@startuml
!include <C4/C4_Component>

title Component Diagram: API Backend — NL Search

Container(frontend, "Web Frontend", "SvelteKit")
ContainerDb(db, "PostgreSQL", "PostgreSQL 16")
Container(ollama, "Ollama", "ollama/ollama — port 11434 (internal only)")

System_Boundary(backend, "API Backend (Spring Boot)") {
    Component(nlCtrl, "NlSearchController", "Spring MVC — POST /api/search/nl", "REST entry point for natural language search. Enforces READ_ALL permission. Uses @AuthenticationPrincipal UserDetails to obtain the caller's email for rate limiting. Delegates to NlQueryParserService and returns NlSearchResponse.")
    Component(rateLimiter, "NlSearchRateLimiter", "Spring Service", "Bucket4j + Caffeine LoadingCache keyed on user email. Allows 5 NL search requests per minute per user. Throws DomainException(SMART_SEARCH_RATE_LIMITED / HTTP 429) when the bucket is exhausted. Node-local — same caveat as LoginRateLimiter.")
    Component(parserSvc, "NlQueryParserService", "Spring Service", "Orchestrates the full NL search pipeline: (1) validates query length, (2) calls OllamaClient.parse() to extract structured intent, (3) resolves keywords to tags via TagService.findByNameContaining(), (4) resolves each person name via PersonService.findByDisplayNameContaining(), (5) applies multi-name / personRole heuristics, (6) delegates to DocumentService.searchDocuments() or searchDocumentsByPersonId(). Returns NlSearchResponse. Never logs raw query content (PII).")
    Component(ollamaClient, "RestClientOllamaClient", "Spring Service — implements OllamaClient + OllamaHealthClient", "HTTP client for the Ollama API. Uses two separate RestClient instances: inference client (30 s read timeout) and health-check client (2 s connect timeout). Calls POST /api/generate with grammar-constrained JSON schema (personNames, personRole, dateFrom, dateTo, keywords). isHealthy() polls GET /api/tags. Null-coalesces absent personNames/keywords to List.of(). Defaults unknown personRole to 'any' with a warning log. Maps timeout/5xx/parse errors to DomainException(SMART_SEARCH_UNAVAILABLE / HTTP 503).")
    Component(ollamaProps, "OllamaProperties", "@ConfigurationProperties(\"app.ollama\")", "Config bean: baseUrl, model (qwen2.5:7b-instruct-q4_K_M), timeoutSeconds (default: 30), healthCheckTimeoutSeconds (default: 2).")
    Component(rateLimitProps, "NlSearchRateLimitProperties", "@ConfigurationProperties(\"app.nl-search.rate-limit\")", "Config bean: maxRequestsPerMinute (default: 5).")
}

Component(personSvc, "PersonService", "Spring Service", "See diagram 3e. findByDisplayNameContaining(fragment) delegates to PersonRepository.searchByName() — covers first+last name, alias, and name aliases via LEFT JOIN.")
Component(documentSvc, "DocumentService", "Spring Service", "See diagram 3b. searchDocuments() for keyword/sender/receiver/date queries. searchDocumentsByPersonId() for OR-semantics single-person queries (person as sender OR receiver, no keyword filter).")
Component(tagSvc, "TagService", "Spring Service", "See diagram 3b. findByNameContaining(fragment) delegates to TagRepository.findByNameContainingIgnoreCase(). resolveEffectiveColors() applies one-level color inheritance in-place on a collection of Tag entities.")

Rel(frontend, nlCtrl, "POST /api/search/nl with JSON query", "HTTP / JSON")
Rel(nlCtrl, rateLimiter, "checkAndConsume(userEmail)")
Rel(nlCtrl, parserSvc, "parse(query)")
Rel(parserSvc, ollamaClient, "parse(rawQuery) — extracts intent", "HTTP / JSON")
Rel(ollamaClient, ollama, "POST /api/generate (grammar-constrained JSON schema)", "HTTP / REST")
Rel(ollamaClient, ollama, "GET /api/tags (health check)", "HTTP / REST")
Rel(parserSvc, tagSvc, "findByNameContaining(keyword) — keyword→tag resolution")
Rel(parserSvc, tagSvc, "resolveEffectiveColors(tags)")
Rel(parserSvc, personSvc, "findByDisplayNameContaining(name) for each extracted name")
Rel(parserSvc, documentSvc, "searchDocuments() or searchDocumentsByPersonId()")
Rel(documentSvc, db, "JPA queries", "JDBC")
Rel(personSvc, db, "JPA queries", "JDBC")
Rel(tagSvc, db, "JPA queries", "JDBC")

@enduml