// SPDX-License-Identifier: MIT

package application

import (
	"context"

	. "github.com/onsi/ginkgo/v2"
	. "github.com/onsi/gomega"

	"github.com/mudler/LocalAI/core/config"
	"github.com/mudler/LocalAI/core/services/galleryop"
	"github.com/mudler/LocalAI/core/services/messaging"
	"github.com/mudler/LocalAI/core/services/nodes"
	"github.com/mudler/LocalAI/core/services/pgbus"
	"github.com/mudler/LocalAI/core/services/syncstate"
	"github.com/mudler/LocalAI/core/services/testutil"
)

// The guard on the one setting that decides whether any broadcast in the
// deployment is ever delivered.
//
// The carrier holds a pinned LISTEN connection opened from a DSN, and publishes
// travel on a pooled handle opened from another. When those two name different
// databases every publish succeeds, every subscribe succeeds, and nothing
// arrives, on every replica, with no error anywhere. There is exactly one
// legitimate DSN, and these specs are what say so in a way that fails when it
// stops being true.
var _ = Describe("opening the deployment's broadcast carrier", func() {
	It("listens on the same database URL the auth pool was built from", func() {
		db, dsn := testutil.SetupTestDBWithDSN()
		cfg := &config.ApplicationConfig{}
		cfg.Auth.DatabaseURL = dsn

		bus, err := newBroadcastBus(context.Background(), cfg, db)
		Expect(err).ToNot(HaveOccurred())
		DeferCleanup(bus.Close)

		// Equality with the field, not "is a PostgreSQL URL": the failure being
		// excluded is two databases, and any DSN passes a shape check.
		Expect(bus.DSN()).To(Equal(cfg.Auth.DatabaseURL))
	})

	It("migrates the spill table, so an oversized broadcast has somewhere to go", func() {
		db, dsn := testutil.SetupTestDBWithDSN()
		cfg := &config.ApplicationConfig{}
		cfg.Auth.DatabaseURL = dsn

		bus, err := newBroadcastBus(context.Background(), cfg, db)
		Expect(err).ToNot(HaveOccurred())
		DeferCleanup(bus.Close)

		Expect(db.Migrator().HasTable(&pgbus.BusMessage{})).To(BeTrue())
	})

	It("refuses to open a carrier whose DSN is not the pool's database", func() {
		db, _ := testutil.SetupTestDBWithDSN()
		_, otherDSN := testutil.SetupTestDBWithDSN()
		cfg := &config.ApplicationConfig{}
		cfg.Auth.DatabaseURL = otherDSN

		_, err := newBroadcastBus(context.Background(), cfg, db)

		Expect(err).To(HaveOccurred())
	})
})

// The partial pin on two wiring lines that cannot be reddened by a spec: the
// newBroadcastBus call, and `Bus: bus` in the returned literal. Neither is a
// compile error when deleted and initDistributed cannot be unit tested while it
// opens NATS first, so what is available is a boot refusal, and this is what
// keeps that refusal honest.
var _ = Describe("refusing a deployment with no broadcast carrier", func() {
	It("accepts services that carry one", func() {
		db, dsn := testutil.SetupTestDBWithDSN()
		cfg := &config.ApplicationConfig{}
		cfg.Auth.DatabaseURL = dsn
		bus, err := newBroadcastBus(context.Background(), cfg, db)
		Expect(err).ToNot(HaveOccurred())
		DeferCleanup(bus.Close)

		Expect(requireBroadcastCarrier(&DistributedServices{Bus: bus})).To(Succeed())
	})

	It("refuses services whose carrier was never assigned, and says what it costs", func() {
		err := requireBroadcastCarrier(&DistributedServices{})

		Expect(err).To(HaveOccurred())
		Expect(err.Error()).To(ContainSubstring("published between replicas"))
		Expect(err.Error()).To(ContainSubstring("shutdown"))
	})

	It("refuses a nil deployment rather than dereferencing it", func() {
		Expect(requireBroadcastCarrier(nil)).ToNot(Succeed())
	})
})

var _ = Describe("shutting the distributed services down", func() {
	It("closes the broadcast carrier", func() {
		// A pinned PostgreSQL session and the goroutine parked on it, per
		// replica restart. Nothing else in this process ever closes it, so the
		// line in the shutdown closure is the whole lifecycle.
		db, dsn := testutil.SetupTestDBWithDSN()
		cfg := &config.ApplicationConfig{}
		cfg.Auth.DatabaseURL = dsn
		bus, err := newBroadcastBus(context.Background(), cfg, db)
		Expect(err).ToNot(HaveOccurred())
		Expect(bus.IsConnected()).To(BeTrue())

		(&DistributedServices{Bus: bus}).Shutdown()

		Expect(bus.IsConnected()).To(BeFalse())
	})
})

// The one place the four state.*.delta families are told which carrier they
// travel on.
//
// It was five field reads before this: the fine-tune service, the quantization
// service, the agent-task setter on two startup paths, the per-user services
// manager and the Open Responses store. Every one of them takes a
// messaging.Broadcaster, which the broker client on the same struct satisfied
// too, so a site left holding that field compiled, started, published and was
// delivered onto a carrier only agent workers read, and nothing failed until
// the broker went away. That field and its type are now gone; collapsing the
// choice into one function is what keeps it a fact these specs can hold, rather
// than a property that lasted only as long as there was one carrier.
var _ = Describe("handing the broadcast carrier to its adopters", func() {
	It("returns the carrier the deployment opened", func() {
		db, dsn := testutil.SetupTestDBWithDSN()
		cfg := &config.ApplicationConfig{}
		cfg.Auth.DatabaseURL = dsn
		bus, err := newBroadcastBus(context.Background(), cfg, db)
		Expect(err).ToNot(HaveOccurred())
		DeferCleanup(bus.Close)

		// Identity and not "is a Broadcaster". There is no second carrier on
		// this struct any more: the family that needed one, agent.<name>.cancel,
		// rides the agent worker's own tunnel now. The identity assertion stays
		// because what it pins is that adopters get THIS bus rather than
		// anything else that satisfies the interface.
		ds := &DistributedServices{Bus: bus}

		Expect(ds.Broadcast()).To(BeIdenticalTo(messaging.Broadcaster(bus)))
	})

	It("returns an interface that reads as absent, not a typed nil, when there is no carrier", func() {
		// Every adopter branches on `bus == nil` to mean standalone. A nil
		// *pgbus.Bus placed in an interface is NOT nil, so that branch would be
		// skipped and the first Set would panic on a request rather than at
		// boot.
		//
		// Compared with == and not with BeNil(). Gomega's BeNil reports a nil
		// POINTER inside an interface as nil, so it passes on exactly the value
		// this spec exists to reject; the first draft of this spec did, and the
		// mutation that removed the guard stayed green.
		var ds *DistributedServices
		Expect(ds.Broadcast() == nil).To(BeTrue(), "a nil deployment must yield an interface that is itself nil")
		Expect((&DistributedServices{}).Broadcast() == nil).To(BeTrue(),
			"a deployment with no carrier must yield an interface that is itself nil, not one wrapping a nil *pgbus.Bus")
	})

	It("gives an adopter a carrier-less map rather than one that panics on the first write", func() {
		// The consequence, driven through the component every adopter builds.
		// A typed nil satisfies `!= nil`, so Start subscribes on it and Set
		// publishes on it, and both dereference a nil *pgbus.Bus on a request
		// path rather than at boot.
		m := syncstate.New(syncstate.Config[string, string]{
			Name: "test.jobs",
			Key:  func(v string) string { return v },
			Bus:  (&DistributedServices{}).Broadcast(),
		})
		Expect(m.Start(context.Background())).To(Succeed())
		DeferCleanup(func() { Expect(m.Close()).To(Succeed()) })

		Expect(func() { Expect(m.Set(context.Background(), "v")).To(Succeed()) }).ToNot(Panic())
	})
})

// The registration of every per-node cache a node's departure evicts.
//
// Four subscribers, registered in one function, on a notifier the health
// monitor is then handed. Every one of those is a line that compiles, starts
// and serves when it is missing: a deployment whose departed nodes keep their
// probe entries, staging rows, prefix affinity and per-node operation progress
// does not fail, log or slow down, it just answers with state for a node that
// left, for the life of the process.
//
// Asserted by NAME and not by count. A count says a cache was forgotten; only
// the names say which, and "which" is the entire content of the failure.
var _ = Describe("wiring the per-node caches a departure evicts", func() {
	// bootDistributed brings a real distributed deployment up against a fresh
	// database, which is what makes these assertions about production wiring
	// rather than about a notifier a spec assembled itself.
	bootDistributed := func(arm ...func(*config.ApplicationConfig)) *DistributedServices {
		GinkgoHelper()
		db, dsn := testutil.SetupTestDBWithDSN()
		ctx, cancel := context.WithCancel(context.Background())
		DeferCleanup(cancel)
		cfg := &config.ApplicationConfig{DataPath: GinkgoT().TempDir(), Context: ctx}
		cfg.Auth.Enabled = true
		cfg.Auth.DatabaseURL = dsn
		cfg.Distributed.Enabled = true
		for _, a := range arm {
			a(cfg)
		}
		ds, err := initDistributed(cfg, db, nil, galleryop.NewGalleryService(cfg, nil))
		Expect(err).ToNot(HaveOccurred())
		DeferCleanup(ds.Shutdown)
		return ds
	}

	It("registers every one of them, on the notifier the health monitor fires", func() {
		// Reached through the health monitor and not through a local variable,
		// because registering the four on a DIFFERENT notifier than the one the
		// monitor was built with evicts nothing while every count still reads
		// four.
		ds := bootDistributed()

		Expect(ds.Health.Departures().SubscriberNames()).To(ConsistOf(
			departurePrefixCache,
			departureProbeCache,
			departureStagingTracker,
			departureGalleryNodes,
			departureControlClients,
			departureStagerClients,
		))
	})

	It("registers no prefix-cache eviction when prefix-cache routing is disabled", func() {
		// --distributed-prefix-cache=false stays a TRUE no-op: there is no
		// index to drop from, so nothing is registered rather than a hook
		// registered onto nothing. The other three are unaffected, which is the
		// half that makes this a statement about S1 and not about the feature
		// flag switching the whole mechanism off.
		ds := bootDistributed(func(cfg *config.ApplicationConfig) {
			cfg.Distributed.PrefixCacheDisabled = true
		})

		Expect(ds.Health.Departures().SubscriberNames()).To(ConsistOf(
			departureProbeCache,
			departureStagingTracker,
			departureGalleryNodes,
			departureControlClients,
			departureStagerClients,
		))
	})

	It("refuses a deployment with no router, naming what its departed nodes would keep", func() {
		err := registerDepartureEvictions(nodes.NewDepartureNotifier(), nil, nil, galleryop.NewGalleryService(&config.ApplicationConfig{}, nil), specControlClient(), specFileStager())

		Expect(err).To(HaveOccurred())
		Expect(err.Error()).To(ContainSubstring("probe-freshness"))
	})

	It("refuses a deployment with no gallery service", func() {
		err := registerDepartureEvictions(nodes.NewDepartureNotifier(), nil, nodes.NewSmartRouter(nil, nodes.SmartRouterOptions{}), nil, specControlClient(), specFileStager())

		Expect(err).To(HaveOccurred())
		Expect(err.Error()).To(ContainSubstring("per-node breakdown"))
	})

	It("refuses a deployment with no control client, naming the streams a departed node would keep", func() {
		err := registerDepartureEvictions(nodes.NewDepartureNotifier(), nil, nodes.NewSmartRouter(nil, nodes.SmartRouterOptions{}), galleryop.NewGalleryService(&config.ApplicationConfig{}, nil), nil, specFileStager())

		Expect(err).To(HaveOccurred())
		Expect(err.Error()).To(ContainSubstring("idle streams"))
	})

	It("refuses a deployment with no file stager", func() {
		err := registerDepartureEvictions(nodes.NewDepartureNotifier(), nil, nodes.NewSmartRouter(nil, nodes.SmartRouterOptions{}), galleryop.NewGalleryService(&config.ApplicationConfig{}, nil), specControlClient(), nil)

		Expect(err).To(HaveOccurred())
		Expect(err.Error()).To(ContainSubstring("cached HTTP client"))
	})

	It("refuses a deployment with no notifier at all", func() {
		err := registerDepartureEvictions(nil, nil, nodes.NewSmartRouter(nil, nodes.SmartRouterOptions{}), galleryop.NewGalleryService(&config.ApplicationConfig{}, nil), specControlClient(), specFileStager())

		Expect(err).To(HaveOccurred())
	})
})

// specControlClient and specFileStager build the two per-node client caches a
// registration needs. Neither is dialled: what the refusal specs assert is that
// the wiring refuses a MISSING one, and what the registration specs assert is
// that a subscriber was registered for it.
func specControlClient() *nodes.ControlClient {
	return nodes.NewControlClient(nil, "")
}

func specFileStager() nodes.FileStager {
	return nodes.NewHTTPFileStager(func(string) (string, error) { return "", nil }, "", nil)
}