package contentmarkerser

import (
	"bytes"
	"encoding/json"
	"errors"
	"sync"
	"testing"
	"time"

	"91porn-server/common/constant/redisconst"
)

type markerCacheStub struct {
	data     Response
	getErr   error
	setData  Response
	setCalls int

	latestListCached   bool
	latestListReviewAt *time.Time
}

type markerRaceCache struct {
	mu      sync.Mutex
	payload string
	exists  bool
}

func (c *markerRaceCache) GetWithJson2Any(_ string, val any) error {
	c.mu.Lock()
	defer c.mu.Unlock()
	if !c.exists {
		return errors.New("cache miss")
	}
	return json.Unmarshal([]byte(c.payload), val)
}

func (c *markerRaceCache) SetNX(_ string, val interface{}, _ time.Duration) (bool, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	if c.exists {
		return false, nil
	}
	payload, ok := val.(string)
	if !ok {
		return false, errors.New("cache value is not JSON text")
	}
	c.payload = payload
	c.exists = true
	return true, nil
}

func (c *markerCacheStub) GetWithJson2Any(key string, val any) error {
	if key == redisconst.GetMostNewModuleVideoListKey(
		homeLatestListSortType,
		homeLatestListPageNumber,
		homeLatestListPageSize,
	) {
		if !c.latestListCached {
			return errors.New("latest list cache miss")
		}
		data := cachedHomeLatestList{}
		if c.latestListReviewAt != nil {
			data.Videos = append(data.Videos, struct {
				ReviewAt time.Time `json:"reviewAt"`
			}{ReviewAt: *c.latestListReviewAt})
		}
		payload, err := json.Marshal(data)
		if err != nil {
			return err
		}
		return json.Unmarshal(payload, val)
	}
	if c.getErr != nil {
		return c.getErr
	}
	payload, err := json.Marshal(c.data)
	if err != nil {
		return err
	}
	return json.Unmarshal(payload, val)
}

func (c *markerCacheStub) SetNX(_ string, val interface{}, _ time.Duration) (bool, error) {
	c.setCalls++
	payload, ok := val.(string)
	if !ok {
		return false, errors.New("cache value is not JSON text")
	}
	if err := json.Unmarshal([]byte(payload), &c.setData); err != nil {
		return false, err
	}
	return true, nil
}

func TestResponseOmitsTodayLatestAt(t *testing.T) {
	payload, err := json.Marshal(Response{})
	if err != nil {
		t.Fatalf("json.Marshal(Response{}) error = %v", err)
	}
	if bytes.Contains(payload, []byte("todayLatestAt")) {
		t.Fatalf("response still contains removed todayLatestAt field: %s", payload)
	}
}

func TestGetCachedReturnsCachedMarkers(t *testing.T) {
	latest := time.Date(2026, 8, 4, 11, 30, 0, 123000000, time.FixedZone("CST", 8*60*60))
	cache := &markerCacheStub{data: Response{HomeLatestAt: &latest}}

	got, err := GetCached(time.Now(), cache)
	if err != nil {
		t.Fatalf("GetCached() error = %v", err)
	}
	if got.HomeLatestAt == nil || !got.HomeLatestAt.Equal(latest) {
		t.Fatalf("GetCached() homeLatestAt = %v, want %v", got.HomeLatestAt, latest)
	}
	if cache.setCalls != 0 {
		t.Fatalf("GetCached() cache writes = %d, want 0", cache.setCalls)
	}
}

func TestReadCachedReportsMiss(t *testing.T) {
	cache := &markerCacheStub{getErr: errors.New("cache miss")}
	if _, ok := ReadCached(cache); ok {
		t.Fatal("ReadCached() hit = true, want false")
	}
	if _, ok := ReadCached(nil); ok {
		t.Fatal("ReadCached(nil) hit = true, want false")
	}
}

func TestGetCachedUsesHomeLatestAtFromCachedList(t *testing.T) {
	markerLatest := time.Date(2026, 8, 4, 11, 30, 0, 0, time.UTC)
	listLatest := markerLatest.Add(-2 * time.Minute)
	cache := &markerCacheStub{
		data:               Response{HomeLatestAt: &markerLatest},
		latestListCached:   true,
		latestListReviewAt: &listLatest,
	}

	got, err := GetCached(time.Now(), cache)
	if err != nil {
		t.Fatalf("GetCached() error = %v", err)
	}
	if got.HomeLatestAt == nil || !got.HomeLatestAt.Equal(listLatest) {
		t.Fatalf("GetCached() homeLatestAt = %v, want cached list time %v", got.HomeLatestAt, listLatest)
	}
}

func TestGetCachedClearsHomeLatestAtForCachedEmptyList(t *testing.T) {
	markerLatest := time.Date(2026, 8, 4, 11, 30, 0, 0, time.UTC)
	cache := &markerCacheStub{
		data:             Response{HomeLatestAt: &markerLatest},
		latestListCached: true,
	}

	got, err := GetCached(time.Now(), cache)
	if err != nil {
		t.Fatalf("GetCached() error = %v", err)
	}
	if got.HomeLatestAt != nil {
		t.Fatalf("GetCached() homeLatestAt = %v, want nil for cached empty list", got.HomeLatestAt)
	}
}

func TestGetCachedLoadsAndWritesCacheBeforeReturning(t *testing.T) {
	latest := time.Date(2026, 8, 4, 11, 31, 0, 0, time.UTC)
	cache := &markerCacheStub{getErr: errors.New("cache miss")}
	loadCalls := 0
	load := func(time.Time) (Response, error) {
		loadCalls++
		return Response{HomeLatestAt: &latest}, nil
	}

	got, err := getCached(time.Now(), cache, load)
	if err != nil {
		t.Fatalf("getCached() error = %v", err)
	}
	if loadCalls != 1 {
		t.Fatalf("getCached() loader calls = %d, want 1", loadCalls)
	}
	if cache.setCalls != 1 || cache.setData.HomeLatestAt == nil {
		t.Fatalf("getCached() cache write = (%d, %v), want one marker write", cache.setCalls, cache.setData.HomeLatestAt)
	}
	if got.HomeLatestAt == nil || !got.HomeLatestAt.Equal(latest) {
		t.Fatalf("getCached() homeLatestAt = %v, want %v", got.HomeLatestAt, latest)
	}
}

func TestGetCachedConcurrentMissReturnsWinningSnapshot(t *testing.T) {
	oldLatest := time.Date(2026, 8, 4, 11, 30, 0, 0, time.UTC)
	newLatest := oldLatest.Add(time.Minute)
	cache := &markerRaceCache{}
	oldLoaderStarted := make(chan struct{})
	releaseOldLoader := make(chan struct{})
	type outcome struct {
		data Response
		err  error
	}
	oldOutcome := make(chan outcome, 1)

	go func() {
		data, err := getCached(time.Now(), cache, func(time.Time) (Response, error) {
			close(oldLoaderStarted)
			<-releaseOldLoader
			return Response{HomeLatestAt: &oldLatest}, nil
		})
		oldOutcome <- outcome{data: data, err: err}
	}()

	<-oldLoaderStarted
	newData, err := getCached(time.Now(), cache, func(time.Time) (Response, error) {
		return Response{HomeLatestAt: &newLatest}, nil
	})
	if err != nil {
		t.Fatalf("new getCached() error = %v", err)
	}
	close(releaseOldLoader)
	oldResult := <-oldOutcome
	if oldResult.err != nil {
		t.Fatalf("old getCached() error = %v", oldResult.err)
	}
	for name, data := range map[string]Response{"new": newData, "old": oldResult.data} {
		if data.HomeLatestAt == nil || !data.HomeLatestAt.Equal(newLatest) {
			t.Fatalf("%s getCached() homeLatestAt = %v, want winning %v", name, data.HomeLatestAt, newLatest)
		}
	}
}