feat: add scaffolder

internal/templates/templates.go

@@ -0,0 +1,97 @@
+package templates
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"os"
+	"path"
+	"sync"
+
+	"golang.org/x/sync/errgroup"
+	"gopkg.in/yaml.v3"
+)
+
+// TemplateIndexer loads all template specifications from the registry, allowing the caller to choose on of them, or simply display their properties.
+type TemplateIndexer struct{}
+
+func NewTemplateIndexer() *TemplateIndexer {
+	return &TemplateIndexer{}
+}
+
+type Template struct {
+	File TemplateFile
+	Path string
+
+	Input map[string]string
+}
+
+type TemplateDefault struct {
+	Path string `yaml:"path"`
+}
+type TemplateInputs map[string]TemplateInput
+
+type TemplateInput struct {
+	Type        string `yaml:"type"`
+	Description string `yaml:"description"`
+	Default     string `yaml:"default"`
+}
+
+type TemplateFileConfig struct {
+	Rename string `yaml:"rename"`
+}
+
+type TemplateFile struct {
+	Name    string          `yaml:"name"`
+	Default TemplateDefault `yaml:"default"`
+	Input   TemplateInputs  `yaml:"input"`
+	Files   map[string]TemplateFileConfig
+}
+
+func (t *TemplateIndexer) Index(ctx context.Context, scaffoldRegistryFolder string, ui *slog.Logger) ([]Template, error) {
+	ui.Debug("Loading templates...")
+
+	templateDirEntries, err := os.ReadDir(scaffoldRegistryFolder)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read templates dir: %w", err)
+	}
+
+	var (
+		templates     = make([]Template, 0)
+		templatesLock sync.Mutex
+	)
+	egrp, _ := errgroup.WithContext(ctx)
+	for _, templateDirEntry := range templateDirEntries {
+		egrp.Go(func() error {
+			templatePath := path.Join(scaffoldRegistryFolder, templateDirEntry.Name())
+
+			content, err := os.ReadFile(path.Join(templatePath, "scaffold.yaml"))
+			if err != nil {
+				return fmt.Errorf("failed to read: %s, %w", templateDirEntry.Name(), err)
+			}
+
+			var template TemplateFile
+			if err := yaml.Unmarshal(content, &template); err != nil {
+				return fmt.Errorf("failed to unmarshal template: %s, %w", string(content), err)
+			}
+
+			templatesLock.Lock()
+			defer templatesLock.Unlock()
+			templates = append(templates, Template{
+				File:  template,
+				Path:  templatePath,
+				Input: make(map[string]string),
+			})
+
+			return nil
+		})
+	}
+
+	if err := egrp.Wait(); err != nil {
+		return nil, err
+	}
+
+	ui.Debug("Done loading templates...", "amount", len(templates))
+
+	return templates, nil
+}