// Package suite is the FLUID conformance harness.
//
// It asserts the seven minimal-conformance requirements of
// FluidAPIStandards.md section 36 and the mechanically checkable subset of the
// sixteen architectural invariants in ArchitectureBlueprint.md section 55.
//
// Everything here runs with no external services and no human steps. A
// conformance claim that needed someone to run through it by hand would be a
// claim nobody re-checks after the first time.
package suite

import (
	"context"
	"crypto/ed25519"
	"fmt"
	"net/http"
	"net/http/httptest"
	"path/filepath"
	"testing"
	"time"

	_ "modernc.org/sqlite"

	echo "github.com/tegwick/fluid-core/examples/echo-interface"
	"github.com/tegwick/fluid-core/internal/contract"
	"github.com/tegwick/fluid-core/internal/evidence"
	"github.com/tegwick/fluid-core/internal/intent"
	"github.com/tegwick/fluid-core/internal/observation"
	"github.com/tegwick/fluid-core/internal/policy"
	"github.com/tegwick/fluid-core/internal/publish"
	"github.com/tegwick/fluid-core/internal/runtime"
	"github.com/tegwick/fluid-core/internal/science"
	"github.com/tegwick/fluid-core/internal/signing"
	"github.com/tegwick/fluid-core/internal/validate"
)

// Interface is the fixture's interface identifier.
const Interface contract.InterfaceID = "echo-interface"

// IntentDocument is the fixture's governing intent.
const IntentDocument = `# Interface Evolution Intent — echo-interface

**Current operational authority mode:**
FLUID-4

## Mission
Serve entries to consumers, and learn from how they ask for them.
`

// Operator is the fixture's human actor.
var Operator = contract.Actor{Type: contract.ActorTypeHuman, ID: "conformance"}

// Harness is a fully wired FLUID deployment over the echo fixture.
type Harness struct {
	T *testing.T

	Store     *evidence.SQLStore
	Intents   *intent.Store
	Registry  *runtime.Registry
	Gateway   *runtime.Gateway
	Emitter   *runtime.Emitter
	Ingest    *observation.Ingest
	Pipeline  *publish.Pipeline
	Validator *validate.OpenAPIValidator
	Signer    *signing.Signer
	PublicKey ed25519.PublicKey

	Hypotheses  *science.HypothesisStore
	Experiments *science.ExperimentController

	adapters map[contract.RevisionID]*httptest.Server
}

// New builds a harness with both fixture revisions published and R-1 stable.
func New(t *testing.T) *Harness {
	t.Helper()
	ctx := context.Background()

	store, err := evidence.OpenSQLite(ctx, filepath.Join(t.TempDir(), "conformance.db"))
	if err != nil {
		t.Fatalf("open evidence store: %v", err)
	}
	t.Cleanup(func() { _ = store.Close() })

	intents := intent.New(store, Interface)
	if _, err := intents.Put(ctx, "IEI-1", IntentDocument); err != nil {
		t.Fatalf("record intent: %v", err)
	}
	if err := intents.SetActive(ctx, "IEI-1"); err != nil {
		t.Fatalf("activate intent: %v", err)
	}

	signer, pub, err := signing.GenerateKey("conformance-key")
	if err != nil {
		t.Fatal(err)
	}

	limits := policy.DefaultLimits()
	// The fixture's intent grants FLUID-4, and the loop under test promotes a
	// contract adaptation, so the fixture permits that class explicitly.
	limits.AllowedAdaptationClasses = append(limits.AllowedAdaptationClasses,
		contract.AdaptationClassContract)
	limits.RequiredMode = intent.ModeExperimental
	gate := policy.NewGate(limits)

	pipeline, err := publish.New(publish.Options{
		Gate: gate, Signer: signer, Store: store, Intents: intents,
	})
	if err != nil {
		t.Fatal(err)
	}

	salt := []byte("conformance-salt-of-sufficient-length")
	ingest, err := observation.NewIngest(store, Interface, observation.DefaultRedactionPolicy(salt))
	if err != nil {
		t.Fatal(err)
	}

	h := &Harness{
		T: t, Store: store, Intents: intents, Pipeline: pipeline,
		Validator: validate.NewOpenAPIValidator(), Signer: signer, PublicKey: pub,
		Ingest:   ingest,
		adapters: map[contract.RevisionID]*httptest.Server{},
	}

	// A verifying registry: the router must accept only signed descriptors.
	h.Registry = runtime.NewVerifiedRegistry(Interface,
		signing.NewVerifier(map[string]ed25519.PublicKey{"conformance-key": pub}))

	h.adapters["R-1"] = httptest.NewServer(echo.NewR1())
	h.adapters["R-2"] = httptest.NewServer(echo.NewR2())
	t.Cleanup(func() {
		for _, s := range h.adapters {
			s.Close()
		}
	})

	h.Emitter = runtime.NewEmitter(ingest, runtime.EmitterOptions{Buffer: 8192, Workers: 2})

	gw, err := runtime.NewGateway(runtime.GatewayOptions{
		Interface: Interface,
		Registry:  h.Registry,
		Resolver:  runtime.NewResolver(h.Registry, true),
		Connector: runtime.NewConnector(),
		Emitter:   h.Emitter,
		Cohorts:   observation.NewCohortEngine("agents", observation.DefaultRedactionPolicy(salt)),
		Response:  runtime.ResponsePolicy{FeedbackPath: "/v1/feedback"},
		Validator: h.Validator,
	})
	if err != nil {
		t.Fatal(err)
	}
	h.Gateway = gw

	h.Hypotheses = science.NewHypothesisStore(store, Interface)
	h.Experiments = science.NewExperimentController(store, h.Hypotheses, Interface)

	h.PublishRevision("R-1", "examples/echo-interface/r1.openapi.yaml", nil)
	h.PublishRevision("R-2", "examples/echo-interface/r2.openapi.yaml",
		[]contract.AdaptationClass{contract.AdaptationClassContract})
	h.InstallPolicy(1, "R-1", nil)

	return h
}

// PublishRevision takes a revision through the full pipeline and registers it.
func (h *Harness) PublishRevision(id contract.RevisionID, contractPath string, classes []contract.AdaptationClass) contract.Revision {
	h.T.Helper()
	ctx := context.Background()

	raw := readRepoFile(h.T, contractPath)
	digest := signing.Digest(raw)

	if err := h.Validator.Register(digest, raw); err != nil {
		h.T.Fatalf("register contract for %s: %v", id, err)
	}

	pc := contract.RevisionPolicyPolicyCheckPassed
	descriptor := contract.Revision{
		SchemaVersion: "0.1",
		ID:            id,
		Interface:     Interface,
		State:         contract.RevisionStateStable,
		Contract: contract.RevisionContract{
			Type:   contract.RevisionContractTypeOpenapi,
			Digest: digest,
			Source: contractPath,
		},
		Runtime: contract.RevisionRuntime{Upstream: h.adapters[id].URL},
		Intent:  contract.RevisionIntent{Version: "IEI-1"},
		Policy: contract.RevisionPolicy{
			Compatibility: contract.RevisionPolicyCompatibilityAdditive,
			SecurityCheck: contract.RevisionPolicySecurityCheckPassed,
			PolicyCheck:   &pc,
		},
	}

	if classes == nil {
		classes = []contract.AdaptationClass{contract.AdaptationClassPresentation}
	}

	verified, report, err := h.Pipeline.Run(ctx, publish.NewCandidate(descriptor, Operator),
		publish.PromotionRequest{
			AdaptationClasses:     classes,
			ComplexityDelta:       0.2,
			RequestedTrafficShare: 0.2,
			Approved:              true,
			ApprovedBy:            &Operator,
		})
	if err != nil {
		h.T.Fatalf("publish %s: %v (%+v)", id, err, report.Stages)
	}
	if err := h.Pipeline.Publish(ctx, verified); err != nil {
		h.T.Fatalf("record %s: %v", id, err)
	}
	if err := h.Registry.PutRevision(verified.Descriptor()); err != nil {
		h.T.Fatalf("register %s: %v", id, err)
	}
	return verified.Descriptor()
}

// InstallPolicy loads a routing policy into the registry.
func (h *Harness) InstallPolicy(generation int64, defaultRevision contract.RevisionID, rules []contract.RoutingPolicyRulesItem) {
	h.T.Helper()
	if rules == nil {
		rules = []contract.RoutingPolicyRulesItem{}
	}
	if err := h.Registry.PutPolicy(contract.RoutingPolicy{
		SchemaVersion:   "0.1",
		Interface:       Interface,
		Generation:      generation,
		DefaultRevision: defaultRevision,
		Rules:           rules,
	}); err != nil {
		h.T.Fatalf("install policy generation %d: %v", generation, err)
	}
}

// Call issues a request through the gateway as a named consumer.
func (h *Harness) Call(consumer, method, target string) *httptest.ResponseRecorder {
	h.T.Helper()
	req := httptest.NewRequest(method, target, nil)
	req.Header.Set("X-FLUID-Consumer", consumer)
	rec := httptest.NewRecorder()
	h.Gateway.ServeHTTP(rec, req)
	return rec
}

// CallPinned issues a request pinned to a specific revision.
func (h *Harness) CallPinned(consumer string, rev contract.RevisionID, method, target string) *httptest.ResponseRecorder {
	h.T.Helper()
	req := httptest.NewRequest(method, target, nil)
	req.Header.Set("X-FLUID-Consumer", consumer)
	req.Header.Set("X-FLUID-Revision", string(rev))
	rec := httptest.NewRecorder()
	h.Gateway.ServeHTTP(rec, req)
	return rec
}

// Drain flushes buffered telemetry so assertions see every event.
//
// It flushes rather than closes: the harness keeps serving after a drain, and
// closing here would mean every later request emitted into a dead emitter.
func (h *Harness) Drain() {
	if !h.Emitter.Flush(5 * time.Second) {
		h.T.Fatal("telemetry did not reach the store within 5s")
	}
}

// Telemetry returns everything recorded for the interface.
func (h *Harness) Telemetry() []contract.FluidTelemetry {
	h.T.Helper()
	rows, err := h.Store.Telemetry(context.Background(),
		evidence.TelemetryFilter{InterfaceID: Interface})
	if err != nil {
		h.T.Fatal(err)
	}
	return rows
}

// Events returns audit events for an entity.
func (h *Harness) Events(entityID string) []contract.FluidEvent {
	h.T.Helper()
	events, err := h.Store.Events(context.Background(), evidence.EventFilter{EntityID: entityID})
	if err != nil {
		h.T.Fatal(err)
	}
	return events
}

// AdapterURL returns a fixture adapter's address.
func (h *Harness) AdapterURL(rev contract.RevisionID) string {
	return h.adapters[rev].URL
}

// StopAdapter kills a fixture adapter, for failure-containment tests.
func (h *Harness) StopAdapter(rev contract.RevisionID) {
	h.adapters[rev].Close()
}

// mustStatus fails unless the response carries the expected status.
func mustStatus(t *testing.T, rec *httptest.ResponseRecorder, want int, context string) {
	t.Helper()
	if rec.Code != want {
		t.Fatalf("%s: status %d, want %d; body %s", context, rec.Code, want, rec.Body.String())
	}
}

var _ = fmt.Sprintf
var _ = http.MethodGet