Add pipeline module registries

internal/framework/pipeline/module.go

@@ -0,0 +1,99 @@
+package pipeline
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+type ModuleStage string
+
+const (
+	StageInput     ModuleStage = "input"
+	StageChunk     ModuleStage = "chunk"
+	StageExtract   ModuleStage = "extract"
+	StageMerge     ModuleStage = "merge"
+	StageNormalize ModuleStage = "normalize"
+	StageValidate  ModuleStage = "validate"
+	StageOutput    ModuleStage = "output"
+)
+
+type ModuleSpec struct {
+	Key      string
+	Stage    ModuleStage
+	Provides []string
+	Requires []string
+}
+
+func defaultModuleSpec(key string, stage ModuleStage) ModuleSpec {
+	return ModuleSpec{
+		Key:   key,
+		Stage: stage,
+	}
+}
+
+func normalizeModuleSpec(spec ModuleSpec) ModuleSpec {
+	return ModuleSpec{
+		Key:      strings.TrimSpace(spec.Key),
+		Stage:    spec.Stage,
+		Provides: normalizeCapabilities(spec.Provides),
+		Requires: normalizeCapabilities(spec.Requires),
+	}
+}
+
+func normalizeCapabilities(values []string) []string {
+	if len(values) == 0 {
+		return nil
+	}
+
+	seen := make(map[string]struct{}, len(values))
+	for _, value := range values {
+		normalized := strings.TrimSpace(value)
+		if normalized == "" {
+			continue
+		}
+		seen[normalized] = struct{}{}
+	}
+	if len(seen) == 0 {
+		return nil
+	}
+
+	capabilities := make([]string, 0, len(seen))
+	for value := range seen {
+		capabilities = append(capabilities, value)
+	}
+	sort.Strings(capabilities)
+	return capabilities
+}
+
+func cloneModuleSpec(spec ModuleSpec) ModuleSpec {
+	return ModuleSpec{
+		Key:      spec.Key,
+		Stage:    spec.Stage,
+		Provides: append([]string(nil), spec.Provides...),
+		Requires: append([]string(nil), spec.Requires...),
+	}
+}
+
+func validateModuleSpec(kind string, expectedStage ModuleStage, spec ModuleSpec) error {
+	if spec.Key == "" {
+		return fmt.Errorf("%s key must not be empty", kind)
+	}
+	if spec.Stage != expectedStage {
+		return fmt.Errorf("%s %q must use %q stage, got %q", kind, spec.Key, expectedStage, spec.Stage)
+	}
+	return nil
+}
+
+func sortedRegistryKeys[C any](constructors map[string]C) []string {
+	if len(constructors) == 0 {
+		return nil
+	}
+
+	keys := make([]string, 0, len(constructors))
+	for key := range constructors {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	return keys
+}