package api

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"github.com/rcourtman/pulse-go-rewrite/internal/config"
	"github.com/rcourtman/pulse-go-rewrite/internal/models"
	"github.com/rcourtman/pulse-go-rewrite/internal/updates"
)

// MockUpdateManager implements UpdateManager interface for testing
type MockUpdateManager struct {
	CheckForUpdatesFunc    func(ctx context.Context, channel string) (*updates.UpdateInfo, error)
	ApplyUpdateFunc        func(ctx context.Context, req updates.ApplyUpdateRequest) error
	GetStatusFunc          func() updates.UpdateStatus
	GetSSECachedStatusFunc func() (updates.UpdateStatus, time.Time)
	AddSSEClientFunc       func(w http.ResponseWriter, clientID string) *updates.SSEClient
	RemoveSSEClientFunc    func(clientID string)
}

func (m *MockUpdateManager) CheckForUpdatesWithChannel(ctx context.Context, channel string) (*updates.UpdateInfo, error) {
	if m.CheckForUpdatesFunc != nil {
		return m.CheckForUpdatesFunc(ctx, channel)
	}
	return nil, nil
}

func (m *MockUpdateManager) ApplyUpdate(ctx context.Context, req updates.ApplyUpdateRequest) error {
	if m.ApplyUpdateFunc != nil {
		return m.ApplyUpdateFunc(ctx, req)
	}
	return nil
}

func (m *MockUpdateManager) GetStatus() updates.UpdateStatus {
	if m.GetStatusFunc != nil {
		return m.GetStatusFunc()
	}
	return updates.UpdateStatus{}
}

func (m *MockUpdateManager) GetSSECachedStatus() (updates.UpdateStatus, time.Time) {
	if m.GetSSECachedStatusFunc != nil {
		return m.GetSSECachedStatusFunc()
	}
	return updates.UpdateStatus{}, time.Time{}
}

func (m *MockUpdateManager) AddSSEClient(w http.ResponseWriter, clientID string) *updates.SSEClient {
	if m.AddSSEClientFunc != nil {
		return m.AddSSEClientFunc(w, clientID)
	}
	return nil
}

func (m *MockUpdateManager) RemoveSSEClient(clientID string) {
	if m.RemoveSSEClientFunc != nil {
		m.RemoveSSEClientFunc(clientID)
	}
}

func TestHandleCheckUpdates_Success(t *testing.T) {
	mockManager := &MockUpdateManager{
		CheckForUpdatesFunc: func(ctx context.Context, channel string) (*updates.UpdateInfo, error) {
			return &updates.UpdateInfo{
				Available:      true,
				LatestVersion:  "v1.2.3",
				CurrentVersion: "v1.0.0",
			}, nil
		},
	}

	h := NewUpdateHandlers(mockManager, nil)
	w := httptest.NewRecorder()
	r := httptest.NewRequest("GET", "/updates/check", nil)

	h.HandleCheckUpdates(w, r)

	if w.Code != http.StatusOK {
		t.Errorf("Expected status 200, got %d", w.Code)
	}

	var info updates.UpdateInfo
	_ = json.NewDecoder(w.Body).Decode(&info)
	if !info.Available || info.LatestVersion != "v1.2.3" {
		t.Errorf("Unexpected response: %+v", info)
	}
}

func TestHandleCheckUpdates_Error(t *testing.T) {
	mockManager := &MockUpdateManager{
		CheckForUpdatesFunc: func(ctx context.Context, channel string) (*updates.UpdateInfo, error) {
			return nil, errors.New("github down")
		},
	}

	h := NewUpdateHandlers(mockManager, nil)
	w := httptest.NewRecorder()
	r := httptest.NewRequest("GET", "/updates/check", nil)

	h.HandleCheckUpdates(w, r)

	if w.Code != http.StatusInternalServerError {
		t.Errorf("Expected status 500, got %d", w.Code)
	}
}

func TestHandleCheckUpdates_InvalidChannel(t *testing.T) {
	mockManager := &MockUpdateManager{
		CheckForUpdatesFunc: func(ctx context.Context, channel string) (*updates.UpdateInfo, error) {
			t.Fatalf("CheckForUpdatesWithChannel should not be called for invalid channels")
			return nil, nil
		},
	}

	h := NewUpdateHandlers(mockManager, nil)
	w := httptest.NewRecorder()
	r := httptest.NewRequest(http.MethodGet, "/updates/check?channel=beta", nil)

	h.HandleCheckUpdates(w, r)

	if w.Code != http.StatusBadRequest {
		t.Fatalf("Expected status %d, got %d", http.StatusBadRequest, w.Code)
	}
}

func TestHandleApplyUpdate_Success(t *testing.T) {
	mockManager := &MockUpdateManager{
		ApplyUpdateFunc: func(ctx context.Context, req updates.ApplyUpdateRequest) error {
			if req.DownloadURL != "http://example.com/update.tar.gz" {
				return errors.New("wrong url")
			}
			return nil
		},
	}

	h := NewUpdateHandlers(mockManager, nil)
	w := httptest.NewRecorder()
	body := `{"downloadUrl": "http://example.com/update.tar.gz"}`
	r := httptest.NewRequest("POST", "/updates/apply", strings.NewReader(body))

	h.HandleApplyUpdate(w, r)

	if w.Code != http.StatusOK {
		t.Errorf("Expected status 200, got %d", w.Code)
	}

	// Note: ApplyUpdate runs in background, so we just check it was accepted
}

func TestHandleApplyUpdate_AlreadyInProgress(t *testing.T) {
	mockManager := &MockUpdateManager{
		ApplyUpdateFunc: func(ctx context.Context, req updates.ApplyUpdateRequest) error {
			return errors.New("update already in progress")
		},
	}

	h := NewUpdateHandlers(mockManager, nil)
	w := httptest.NewRecorder()
	body := `{"downloadUrl": "https://example.com/update.tar.gz"}`
	r := httptest.NewRequest(http.MethodPost, "/updates/apply", strings.NewReader(body))

	h.HandleApplyUpdate(w, r)

	if w.Code != http.StatusConflict {
		t.Fatalf("Expected status %d, got %d", http.StatusConflict, w.Code)
	}
	if !strings.Contains(strings.ToLower(w.Body.String()), "already in progress") {
		t.Fatalf("expected conflict message, got %q", w.Body.String())
	}
}

func TestHandleApplyUpdate_InvalidRequestBody(t *testing.T) {
	mockManager := &MockUpdateManager{
		ApplyUpdateFunc: func(ctx context.Context, req updates.ApplyUpdateRequest) error {
			t.Fatalf("ApplyUpdate should not be called for invalid request bodies")
			return nil
		},
	}

	h := NewUpdateHandlers(mockManager, nil)

	t.Run("rejects unknown fields", func(t *testing.T) {
		w := httptest.NewRecorder()
		body := `{"downloadUrl":"https://example.com/update.tar.gz","unexpected":"x"}`
		r := httptest.NewRequest(http.MethodPost, "/updates/apply", strings.NewReader(body))

		h.HandleApplyUpdate(w, r)
		if w.Code != http.StatusBadRequest {
			t.Fatalf("Expected status %d, got %d", http.StatusBadRequest, w.Code)
		}
	})

	t.Run("rejects trailing json", func(t *testing.T) {
		w := httptest.NewRecorder()
		body := `{"downloadUrl":"https://example.com/update.tar.gz"} {"extra":true}`
		r := httptest.NewRequest(http.MethodPost, "/updates/apply", strings.NewReader(body))

		h.HandleApplyUpdate(w, r)
		if w.Code != http.StatusBadRequest {
			t.Fatalf("Expected status %d, got %d", http.StatusBadRequest, w.Code)
		}
	})

	t.Run("rejects whitespace download url", func(t *testing.T) {
		w := httptest.NewRecorder()
		body := `{"downloadUrl":"   "}`
		r := httptest.NewRequest(http.MethodPost, "/updates/apply", strings.NewReader(body))

		h.HandleApplyUpdate(w, r)
		if w.Code != http.StatusBadRequest {
			t.Fatalf("Expected status %d, got %d", http.StatusBadRequest, w.Code)
		}
		if !strings.Contains(strings.ToLower(w.Body.String()), "download url is required") {
			t.Fatalf("expected missing URL error, got %q", w.Body.String())
		}
	})
}

func TestHandleApplyUpdate_InvalidChannel(t *testing.T) {
	mockManager := &MockUpdateManager{
		ApplyUpdateFunc: func(ctx context.Context, req updates.ApplyUpdateRequest) error {
			t.Fatalf("ApplyUpdate should not be called for invalid channels")
			return nil
		},
	}

	h := NewUpdateHandlers(mockManager, nil)
	w := httptest.NewRecorder()
	body := `{"downloadUrl":"https://github.com/rcourtman/Pulse/releases/download/v6.0.0/pulse-v6.0.0-linux-amd64.tar.gz"}`
	r := httptest.NewRequest(http.MethodPost, "/updates/apply?channel=beta", strings.NewReader(body))

	h.HandleApplyUpdate(w, r)

	if w.Code != http.StatusBadRequest {
		t.Fatalf("Expected status %d, got %d", http.StatusBadRequest, w.Code)
	}
}

func TestHandleApplyUpdate_StableRejectsPrereleaseTarget(t *testing.T) {
	mockManager := &MockUpdateManager{
		ApplyUpdateFunc: func(ctx context.Context, req updates.ApplyUpdateRequest) error {
			return errors.New("stable channel cannot install prerelease builds")
		},
	}

	h := NewUpdateHandlers(mockManager, nil)
	w := httptest.NewRecorder()
	body := `{"downloadUrl":"https://github.com/rcourtman/Pulse/releases/download/v6.0.0-rc.1/pulse-v6.0.0-rc.1-linux-amd64.tar.gz"}`
	r := httptest.NewRequest(http.MethodPost, "/updates/apply?channel=stable", strings.NewReader(body))

	h.HandleApplyUpdate(w, r)

	if w.Code != http.StatusConflict {
		t.Fatalf("Expected status %d, got %d", http.StatusConflict, w.Code)
	}
	if !strings.Contains(strings.ToLower(w.Body.String()), "prerelease") {
		t.Fatalf("expected prerelease conflict message, got %q", w.Body.String())
	}
}

func TestHandleApplyUpdate_BlocksWhenReadinessBlocked(t *testing.T) {
	setMockModeForTest(t, true)

	now := time.Date(2026, 5, 28, 12, 0, 0, 0, time.UTC)
	applyCalled := false
	mockManager := &MockUpdateManager{
		ApplyUpdateFunc: func(ctx context.Context, req updates.ApplyUpdateRequest) error {
			applyCalled = true
			return nil
		},
	}

	h := NewUpdateHandlers(mockManager, nil)
	h.now = func() time.Time { return now }
	h.SetUpdateReadinessSources(
		func(context.Context) *config.Config {
			return &config.Config{}
		},
		func(context.Context) []models.Host {
			return []models.Host{{
				ID:           "host-1",
				Hostname:     "host-1",
				LastSeen:     now.Add(-30 * time.Second),
				AgentVersion: "5.1.23",
				IsLegacy:     true,
			}}
		},
	)
	h.registry.Register("mock", &mockUpdater{
		prepareFunc: func(ctx context.Context, req updates.UpdateRequest) (*updates.UpdatePlan, error) {
			if req.Version != "v6.0.0" {
				t.Fatalf("PrepareUpdate version = %q, want v6.0.0", req.Version)
			}
			return &updates.UpdatePlan{
				CanAutoUpdate:   true,
				RollbackSupport: true,
				Instructions:    []string{"install"},
			}, nil
		},
	})

	w := httptest.NewRecorder()
	body := `{"downloadUrl":"https://github.com/rcourtman/Pulse/releases/download/v6.0.0/pulse-v6.0.0-linux-amd64.tar.gz"}`
	r := httptest.NewRequest(http.MethodPost, "/updates/apply?channel=stable", strings.NewReader(body))

	h.HandleApplyUpdate(w, r)

	if w.Code != http.StatusConflict {
		t.Fatalf("Expected status %d, got %d: %s", http.StatusConflict, w.Code, w.Body.String())
	}
	if applyCalled {
		t.Fatal("ApplyUpdate should not be called when readiness is blocked")
	}
	if !strings.Contains(w.Body.String(), "Resolve 1 blocked upgrade check") {
		t.Fatalf("expected readiness summary, got %q", w.Body.String())
	}
}

func TestHandleUpdateStatus_Fresh(t *testing.T) {
	mockManager := &MockUpdateManager{
		GetStatusFunc: func() updates.UpdateStatus {
			return updates.UpdateStatus{Status: "idle"}
		},
	}

	h := NewUpdateHandlers(mockManager, nil)
	w := httptest.NewRecorder()
	r := httptest.NewRequest("GET", "/updates/status", nil)

	h.HandleUpdateStatus(w, r)

	if w.Code != http.StatusOK {
		t.Errorf("Expected status 200, got %d", w.Code)
	}
	if w.Header().Get("X-Cache") != "MISS" {
		t.Error("Expected X-Cache: MISS")
	}
}

func TestHandleUpdateStatus_Cached(t *testing.T) {
	mockManager := &MockUpdateManager{
		GetStatusFunc: func() updates.UpdateStatus {
			return updates.UpdateStatus{Status: "fresh"}
		},
		GetSSECachedStatusFunc: func() (updates.UpdateStatus, time.Time) {
			return updates.UpdateStatus{Status: "cached"}, time.Now()
		},
	}

	h := NewUpdateHandlers(mockManager, nil)

	// First request - MISS
	r1 := httptest.NewRequest("GET", "/updates/status", nil)
	r1.RemoteAddr = "1.2.3.4:1234"
	w1 := httptest.NewRecorder()
	h.HandleUpdateStatus(w1, r1)

	if w1.Header().Get("X-Cache") != "MISS" {
		t.Error("Expected first request to be MISS")
	}

	// Second request immediately after - HIT
	r2 := httptest.NewRequest("GET", "/updates/status", nil)
	r2.RemoteAddr = "1.2.3.4:5678" // Same IP
	w2 := httptest.NewRecorder()
	h.HandleUpdateStatus(w2, r2)

	if w2.Header().Get("X-Cache") != "HIT" {
		t.Error("Expected second request to be HIT")
	}

	var status updates.UpdateStatus
	_ = json.NewDecoder(w2.Body).Decode(&status)
	if status.Status != "cached" {
		t.Errorf("Expected cached status, got %s", status.Status)
	}
}

func TestHandleUpdateStream(t *testing.T) {
	mockManager := &MockUpdateManager{
		AddSSEClientFunc: func(w http.ResponseWriter, clientID string) *updates.SSEClient {
			return &updates.SSEClient{
				ID:      clientID,
				Done:    make(chan bool),
				Flusher: w.(http.Flusher),
			}
		},
		RemoveSSEClientFunc: func(clientID string) {},
	}

	h := NewUpdateHandlers(mockManager, nil)
	w := httptest.NewRecorder()
	r := httptest.NewRequest("GET", "/updates/stream", nil)

	// Create context that we can cancel to simulate client disconnect
	ctx, cancel := context.WithCancel(context.Background())
	r = r.WithContext(ctx)

	// This blocks until context cancel, so run in goroutine
	done := make(chan bool)
	go func() {
		h.HandleUpdateStream(w, r)
		close(done)
	}()

	// Give it a moment to establish
	time.Sleep(50 * time.Millisecond)

	// Cancel/Disconnect
	cancel()

	select {
	case <-done:
		// Success
	case <-time.After(1 * time.Second):
		t.Fatal("HandleUpdateStream didn't return after context cancel")
	}

	if w.Header().Get("Content-Type") != "text/event-stream" {
		t.Error("Expected text/event-stream content type")
	}
}

func TestHandleUpdateStream_StreamingNotSupported(t *testing.T) {
	mockManager := &MockUpdateManager{
		AddSSEClientFunc: func(w http.ResponseWriter, clientID string) *updates.SSEClient {
			return nil
		},
	}

	h := NewUpdateHandlers(mockManager, nil)
	w := httptest.NewRecorder()
	r := httptest.NewRequest(http.MethodGet, "/updates/stream", nil)

	h.HandleUpdateStream(w, r)

	if w.Code != http.StatusInternalServerError {
		t.Fatalf("Expected status 500, got %d", w.Code)
	}
}

func TestHandleListUpdateHistory(t *testing.T) {
	tmp := t.TempDir()
	history, _ := updates.NewUpdateHistory(tmp)

	// Pre-populate history
	if _, err := history.CreateEntry(context.Background(), updates.UpdateHistoryEntry{
		EventID:   "test-entry",
		Status:    updates.StatusSuccess,
		VersionTo: "v1.2.3",
	}); err != nil {
		t.Fatalf("Failed to create history entry: %v", err)
	}

	h := NewUpdateHandlers(&MockUpdateManager{}, history)
	w := httptest.NewRecorder()
	r := httptest.NewRequest("GET", "/updates/history", nil)

	h.HandleListUpdateHistory(w, r)

	if w.Code != http.StatusOK {
		t.Errorf("Expected status 200, got %d", w.Code)
	}

	var entries []updates.UpdateHistoryEntry
	_ = json.NewDecoder(w.Body).Decode(&entries)
	if len(entries) != 1 {
		t.Errorf("Expected 1 entry, got %d", len(entries))
	}
}

func TestHandleListUpdateHistory_ErrorPaths(t *testing.T) {
	h := NewUpdateHandlers(&MockUpdateManager{}, nil)

	t.Run("method not allowed", func(t *testing.T) {
		w := httptest.NewRecorder()
		r := httptest.NewRequest(http.MethodPost, "/updates/history", nil)
		h.HandleListUpdateHistory(w, r)
		if w.Code != http.StatusMethodNotAllowed {
			t.Fatalf("Expected status 405, got %d", w.Code)
		}
	})

	t.Run("history unavailable", func(t *testing.T) {
		w := httptest.NewRecorder()
		r := httptest.NewRequest(http.MethodGet, "/updates/history", nil)
		h.HandleListUpdateHistory(w, r)
		if w.Code != http.StatusServiceUnavailable {
			t.Fatalf("Expected status 503, got %d", w.Code)
		}
	})
}

func TestHandleGetUpdateHistoryEntry(t *testing.T) {
	tmp := t.TempDir()
	history, _ := updates.NewUpdateHistory(tmp)

	// Pre-populate history
	if _, err := history.CreateEntry(context.Background(), updates.UpdateHistoryEntry{
		EventID:   "test-entry-1",
		Status:    updates.StatusSuccess,
		VersionTo: "v1.2.3",
	}); err != nil {
		t.Fatalf("Failed to create history entry: %v", err)
	}

	h := NewUpdateHandlers(&MockUpdateManager{}, history)
	w := httptest.NewRecorder()
	r := httptest.NewRequest("GET", "/updates/history/entry?id=test-entry-1", nil)

	h.HandleGetUpdateHistoryEntry(w, r)

	if w.Code != http.StatusOK {
		t.Errorf("Expected status 200, got %d", w.Code)
	}

	var entry updates.UpdateHistoryEntry
	_ = json.NewDecoder(w.Body).Decode(&entry)
	if entry.EventID != "test-entry-1" {
		t.Errorf("Expected EventID test-entry-1, got %s", entry.EventID)
	}
}

func TestHandleGetUpdateHistoryEntry_ErrorPaths(t *testing.T) {
	tmp := t.TempDir()
	history, err := updates.NewUpdateHistory(tmp)
	if err != nil {
		t.Fatalf("failed to create update history: %v", err)
	}

	h := NewUpdateHandlers(&MockUpdateManager{}, history)

	t.Run("method not allowed", func(t *testing.T) {
		w := httptest.NewRecorder()
		r := httptest.NewRequest(http.MethodPost, "/updates/history/entry?id=test-entry", nil)
		h.HandleGetUpdateHistoryEntry(w, r)
		if w.Code != http.StatusMethodNotAllowed {
			t.Fatalf("Expected status 405, got %d", w.Code)
		}
	})

	t.Run("missing id", func(t *testing.T) {
		w := httptest.NewRecorder()
		r := httptest.NewRequest(http.MethodGet, "/updates/history/entry", nil)
		h.HandleGetUpdateHistoryEntry(w, r)
		if w.Code != http.StatusBadRequest {
			t.Fatalf("Expected status 400, got %d", w.Code)
		}
	})

	t.Run("entry not found", func(t *testing.T) {
		w := httptest.NewRecorder()
		r := httptest.NewRequest(http.MethodGet, "/updates/history/entry?id=does-not-exist", nil)
		h.HandleGetUpdateHistoryEntry(w, r)
		if w.Code != http.StatusNotFound {
			t.Fatalf("Expected status 404, got %d", w.Code)
		}
	})

	t.Run("history unavailable", func(t *testing.T) {
		w := httptest.NewRecorder()
		r := httptest.NewRequest(http.MethodGet, "/updates/history/entry?id=test-entry", nil)
		NewUpdateHandlers(&MockUpdateManager{}, nil).HandleGetUpdateHistoryEntry(w, r)
		if w.Code != http.StatusServiceUnavailable {
			t.Fatalf("Expected status 503, got %d", w.Code)
		}
	})
}

func TestDoCleanupRateLimits(t *testing.T) {
	h := NewUpdateHandlers(nil, nil)
	now := time.Now()
	h.statusRateLimits["old"] = now.Add(-15 * time.Minute)
	h.statusRateLimits["new"] = now.Add(-5 * time.Minute)

	h.doCleanupRateLimits(now)

	if _, ok := h.statusRateLimits["old"]; ok {
		t.Error("Old entry not cleaned up")
	}
	if _, ok := h.statusRateLimits["new"]; !ok {
		t.Error("New entry cleaned up prematurely")
	}
}

type mockUpdater struct {
	updates.Updater
	prepareFunc func(ctx context.Context, req updates.UpdateRequest) (*updates.UpdatePlan, error)
}

func (m *mockUpdater) PrepareUpdate(ctx context.Context, req updates.UpdateRequest) (*updates.UpdatePlan, error) {
	return m.prepareFunc(ctx, req)
}

func TestHandleGetUpdatePlan(t *testing.T) {
	// Set mock mode so GetCurrentVersion returns "mock"
	setMockModeForTest(t, true)

	mu := &mockUpdater{
		prepareFunc: func(ctx context.Context, req updates.UpdateRequest) (*updates.UpdatePlan, error) {
			return &updates.UpdatePlan{
				Instructions: []string{"test"},
			}, nil
		},
	}

	h := NewUpdateHandlers(nil, nil)
	h.registry.Register("mock", mu)

	// Test missing version
	r := httptest.NewRequest("GET", "/api/updates/plan", nil)
	w := httptest.NewRecorder()
	h.HandleGetUpdatePlan(w, r)
	if w.Code != http.StatusBadRequest {
		t.Errorf("Expected 400, got %d", w.Code)
	}

	// Test success
	r = httptest.NewRequest("GET", "/api/updates/plan?version=v1.2.3", nil)
	w = httptest.NewRecorder()
	h.HandleGetUpdatePlan(w, r)

	if w.Code != http.StatusOK {
		t.Errorf("Expected 200, got %d: %s", w.Code, w.Body.String())
	}

	var plan updates.UpdatePlan
	_ = json.NewDecoder(w.Body).Decode(&plan)
	if len(plan.Instructions) != 1 {
		t.Errorf("Expected 1 instruction, got %d", len(plan.Instructions))
	}
	if plan.Prerequisites == nil {
		t.Fatal("expected prerequisites to normalize to an empty slice")
	}
}

func TestHandleGetUpdatePlan_IncludesUpgradeReadiness(t *testing.T) {
	setMockModeForTest(t, true)

	now := time.Date(2026, 5, 28, 12, 0, 0, 0, time.UTC)
	rawToken := "abcdef1234567890abcdef1234567890"
	record, err := config.NewAPITokenRecord(rawToken, "agent", []string{config.ScopeAgentReport})
	if err != nil {
		t.Fatalf("NewAPITokenRecord: %v", err)
	}

	h := NewUpdateHandlers(nil, nil)
	h.now = func() time.Time { return now }
	h.SetUpdateReadinessSources(
		func(context.Context) *config.Config {
			return &config.Config{APITokens: []config.APITokenRecord{*record}}
		},
		func(context.Context) []models.Host {
			return []models.Host{{
				ID:           "host-1",
				Hostname:     "host-1",
				LastSeen:     now.Add(-30 * time.Second),
				AgentVersion: "5.1.23",
				IsLegacy:     true,
			}}
		},
	)
	h.registry.Register("mock", &mockUpdater{
		prepareFunc: func(ctx context.Context, req updates.UpdateRequest) (*updates.UpdatePlan, error) {
			return &updates.UpdatePlan{
				CanAutoUpdate:   true,
				RollbackSupport: true,
				Instructions:    []string{"install"},
			}, nil
		},
	})

	w := httptest.NewRecorder()
	r := httptest.NewRequest(http.MethodGet, "/api/updates/plan?version=v6.0.0", nil)
	h.HandleGetUpdatePlan(w, r)

	if w.Code != http.StatusOK {
		t.Fatalf("Expected status 200, got %d: %s", w.Code, w.Body.String())
	}

	var plan updates.UpdatePlan
	if err := json.NewDecoder(w.Body).Decode(&plan); err != nil {
		t.Fatalf("decode plan: %v", err)
	}
	if plan.Readiness == nil {
		t.Fatal("expected readiness on update plan")
	}
	if plan.Readiness.Status != "attention" {
		t.Fatalf("readiness status = %q, want attention: %#v", plan.Readiness.Status, plan.Readiness)
	}
	if len(plan.Readiness.Checks) != 4 {
		t.Fatalf("readiness checks = %d, want 4", len(plan.Readiness.Checks))
	}
	if got := plan.Readiness.Checks[2].ID; got != "agent-migration-security" {
		t.Fatalf("readiness check[2] id = %q, want agent-migration-security", got)
	}
	if got := plan.Readiness.Checks[2].Status; got != "warning" {
		t.Fatalf("agent migration security status = %q, want warning", got)
	}
}

func TestHandleGetUpdatePlan_InvalidChannel(t *testing.T) {
	setMockModeForTest(t, true)

	h := NewUpdateHandlers(nil, nil)
	h.registry.Register("mock", &mockUpdater{
		prepareFunc: func(ctx context.Context, req updates.UpdateRequest) (*updates.UpdatePlan, error) {
			t.Fatalf("PrepareUpdate should not be called for invalid channels")
			return nil, nil
		},
	})

	w := httptest.NewRecorder()
	r := httptest.NewRequest(http.MethodGet, "/api/updates/plan?version=v1.2.3&channel=beta", nil)
	h.HandleGetUpdatePlan(w, r)

	if w.Code != http.StatusBadRequest {
		t.Fatalf("Expected status %d, got %d", http.StatusBadRequest, w.Code)
	}
}

func TestHandleGetUpdatePlan_PrepareError(t *testing.T) {
	setMockModeForTest(t, true)

	h := NewUpdateHandlers(nil, nil)
	h.registry.Register("mock", &mockUpdater{
		prepareFunc: func(ctx context.Context, req updates.UpdateRequest) (*updates.UpdatePlan, error) {
			return nil, errors.New("prepare failed")
		},
	})

	w := httptest.NewRecorder()
	r := httptest.NewRequest(http.MethodGet, "/api/updates/plan?version=v1.2.3", nil)
	h.HandleGetUpdatePlan(w, r)

	if w.Code != http.StatusInternalServerError {
		t.Fatalf("Expected status 500, got %d", w.Code)
	}
}

func TestHandleGetUpdatePlan_ManualFallback(t *testing.T) {
	h := NewUpdateHandlers(nil, nil)

	w := httptest.NewRecorder()
	r := httptest.NewRequest(http.MethodGet, "/api/updates/plan?version=v6.0.0-rc.1", nil)
	h.HandleGetUpdatePlan(w, r)

	if w.Code != http.StatusOK {
		t.Fatalf("Expected status 200, got %d: %s", w.Code, w.Body.String())
	}

	var plan updates.UpdatePlan
	if err := json.NewDecoder(w.Body).Decode(&plan); err != nil {
		t.Fatalf("decode plan: %v", err)
	}

	if plan.CanAutoUpdate {
		t.Fatalf("Expected manual fallback plan to disable auto updates")
	}
	if len(plan.Instructions) == 0 {
		t.Fatalf("Expected manual fallback plan to include instructions")
	}
	if len(plan.Prerequisites) == 0 {
		t.Fatalf("Expected manual fallback plan to include prerequisites")
	}
}