Add shared ConfigKit loading and runtime settings conversion

internal/config/load.go

@@ -0,0 +1,91 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"sort"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+	renderformat "gitea.maximumdirect.net/eric/scriptorium/internal/format"
+)
+
+// LoadOptions selects one application source and explicit configuration values.
+type LoadOptions struct {
+	Path      string
+	Explicit  bool
+	Overlay   string
+	Overrides []configkit.Override
+}
+
+// Load resolves one ConfigKit document without changing the executable's legacy loader.
+func Load(options LoadOptions) (*configkit.Result[Document], error) {
+	var source configkit.Source
+	if options.Explicit {
+		source = configkit.File(options.Path)
+	} else {
+		selected := ""
+		for _, candidate := range defaultConfigSearchPaths {
+			if _, err := os.Stat(candidate); err == nil {
+				selected = candidate
+				break
+			} else if !errors.Is(err, os.ErrNotExist) {
+				reason := "filesystem error"
+				if errors.Is(err, os.ErrPermission) {
+					reason = "permission denied"
+				}
+				return nil, fmt.Errorf("cannot inspect configuration path %q: %s", candidate, reason)
+			}
+		}
+		if selected == "" {
+			source = configkit.NoSource()
+		} else {
+			source = configkit.File(selected)
+		}
+	}
+
+	result, err := configkit.Load(source, configkit.Options[Document]{
+		Definition: documentDefinition(),
+		Overrides:  options.Overrides,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("load application configuration: %w", err)
+	}
+	return result, nil
+}
+
+// Settings converts a validated document without another merge or normalization.
+func Settings(document Document) AppSettings {
+	settings := AppSettings{
+		PromptDir:           document.PromptDir,
+		ProfileDir:          document.ProfileDir,
+		SchemaDir:           document.SchemaDir,
+		ServerAddr:          document.Server.Addr,
+		ArtifactRoot:        document.Server.ArtifactRoot,
+		MaxRequestBytes:     document.Server.MaxRequestBytes,
+		MaxArtifactBytes:    document.Server.MaxArtifactBytes,
+		MaxResponseBytes:    document.Server.MaxResponseBytes,
+		DefaultRenderFormat: renderformat.PreparedRunOutputFormat(document.Defaults.RenderFormat),
+		TransientRetries:    document.TransientRetries,
+	}
+	if document.Backends != nil {
+		ids := make([]string, 0, len(document.Backends))
+		for id := range document.Backends {
+			ids = append(ids, id)
+		}
+		sort.Strings(ids)
+		settings.Backends = make([]BackendSettings, 0, len(ids))
+		for _, id := range ids {
+			backend := document.Backends[id]
+			settings.Backends = append(settings.Backends, BackendSettings{
+				ID:               id,
+				Endpoint:         backend.Endpoint,
+				APIKeyEnv:        backend.APIKeyEnv,
+				ExtraParams:      backend.ExtraParams,
+				ConcurrencyLimit: backend.ConcurrencyLimit,
+				QueueCapacity:    backend.QueueCapacity,
+			})
+		}
+	}
+	return settings
+}