package engine

import "go.maximumdirect.net/configkit/internal/document"

func appendInheritanceExplanation(explanation *Explanation, working **document.Node, query Path, model *historyModel, selections historyReplaySelections, secrets map[string]bool) {
	if model == nil {
		return
	}
	for _, payload := range model.inheritancePayloads {
		for operationIndex, operation := range payload.operations {
			if operation.control != nil {
				ref := historyPayloadRef{phase: historyPhaseInheritance, id: 0, substep: operationIndex * 2}
				selection, selected := selections.byPayload[ref]
				if !selected {
					continue
				}
				before := valueSnapshot(*working, query, secrets)
				replaceHistoryPath(working, operation.control.path, nil)
				after := valueSnapshot(*working, query, secrets)
				appendInheritanceChange(explanation, selection, before, after)
				continue
			}
			if operation.transfer == nil {
				continue
			}
			parentRef := historyPayloadRef{phase: historyPhaseInheritance, id: 0, substep: operationIndex * 2}
			childRef := historyPayloadRef{phase: historyPhaseInheritance, id: 0, substep: operationIndex*2 + 1}
			parentSelection, hasParent := selections.byPayload[parentRef]
			childSelection, hasChild := selections.byPayload[childRef]
			before := valueSnapshot(*working, query, secrets)
			replaceHistoryPath(working, operation.transfer.to, operation.parent)
			// A record keeps its own identity throughout inheritance. Restore it
			// before taking enclosing snapshots as well as direct field snapshots.
			for _, field := range operation.identityFields {
				identity, _ := documentAtPath(operation.effective, Keys(field))
				replaceHistoryPath(working, operation.transfer.to.Key(field), identity)
			}
			afterParent := valueSnapshot(*working, query, secrets)
			if hasParent {
				appendInheritanceChange(explanation, parentSelection, before, afterParent)
			}
			replaceHistoryPath(working, operation.transfer.to, operation.effective)
			afterChild := valueSnapshot(*working, query, secrets)
			if hasChild {
				appendInheritanceChange(explanation, childSelection, afterParent, afterChild)
			}
		}
	}
}

func appendInheritanceChange(explanation *Explanation, selection historySelection, before, after ValueSnapshot) {
	if !selection.hasAttribution {
		return
	}
	explanation.History = append(explanation.History, ValueChange{
		Before:       before,
		After:        after,
		Origin:       cloneOrigin(selection.attribution.origin),
		Reasons:      append([]string(nil), selection.attribution.reasons...),
		Dependencies: clonePaths(selection.attribution.dependencies),
	})
}