# effective-stability-tier.rq
# -----------------------------------------------------------------------------
# Compute the effective release contract of a CDS view as the MIN of all the
# views it depends on, transitively. Returns the worst-case tier ("C1" if
# any transitive binding lands on C1, etc.).
#
# Parameters:
#   $viewName — sap:CDSView with this name (e.g. "ZC_TopCustomersBySales")

PREFIX atlas: <https://atlas.naburis.cloud/ontology#>
PREFIX sap:   <https://atlas.naburis.cloud/ontology/sap#>

SELECT ?view ?effectiveTier (MIN(?tierValue) AS ?effectiveTierValue)
WHERE {
  # Map a C0/C1/C2 string to a comparable integer: C2=2, C1=1, C0=0.
  VALUES (?tierCode ?tierValue) {
    ("C2" 2) ("C1" 1) ("C0" 0)
  }

  ?root sap:hasVDMViewType ?rootType ;
        sap:hasField/sap:fieldRole "key" ;
        sap:hasField/^sap:hasField ?root .  # self-match, anchors root
  ?root rdfs:label $viewName .

  # Traverse dependencies via sap:hasAssociation → sap:targetsView,
  # then again transitively with a SPARQL 1.1 path.
  ?root (sap:hasAssociation/sap:targetsView)* ?view .

  # Each dependency's own contract
  ?view sap:hasReleaseContract ?contract .
  ?contract sap:hasReleaseState ?tierCode .
}
GROUP BY ?view ?effectiveTier
ORDER BY ?effectiveTierValue
LIMIT 1