package handlers

// system_handler_test.go — MAJ-4 補丁：shutdown-notify endpoint 單元測試
//
// 驗證 POST /api/system/shutdown-notify 的行為：
//  1. reason=quit  → 200 + 廣播 payload.reason = "quit"
//  2. reason=restart → 200 + 廣播 payload.reason = "restart"
//  3. reason=invalid / 空 → 200 + 廣播 payload.reason = "unknown"
//  4. wsHub = nil → 仍回 200（不 panic）
//
// 用 spy broadcaster 代替 real *ws.Hub，避免測試需要真的 goroutine / channel。

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

	"github.com/gin-gonic/gin"
)

func init() {
	gin.SetMode(gin.TestMode)
}

// spyBroadcaster 實作 shutdownNotifyBroadcaster，把每次呼叫紀錄起來供斷言。
type spyBroadcaster struct {
	mu    sync.Mutex
	calls []spyCall
}

type spyCall struct {
	room string
	data map[string]interface{}
}

func (s *spyBroadcaster) BroadcastToRoom(room string, data interface{}) {
	s.mu.Lock()
	defer s.mu.Unlock()
	// 把 gin.H 轉成 map[string]interface{} 方便比對
	m := map[string]interface{}{}
	switch v := data.(type) {
	case gin.H:
		for k, val := range v {
			m[k] = val
		}
	case map[string]interface{}:
		m = v
	default:
		// 最後一招：透過 JSON round-trip
		b, _ := json.Marshal(data)
		_ = json.Unmarshal(b, &m)
	}
	s.calls = append(s.calls, spyCall{room: room, data: m})
}

func (s *spyBroadcaster) snapshot() []spyCall {
	s.mu.Lock()
	defer s.mu.Unlock()
	out := make([]spyCall, len(s.calls))
	copy(out, s.calls)
	return out
}

// newTestHandler 組一個 SystemHandler 但用 spy broadcaster 替代 real Hub。
func newTestHandler(spy *spyBroadcaster) *SystemHandler {
	h := &SystemHandler{
		startTime: time.Now(),
		version:   "test",
		buildTime: "test-build",
		bootID:    "test-boot-id",
	}
	if spy != nil {
		h.wsHub = spy
	}
	return h
}

// newTestRouter 建一個只掛 shutdown-notify 的最小 router。
func newTestRouter(h *SystemHandler) *gin.Engine {
	r := gin.New()
	r.POST("/api/system/shutdown-notify", h.ShutdownNotify)
	return r
}

// 整組測試前把 sleep 時間歸零，避免拖慢 test suite。
func withNoSleep(t *testing.T) {
	t.Helper()
	orig := shutdownNotifySleepDuration
	shutdownNotifySleepDuration = 0
	t.Cleanup(func() {
		shutdownNotifySleepDuration = orig
	})
}

func TestShutdownNotify_ReasonQuit(t *testing.T) {
	withNoSleep(t)

	spy := &spyBroadcaster{}
	h := newTestHandler(spy)
	r := newTestRouter(h)

	req := httptest.NewRequest(http.MethodPost, "/api/system/shutdown-notify?reason=quit", nil)
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("want 200, got %d; body=%s", w.Code, w.Body.String())
	}

	var body struct {
		OK     bool   `json:"ok"`
		Reason string `json:"reason"`
	}
	if err := json.Unmarshal(w.Body.Bytes(), &body); err != nil {
		t.Fatalf("bad json response: %v", err)
	}
	if !body.OK || body.Reason != "quit" {
		t.Errorf("response fields wrong: %+v", body)
	}

	calls := spy.snapshot()
	if len(calls) != 1 {
		t.Fatalf("want 1 broadcast, got %d", len(calls))
	}
	if calls[0].room != "system" {
		t.Errorf("want room=system, got %q", calls[0].room)
	}
	if calls[0].data["type"] != "server:shutdown-imminent" {
		t.Errorf("want type=server:shutdown-imminent, got %v", calls[0].data["type"])
	}
	if calls[0].data["reason"] != "quit" {
		t.Errorf("want reason=quit, got %v", calls[0].data["reason"])
	}
	if _, ok := calls[0].data["ts"]; !ok {
		t.Errorf("payload missing ts")
	}
}

func TestShutdownNotify_ReasonRestart(t *testing.T) {
	withNoSleep(t)

	spy := &spyBroadcaster{}
	h := newTestHandler(spy)
	r := newTestRouter(h)

	req := httptest.NewRequest(http.MethodPost, "/api/system/shutdown-notify?reason=restart", nil)
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("want 200, got %d", w.Code)
	}

	calls := spy.snapshot()
	if len(calls) != 1 || calls[0].data["reason"] != "restart" {
		t.Fatalf("want 1 broadcast reason=restart, got %+v", calls)
	}
}

func TestShutdownNotify_ReasonInvalid(t *testing.T) {
	withNoSleep(t)

	cases := []string{"", "halt", "kill9", "QUIT" /* 大小寫不同應視為 unknown */}
	for _, reasonQuery := range cases {
		name := reasonQuery
		if name == "" {
			name = "empty"
		}
		t.Run("reason_"+name, func(t *testing.T) {
			spy := &spyBroadcaster{}
			h := newTestHandler(spy)
			r := newTestRouter(h)

			url := "/api/system/shutdown-notify"
			if reasonQuery != "" {
				url += "?reason=" + reasonQuery
			}
			req := httptest.NewRequest(http.MethodPost, url, nil)
			w := httptest.NewRecorder()
			r.ServeHTTP(w, req)

			if w.Code != http.StatusOK {
				t.Fatalf("want 200, got %d", w.Code)
			}

			var body struct {
				OK     bool   `json:"ok"`
				Reason string `json:"reason"`
			}
			_ = json.Unmarshal(w.Body.Bytes(), &body)
			if body.Reason != "unknown" {
				t.Errorf("want response.reason=unknown, got %q", body.Reason)
			}

			calls := spy.snapshot()
			if len(calls) != 1 {
				t.Fatalf("want 1 broadcast, got %d", len(calls))
			}
			if calls[0].data["reason"] != "unknown" {
				t.Errorf("want payload.reason=unknown, got %v", calls[0].data["reason"])
			}
		})
	}
}

func TestShutdownNotify_NoHub(t *testing.T) {
	withNoSleep(t)

	// wsHub = nil 代表單元測試或啟動失敗情境。handler 不應 panic，必須回 200。
	h := newTestHandler(nil)
	r := newTestRouter(h)

	req := httptest.NewRequest(http.MethodPost, "/api/system/shutdown-notify?reason=quit", nil)
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("want 200 even without hub, got %d", w.Code)
	}
}

// TestShutdownNotify_DefaultSleepIsPositive 保護常數不被誤改為 0 在生產路徑上。
// 單元測試透過 withNoSleep 暫時設為 0，這裡只驗證原始預設值。
func TestShutdownNotify_DefaultSleepIsPositive(t *testing.T) {
	if shutdownNotifySleepDuration <= 0 {
		t.Errorf("shutdownNotifySleepDuration should be > 0 in production, got %v", shutdownNotifySleepDuration)
	}
}