@startuml bv-identity-map-freeze
!pragma layout smetana
title Identity Map — Freezing hk_durable on first assignment
skinparam backgroundColor #fafbfc
skinparam defaultFontName SansSerif
skinparam shadowing false
skinparam ArrowColor #5a6a7e
skinparam rectangle {
  FontSize 12
  BorderThickness 1
}
skinparam package {
  FontSize 13
  BorderColor #4a5568
  BackgroundColor #ffffff
}

left to right direction

package "Load 1: Initial Cluster Formation (2024-02-15)" as L1 #edf0f4 {
  rectangle "Same-As Link\nMaster: O100\nDuplicate: K100" as L1_SameAs #e8f0fb
  rectangle "IdentityMapAssignLogic\nMint hk_durable = HASH(O100)\nrule_version = 1" as L1_Logic #fff6e8
  rectangle "map_person Table\nO100 ➔ hk_durable: HASH(O100) (v1)\nK100 ➔ hk_durable: HASH(O100) (v1)" as L1_Map #e8f0fb
  
  L1_SameAs --> L1_Logic
  L1_Logic --> L1_Map : Insert initial map
}

package "Load 2: Master Flips to K100 (2024-03-15)" as L2 #edf0f4 {
  rectangle "Same-As Link\nMaster: K100 (FLIPPED!)\nDuplicate: O100" as L2_SameAs #fff6e8
  rectangle "IdentityMapAssignLogic\nCheck existing cluster:\nhk_durable already exists!\nKEEP FROZEN HASH(O100)\nrule_version = 2" as L2_Logic #f3ebfb
  rectangle "map_person Table\nO100 ➔ FROZEN HASH(O100) (v2)\nK100 ➔ FROZEN HASH(O100) (v2)\npreferred_bk updated" as L2_Map #e7f6ed

  L2_SameAs --> L2_Logic
  L2_Logic --> L2_Map : Update master & version\n(hk_durable NOT rewritten!)
}

package "Business Vault SCD2 Timeline" as SCD2 #f3ebfb {
  rectangle "bv_person_bvr\nConsolidated grain: HASH(O100)\nNo historical key churn\nDownstream marts stay stable!" as SCD2_Target #e7f6ed
}

L1_Map --> SCD2_Target : As-of lookup
L2_Map --> SCD2_Target : As-of lookup
@enduml