@startuml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Component.puml

LAYOUT_TOP_DOWN()

title LOTTY Backend - C4 Component

Container_Boundary(api, "Backend Container (Django + Django Ninja)") {
  Component(decision_endpoint, "Decision Endpoint", "api/v1/decision/endpoints.py", "POST /api/v1/decide")
  Component(decision_service, "Decision Service", "apps/decision/services.py", "Flag lookup, targeting DSL, limits/conflicts, hash-based assignment, decide-result cache, sync/async decision persistence")

  Component(events_endpoint, "Events Endpoint", "api/v1/events/endpoints.py", "POST /api/v1/events")
  Component(events_service, "Events Service", "apps/events/services.py", "Validation, dedup, exposure/conversion attribution, pending promotion")
  Component(events_tasks, "Events Tasks", "apps/events/tasks.py", "persist_decision, cleanup pending")

  Component(reports_endpoint, "Reports Endpoint", "api/v1/reports/endpoints.py", "GET /reports/{experiment_id}")
  Component(reports_service, "Reports Service", "apps/reports/services.py", "Per-variant metrics (ratio/count/average/percentile)")

  Component(guardrails_service, "Guardrails Service", "apps/guardrails/services.py", "Threshold checks, auto pause/rollback")
}

ContainerDb(db, "Relational DB", "PostgreSQL / SQLite", "Flags, experiments, variants, decisions, events, exposures")
Container(cache, "Cache + Broker", "Valkey / Redis / LocMem", "Flag/active experiment/decide-result cache, Celery broker")
Container(worker, "Celery Worker / Beat", "Celery", "Periodic guardrails/notifications/cleanup + async decision persistence")

Rel(decision_endpoint, decision_service, "Delegates")
Rel(decision_service, cache, "Reads cached flag / active experiment")
Rel(decision_service, db, "Reads variants, writes Decision")

Rel(events_endpoint, events_service, "Delegates batch")
Rel(events_service, db, "Writes Event / Exposure / PendingEvent")
Rel(events_tasks, db, "Writes Decision async")

Rel(reports_endpoint, reports_service, "Builds report")
Rel(reports_service, db, "Reads attributed events / exposures")

Rel(guardrails_service, reports_service, "Uses metric calculations")
Rel(guardrails_service, db, "Writes triggers, updates experiment status")
Rel(worker, guardrails_service, "Periodic check_all")

@enduml