package authsession

import (
	"context"
	"encoding/json"
	"net/http"
	"sync"
	"testing"
	"time"

	"galaxy/authsession/internal/domain/common"
	"galaxy/authsession/internal/domain/devicesession"
	"galaxy/authsession/internal/ports"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// gatedCreateSessionStore blocks the first target successful Create calls
// after they persist the session, which lets concurrency tests force overlap
// between confirm and competing revoke/block flows.
type gatedCreateSessionStore struct {
	delegate ports.SessionStore
	target   int

	arrived chan common.DeviceSessionID
	release chan struct{}

	mu          sync.Mutex
	seenCreates int
	releaseOnce sync.Once
}

// newGatedCreateSessionStore wraps delegate with deterministic post-create
// gating for the first target successful session creations.
func newGatedCreateSessionStore(delegate ports.SessionStore, target int) *gatedCreateSessionStore {
	return &gatedCreateSessionStore{
		delegate: delegate,
		target:   target,
		arrived:  make(chan common.DeviceSessionID, target),
		release:  make(chan struct{}),
	}
}

// Create delegates persistence first and then blocks the first configured
// number of successful creations until Release is called.
func (s *gatedCreateSessionStore) Create(ctx context.Context, record devicesession.Session) error {
	if err := s.delegate.Create(ctx, record); err != nil {
		return err
	}

	s.mu.Lock()
	shouldGate := s.seenCreates < s.target
	if shouldGate {
		s.seenCreates++
	}
	s.mu.Unlock()

	if !shouldGate {
		return nil
	}

	s.arrived <- record.ID

	select {
	case <-s.release:
		return nil
	case <-ctx.Done():
		return ctx.Err()
	}
}

// WaitForCreates waits for count gated successful Create calls and returns the
// corresponding device session identifiers in arrival order.
func (s *gatedCreateSessionStore) WaitForCreates(t *testing.T, count int) []common.DeviceSessionID {
	t.Helper()

	ids := make([]common.DeviceSessionID, 0, count)
	timeout := time.After(5 * time.Second)

	for len(ids) < count {
		select {
		case id := <-s.arrived:
			ids = append(ids, id)
		case <-timeout:
			require.FailNowf(t, "test failed", "timed out waiting for %d gated session creations", count)
		}
	}

	return ids
}

// Release unblocks every gated Create call.
func (s *gatedCreateSessionStore) Release() {
	s.releaseOnce.Do(func() {
		close(s.release)
	})
}

// Get delegates to the wrapped session store.
func (s *gatedCreateSessionStore) Get(ctx context.Context, deviceSessionID common.DeviceSessionID) (devicesession.Session, error) {
	return s.delegate.Get(ctx, deviceSessionID)
}

// ListByUserID delegates to the wrapped session store.
func (s *gatedCreateSessionStore) ListByUserID(ctx context.Context, userID common.UserID) ([]devicesession.Session, error) {
	return s.delegate.ListByUserID(ctx, userID)
}

// CountActiveByUserID delegates to the wrapped session store.
func (s *gatedCreateSessionStore) CountActiveByUserID(ctx context.Context, userID common.UserID) (int, error) {
	return s.delegate.CountActiveByUserID(ctx, userID)
}

// Revoke delegates to the wrapped session store.
func (s *gatedCreateSessionStore) Revoke(ctx context.Context, input ports.RevokeSessionInput) (ports.RevokeSessionResult, error) {
	return s.delegate.Revoke(ctx, input)
}

// RevokeAllByUserID delegates to the wrapped session store.
func (s *gatedCreateSessionStore) RevokeAllByUserID(ctx context.Context, input ports.RevokeUserSessionsInput) (ports.RevokeUserSessionsResult, error) {
	return s.delegate.RevokeAllByUserID(ctx, input)
}

var _ ports.SessionStore = (*gatedCreateSessionStore)(nil)

func TestProductionHardeningConcurrentIdenticalConfirmsConvergeToOneActiveSession(t *testing.T) {
	t.Parallel()

	env := newHardeningEnvironment(t)
	var gate *gatedCreateSessionStore
	app := newHardeningApp(t, env, hardeningAppOptions{
		SeedExistingUser: true,
		WrapSessionStore: func(delegate ports.SessionStore) ports.SessionStore {
			gate = newGatedCreateSessionStore(delegate, 2)
			return gate
		},
	})

	challengeID, code := app.SendChallenge(t, gatewayCompatibilityEmail)
	requestBody := gatewayCompatibilityConfirmRequest(challengeID, code, gatewayCompatibilityClientPublicKey)

	responses := make([]gatewayCompatibilityHTTPResponse, 2)
	start := make(chan struct{})

	var requests sync.WaitGroup
	requests.Add(2)
	for index := range responses {
		go func(index int) {
			defer requests.Done()
			<-start
			responses[index] = gatewayCompatibilityPostJSONValue(t, app.publicBaseURL+"/api/v1/public/auth/confirm-email-code", requestBody)
		}(index)
	}

	close(start)
	createdIDs := gate.WaitForCreates(t, 2)
	require.Len(t, createdIDs, 2)
	assert.NotEqual(t, createdIDs[0], createdIDs[1])

	gate.Release()
	requests.Wait()

	var deviceSessionIDs []string
	for _, response := range responses {
		assert.Equal(t, http.StatusOK, response.StatusCode)

		var body struct {
			DeviceSessionID string `json:"device_session_id"`
		}
		require.NoError(t, json.Unmarshal([]byte(response.Body), &body))
		deviceSessionIDs = append(deviceSessionIDs, body.DeviceSessionID)
	}
	require.Len(t, deviceSessionIDs, 2)
	assert.Equal(t, deviceSessionIDs[0], deviceSessionIDs[1])

	records, err := app.sessionStore.ListByUserID(context.Background(), common.UserID("user-1"))
	require.NoError(t, err)
	require.Len(t, records, 2)

	activeCount := 0
	revokedCount := 0
	for _, record := range records {
		switch record.Status {
		case devicesession.StatusActive:
			activeCount++
			assert.Equal(t, common.DeviceSessionID(deviceSessionIDs[0]), record.ID)
		case devicesession.StatusRevoked:
			revokedCount++
			require.NotNil(t, record.Revocation)
			assert.Equal(t, common.RevokeReasonCode("confirm_race_repair"), record.Revocation.ReasonCode)
		default:
			require.Failf(t, "test failed", "unexpected final session status %q", record.Status)
		}
	}
	assert.Equal(t, 1, activeCount)
	assert.Equal(t, 1, revokedCount)

	cacheRecord := env.MustReadGatewayCacheRecord(t, deviceSessionIDs[0])
	assert.Equal(t, "active", cacheRecord.Status)
}

func TestProductionHardeningConcurrentConfirmAndRevokeAllKeepProjectionConsistent(t *testing.T) {
	t.Parallel()

	env := newHardeningEnvironment(t)
	var gate *gatedCreateSessionStore
	app := newHardeningApp(t, env, hardeningAppOptions{
		SeedExistingUser: true,
		WrapSessionStore: func(delegate ports.SessionStore) ports.SessionStore {
			gate = newGatedCreateSessionStore(delegate, 1)
			return gate
		},
	})

	challengeID, code := app.SendChallenge(t, gatewayCompatibilityEmail)
	confirmResponseCh := make(chan gatewayCompatibilityHTTPResponse, 1)
	go func() {
		confirmResponseCh <- gatewayCompatibilityPostJSONValue(
			t,
			app.publicBaseURL+"/api/v1/public/auth/confirm-email-code",
			gatewayCompatibilityConfirmRequest(challengeID, code, gatewayCompatibilityClientPublicKey),
		)
	}()

	createdIDs := gate.WaitForCreates(t, 1)
	sessionID := createdIDs[0].String()

	revokeAllResponse := gatewayCompatibilityPostJSON(
		t,
		app.internalBaseURL+"/api/v1/internal/users/user-1/sessions/revoke-all",
		`{"reason_code":"logout_all","actor":{"type":"system"}}`,
	)
	assert.Equal(t, http.StatusOK, revokeAllResponse.StatusCode)
	assert.JSONEq(t, `{"outcome":"revoked","user_id":"user-1","affected_session_count":1,"affected_device_session_ids":["`+sessionID+`"]}`, revokeAllResponse.Body)

	gate.Release()
	confirmResponse := <-confirmResponseCh
	assert.Equal(t, http.StatusOK, confirmResponse.StatusCode)

	var confirmBody struct {
		DeviceSessionID string `json:"device_session_id"`
	}
	require.NoError(t, json.Unmarshal([]byte(confirmResponse.Body), &confirmBody))
	assert.Equal(t, sessionID, confirmBody.DeviceSessionID)

	records, err := app.sessionStore.ListByUserID(context.Background(), common.UserID("user-1"))
	require.NoError(t, err)
	require.Len(t, records, 1)
	assert.Equal(t, devicesession.StatusRevoked, records[0].Status)
	require.NotNil(t, records[0].Revocation)
	assert.Equal(t, devicesession.RevokeReasonLogoutAll, records[0].Revocation.ReasonCode)

	cacheRecord := env.MustReadGatewayCacheRecord(t, sessionID)
	assert.Equal(t, "revoked", cacheRecord.Status)
	require.NotNil(t, cacheRecord.RevokedAtMS)
}

func TestProductionHardeningConcurrentBlockUserAndConfirmDoNotLeakActiveSession(t *testing.T) {
	t.Parallel()

	env := newHardeningEnvironment(t)
	var gate *gatedCreateSessionStore
	app := newHardeningApp(t, env, hardeningAppOptions{
		SeedExistingUser: true,
		WrapSessionStore: func(delegate ports.SessionStore) ports.SessionStore {
			gate = newGatedCreateSessionStore(delegate, 1)
			return gate
		},
	})

	challengeID, code := app.SendChallenge(t, gatewayCompatibilityEmail)
	initialAttempts := app.mailSender.RecordedAttempts()
	require.Len(t, initialAttempts, 1)

	confirmResponseCh := make(chan gatewayCompatibilityHTTPResponse, 1)
	go func() {
		confirmResponseCh <- gatewayCompatibilityPostJSONValue(
			t,
			app.publicBaseURL+"/api/v1/public/auth/confirm-email-code",
			gatewayCompatibilityConfirmRequest(challengeID, code, gatewayCompatibilityClientPublicKey),
		)
	}()

	createdIDs := gate.WaitForCreates(t, 1)
	sessionID := createdIDs[0].String()

	blockResponse := gatewayCompatibilityPostJSON(
		t,
		app.internalBaseURL+"/api/v1/internal/user-blocks",
		`{"email":"pilot@example.com","reason_code":"policy_blocked","actor":{"type":"admin"}}`,
	)
	assert.Equal(t, http.StatusOK, blockResponse.StatusCode)
	assert.JSONEq(t, `{"outcome":"blocked","subject_kind":"email","subject_value":"pilot@example.com","affected_session_count":1,"affected_device_session_ids":["`+sessionID+`"]}`, blockResponse.Body)

	gate.Release()
	confirmResponse := <-confirmResponseCh
	assert.Contains(t, []int{http.StatusOK, http.StatusForbidden}, confirmResponse.StatusCode)

	records, err := app.sessionStore.ListByUserID(context.Background(), common.UserID("user-1"))
	require.NoError(t, err)
	require.Len(t, records, 1)
	assert.Equal(t, devicesession.StatusRevoked, records[0].Status)
	require.NotNil(t, records[0].Revocation)
	assert.Equal(t, devicesession.RevokeReasonUserBlocked, records[0].Revocation.ReasonCode)

	cacheRecord := env.MustReadGatewayCacheRecord(t, sessionID)
	assert.Equal(t, "revoked", cacheRecord.Status)
	require.NotNil(t, cacheRecord.RevokedAtMS)

	followupSend := gatewayCompatibilityPostJSONValue(t, app.publicBaseURL+"/api/v1/public/auth/send-email-code", map[string]string{
		"email": gatewayCompatibilityEmail,
	})
	assert.Equal(t, http.StatusOK, followupSend.StatusCode)

	var sendBody struct {
		ChallengeID string `json:"challenge_id"`
	}
	require.NoError(t, json.Unmarshal([]byte(followupSend.Body), &sendBody))
	assert.NotEmpty(t, sendBody.ChallengeID)
	assert.Len(t, app.mailSender.RecordedAttempts(), 1)

	followupConfirm := gatewayCompatibilityPostJSONValue(
		t,
		app.publicBaseURL+"/api/v1/public/auth/confirm-email-code",
		gatewayCompatibilityConfirmRequest(sendBody.ChallengeID, gatewayCompatibilityCode, gatewayCompatibilityClientPublicKey),
	)
	assert.Equal(t, http.StatusForbidden, followupConfirm.StatusCode)
	assert.JSONEq(t, `{"error":{"code":"blocked_by_policy","message":"authentication is blocked by policy"}}`, followupConfirm.Body)
}