added oauth flow to get authorization code

internal/discord/config.go

@@ -0,0 +1,50 @@
+package discord
+
+import (
+	"strings"
+
+	"git.haelnorr.com/h/golib/env"
+	"github.com/pkg/errors"
+)
+
+type Config struct {
+	ClientID     string // ENV DISCORD_CLIENT_ID: Discord application client ID (required)
+	ClientSecret string // ENV DISCORD_CLIENT_SECRET: Discord application client secret (required)
+	OAuthScopes  string // Authorisation scopes for OAuth
+	RedirectPath string // ENV DISCORD_REDIRECT_PATH: Path for the OAuth redirect handler (required)
+}
+
+func ConfigFromEnv() (any, error) {
+	cfg := &Config{
+		ClientID:     env.String("DISCORD_CLIENT_ID", ""),
+		ClientSecret: env.String("DISCORD_CLIENT_SECRET", ""),
+		OAuthScopes:  getOAuthScopes(),
+		RedirectPath: env.String("DISCORD_REDIRECT_PATH", ""),
+	}
+
+	// Check required fields
+	if cfg.ClientID == "" {
+		return nil, errors.New("Envar not set: DISCORD_CLIENT_ID")
+	}
+	if cfg.ClientSecret == "" {
+		return nil, errors.New("Envar not set: DISCORD_CLIENT_SECRET")
+	}
+	if cfg.RedirectPath == "" {
+		return nil, errors.New("Envar not set: DISCORD_REDIRECT_PATH")
+	}
+
+	return cfg, nil
+}
+
+func getOAuthScopes() string {
+	list := []string{
+		"connections",
+		"email",
+		"guilds",
+		"gdm.join",
+		"guilds.members.read",
+		"identify",
+	}
+	scopes := strings.Join(list, "+")
+	return scopes
+}