package api

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

	"github.com/gin-gonic/gin"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"visiona-backend/internal/device"
	"visiona-backend/internal/session"
)

// newDevicesFixture 建立 router 並塞好必要依賴（InMemory repo + fakeSessionStore）。
//
// Phase 0.7 security fix C1：移除 Deps.StaticUserID（見 .autoflow/05-implementation/review/phase-0.7-security-audit.md）。
// 改由 injectStaticUserContext 顯式注入 UserContext，handler 強制要求 UserContext 非空。
func newDevicesFixture(t *testing.T, sessions []any) *gin.Engine {
	t.Helper()
	r := gin.New()
	r.Use(RequestIDMiddleware())
	r.Use(injectStaticUserContext("demo-user", ""))
	g := r.Group("/api")
	_ = sessions // 暫用，下方 helper 內建
	registerDeviceRoutes(g, Deps{
		DeviceRepo:   device.NewInMemoryRepository(),
		SessionStore: &fakeSessionStore{}, // 無 session
	})
	return r
}

// TestDevicesList_Empty 驗證沒 device 時回空陣列。
func TestDevicesList_Empty(t *testing.T) {
	r := newDevicesFixture(t, nil)

	w := httptest.NewRecorder()
	r.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/api/devices", nil))
	require.Equal(t, http.StatusOK, w.Code)

	var sb SuccessBody
	require.NoError(t, json.Unmarshal(w.Body.Bytes(), &sb))
	arr, ok := sb.Data.([]any)
	require.True(t, ok)
	assert.Empty(t, arr)
}

// TestDevicesList_ReturnsOwnDevicesOnly 驗證只回當前 user 的 device。
func TestDevicesList_ReturnsOwnDevicesOnly(t *testing.T) {
	repo := device.NewInMemoryRepository()
	ctx := context.Background()
	now := time.Now().UTC()
	require.NoError(t, repo.Save(ctx, &device.Device{
		ID: "mine", OwnerUserID: "demo-user", Name: "A", DeviceType: "kl520",
		RemoteStatus: device.RemoteStatusOnline, Status: device.USBStatusOnline,
		CreatedAt: now,
	}))
	require.NoError(t, repo.Save(ctx, &device.Device{
		ID: "theirs", OwnerUserID: "other", Name: "B", DeviceType: "kl520",
		CreatedAt: now,
	}))

	r := gin.New()
	r.Use(RequestIDMiddleware())
	r.Use(injectStaticUserContext("demo-user", ""))
	g := r.Group("/api")
	registerDeviceRoutes(g, Deps{
		DeviceRepo:   repo,
		SessionStore: &fakeSessionStore{},
	})

	w := httptest.NewRecorder()
	r.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/api/devices", nil))
	require.Equal(t, http.StatusOK, w.Code)

	var sb SuccessBody
	require.NoError(t, json.Unmarshal(w.Body.Bytes(), &sb))
	arr := sb.Data.([]any)
	require.Len(t, arr, 1, "只應看到自己的 device")
	first := arr[0].(map[string]any)
	assert.Equal(t, "mine", first["id"])
	assert.Equal(t, false, first["tunnel_online"], "沒 session → tunnel_online=false")
}

// TestDevicesGet_NotOwner 驗證非 owner 被擋 403。
func TestDevicesGet_NotOwner(t *testing.T) {
	repo := device.NewInMemoryRepository()
	require.NoError(t, repo.Save(context.Background(), &device.Device{
		ID: "x", OwnerUserID: "other", Name: "a", DeviceType: "kl520",
	}))

	r := gin.New()
	r.Use(RequestIDMiddleware())
	r.Use(injectStaticUserContext("demo-user", ""))
	g := r.Group("/api")
	registerDeviceRoutes(g, Deps{
		DeviceRepo:   repo,
		SessionStore: &fakeSessionStore{},
	})

	w := httptest.NewRecorder()
	r.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/api/devices/x", nil))
	assert.Equal(t, http.StatusForbidden, w.Code)
}

// TestDevicesGet_NotFound 驗證不存在回 404。
func TestDevicesGet_NotFound(t *testing.T) {
	r := newDevicesFixture(t, nil)

	w := httptest.NewRecorder()
	r.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/api/devices/ghost", nil))
	assert.Equal(t, http.StatusNotFound, w.Code)
}

// deadlineRecordingStore 記錄 List 收到的 ctx 剩餘 deadline，並回一筆命中 session。
// 用來驗證 detail handler 給 resolveTunnelStatus 的 ctx 有足夠預算（≥3s，非被前面
// DB 呼叫吃掉的殘餘）。
type deadlineRecordingStore struct {
	fakeSessionStore
	gotRemaining time.Duration
	hasDeadline  bool
}

func (s *deadlineRecordingStore) List(ctx context.Context) ([]*session.Summary, error) {
	if dl, ok := ctx.Deadline(); ok {
		s.hasDeadline = true
		s.gotRemaining = time.Until(dl)
	}
	return []*session.Summary{
		{UserID: "demo-user", LastHeartbeat: time.Now().UTC()},
	}, nil
}

// TestDevicesGet_TunnelCtxHasFullBudget 驗證 R-3 離線誤判修復：
// detail endpoint 給 tunnel 判定的 ctx 有完整 3s 預算（獨立於前面的 DeviceRepo.Get），
// 且能正確回 tunnel_online=true。修復前 detail 用同一個 2s ctx，前面的 DB 呼叫吃掉時間後
// 打 relay 的 store.List 常逾時被靜默判離線。
func TestDevicesGet_TunnelCtxHasFullBudget(t *testing.T) {
	repo := device.NewInMemoryRepository()
	require.NoError(t, repo.Save(context.Background(), &device.Device{
		ID: "mine", OwnerUserID: "demo-user", Name: "kl520", DeviceType: "kl520",
	}))

	store := &deadlineRecordingStore{}
	r := gin.New()
	r.Use(RequestIDMiddleware())
	r.Use(injectStaticUserContext("demo-user", ""))
	g := r.Group("/api")
	registerDeviceRoutes(g, Deps{
		DeviceRepo:   repo,
		SessionStore: store,
	})

	w := httptest.NewRecorder()
	r.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/api/devices/mine", nil))
	require.Equal(t, http.StatusOK, w.Code)

	var sb SuccessBody
	require.NoError(t, json.Unmarshal(w.Body.Bytes(), &sb))
	item := sb.Data.(map[string]any)
	assert.Equal(t, true, item["tunnel_online"], "命中 session 應判 tunnel_online=true")

	// 核心斷言：tunnel 判定拿到的 ctx 剩餘預算應接近完整 3s（獨立 ctx），
	// 而非修復前殘餘的 <2s。給寬鬆下界 2.5s 容忍測試機排程抖動。
	require.True(t, store.hasDeadline, "tunnel ctx 應有 deadline")
	assert.Greater(t, store.gotRemaining, 2500*time.Millisecond,
		"tunnel 判定應拿到近乎完整的 3s 預算，不被前面 DeviceRepo.Get 吃掉")
}

// TestResolveTunnelStatus_ListTimeoutTreatedOffline 驗證嫌疑 1 語意保留：
// store.List 逾時（context deadline exceeded）→ 靜默判離線（fail-safe 不變）。
func TestResolveTunnelStatus_ListTimeoutTreatedOffline(t *testing.T) {
	store := &fakeSessionStore{listErr: context.DeadlineExceeded}
	alive, _ := resolveTunnelStatus(
		context.Background(), store, "demo-user", nil, "detail", "test-req")
	assert.False(t, alive, "List 逾時應判離線（fail-safe 語意保留）")
}

// TestResolveTunnelStatus_NoMatchTreatedOffline 驗證嫌疑 2 語意：
// 拿到 list 但沒有一筆命中 userID → 判離線。
func TestResolveTunnelStatus_NoMatchTreatedOffline(t *testing.T) {
	store := &fakeSessionStore{sessions: []*session.Summary{
		{UserID: "someone-else", LastHeartbeat: time.Now().UTC()},
	}}
	alive, _ := resolveTunnelStatus(
		context.Background(), store, "demo-user", nil, "detail", "test-req")
	assert.False(t, alive, "無命中 session 應判離線")
}