Remove network requests from actions.NewClient (#2219)

Co-authored-by: Nikola Jokic <jokicnikola07@gmail.com>

github/actions/config.go

@@ -0,0 +1,98 @@
+package actions
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+var ErrInvalidGitHubConfigURL = fmt.Errorf("invalid config URL, should point to an enterprise, org, or repository")
+
+type GitHubScope int
+
+const (
+	GitHubScopeUnknown GitHubScope = iota
+	GitHubScopeEnterprise
+	GitHubScopeOrganization
+	GitHubScopeRepository
+)
+
+type GitHubConfig struct {
+	ConfigURL *url.URL
+	Scope     GitHubScope
+
+	Enterprise   string
+	Organization string
+	Repository   string
+
+	IsHosted bool
+}
+
+func ParseGitHubConfigFromURL(in string) (*GitHubConfig, error) {
+	u, err := url.Parse(in)
+	if err != nil {
+		return nil, err
+	}
+
+	isHosted := u.Host == "github.com" ||
+		u.Host == "www.github.com" ||
+		u.Host == "github.localhost"
+
+	configURL := &GitHubConfig{
+		ConfigURL: u,
+		IsHosted:  isHosted,
+	}
+
+	invalidURLError := fmt.Errorf("%q: %w", u.String(), ErrInvalidGitHubConfigURL)
+
+	pathParts := strings.Split(strings.TrimPrefix(u.Path, "/"), "/")
+
+	switch len(pathParts) {
+	case 1: // Organization
+		if pathParts[0] == "" {
+			return nil, invalidURLError
+		}
+
+		configURL.Scope = GitHubScopeOrganization
+		configURL.Organization = pathParts[0]
+
+	case 2: // Repository or enterprise
+		if strings.ToLower(pathParts[0]) == "enterprises" {
+			configURL.Scope = GitHubScopeEnterprise
+			configURL.Enterprise = pathParts[1]
+			break
+		}
+
+		configURL.Scope = GitHubScopeRepository
+		configURL.Organization = pathParts[0]
+		configURL.Repository = pathParts[1]
+	default:
+		return nil, invalidURLError
+	}
+
+	return configURL, nil
+}
+
+func (c *GitHubConfig) GitHubAPIURL(path string) *url.URL {
+	result := &url.URL{
+		Scheme: c.ConfigURL.Scheme,
+	}
+
+	switch c.ConfigURL.Host {
+	// Hosted
+	case "github.com", "github.localhost":
+		result.Host = fmt.Sprintf("api.%s", c.ConfigURL.Host)
+	// re-routing www.github.com to api.github.com
+	case "www.github.com":
+		result.Host = "api.github.com"
+
+	// Enterprise
+	default:
+		result.Host = c.ConfigURL.Host
+		result.Path = "/api/v3"
+	}
+
+	result.Path += path
+
+	return result
+}