autodelete

import (
	"fmt"
	"net/http"
	"strconv"

	"strings"

	"github.com/bwmarrin/discordgo"
	"golang.org/x/oauth2"
)

var oauthConfig *oauth2.Config

func (b *Bot) oauthConfig() *oauth2.Config {
	if oauthConfig != nil {
		return oauthConfig
	}
	oauthConfig = &oauth2.Config{
		ClientID:     b.ClientID,
		ClientSecret: b.ClientSecret,
		Endpoint: oauth2.Endpoint{
			AuthURL:  discordgo.EndpointOauth2 + "authorize",
			TokenURL: discordgo.EndpointOauth2 + "token",
		},
		Scopes:      []string{"bot"},
		RedirectURL: fmt.Sprintf("%s%s", b.HTTP.Public, "/discord_auto_delete/oauth/callback"),
	}
	return oauthConfig
}

func (b *Bot) OAuthStartURL() string {
	return b.oauthConfig().AuthCodeURL("not_necessary_for_discord",
		oauth2.SetAuthURLParam("permissions", strconv.Itoa(discordgo.PermissionManageMessages)))
}

func (b *Bot) HTTPOAuthStart(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Location", b.OAuthStartURL())
	w.WriteHeader(http.StatusFound)
}

func (b *Bot) HTTPOAuthCallback(w http.ResponseWriter, r *http.Request) {
	err := r.ParseForm()
	if err != nil {
		http.Error(w, "bad form", 400)
		return
	}
	if r.Form.Get("code") == "" {
		http.Error(w, "no authcode", 400)
		return
	}

	t, err := b.oauthConfig().Exchange(r.Context(), r.Form.Get("code"))
	if err != nil && strings.Contains(err.Error(), "invalid_client") {
		fmt.Fprint(w, "OK, bot joined\nUse '@AutoDelete setup' to get started")
		return
	} else if err != nil {
		fmt.Printf("%T %v", err, err)
		http.Error(w, "bad token", http.StatusUnprocessableEntity)
		return
	}

	fmt.Println(t)
	w.WriteHeader(200)
	fmt.Fprint(w, "OK, bot joined\nUse '@AutoDelete setup' to get started")
}