//go:build integration

package integration_test

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"net"
	"net/http"
	"net/http/httptest"
	"sync/atomic"
	"testing"
	"time"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgxpool"
	"github.com/nats-io/nats.go/jetstream"
	"github.com/testcontainers/testcontainers-go"
	tcpostgres "github.com/testcontainers/testcontainers-go/modules/postgres"
	"github.com/testcontainers/testcontainers-go/wait"
	"google.golang.org/grpc"

	"github.com/alchemistkay/guestguard/internal/api"
	"github.com/alchemistkay/guestguard/internal/auth"
	"github.com/alchemistkay/guestguard/internal/fraud"
	pb "github.com/alchemistkay/guestguard/internal/fraudpb"
	"github.com/alchemistkay/guestguard/internal/natspub"
	"github.com/alchemistkay/guestguard/internal/storage"
)

// TestE2EHappyPath spins up real Postgres + NATS containers and an in-process
// stub fraud gRPC server, then walks both the async (access → fraud.scored
// → access_logs.flagged) and sync (RSVP submit) flows we manually verified
// with `docker compose up`. This is the regression net for that walkthrough.
func TestE2EHappyPath(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping integration test in -short mode")
	}

	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
	t.Cleanup(cancel)

	logger := slog.New(slog.NewTextHandler(io.Discard, nil))

	dsn := startPostgres(t, ctx)
	natsURL := startNATS(t, ctx)

	db, err := storage.NewDB(ctx, dsn)
	must(t, err, "connect db")
	t.Cleanup(db.Close)
	must(t, db.Migrate(ctx), "migrate")

	natsClient, err := natspub.Connect(ctx, natsURL, logger)
	must(t, err, "connect nats")
	t.Cleanup(natsClient.Close)

	stub := startStubFraudGRPC(t)
	fraudClient, err := fraud.Dial(ctx, stub.Addr, 2*time.Second, logger)
	must(t, err, "dial fraud")
	t.Cleanup(func() { _ = fraudClient.Close() })

	accessLogs := storage.NewAccessLogRepo(db)
	sub, err := natspub.NewFraudScoredSubscriber(ctx, natsClient, "test-fraud-scored",
		func(ctx context.Context, evt natspub.FraudScored) error {
			return accessLogs.ApplyScore(ctx, storage.ApplyScoreParams{
				AccessLogID: evt.AccessLogID,
				Score:       evt.Score,
				Reasons:     evt.Reasons,
				Flagged:     evt.Score >= 60,
			})
		}, logger)
	must(t, err, "create fraud subscriber")
	consumeCtx, err := sub.Start(ctx)
	must(t, err, "start fraud subscriber")
	t.Cleanup(consumeCtx.Stop)

	rsvpCounter := subscribeRSVPConfirmed(t, ctx, natsClient)

	apiSrv, err := api.NewServer(api.ServerDeps{
		Logger:               logger,
		DB:                   db,
		AccessPublisher:      natsClient,
		RSVPPublisher:        natsClient,
		FraudScorer:          fraudClient,
		TokenTTL:             24 * time.Hour,
		JWTSecret:            "test-secret-must-be-at-least-32-bytes-long-xx",
		JWTIssuer:            "guestguard-test",
		AccessTokenTTL:       15 * time.Minute,
		RefreshTokenTTL:      24 * time.Hour,
		EmailVerificationTTL: 1 * time.Hour,
		PasswordResetTTL:     1 * time.Hour,
		PublicBaseURL:        "http://localhost",
	})
	must(t, err, "build api server")
	srv := httptest.NewServer(apiSrv.Handler())
	t.Cleanup(srv.Close)

	hostID := insertHost(t, ctx, db.Pool)
	hostToken := issueHostToken(t, hostID)

	t.Run("async access flow flags access_logs", func(t *testing.T) {
		eventID := createEvent(t, srv.URL, hostToken, "Async Test", "async-test")
		guestID := createGuest(t, srv.URL, hostToken, eventID, "Async Guest")
		token := issueToken(t, srv.URL, hostToken, eventID, guestID)

		accessResp := getAccess(t, srv.URL, token)

		stub.SetNext(72, "high", []string{"fingerprint differs from baseline"})

		// Simulate the fraud-engine side of the pipeline: the engine consumes
		// access.attempted from NATS and publishes fraud.scored back. We do
		// the same publish directly so we don't need the Python service in the
		// test.
		mustPublishFraudScored(t, ctx, natsClient, natspub.FraudScored{
			EventID:     eventID,
			GuestID:     guestID,
			TokenID:     accessResp.Token.ID,
			AccessLogID: accessResp.AccessLog,
			Score:       72,
			Risk:        "high",
			Reasons:     []string{"fingerprint differs from baseline"},
			ScoredAt:    time.Now().UTC(),
		})

		waitForFlagged(t, ctx, db.Pool, accessResp.AccessLog, 72, true)
	})

	t.Run("sync rsvp flow records rsvp and marks token used", func(t *testing.T) {
		eventID := createEvent(t, srv.URL, hostToken, "Sync Test", "sync-test")
		guestID := createGuest(t, srv.URL, hostToken, eventID, "Sync Guest")
		token := issueToken(t, srv.URL, hostToken, eventID, guestID)

		stub.SetNext(15, "low", nil)

		rsvpResp := submitRSVP(t, srv.URL, token, map[string]any{
			"response":  "attending",
			"plus_ones": 0,
		})

		if rsvpResp.Blocked {
			t.Fatalf("expected blocked=false, got %+v", rsvpResp)
		}
		if rsvpResp.Decision.Score != 15 || rsvpResp.Decision.Risk != "low" || !rsvpResp.Decision.Used {
			t.Fatalf("unexpected decision: %+v", rsvpResp.Decision)
		}
		if rsvpResp.RSVP == nil || rsvpResp.RSVP.RiskScore == nil || *rsvpResp.RSVP.RiskScore != 15 {
			t.Fatalf("rsvp missing risk_score=15: %+v", rsvpResp.RSVP)
		}

		assertTokenUsed(t, ctx, db.Pool, guestID)
		waitForRSVPConfirmed(t, rsvpCounter, 1)
	})

	t.Run("sync rsvp flow blocks when fraud score is BLOCK", func(t *testing.T) {
		eventID := createEvent(t, srv.URL, hostToken, "Block Test", "block-test")
		guestID := createGuest(t, srv.URL, hostToken, eventID, "Block Guest")
		token := issueToken(t, srv.URL, hostToken, eventID, guestID)

		stub.SetNext(95, "block", []string{"fingerprint differs from baseline", "ip address changed"})

		req, _ := http.NewRequestWithContext(ctx, http.MethodPost,
			srv.URL+"/rsvp/"+token,
			bytes.NewReader([]byte(`{"response":"attending","plus_ones":0}`)))
		req.Header.Set("Content-Type", "application/json")
		resp, err := http.DefaultClient.Do(req)
		must(t, err, "POST /rsvp")
		defer resp.Body.Close()

		if resp.StatusCode != http.StatusForbidden {
			body, _ := io.ReadAll(resp.Body)
			t.Fatalf("expected 403 for BLOCK, got %d: %s", resp.StatusCode, body)
		}

		assertNoRSVP(t, ctx, db.Pool, guestID)
		assertTokenStatus(t, ctx, db.Pool, guestID, "active")
	})
}

// --- container helpers ---

func startPostgres(t *testing.T, ctx context.Context) string {
	t.Helper()
	c, err := tcpostgres.Run(ctx,
		"postgres:16-alpine",
		tcpostgres.WithDatabase("guestguard"),
		tcpostgres.WithUsername("guestguard"),
		tcpostgres.WithPassword("guestguard"),
		testcontainers.WithWaitStrategy(
			wait.ForLog("database system is ready to accept connections").
				WithOccurrence(2).
				WithStartupTimeout(60*time.Second),
		),
	)
	must(t, err, "start postgres container")
	t.Cleanup(func() { _ = c.Terminate(context.Background()) })

	dsn, err := c.ConnectionString(ctx, "sslmode=disable")
	must(t, err, "postgres connection string")
	return dsn
}

func startNATS(t *testing.T, ctx context.Context) string {
	t.Helper()
	req := testcontainers.ContainerRequest{
		Image:        "nats:2.10-alpine",
		ExposedPorts: []string{"4222/tcp"},
		Cmd:          []string{"-js"},
		WaitingFor:   wait.ForLog("Server is ready").WithStartupTimeout(60 * time.Second),
	}
	c, err := testcontainers.GenericContainer(ctx, testcontainers.GenericContainerRequest{
		ContainerRequest: req,
		Started:          true,
	})
	must(t, err, "start nats container")
	t.Cleanup(func() { _ = c.Terminate(context.Background()) })

	host, err := c.Host(ctx)
	must(t, err, "nats host")
	port, err := c.MappedPort(ctx, "4222/tcp")
	must(t, err, "nats port")
	return fmt.Sprintf("nats://%s:%s", host, port.Port())
}

// --- stub fraud gRPC server ---

type stubFraud struct {
	pb.UnimplementedFraudServiceServer
	Addr   string
	server *grpc.Server

	score   atomic.Int32
	risk    atomic.Value // string
	reasons atomic.Value // []string
}

func (s *stubFraud) Score(ctx context.Context, req *pb.ScoreRequest) (*pb.ScoreResponse, error) {
	risk := pb.Risk_RISK_LOW
	switch s.risk.Load().(string) {
	case "low":
		risk = pb.Risk_RISK_LOW
	case "medium":
		risk = pb.Risk_RISK_MEDIUM
	case "high":
		risk = pb.Risk_RISK_HIGH
	case "block":
		risk = pb.Risk_RISK_BLOCK
	}
	var reasons []string
	if r, _ := s.reasons.Load().([]string); r != nil {
		reasons = r
	}
	return &pb.ScoreResponse{
		Score:   s.score.Load(),
		Risk:    risk,
		Reasons: reasons,
	}, nil
}

func (s *stubFraud) SetNext(score int, risk string, reasons []string) {
	s.score.Store(int32(score))
	s.risk.Store(risk)
	s.reasons.Store(reasons)
}

func startStubFraudGRPC(t *testing.T) *stubFraud {
	t.Helper()
	lis, err := net.Listen("tcp", "127.0.0.1:0")
	must(t, err, "listen for stub fraud")

	s := &stubFraud{Addr: lis.Addr().String()}
	s.risk.Store("low")
	s.reasons.Store([]string(nil))

	s.server = grpc.NewServer()
	pb.RegisterFraudServiceServer(s.server, s)

	go func() { _ = s.server.Serve(lis) }()
	t.Cleanup(s.server.Stop)
	return s
}

// --- HTTP helpers ---

func createEvent(t *testing.T, base, accessToken string, name, slug string) uuid.UUID {
	t.Helper()
	body := map[string]any{
		"name":       name,
		"slug":       slug,
		"event_date": time.Now().Add(30 * 24 * time.Hour).UTC().Format(time.RFC3339),
		"venue":      "Integration Hall",
	}
	var out struct{ ID uuid.UUID `json:"id"` }
	postJSONAuthed(t, base+"/events", accessToken, body, http.StatusCreated, &out)
	return out.ID
}

func createGuest(t *testing.T, base, accessToken string, eventID uuid.UUID, name string) uuid.UUID {
	t.Helper()
	var out struct{ ID uuid.UUID `json:"id"` }
	postJSONAuthed(t, fmt.Sprintf("%s/events/%s/guests", base, eventID), accessToken,
		map[string]any{"name": name}, http.StatusCreated, &out)
	return out.ID
}

func issueToken(t *testing.T, base, accessToken string, eventID, guestID uuid.UUID) string {
	t.Helper()
	var out struct{ Token string `json:"token"` }
	postJSONAuthed(t, fmt.Sprintf("%s/events/%s/guests/%s/tokens", base, eventID, guestID),
		accessToken, nil, http.StatusCreated, &out)
	return out.Token
}

type accessResponse struct {
	Token     *struct{ ID uuid.UUID `json:"id"` } `json:"token"`
	AccessLog uuid.UUID                            `json:"access_log_id"`
}

func getAccess(t *testing.T, base, token string) accessResponse {
	t.Helper()
	resp, err := http.Get(base + "/access/" + token)
	must(t, err, "GET /access")
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		t.Fatalf("GET /access status=%d body=%s", resp.StatusCode, body)
	}
	var out accessResponse
	must(t, json.NewDecoder(resp.Body).Decode(&out), "decode access")
	return out
}

type submitRSVPResponse struct {
	RSVP *struct {
		ID        uuid.UUID `json:"id"`
		RiskScore *int      `json:"risk_score"`
	} `json:"rsvp"`
	Decision fraud.Decision `json:"fraud"`
	Blocked  bool           `json:"blocked"`
}

func submitRSVP(t *testing.T, base, token string, body map[string]any) submitRSVPResponse {
	t.Helper()
	var out submitRSVPResponse
	postJSON(t, base+"/rsvp/"+token, body, http.StatusCreated, &out)
	return out
}

func postJSON(t *testing.T, url string, body any, wantStatus int, out any) {
	t.Helper()
	postJSONAuthed(t, url, "", body, wantStatus, out)
}

func postJSONAuthed(t *testing.T, url, bearer string, body any, wantStatus int, out any) {
	t.Helper()
	var rdr io.Reader
	if body != nil {
		b, _ := json.Marshal(body)
		rdr = bytes.NewReader(b)
	}
	req, err := http.NewRequest(http.MethodPost, url, rdr)
	must(t, err, "build request "+url)
	if rdr != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	if bearer != "" {
		req.Header.Set("Authorization", "Bearer "+bearer)
	}
	resp, err := http.DefaultClient.Do(req)
	must(t, err, "do request "+url)
	defer resp.Body.Close()

	if resp.StatusCode != wantStatus {
		body, _ := io.ReadAll(resp.Body)
		t.Fatalf("%s status=%d want=%d body=%s", url, resp.StatusCode, wantStatus, body)
	}
	if out != nil {
		must(t, json.NewDecoder(resp.Body).Decode(out), "decode response from "+url)
	}
}

// --- DB helpers ---

func insertHost(t *testing.T, ctx context.Context, pool *pgxpool.Pool) uuid.UUID {
	t.Helper()
	var id uuid.UUID
	err := pool.QueryRow(ctx,
		`INSERT INTO users (email, name, email_verified, email_verified_at)
		 VALUES ($1, $2, TRUE, now()) RETURNING id`,
		fmt.Sprintf("test-%d@guestguard.test", time.Now().UnixNano()),
		"Integration Host",
	).Scan(&id)
	must(t, err, "insert host")
	// Default test hosts to the Business tier so existing tests that
	// create multiple events for one host aren't tripped up by the
	// free-tier limit (1 event / month). Tests that specifically exercise
	// the free-tier path skip this helper.
	grantBusinessTier(t, ctx, pool, id)
	return id
}

// grantBusinessTier inserts an active Business subscription row for the
// given user so tier-enforcement middleware grants unlimited events.
func grantBusinessTier(t *testing.T, ctx context.Context, pool *pgxpool.Pool, userID uuid.UUID) {
	t.Helper()
	_, err := pool.Exec(ctx, `
        INSERT INTO subscriptions (user_id, stripe_customer_id, tier, status)
        VALUES ($1::uuid, 'cus_test_' || replace($1::uuid::text, '-', ''), 'business', 'active')
    `, userID.String())
	must(t, err, "grant business tier")
}

// issueHostToken mints a Bearer access token for an existing host using the
// same JWT secret/issuer the test API server was constructed with. This
// lets integration tests skip the signup/verify/login dance.
func issueHostToken(t *testing.T, hostID uuid.UUID) string {
	t.Helper()
	signer, err := auth.NewJWTSigner(testJWTSecret, 5*time.Minute, testJWTIssuer)
	must(t, err, "build jwt signer")
	tok, _, err := signer.Issue(hostID, time.Now())
	must(t, err, "issue jwt")
	return tok
}

const (
	testJWTSecret = "test-secret-must-be-at-least-32-bytes-long-xx"
	testJWTIssuer = "guestguard-test"
)

func waitForFlagged(t *testing.T, ctx context.Context, pool *pgxpool.Pool, accessLogID uuid.UUID, wantScore int, wantFlagged bool) {
	t.Helper()
	deadline := time.Now().Add(10 * time.Second)
	for time.Now().Before(deadline) {
		var (
			score   *int
			flagged bool
		)
		err := pool.QueryRow(ctx,
			`SELECT risk_score, flagged FROM access_logs WHERE id = $1`,
			accessLogID,
		).Scan(&score, &flagged)
		if err == nil && score != nil && *score == wantScore && flagged == wantFlagged {
			return
		}
		time.Sleep(100 * time.Millisecond)
	}
	t.Fatalf("access_log %s did not reach score=%d flagged=%v within 10s", accessLogID, wantScore, wantFlagged)
}

func assertTokenUsed(t *testing.T, ctx context.Context, pool *pgxpool.Pool, guestID uuid.UUID) {
	t.Helper()
	var status string
	err := pool.QueryRow(ctx,
		`SELECT status FROM tokens WHERE guest_id = $1`, guestID,
	).Scan(&status)
	must(t, err, "load token status")
	if status != "used" {
		t.Fatalf("expected token status=used for guest %s, got %s", guestID, status)
	}
}

func assertTokenStatus(t *testing.T, ctx context.Context, pool *pgxpool.Pool, guestID uuid.UUID, want string) {
	t.Helper()
	var status string
	err := pool.QueryRow(ctx,
		`SELECT status FROM tokens WHERE guest_id = $1`, guestID,
	).Scan(&status)
	must(t, err, "load token status")
	if status != want {
		t.Fatalf("expected token status=%s for guest %s, got %s", want, guestID, status)
	}
}

func assertNoRSVP(t *testing.T, ctx context.Context, pool *pgxpool.Pool, guestID uuid.UUID) {
	t.Helper()
	var n int
	err := pool.QueryRow(ctx,
		`SELECT count(*) FROM rsvps WHERE guest_id = $1`, guestID,
	).Scan(&n)
	must(t, err, "count rsvps")
	if n != 0 {
		t.Fatalf("expected 0 rsvps for blocked guest %s, got %d", guestID, n)
	}
}

// --- NATS helpers ---

func mustPublishFraudScored(t *testing.T, ctx context.Context, c *natspub.Client, evt natspub.FraudScored) {
	t.Helper()
	body, _ := json.Marshal(evt)
	_, err := c.JetStream().Publish(ctx, natspub.SubjectFraudScored, body)
	must(t, err, "publish fraud.scored")
}

func subscribeRSVPConfirmed(t *testing.T, ctx context.Context, c *natspub.Client) *atomic.Int32 {
	t.Helper()
	cons, err := c.JetStream().CreateOrUpdateConsumer(ctx, natspub.StreamName, jetstream.ConsumerConfig{
		Durable:       "test-rsvp-confirmed",
		Name:          "test-rsvp-confirmed",
		FilterSubject: natspub.SubjectRSVPConfirmed,
		AckPolicy:     jetstream.AckExplicitPolicy,
		DeliverPolicy: jetstream.DeliverAllPolicy,
	})
	must(t, err, "create rsvp consumer")

	var counter atomic.Int32
	cc, err := cons.Consume(func(msg jetstream.Msg) {
		counter.Add(1)
		_ = msg.Ack()
	})
	must(t, err, "consume rsvp.confirmed")
	t.Cleanup(cc.Stop)
	return &counter
}

func waitForRSVPConfirmed(t *testing.T, counter *atomic.Int32, want int32) {
	t.Helper()
	deadline := time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		if counter.Load() >= want {
			return
		}
		time.Sleep(50 * time.Millisecond)
	}
	t.Fatalf("expected %d rsvp.confirmed events, saw %d", want, counter.Load())
}

// --- misc ---

func must(t *testing.T, err error, op string) {
	t.Helper()
	if err != nil {
		t.Fatalf("%s: %v", op, err)
	}
}