package service

import (
	"context"
	"sync"
	"testing"
	"time"

	"github.com/1024XEngineer/xinfra/server/internal/model"
)

// newTestDeliveryService 创建一个用于测试的 DeliveryService，不需要真实的 DB 和配置。
// 仅适用于测试 pub/sub、缓存等内存逻辑。
func newTestDeliveryService() *DeliveryService {
	return &DeliveryService{
		streams:     make(map[string]map[chan DeliveryTaskSnapshot]struct{}),
		stdoutCache: make(map[string]*stdoutCacheItem),
	}
}

func TestSubscribeTask(t *testing.T) {
	svc := newTestDeliveryService()
	ctx := context.Background()
	_ = ctx

	taskID := "test-task-1"

	// 订阅任务
	ch, cancel := svc.SubscribeTask(taskID)
	defer cancel()

	// 验证 channel 已注册
	svc.streamMu.Lock()
	if _, ok := svc.streams[taskID]; !ok {
		svc.streamMu.Unlock()
		t.Fatal("SubscribeTask did not register channel in streams map")
	}
	svc.streamMu.Unlock()

	// 模拟 broadcastTask 推送 snapshot
	snapshot := DeliveryTaskSnapshot{
		Task: &model.DeliveryTask{ID: taskID, Status: model.TaskRunning},
	}
	svc.streamMu.Lock()
	for ch := range svc.streams[taskID] {
		select {
		case ch <- snapshot:
		default:
		}
	}
	svc.streamMu.Unlock()

	// 接收推送
	select {
	case received := <-ch:
		if received.Task == nil || received.Task.ID != taskID {
			t.Fatalf("received snapshot task ID = %v, want %q", received.Task, taskID)
		}
		if received.Task.Status != model.TaskRunning {
			t.Fatalf("received snapshot status = %q, want %q", received.Task.Status, model.TaskRunning)
		}
	case <-time.After(time.Second):
		t.Fatal("timeout waiting for snapshot from SubscribeTask")
	}
}

func TestSubscribeTask_Cancel(t *testing.T) {
	svc := newTestDeliveryService()
	taskID := "test-task-cancel"

	ch, cancel := svc.SubscribeTask(taskID)

	// 调用 cancel
	cancel()

	// 验证 channel 已关闭
	select {
	case _, ok := <-ch:
		if ok {
			t.Fatal("channel should be closed after cancel, but got a value")
		}
	case <-time.After(time.Second):
		t.Fatal("timeout waiting for channel close")
	}

	// 验证已从 streams 中移除
	svc.streamMu.Lock()
	if subs := svc.streams[taskID]; subs != nil && len(subs) > 0 {
		svc.streamMu.Unlock()
		t.Fatal("cancel did not remove channel from streams map")
	}
	svc.streamMu.Unlock()
}

func TestSubscribeTask_MultipleSubscribers(t *testing.T) {
	svc := newTestDeliveryService()
	taskID := "test-task-multi"

	ch1, cancel1 := svc.SubscribeTask(taskID)
	defer cancel1()
	ch2, cancel2 := svc.SubscribeTask(taskID)
	defer cancel2()
	ch3, cancel3 := svc.SubscribeTask(taskID)
	defer cancel3()

	// 验证三个订阅者都已注册
	svc.streamMu.Lock()
	subs := svc.streams[taskID]
	if len(subs) != 3 {
		svc.streamMu.Unlock()
		t.Fatalf("expected 3 subscribers, got %d", len(subs))
	}
	svc.streamMu.Unlock()

	// 推送 snapshot
	snapshot := DeliveryTaskSnapshot{
		Task: &model.DeliveryTask{ID: taskID, Status: model.TaskFinished},
	}
	svc.streamMu.Lock()
	for ch := range svc.streams[taskID] {
		select {
		case ch <- snapshot:
		default:
		}
	}
	svc.streamMu.Unlock()

	// 验证三个订阅者都收到
	for i, ch := range []<-chan DeliveryTaskSnapshot{ch1, ch2, ch3} {
		select {
		case received := <-ch:
			if received.Task == nil || received.Task.Status != model.TaskFinished {
				t.Fatalf("subscriber %d: expected TaskFinished, got %+v", i+1, received)
			}
		case <-time.After(time.Second):
			t.Fatalf("subscriber %d: timeout waiting for snapshot", i+1)
		}
	}
}

func TestSubscribeTask_CancelOneDoesNotAffectOthers(t *testing.T) {
	svc := newTestDeliveryService()
	taskID := "test-task-cancel-one"

	ch1, cancel1 := svc.SubscribeTask(taskID)
	_, cancel2 := svc.SubscribeTask(taskID)
	_ = cancel2

	// 取消第一个订阅者
	cancel1()

	// 验证还剩一个订阅者
	svc.streamMu.Lock()
	subs := svc.streams[taskID]
	if len(subs) != 1 {
		svc.streamMu.Unlock()
		t.Fatalf("expected 1 subscriber after cancel, got %d", len(subs))
	}
	svc.streamMu.Unlock()

	// 推送 snapshot
	snapshot := DeliveryTaskSnapshot{
		Task: &model.DeliveryTask{ID: taskID, Status: model.TaskRunning},
	}
	svc.streamMu.Lock()
	for ch := range svc.streams[taskID] {
		select {
		case ch <- snapshot:
		default:
		}
	}
	svc.streamMu.Unlock()

	// ch1 已关闭，不应收到消息
	select {
	case _, ok := <-ch1:
		if ok {
			t.Fatal("ch1 should be closed after cancel")
		}
	case <-time.After(100 * time.Millisecond):
		// OK: channel is closed, no value received
	}
}

func TestBroadcastTask_ClosedChannelCleanup(t *testing.T) {
	svc := newTestDeliveryService()
	taskID := "test-task-cleanup"

	// 创建一个订阅者并立即关闭
	_, cancel := svc.SubscribeTask(taskID)
	cancel()
	// 等待 cancel 完成
	time.Sleep(10 * time.Millisecond)

	// 创建一个新的正常订阅者
	ch2, cancel2 := svc.SubscribeTask(taskID)
	defer cancel2()

	// 模拟 broadcastTask 行为（带 recover）
	snapshot := DeliveryTaskSnapshot{
		Task: &model.DeliveryTask{ID: taskID, Status: model.TaskRunning},
	}

	svc.streamMu.Lock()
	var closedChannels []chan DeliveryTaskSnapshot
	for ch := range svc.streams[taskID] {
		func() {
			defer func() {
				if r := recover(); r != nil {
					closedChannels = append(closedChannels, ch)
				}
			}()
			select {
			case ch <- snapshot:
			default:
			}
		}()
	}
	for _, ch := range closedChannels {
		delete(svc.streams[taskID], ch)
	}
	if len(svc.streams[taskID]) == 0 {
		delete(svc.streams, taskID)
	}
	svc.streamMu.Unlock()

	// 验证 closed channel 被清理
	svc.streamMu.Lock()
	if subs := svc.streams[taskID]; subs != nil && len(subs) != 1 {
		svc.streamMu.Unlock()
		t.Fatalf("expected 1 subscriber after cleanup, got %d", len(subs))
	}
	svc.streamMu.Unlock()

	// 正常订阅者应该收到消息
	select {
	case received := <-ch2:
		if received.Task == nil || received.Task.ID != taskID {
			t.Fatalf("expected task ID %q, got %+v", taskID, received)
		}
	case <-time.After(time.Second):
		t.Fatal("timeout waiting for snapshot from normal subscriber")
	}
}

func TestInvalidateStdoutCache(t *testing.T) {
	svc := newTestDeliveryService()

	// 填充缓存
	svc.cacheMu.Lock()
	svc.stdoutCache["job-1"] = &stdoutCacheItem{stdout: "cached output", createdAt: time.Now()}
	svc.cacheMu.Unlock()

	// 验证缓存命中
	svc.cacheMu.RLock()
	item, ok := svc.stdoutCache["job-1"]
	svc.cacheMu.RUnlock()
	if !ok {
		t.Fatal("cache entry not found before invalidation")
	}
	if item.stdout != "cached output" {
		t.Fatalf("cache stdout = %q, want %q", item.stdout, "cached output")
	}

	// 失效缓存
	svc.InvalidateStdoutCache("job-1")

	// 验证缓存已失效
	svc.cacheMu.RLock()
	_, ok = svc.stdoutCache["job-1"]
	svc.cacheMu.RUnlock()
	if ok {
		t.Fatal("cache entry still exists after invalidation")
	}
}

func TestInvalidateStdoutCache_NonExistent(t *testing.T) {
	svc := newTestDeliveryService()

	// 对不存在的 key 调用 invalidate 不应 panic
	svc.InvalidateStdoutCache("non-existent-job")

	// 验证缓存为空
	svc.cacheMu.RLock()
	size := len(svc.stdoutCache)
	svc.cacheMu.RUnlock()
	if size != 0 {
		t.Fatalf("cache size = %d, want 0", size)
	}
}

func TestStdoutCache_TTLExpiry(t *testing.T) {
	svc := newTestDeliveryService()

	// 填充一个已过期的缓存条目
	svc.cacheMu.Lock()
	svc.stdoutCache["job-expired"] = &stdoutCacheItem{
		stdout:    "old output",
		createdAt: time.Now().Add(-stdoutCacheTTL - time.Second),
	}
	svc.cacheMu.Unlock()

	// 模拟 AWXJobStdout 的缓存检查逻辑
	svc.cacheMu.RLock()
	cacheHit := false
	if item, ok := svc.stdoutCache["job-expired"]; ok {
		if time.Since(item.createdAt) < stdoutCacheTTL {
			cacheHit = true
		}
	}
	svc.cacheMu.RUnlock()

	if cacheHit {
		t.Fatal("expired cache entry should not be a hit")
	}
}

func TestStdoutCache_FreshEntry(t *testing.T) {
	svc := newTestDeliveryService()

	// 填充一个新鲜的缓存条目
	svc.cacheMu.Lock()
	svc.stdoutCache["job-fresh"] = &stdoutCacheItem{
		stdout:    "fresh output",
		createdAt: time.Now(),
	}
	svc.cacheMu.Unlock()

	// 模拟 AWXJobStdout 的缓存检查逻辑
	svc.cacheMu.RLock()
	cacheHit := false
	var cachedStdout string
	if item, ok := svc.stdoutCache["job-fresh"]; ok {
		if time.Since(item.createdAt) < stdoutCacheTTL {
			cacheHit = true
			cachedStdout = item.stdout
		}
	}
	svc.cacheMu.RUnlock()

	if !cacheHit {
		t.Fatal("fresh cache entry should be a hit")
	}
	if cachedStdout != "fresh output" {
		t.Fatalf("cached stdout = %q, want %q", cachedStdout, "fresh output")
	}
}

func TestSubscribeTask_ConcurrentSafety(t *testing.T) {
	svc := newTestDeliveryService()
	taskID := "test-concurrent"

	var wg sync.WaitGroup
	const goroutines = 50

	// 并发订阅
	cancels := make([]func(), goroutines)
	for i := 0; i < goroutines; i++ {
		wg.Add(1)
		go func(idx int) {
			defer wg.Done()
			_, cancel := svc.SubscribeTask(taskID)
			cancels[idx] = cancel
		}(i)
	}
	wg.Wait()

	// 验证所有订阅者都已注册
	svc.streamMu.Lock()
	subs := svc.streams[taskID]
	if len(subs) != goroutines {
		svc.streamMu.Unlock()
		t.Fatalf("expected %d subscribers, got %d", goroutines, len(subs))
	}
	svc.streamMu.Unlock()

	// 并发取消
	for _, cancel := range cancels {
		wg.Add(1)
		go func(c func()) {
			defer wg.Done()
			c()
		}(cancel)
	}
	wg.Wait()

	// 验证所有订阅者都已移除
	svc.streamMu.Lock()
	if subs := svc.streams[taskID]; subs != nil && len(subs) > 0 {
		svc.streamMu.Unlock()
		t.Fatalf("expected 0 subscribers after concurrent cancel, got %d", len(subs))
	}
	svc.streamMu.Unlock()
}

func TestStdoutCache_ConcurrentAccess(t *testing.T) {
	svc := newTestDeliveryService()

	var wg sync.WaitGroup
	const goroutines = 50

	// 并发写入缓存
	for i := 0; i < goroutines; i++ {
		wg.Add(1)
		go func(idx int) {
			defer wg.Done()
			jobID := "job-" + string(rune('A'+idx%26))
			svc.cacheMu.Lock()
			svc.stdoutCache[jobID] = &stdoutCacheItem{
				stdout:    "output",
				createdAt: time.Now(),
			}
			svc.cacheMu.Unlock()
		}(i)
	}

	// 并发读取缓存
	for i := 0; i < goroutines; i++ {
		wg.Add(1)
		go func(idx int) {
			defer wg.Done()
			jobID := "job-" + string(rune('A'+idx%26))
			svc.cacheMu.RLock()
			_ = svc.stdoutCache[jobID]
			svc.cacheMu.RUnlock()
		}(i)
	}

	// 并发失效缓存
	for i := 0; i < goroutines; i++ {
		wg.Add(1)
		go func(idx int) {
			defer wg.Done()
			jobID := "job-" + string(rune('A'+idx%26))
			svc.InvalidateStdoutCache(jobID)
		}(i)
	}

	wg.Wait()
}