// Package server wires the HTTP surface for tenant-registry.
//
// All routes are registered in NewRouter; per-concern handlers live in
// peer files (tenants.go, catalog.go, apikeys.go, audit.go, keycloak.go).
package server

import (
	"errors"
	"log/slog"
	"net/http"

	"gitea.meghsakha.com/platform/tenant-registry/internal/authn"
	"gitea.meghsakha.com/platform/tenant-registry/internal/config"
	"gitea.meghsakha.com/platform/tenant-registry/internal/keycloak"
	"gitea.meghsakha.com/platform/tenant-registry/internal/store"
)

// Server bundles the dependencies every handler needs.
type Server struct {
	Cfg      *config.Config
	Log      *slog.Logger
	Store    store.Store
	Keycloak keycloak.Adapter // never nil — main wires Mock when KC env is unset
	Auth     *authn.Verifier  // nil ⇒ AUTH_ENABLED=false, API is open (dev only)
}

// NewRouter builds the http.Handler with logging middleware applied.
//
// Route auth classes (ratified auth design): /healthz and /readyz are
// PUBLIC_EXPLICIT (orca probes, no auth by design); every other route is
// INTERNAL_SERVICE_ONLY and sits behind requireAuth. New routes land in
// the protected mux by construction — registering one on the root mux is
// the exception and needs a PUBLIC_EXPLICIT justification comment.
func NewRouter(s *Server) http.Handler {
	root := http.NewServeMux()

	// PUBLIC_EXPLICIT: health + status probes.
	root.HandleFunc("GET /healthz", s.healthz)
	root.HandleFunc("GET /readyz", s.readyz)

	mux := http.NewServeMux()

	// tenants
	mux.HandleFunc("POST /v1/tenants", s.createTenant)
	mux.HandleFunc("GET /v1/tenants/{id}", s.getTenant)
	mux.HandleFunc("GET /v1/tenants/by-slug/{slug}", s.getTenantBySlug)
	mux.HandleFunc("POST /v1/tenants/{id}/activate", s.activateTenant)
	mux.HandleFunc("POST /v1/tenants/{id}/cancel", s.cancelTenant)

	// entitlements
	mux.HandleFunc("GET /v1/entitlements", s.listTenantProducts)

	// catalog
	mux.HandleFunc("GET /v1/catalog", s.getCatalog)
	mux.HandleFunc("POST /v1/catalog/request", s.catalogRequest)
	mux.HandleFunc("POST /v1/catalog/trial-request", s.catalogTrialRequest)

	// api keys
	mux.HandleFunc("POST /v1/api-keys", s.createAPIKey)
	mux.HandleFunc("GET /v1/api-keys", s.listAPIKeys)
	mux.HandleFunc("DELETE /v1/api-keys/{id}", s.revokeAPIKey)
	mux.HandleFunc("POST /v1/internal/api-keys/verify", s.verifyAPIKey)

	// audit
	mux.HandleFunc("POST /v1/audit", s.appendAudit)
	mux.HandleFunc("GET /v1/audit", s.listAudit)

	// keycloak claims refresh — the URL the protocol mapper would call at
	// token issuance to grab the up-to-date entitlement bundle. Today the
	// dev realm projects user attributes (set by SyncClaims) — this is
	// the "pull" complement for when the realm is reconfigured to fetch.
	mux.HandleFunc("POST /v1/internal/keycloak/claims", s.kcClaims)

	// memberships — the B2 membership authority: which tenants does a
	// JWT subject belong to, with which org_roles and entitlements.
	mux.HandleFunc("GET /v1/users/{id}/memberships", s.getUserMemberships)

	root.Handle("/", s.requireAuth(mux))
	return logRequest(s.Log)(root)
}

// requireAuth gates the INTERNAL_SERVICE_ONLY routes. With Auth nil
// (AUTH_ENABLED=false) it passes through — the startup log carries the
// warning, and the Auth-5 activation flips the env, not the code.
func (s *Server) requireAuth(next http.Handler) http.Handler {
	if s.Auth == nil {
		return next
	}
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p, err := s.Auth.Verify(r.Context(), r.Header.Get("Authorization"))
		if err != nil {
			if errors.Is(err, authn.ErrNoToken) {
				writeError(w, http.StatusUnauthorized, "TOKEN_MISSING", "bearer token required")
				return
			}
			// Signature, issuer, expiry, and audience failures all land
			// here; the message says which without echoing the token.
			writeError(w, http.StatusUnauthorized, "TOKEN_INVALID", err.Error())
			return
		}
		next.ServeHTTP(w, r.WithContext(authn.WithPrincipal(r.Context(), p)))
	})
}

func (s *Server) healthz(w http.ResponseWriter, _ *http.Request) {
	writeJSON(w, http.StatusOK, map[string]string{"status": "ok"})
}

func (s *Server) readyz(w http.ResponseWriter, r *http.Request) {
	if err := s.Store.Ping(r.Context()); err != nil {
		writeError(w, http.StatusServiceUnavailable, "store_unavailable", err.Error())
		return
	}
	if err := s.Keycloak.Health(r.Context()); err != nil {
		writeError(w, http.StatusServiceUnavailable, "keycloak_unavailable", err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "ready"})
}