// backend\sse.go
package main

import (
	"bytes"
	"encoding/json"
	"net/http"
	"sort"
	"strings"
	"sync/atomic"
	"time"

	"github.com/r3labs/sse/v2"
)

// -------------------- SSE server --------------------

type appSSE struct {
	server *sse.Server
}

var sseApp *appSSE

type jobEvent struct {
	Type             string    `json:"type"`
	Model            string    `json:"model"`
	JobID            string    `json:"jobId"`
	Status           JobStatus `json:"status"`
	Phase            string    `json:"phase,omitempty"`
	Progress         int       `json:"progress,omitempty"`
	SourceURL        string    `json:"sourceUrl,omitempty"`
	Output           string    `json:"output,omitempty"`
	StartedAt        string    `json:"startedAt,omitempty"`
	StartedAtMs      int64     `json:"startedAtMs,omitempty"`
	EndedAt          string    `json:"endedAt,omitempty"`
	EndedAtMs        int64     `json:"endedAtMs,omitempty"`
	SizeBytes        int64     `json:"sizeBytes,omitempty"`
	DurationSeconds  float64   `json:"durationSeconds,omitempty"`
	PreviewState     string    `json:"previewState,omitempty"`
	RoomStatus       string    `json:"roomStatus,omitempty"`
	IsOnline         bool      `json:"isOnline,omitempty"`
	ModelImageURL    string    `json:"modelImageUrl,omitempty"`
	ModelChatRoomURL string    `json:"modelChatRoomUrl,omitempty"`
	TS               int64     `json:"ts"`
}

type ssePublishItem struct {
	EventName string
	Data      []byte
}

func visibleJobEventsJSON() []ssePublishItem {
	nowTs := time.Now().UnixMilli()
	out := make([]ssePublishItem, 0, 64)

	jobsMu.Lock()
	defer jobsMu.Unlock()

	for _, j := range jobs {
		if j == nil || j.Hidden {
			continue
		}

		eventName := sseModelEventNameForJob(j)
		if eventName == "" {
			continue
		}

		payload := jobEvent{
			Type:            "job_upsert",
			Model:           eventName,
			JobID:           j.ID,
			Status:          j.Status,
			Phase:           j.Phase,
			Progress:        j.Progress,
			SourceURL:       j.SourceURL,
			Output:          j.Output,
			StartedAt:       j.StartedAt.Format(time.RFC3339Nano),
			StartedAtMs:     j.StartedAtMs,
			SizeBytes:       j.SizeBytes,
			DurationSeconds: j.DurationSeconds,
			PreviewState:    j.PreviewState,
			TS:              nowTs,
		}

		if sm := sseStoredModelForJob(j); sm != nil {
			payload.RoomStatus = strings.ToLower(strings.TrimSpace(sm.RoomStatus))
			payload.IsOnline = sm.IsOnline
			payload.ModelImageURL = strings.TrimSpace(sm.ImageURL)
			payload.ModelChatRoomURL = strings.TrimSpace(sm.ChatRoomURL)
		}

		if j.EndedAt != nil {
			payload.EndedAt = j.EndedAt.Format(time.RFC3339Nano)
			payload.EndedAtMs = j.EndedAtMs
		}

		b, err := json.Marshal(payload)
		if err != nil {
			continue
		}

		out = append(out, ssePublishItem{
			EventName: eventName,
			Data:      b,
		})
	}

	return out
}

func visibleRoomStateEventsJSON() []ssePublishItem {
	nowTs := time.Now().UnixMilli()
	out := make([]ssePublishItem, 0, 128)

	if cbModelStore == nil {
		return out
	}

	models := cbModelStore.List()
	for _, sm := range models {
		if strings.ToLower(strings.TrimSpace(sm.Host)) != "chaturbate.com" {
			continue
		}

		modelKey := strings.ToLower(strings.TrimSpace(sm.ModelKey))
		if modelKey == "" {
			continue
		}

		payload := jobEvent{
			Type:             "room_state",
			Model:            modelKey,
			RoomStatus:       strings.ToLower(strings.TrimSpace(sm.RoomStatus)),
			IsOnline:         sm.IsOnline,
			ModelImageURL:    strings.TrimSpace(sm.ImageURL),
			ModelChatRoomURL: strings.TrimSpace(sm.ChatRoomURL),
			TS:               nowTs,
		}

		b, err := json.Marshal(payload)
		if err != nil {
			continue
		}

		out = append(out, ssePublishItem{
			EventName: modelKey,
			Data:      b,
		})
	}

	return out
}

func publishJobUpsert(j *RecordJob) {
	if j == nil || j.Hidden {
		return
	}

	eventName := sseModelEventNameForJob(j)
	if eventName == "" {
		return
	}

	payload := jobEvent{
		Type:            "job_upsert",
		Model:           eventName,
		JobID:           j.ID,
		Status:          j.Status,
		Phase:           j.Phase,
		Progress:        j.Progress,
		SourceURL:       j.SourceURL,
		Output:          j.Output,
		StartedAt:       j.StartedAt.Format(time.RFC3339Nano),
		StartedAtMs:     j.StartedAtMs,
		EndedAtMs:       j.EndedAtMs,
		SizeBytes:       j.SizeBytes,
		DurationSeconds: j.DurationSeconds,
		PreviewState:    j.PreviewState,
		TS:              time.Now().UnixMilli(),
	}

	if sm := sseStoredModelForJob(j); sm != nil {
		payload.RoomStatus = strings.ToLower(strings.TrimSpace(sm.RoomStatus))
		payload.IsOnline = sm.IsOnline
		payload.ModelImageURL = strings.TrimSpace(sm.ImageURL)
		payload.ModelChatRoomURL = strings.TrimSpace(sm.ChatRoomURL)
	}

	if j.EndedAt != nil {
		payload.EndedAt = j.EndedAt.Format(time.RFC3339Nano)
	}

	b, _ := json.Marshal(payload)
	publishSSE(eventName, b)
}

func publishJobRemove(j *RecordJob) {
	if j == nil || j.Hidden {
		return
	}

	eventName := sseModelEventNameForJob(j)
	if eventName == "" {
		return
	}

	b, _ := json.Marshal(jobEvent{
		Type:  "job_remove",
		Model: eventName,
		JobID: j.ID,
		TS:    time.Now().UnixMilli(),
	})

	publishSSE(eventName, b)
}

func publishRoomStateForModel(sm *StoredModel) {
	if sm == nil {
		return
	}

	if strings.ToLower(strings.TrimSpace(sm.Host)) != "chaturbate.com" {
		return
	}

	modelKey := strings.ToLower(strings.TrimSpace(sm.ModelKey))
	if modelKey == "" {
		return
	}

	payload := jobEvent{
		Type:             "room_state",
		Model:            modelKey,
		RoomStatus:       strings.ToLower(strings.TrimSpace(sm.RoomStatus)),
		IsOnline:         sm.IsOnline,
		ModelImageURL:    strings.TrimSpace(sm.ImageURL),
		ModelChatRoomURL: strings.TrimSpace(sm.ChatRoomURL),
		TS:               time.Now().UnixMilli(),
	}

	b, _ := json.Marshal(payload)
	publishSSE(modelKey, b)
}

func sseModelEventNameForJob(j *RecordJob) string {
	if j == nil {
		return ""
	}

	src := strings.TrimSpace(j.SourceURL)

	switch detectProvider(src) {
	case "chaturbate":
		if u := strings.TrimSpace(extractUsername(src)); u != "" {
			return strings.ToLower(u)
		}
	case "mfc":
		if u := strings.TrimSpace(extractMFCUsername(src)); u != "" {
			return strings.ToLower(u)
		}
	}

	return ""
}

func sseStoredModelForJob(j *RecordJob) *StoredModel {
	if j == nil || cbModelStore == nil {
		return nil
	}

	src := strings.TrimSpace(j.SourceURL)
	if src == "" {
		return nil
	}

	host := ""
	modelKey := ""

	switch detectProvider(src) {
	case "chaturbate":
		host = "chaturbate.com"
		modelKey = strings.ToLower(strings.TrimSpace(extractUsername(src)))
	default:
		return nil
	}

	if host == "" || modelKey == "" {
		return nil
	}

	m, ok := cbModelStore.GetByHostAndModelKey(host, modelKey)
	if !ok {
		return nil
	}

	return m
}

func initSSE() {
	srv := sse.New()
	srv.SplitData = true

	stream := srv.CreateStream("events")
	stream.AutoReplay = false

	sseApp = &appSSE{
		server: srv,
	}

	// Debounced broadcaster (done changed)
	go func() {
		for range doneNotify {
			time.Sleep(40 * time.Millisecond)
			for {
				select {
				case <-doneNotify:
				default:
					goto SEND
				}
			}
		SEND:
			seq := atomic.AddUint64(&doneSeq, 1)
			b, _ := json.Marshal(map[string]any{
				"type": "doneChanged",
				"seq":  seq,
				"ts":   time.Now().UnixMilli(),
			})
			publishSSE("doneChanged", b)
		}
	}()

	// Debounced broadcaster (assets)
	go func() {
		for range assetsNotify {
			time.Sleep(80 * time.Millisecond)
			for {
				select {
				case <-assetsNotify:
				default:
					goto SEND
				}
			}
		SEND:
			b := assetsSnapshotJSON()
			if len(b) > 0 {
				publishSSE("state", b)
			}
		}
	}()

	// Per running job: 1 SSE event per second
	go func() {
		t := time.NewTicker(1 * time.Second)
		defer t.Stop()

		for range t.C {
			events := visibleJobEventsJSON()
			for _, ev := range events {
				if len(ev.Data) == 0 || ev.EventName == "" {
					continue
				}
				publishSSE(ev.EventName, ev.Data)
			}
		}
	}()

	// Room state snapshot: 1 SSE event per second for known chaturbate models
	go func() {
		t := time.NewTicker(1 * time.Second)
		defer t.Stop()

		lastByModel := map[string]string{}

		for range t.C {
			events := visibleRoomStateEventsJSON()
			nextByModel := make(map[string]string, len(events))

			for _, ev := range events {
				if len(ev.Data) == 0 || ev.EventName == "" {
					continue
				}

				key := ev.EventName
				payloadKey := string(ev.Data)
				nextByModel[key] = payloadKey

				if prev, ok := lastByModel[key]; ok && prev == payloadKey {
					continue
				}

				publishSSE(ev.EventName, ev.Data)
			}

			lastByModel = nextByModel
		}
	}()
}

func publishSSE(eventName string, data []byte) {
	if sseApp == nil || sseApp.server == nil {
		return
	}
	if len(data) == 0 {
		return
	}

	sseApp.server.Publish("events", &sse.Event{
		Event: []byte(eventName),
		Data:  data,
	})
}

// -------------------- notify channels --------------------

var (
	doneNotify = make(chan struct{}, 1)
	doneSeq    uint64

	assetsNotify = make(chan struct{}, 1)
)

func notifyDoneChanged() {
	select {
	case doneNotify <- struct{}{}:
	default:
	}
}

func notifyAssetsChanged() {
	select {
	case assetsNotify <- struct{}{}:
	default:
	}
}

// -------------------- snapshots --------------------

func jobsSnapshotJSON() []byte {
	jobsMu.Lock()
	list := make([]*RecordJob, 0, len(jobs))
	for _, j := range jobs {
		if j == nil || j.Hidden {
			continue
		}
		c := *j
		c.cancel = nil
		list = append(list, &c)
	}
	jobsMu.Unlock()

	sort.Slice(list, func(i, j int) bool {
		return list[i].StartedAt.After(list[j].StartedAt)
	})

	b, _ := json.Marshal(list)
	return b
}

func assetsSnapshotJSON() []byte {
	assetsTaskMu.Lock()
	st := assetsTaskState
	assetsTaskMu.Unlock()

	b, _ := json.Marshal(st)
	return b
}

// -------------------- unified stream handler --------------------

func eventsStream(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		http.Error(w, "Nur GET erlaubt", http.StatusMethodNotAllowed)
		return
	}

	if sseApp == nil || sseApp.server == nil {
		http.Error(w, "SSE nicht initialisiert", http.StatusInternalServerError)
		return
	}

	q := r.URL.Query()
	q.Set("stream", "events")

	r2 := r.Clone(r.Context())
	r2.URL.RawQuery = q.Encode()

	sseApp.server.ServeHTTP(w, r2)
}

// -------------------- optional helper --------------------

func publishRawSSE(eventName string, buf *bytes.Buffer) {
	if buf == nil {
		return
	}
	publishSSE(eventName, buf.Bytes())
}