Add helper to collect previous-session artifact input requirements

internal/artifacts/previous_requirements.go

@@ -0,0 +1,112 @@
+package artifacts
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/narratio/internal/config"
+)
+
+// PreviousArtifactRequirement describes one previous-session artifact dependency.
+type PreviousArtifactRequirement struct {
+	Name     string
+	Required bool
+	Sources  []string
+}
+
+// CollectPreviousArtifactRequirements scans enabled Scriptorium artifacts and returns
+// deduplicated previous-session artifact requirements in deterministic order.
+func CollectPreviousArtifactRequirements(
+	artifactsCfg map[string]config.ScriptoriumArtifactConfig,
+) []PreviousArtifactRequirement {
+	if len(artifactsCfg) == 0 {
+		return nil
+	}
+
+	artifactNames := sortedScriptoriumArtifactNames(artifactsCfg)
+	byName := map[string]PreviousArtifactRequirement{}
+
+	for _, artifactName := range artifactNames {
+		artifactCfg := artifactsCfg[artifactName]
+		if !artifactCfg.Enabled {
+			continue
+		}
+
+		inputNames := sortedScriptoriumInputKeys(artifactCfg.Inputs)
+		for _, inputName := range inputNames {
+			inputCfg := artifactCfg.Inputs[inputName]
+			previousName, ok := PreviousSessionArtifactName(inputCfg.Source)
+			if !ok {
+				continue
+			}
+
+			location := fmt.Sprintf(
+				"pipeline.scriptorium.artifacts.%s.inputs.%s.source",
+				artifactName,
+				inputName,
+			)
+			requirement := byName[previousName]
+			requirement.Name = previousName
+			requirement.Required = requirement.Required || inputCfg.Required
+			requirement.Sources = append(requirement.Sources, location)
+			byName[previousName] = requirement
+		}
+	}
+
+	if len(byName) == 0 {
+		return nil
+	}
+
+	requirements := make([]PreviousArtifactRequirement, 0, len(byName))
+	for _, requirement := range byName {
+		requirement.Sources = dedupeAndSortStrings(requirement.Sources)
+		requirements = append(requirements, requirement)
+	}
+	sort.Slice(requirements, func(i, j int) bool {
+		return requirements[i].Name < requirements[j].Name
+	})
+	return requirements
+}
+
+func sortedScriptoriumArtifactNames(artifactsCfg map[string]config.ScriptoriumArtifactConfig) []string {
+	names := make([]string, 0, len(artifactsCfg))
+	for name := range artifactsCfg {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+func sortedScriptoriumInputKeys(inputs map[string]config.ScriptoriumInputConfig) []string {
+	if len(inputs) == 0 {
+		return nil
+	}
+	names := make([]string, 0, len(inputs))
+	for name := range inputs {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+func dedupeAndSortStrings(values []string) []string {
+	if len(values) == 0 {
+		return nil
+	}
+	seen := map[string]struct{}{}
+	out := make([]string, 0, len(values))
+	for _, value := range values {
+		trimmed := strings.TrimSpace(value)
+		if trimmed == "" {
+			continue
+		}
+		if _, ok := seen[trimmed]; ok {
+			continue
+		}
+		seen[trimmed] = struct{}{}
+		out = append(out, trimmed)
+	}
+	sort.Strings(out)
+	return out
+}